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Abe, S., M. Kurosaka, et al. (1993). "Light and electron microscopic study of remodeling and maturation process in autogenous graft for anterior cruciate ligament reconstruction." Arthroscopy 9(4):394-405, 1993 9(4): 394-405.

We evaluated the remodeling process of autogenous patellar tendon graft for anterior cruciate ligament (ACL) reconstruction by means of light microscopic (LM) and electron microscopic (EM) examinations from the biopsy specimens obtained at the time of second-look arthroscopy. Twenty-one patients were examined at various times postoperatively (from 6 weeks to 15 months, mean 9.5 months), and the results were correlated with the morphology of normal patellar tendon and normal ACL. Our study showed that the graft was revascularized in the early postoperative period, fibroblastic remodeling took place, and the graft obtained gross similarity to the original ACL on their arthroscopic and LM appearances at approximately 1 year postoperatively. However, EM study showed that at both approximately 6 months and 1 year postoperatively the grafts consisted equally of active fibroblasts with a higher cytoplasm-to-nucleus ratio compared with normal ACL. Collagen fibrils of these grafts were of uniformly small diameter compared with normal patellar tendon and ACL. Our results with ultrastructural study suggest that the grafts were still immature even at 1 year postoperatively.

Aglietti, P., R. Buzzi, et al. (1993). "Patellofemoral problems after intraarticular anterior cruciate ligament reconstruction." Clinical Orthopaedics & Related Research (288):195-204, 1993 Mar(288): 195-204.

A series of 226 anterior cruciate ligament (ACL) reconstructions were reviewed to determine the incidence of patellofemoral (PF) problems and the associated prognostic factors. Patients were divided into four groups according to the type of injury (acute or chronic) and operation (through an arthrotomy or arthroscopic assisted). The average follow-up period was 39 months. Overall there was a 5% incidence of PF crepitus with pain and/or swelling, and a further 20% of clear PF crepitus without pain. The change from open surgery and cast to arthroscopic surgery and early motion allowed a decrease of PF problems from 40% to 21% in acute injuries, but the difference was less marked in chronic knees. A deficit greater than 10% at the one-leg hop test was present in 75% of the knees with PF crepitus and pain. The height of the patella was increased in 5% and decreased in 17% of the knees. Patients with rehabilitation difficulties had the largest decrease in patella height, whereas a patella alta was more frequent after patellar tendon reconstruction. A significant correlation was found between PF problems and female gender, positive congruence angle, preoperative PF crepitation, rehabilitation difficulties, flexion loss greater than 10 degrees, extension loss greater than 5 degrees, and variation in the height of the patella. The importance of avoiding immobilization, rehabilitation difficulties, and permanent flexion or extension loss is emphasized.

Aglietti, P. B., R.; Zaccherotti,G.; De Biase,P. "Patellar tendon versus doubled semitendinosus and gracilis tendons for anterior cruciate ligament reconstruction." Am.J.Sports Med. 22(2): 211-217.

The results of intraarticular anterior cruciate ligament reconstruction with either the patellar tendon or the semitendinosus and gracilis tendons (four strands) were prospectively compared in a consecutive series of 60 patients with chronic injuries. A single surgeon performed arthroscopically assisted reconstructions in an alternating sequence. Preoperative and operative data revealed no significant differences between the two groups. After 28 months of followup there were no significant differences in the incidence of symptoms, and recurrent giving way was present in only one knee with semitendinosus and gracilis tendon graft. Return to sport participation was more frequent in the patellar tendon group (80% versus 43%, P < 0.01). A minor extension loss (< or = 3 degrees) was more frequent in the patellar tendon group (47% versus 3%, P < 0.001). Other differences between the two groups were not significant. KT-2000 arthrometer side-to-side difference of anterior displacement > 5 mm at 30 pounds was present in 13% of the knees with patellar tendon grafts and in 20% of those with semitendinosus and gracilis; a patellofemoral crepitation developed in 17% and 3% of the two groups, respectively. Based on these data we routinely use patellar tendon grafts. Semitendinosus and gracilis tendons are preferred in selected cases: older patients, patients with preexisting patellofemoral problems, and those with failed patellar tendon grafts

Aglietti, P. B., R.; and Bassi, P.B. (1988). "Arthroscpic partial menisectomy in the anterior cruciate deficient knee." Am. J. Sports Med 16: 597-602.

Aglietti, P. B., R.; Menchetti,P.M.; Giron,F. (1996). "Arthroscopically assisted semitendinosus and gracilis tendon graft in reconstruction for acute anterior cruciate ligament injuries in athletes." Am.J.Sports Med. 24(6): 726-731.

We evaluated 69 arthroscopically assisted anterior cruciate ligament reconstructions for acute tears at an average followup of 60 months. We used a distally based single semitendinosus and gracilis tendon graft passed over the top and fixed to the femur. Combined medial collateral ligament lesions were seen in 30 knees, and they were repaired when found in the distal third (18 knees). The patients were instructed to recover motion preoperatively, and an early range of motion program was used postoperatively. At followup, symptoms of giving way were seen in five knees (7%). Graft failure was seen in seven knees (10%); failure was defined as a positive pivot shift (clunk or gross) or a side-to- side difference in anterior tibial displacement greater than 5 mm, as measured with a KT-1000 arthrometer. Permanent extension loss (3 degrees to 5 degrees) was found in two knees (3%). Patellofemoral crepitation was seen in eight knees (12%), but the condition was symptomatic in only one knee. Forty-six patients (67%) were active in pivoting sports before surgery and 37 (54%) remained active in these sports at followup. We concluded that this operation is simple, effective, and has a low complication rate. Further studies are necessary to elucidate if a stronger graft (e.g., a patellar tendon) would decrease the rate of graft failure without increasing complications

Amiel, D. K., J.B.; and Akeson, W.H. (1986). "The natural history of the anterior cruciate ligament autograft of patellar tendon." Am. J. Sports Med 14: 449-462.

Amis, A. A. and B. E. Scammell (1993). "Biomechanics of intra-articular and extra-articular reconstruction of the anterior cruciate ligament." Journal of Bone & Joint Surgery - British Volume 75(5):812-7, 1993 Sep 75(5): 812-7.

Many methods of reconstruction for ACL deficiency have been described, but little is known about their biomechanical properties. We examined extra-articular (EA), intra-articular (IA) and combined (EA+IA) reconstructions in ten cadaver knees after the ACL had been ruptured by the performance of a rapid anterior drawer movement. Stability at each stage before and after rupture and reconstruction was tested by anterior drawer, Lachman, varus-valgus and tibial rotation tests. Both IA and IA+EA reconstructions restored normal stability, while EA reconstructions improved stability but did not restore it to normal. The addition of an EA procedure to an IA procedure made no difference to knee stability. We conclude that in cases of isolated ACL deficiency there is no biomechanical basis for EA reconstruction, either alone or in addition to an IA reconstruction.

Andersen, H. N. and P. A. Frandsen (1993). "Assessment of anterior cruciate laxity using the Genucom System." International Orthopaedics 17(6):375-83, 1993 Dec 17(6): 375-83.

One hundred subjects with normal knees and 47 patients with chronic rupture of the anterior cruciate ligament were tested in the Genucom Knee Analysis System; the 13 different laxity tests were carried out on both knees. Measurements on right and left knees in normal subjects showed that only the lateral pivot shift test, performed at 25 degrees of knee flexion, had a good side-to-side correlation, but did not differentiate the involved and uninvolved knees in the patients with anterior cruciate ligament deficiency. The sensitivity of the lateral pivot shift was 30% and specificity 91%. The corresponding figures for the anterior drawer test at 30 degrees flexion using 93 N force were 45% and 88%. Measurements showed great variation. Care should be taken in interpreting the results from the Genucom System. It should be considered as an experimental device with little value in assessing patients with anterior cruciate ligament deficiency.

Andersson, A. C. (1993). "Knee laxity and function after conservative treatment of anterior cruciate ligament injuries. A prospective study." International Journal of Sports Medicine 14(3):150-3, 1993 Apr 14(3): 150-3.

Knee laxity and function were investigated in a prospective study including 40 patients with acute anterior cruciate ligament injury and 11 patients with minor knee injury not involving the cruciate ligaments (controls). None of the patients had primary ligament repair. Instrumental testing (OSI, Hayward, California) of the static laxity of both knees was performed at one, three, six, and 12 months after the injury. The initial laxity of the anterior cruciate-deficient knees was greater than that of the controls. At 12 months the laxity at 180N tibial load for the patients with anterior cruciate ligament injury exceeded the laxity found within one month of injury. At 12 months half of these patients complained of symptoms of instability and one out of four patients had had severe subluxations with accompanying haemarthrosis. Patients with combined anterior cruciate and medial collateral ligament injury had the greatest initial laxity and the worst outcome. In all, 20% of the patients were scheduled for reconstruction of the anterior cruciate ligament during the observation period.

Andriacchi, T. P. and D. Birac (1993). "Functional testing in the anterior cruciate ligament-deficient knee." Clinical Orthopaedics & Related Research (288):40-7, 1993 Mar(288): 40-7.

Functional testing of patients with anterior cruciate ligament (ACL) deficient knees and normal subjects during stressful activities such as running to a cut and running to a stop and during activities common to daily life, such as walking, stair climbing, and jogging, is presented. Analysis focused on the application of these tests to treatment planning and clinical evaluation. Functional testing during stressful activities indicates that some patients with ACL-deficient knees have higher than normal net hamstring moments during the early phase of these activities. These results suggest dynamic muscular substitution using the hamstrings in patients with chronic ACL-deficient knees. Patients tested during less stressful activities, such as walking and stair climbing, also demonstrated substantial differences from ACL-intact subjects. The majority of patients tended to reduce the net quadriceps moment when the knee was near full extension. Approximately 75% of the patients who were ACL-deficient developed this type of adaptation, which appears to be a subconscious method of avoiding the net anterior pull of the quadriceps mechanism when the knee is near full extension. Functional testing of the ACL-deficient knee provides meaningful information that cannot be obtained by simpler clinical tests. This information can be extremely useful in the selection and evaluation of patients with certain treatment modalities, since it seems to be directly related to some patients' ability to functionally adapt to the loss of the ACL.

Appell, H. J., S. Gloser, et al. (1993). "Skeletal muscle damage during tourniquet-induced ischaemia. The initial step towards atrophy after orthopaedic surgery?" European Journal of Applied Physiology & Occupational Physiology 67(4):342-7, 1993 67(4): 342-7.

Muscle biopsies from the vastus lateralis muscle of patients who had undergone anterior cruciate ligament surgery under conditions of tourniquet-induced ischaemia were examined under the electron microscope at different periods of time up to 90 min of ischaemia. The severity of the alterations in ultrastructure appeared to depend on the period of ischaemia. The pathological changes consisted of accumulation of lysosomes, persistent intrafibre oedema, and some extracellular oedema. Signs of fibre necrosis were found after 90 min of ischaemia. Capillary ultrastructure was only altered with regard to some swelling of the endothelium and marked thickening of the basement membrane. It was concluded that skeletal muscle could be severely affected even during relatively short periods of ischaemia, which might facilitate the development of muscle atrophy during immobilization after orthopaedic surgery.

Arendt, E. D., R. (1995). "Knee injury patterns among men and women in collegiate basketball and soccer. NCAA data and review of literature." Am.J.Sports Med. 23(6): 694-701.

Women's participation in intercollegiate athletics has increased dramatically in recent years. Greater participation has increased awareness of health and medical issues specific to the female athlete. Some reports have noted a higher susceptibility to knee injury, specifically injuries to the anterior cruciate ligament, in female athletes as compared with their male counterparts. We performed a 5- year evaluation of anterior cruciate ligament injuries in collegiate men's and women's soccer and basketball programs using the National College Athletic Association Injury Surveillance System. Results showed significantly higher anterior cruciate ligament injury rates in both female sports compared with the male sports. Noncontact mechanisms were the primary cause of anterior cruciate ligament injury in both female sports. Possible causative factors for this increase in anterior cruciate ligament injuries among women may be extrinsic (body movement, muscular strength, shoe-surface interface, and skill level) or intrinsic (joint laxity, limb alignment, notch dimensions, and ligament size)

Arms, S. W. P., M.H.; Johnson, R.J.; Fischer, R.A.; Arvidsson, Inga; and Eriksson, Ejnar (1984). "The biomechanics of anterior cruciate ligament rehabilitation and reconstruction." Am. J. Sports Med 12: 8-18.

Arnoczky, S. P. (1983). "Anatomy of the anterior cruciate ligament." Clin Orthop(172): 19-25.

The anterior cruciate ligament (ACL) is a multifascicular structure whose femoral and tibial attachments, as well as spatial orientation within the knee, are directly related to its function as a constraint of joint motion. The ACL is made up of multiple collagen bundles that give rise to the multifascicular nature of the ligament. This arrangement results in a different portion of the ligament being taut and therefore functional, throughout the range of motion. The ACL receives its blood supply from branches of the middle genicular artery, which from a vascular synovial envelope around the ligament. These periligamentous vessels penetrate the ligament transversely and anastomose with a longitudinal network of endoligamentous vessels. The body attachments do not contribute significantly to the vascularity of the ligament. The nerve supply to the ACL originates from the tibial nerve. Although the majority of fibers appear to have a vasomotor function, some fibers may serve a proprioceptive or sensory function.

Arnoczky, S. P., G. B. Tarvin, et al. (1982). "Anterior cruciate ligament replacement using patellar tendon. An evaluation of graft revascularization in the dog." J Bone Joint Surg Am 64(2): 217-24.

We investigated the revascularization pattern of patellar tendon grafts used to replace the anterior cruciate ligament in thirty-six dogs by histological and tissue-clearing (Spalteholz) techniques. Initially the grafts were avascular, but by six weeks they were completely ensheathed in a vascular synovial envelope. The soft tissues of the infrapatellar fat pad, the tibial remnant of the anterior cruciate ligament, and the posterior synovial tissues contributed to this synovial vasculature. Intrinsic revascularization of the patellar tendon graft progressed from the proximal and distal portions of the graft centrally and was complete by twenty weeks. The tibial attachment of the patellar tendon graft did not contribute any vessels to the revascularization process. At one year, the vascular and histological appearance of the patellar tendon graft resembled that of a normal anterior cruciate ligament. Clinical Relevance: The absence of perfused vessels within the patellar tendon graft immediately after transplantation within the knee joint and the failure of the osseous insertion of the graft to contribute vessels to the revascularization process suggest that although it is left attached at the tibia, the patellar tendon graft is essentially an avascular free graft at transplantation. The contribution of the soft tissues of the knee to the revascularization process of the graft suggests preservation and utilization of the infrapatellar fat pad and synovial tissue to optimize the graft's revascularization and ultimate viability.

Aronowitz, E. R. G., T.J.; Goode,J.R.; Gregg,J.R.; Meyer,J.S. (2000). "Anterior cruciate ligament reconstruction in adolescents with open physes." Am.J.Sports Med. 28(2): 168-175.

The purpose of this study was to evaluate anterior cruciate ligament reconstructions performed in adolescents with open physes and a skeletal age of at least 14 years. At one center, from 1992 to 1996, 19 adolescents (ages, 11 to 15 years) with open physes and a skeletal age of at least 14 years underwent arthroscopic anterior cruciate ligament reconstruction using an Achilles tendon allograft placed through drill holes across the open physes in both the distal femur and proximal tibia. Fifteen patients returned for reevaluation at an average of 25 months postoperatively (range, 12 to 60 months); the remaining four patients were interviewed by telephone. There were no significant leg- length discrepancies or angular deformities as determined by scanograms and anteroposterior and lateral radiographs of the femur and tibia. The mean Lysholm knee score was 97 (range, 94 to 100) and the mean KT-1000 arthrometer side-to-side difference at 20 pounds of anterior force was 1.7 mm (range, 0.0 to 3.0). All patients were satisfied with the results of surgery, and 16 of 19 patients returned to the same sport they were participating in before the injury. This study demonstrates that anterior cruciate ligament reconstruction using an Achilles tendon allograft is a viable treatment option for skeletally immature patients with a skeletal age of 14 years who have sustained midsubstance tears of the anterior cruciate ligament

Bagnolesi, P., A. Cilotti, et al. (1993). "[Reconstruction of the anterior cruciate ligament using the patellar tendon: its magnetic resonance evaluation]." Radiologia Medica 86(1-2):81-8, 1993 Jul-Aug 86(1-2): 81-8.

MRI of the knee was performed in 30 patients who had been submitted to arthroscopically-guided reconstruction of the anterior cruciate ligament from patellar tendon. The autograft structure was investigated and MR results were correlated with clinical findings. Partial/total meniscectomy had been carried out in 21/30 cases. The patients were imaged at various postoperative intervals (3-24 months) by means of an 0.5-T magnet (GE MR Max Plus) in full knee extension and internal rotation. Sagittal and axial T1-weighted images (slice thickness: 3 mm) were combined with real-time reconstruction which better demonstrated the whole graft. T2-weighted coronal images (slice thickness: 5 mm) were also acquired. In each patient the following clinical variables were considered: anterior drawer sign, Lachman test, pivot shift, degree of leg extension, and finally functional recovery. The following MR variables were then considered: structure and alignment of bone tunnels, structure and signal intensity of the graft, degree of synovial inflammation, structure and signal intensity of the posterior cruciate ligament and finally structure of the menisci and/or meniscal residues. Symptoms-MR correlation suggests that the different outcome of surgical reconstruction may depend on the correct alignment of the tibial and femoral bone tunnels and on good meniscal condition. Bone tunnels must be located on the same plane, posterior and parallel to the slope of the intercondylar roof, since angulation causes the latter to impact the graft during knee extension, with inflammation and risk for rupture. As for menisci, tiny residues or total ablation overload tha graft, whose signal increases and whose synovia becomes inflamed. The latter pattern is always distinguished from that of the autograft, whose signal intensity seems not to change in time. In conclusion, MR proved an accurate and non-invasive technique to image this kind of postoperative knee, since metallic artifacts do not reach the joint space.

Baker, C. L., Jr. and J. Graham (1993). "Intraarticular ACL reconstruction using the patellar tendon: arthroscopic technique." Orthopedics 16(4):437-41, 1993 Apr 16(4): 437-41.

Endoscopic ACL reconstruction using the bone-patellar tendon-bone autograft has been shown to have good, reliable results. The procedure provides excellent reproducible fixation immediately and allows for early aggressive rehabilitation that includes range of motion, strengthening, and rapid return to sports.

Barber, F. A. (2000). "Flipped patellar tendon autograft anterior cruciate ligament reconstruction." Arthroscopy 16(5): 483-490.

To determine the efficacy of an anterior cruciate ligament (ACL) graft that customizes length and facilitates anatomic outlet fixation, a prospective study of the "flipped" patellar tendon autograft ACL reconstruction began in 1995. This technique shortens the tendon portion to match the intra-articular length by rotating 1 bone plug 180 degrees proximally onto the tendon, thus flipping the bone plug over its ligamentous insertion. Bioscrews (poly L-lactic acid; Linvatec, Largo, FL) secured the grafts. All patients undergoing this procedure with a minimum 21 months follow-up were reviewed. Preoperative and postoperative Tegner, Lysholm, and IKDC activity scores, and Lachman and pivot shift tests were obtained. Postoperative KT testing and radiographs were obtained. Fifty patients were followed-up for an average of 28 months (range, 21 to 39 months). Average patient age was 34 years (range, 16 to 52 years). Tegner scores increased from 2.0 preoperatively to 6.0 postoperatively. Lysholm scores increased from 46 preoperatively to 93 at follow-up, with 86% excellent (66%) or good (20%). IKDC activity scores increased from 3.1 preoperatively to 1.7 postoperatively. KT manual-maximum difference at follow-up averaged 0.7 mm, with 74% less than 3-mm, 18% 3- to 5-mm, and 8% greater than 5-mm difference. Postoperative Lachman results were 0 in 45 patients and 1+ in 5 patients. Postoperative pivot shift was absent in all but 1 patient. Full extension was achieved in all cases and flexion averaged 136 degrees with no patient having less than 120 degrees flexion. No lytic bone changes or tunnel widening were seen. The flipped patellar tendon autograft reduces graft length to its intra-articular portion, increasing graft stability, isometry, and stiffness, and avoiding tunnel graft mismatch with clinically excellent results

Barber, F. A., B. F. Elrod, et al. (1996). "Is an anterior cruciate ligament reconstruction outcome age dependent?" Arthroscopy 12(6): 720-5.

Treatment of a torn anterior cruciate ligament (ACL) in older patients must be considered in relation to healing delays, rehabilitation difficulties, stiffness, arthritis, and actual athletic demands. This study compares ACL reconstructions in patients 40-years old and older with those under 40-years old and contrasts these to published nonoperative data in the 40 and older patient. Patients undergoing ACL reconstruction between 1992 and 1994 were preoperatively and postoperatively assessed with Lysholm, Tegner, KT, radiographic, and clinical examinations. They were divided into two groups: those 40 years and older (group 1) and those 39 years and younger (group 2). Group 1 had 33 patients with an average age of 44 years (range, 40 to 52 years). Radiographic Fairbank changes were absent. Group 2 had 170 patients with an average age of 27 years (range, 16 to 39 years). Group 1 preoperative instability and intake data were not statistically different from those of group 2. Average follow-up was 21 months for both groups. Both groups showed significant improvement in all parameters at 12- and 24-month follow-up examinations. Lysholm scores, Tegner scores, average KT manual maximum side-to-side differences, Lachman tests, and pivot shift testing were not statistically different in either group. Using Lysholm criteria, in group 1, 89% had excellent/good results, and 11% fair/poor results. This was not statistically different from group 2, which showed 91% excellent/good results and 9% fair/poor results at 24-month follow-up examination. For this age group, nonoperative treatment reports indicate 57% excellent/good results and 43% fair/poor results. The outcomes between these groups are the same and fail to establish the age of 40 years as a barrier to successful ACL reconstruction.

Barber, F. A., B. F. Elrod, et al. (1996). "Is an anterior cruciate ligament reconstruction outcome age dependent?" Arthroscopy 12(6): 720-5.

Barber, S. D., F. R. Noyes, et al. (1992). "Rehabilitation after ACL reconstruction: function testing." Orthopedics 15(8): 969-74.

Barber-Westin, S. D. and F. R. Noyes (1993). "The effect of rehabilitation and return to activity on anterior-posterior knee displacements after anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(2):264-70, 1993 Mar-Apr 21(2): 264-70.

Anterior-posterior knee displacements were measured sequentially with the KT-1000 arthrometer on 84 patients after anterior cruciate ligament reconstruction for chronic deficiency. We determined the correlations between the initial onset of abnormal displacements (greater than 2.5 mm between limbs) and time from surgery or the phase of rehabilitation. Group 1 (N = 52) had a bone-patellar tendon-bone allograft and Group 2 (N = 32), an iliotibial band extraarticular procedure in addition to the allograft. The mean followup was 37 months (range, 23 to 65). At followup in Group 1, 24 patients (46%) had less than 3 mm of displacement between limbs, 22 (42%) had 3 to 5.5 mm, and 6 (12%) had greater than 5.5 mm. In Group 2, 23 patients (72%) had less than 3 mm of displacement, 8 (25%) had 3 to 5.5 mm, and 1 (3%) had greater than 5.5 mm. The difference between the groups was significant (P < 0.05). The advanced rehabilitation program of immediate knee motion and early weightbearing, did not result in an increased incidence of abnormal displacements in the early phases. The abnormal displacements typically occurred during the latter two rehabilitation phases (intensive strength training or return to sports). Further, one-third of the abnormal displacement occurred more than 2 years postoperatively.

Barber-Westin, S. D., F. R. Noyes, et al. (1999). "Rigorous statistical reliability, validity, and responsiveness testing of the Cincinnati knee rating system in 350 subjects with uninjured, injured, or anterior cruciate ligament-reconstructed knees." Am J Sports Med 27(4): 402-16.

Although many instruments are used to assess outcome after knee ligament reconstruction, their reliability, validity, and responsiveness have not been adequately proven. Our purpose was to assess these statistical measures in a commonly used instrument, the Cincinnati Knee Rating System. Reliability was determined from the responses of 100 subjects who completed the instrument twice, a mean of 7 days apart. Validity and responsiveness were assessed from 250 patients observed for at least 2 years after autogenous ACL reconstruction. Questionnaire items included symptoms, functional limitations with sports and daily activities, patient perception of the knee condition, and sports- and occupational-activity levels. The items demonstrated high test-retest reliability, supporting their use in evaluating groups of patients between two different treatment periods (all intraclass correlation coefficients > 0.70). In addition, the questionnaire demonstrated good content validity, construct validity, and item-discriminant validity. For the overall rating score, no "floor effects" (worst score possible) were found before or after surgery. No "ceiling effects" (best score possible) were found before surgery, and, at follow-up, these effects were calculated in only 22 patients (9%). The questions were found to be highly responsive to detecting changes between evaluations. The data demonstrated that this rating system has acceptable reliability, validity, and responsiveness for use in outcome studies after knee ligament reconstruction.

Barber-Westin, S. D. N., F.R.; Andrews,M. (1997). "A rigorous comparison between the sexes of results and complications after anterior cruciate ligament reconstruction." Am.J.Sports Med. 25(4): 514-526.

Although there is a higher relative incidence of anterior cruciate ligament injuries in female than in comparable male athletes according to the literature, the majority of populations studied after reconstruction are male-dominated. We wished to determine whether a selection bias for reconstruction based on sex is warranted according to complications and outcome. Ninety-four patients (47 of each sex) were matched for chronicity of injury, age, preoperative sports activity levels, articular cartilage condition, and months of followup. All had patellar tendon autogenous reconstruction and a similar program of immediate knee motion and early return to function. The results were rated with the Cincinnati Knee Rating System. At a mean of 26 months postoperatively, there were no significant differences for complications or outcome between men and women. Women required an average of six more rehabilitation visits than men; however, none required additional surgery for knee motion complications and the rate of patellofemoral crepitus conversion was only 7%, lower than that found for men (15%). The overall failure rate was low, only 6% for women and 4% for men. We concluded that the functional rehabilitation program was effective, postoperative complications were few, and no scientific basis exists to use sex alone as a selection criteria for anterior cruciate ligament reconstruction

Barber-Westin, S. D. N., F.R.; Heckmann,T.P.; Shaffer,B.L. (1999). "The effect of exercise and rehabilitation on anterior-posterior knee displacements after anterior cruciate ligament autograft reconstruction." Am.J.Sports Med. 27(1): 84-93.

We studied the effect of rehabilitation strength training and return to activities on anterior-posterior knee displacements after patellar tendon autogenous anterior cruciate ligament reconstruction. A total of 938 measurements were sequentially collected for 142 patients with the KT-2000 arthrometer. Rehabilitation included immediate knee motion and early weightbearing, light sports at 6 months, and competitive sports at 8 months or later. At a minimum of 2 years after surgery, 121 patients (85%) had normal displacements (less than 3 mm of increase at 134 N), 14 (10%) had 3 to 5.5 mm of increase (partial function), and 7 (5%) had more than 5.5 mm of increase (failed). There was no association found between the initial onset of the abnormal displacements in the 21 knees and either the amount of time after surgery or the rehabilitation program. Six of the seven grafts that failed did so in the 1st postoperative year. Serial displacement measurements allow early detection of graft stretching and subsequent modification of rehabilitation or delay in return to strenuous activities. These measurements sho

Barrett, G. R. and L. D. Field (1993). "Comparison of patella tendon versus patella tendon/Kennedy ligament augmentation device for anterior cruciate ligament reconstruction: study of results, morbidity, and complications." Arthroscopy 9(6):624-32, 1993 9(6): 624-32.

In a study designed to evaluate the efficacy of supplementing patellar tendon bone-tendon-bone intraarticular anterior cruciate ligament (ACL) reconstructions with the polypropylene braid ligament augmentation device (Kennedy LAD; 3M, Minneapolis, MN), 75 consecutive patients treated between July 1988 and January 1990 with isolated ACL disruptions in whom no associated ligament injury was present were offered the LAD as part of their preoperative consent. Interference screws at both bone plugs were used. Group I was composed of 25 patients (10 acute, 15 chronic) with ACL disruptions who had the LAD added to their reconstruction. Group II was composed of 50 patients (24 acute, 26 chronic) who underwent an identical surgical procedure except that the LAD was not used. Objective and subjective assessments were made throughout the postoperative course, with the longest follow-up an average of 24 months postoperatively. Statistical analysis of these findings failed to show any statistically significant differences between the groups. Complications that occurred among the augmented group included infection, synovitis, effusion, and recurrence of instability, intraarticular adhesions, hemarthrosis, and painful hardware. This study demonstrates that the LAD added to the morbidity and severity in this series. It does not seem to improve results and is therefore not recommended for use in this manner.

Barrett, G. R., L. L. Line, Jr., et al. (1993). "The Dacron ligament prosthesis in anterior cruciate ligament reconstruction. A four-year review." American Journal of Sports Medicine 21(3):367-73, 1993 May-Jun 21(3): 367-73.

We studied 40 patients who underwent reconstruction for chronic anterior cruciate ligament deficiency with a Dacron ligament prosthesis using a modified MacIntosh over-the-top technique, augmented with iliotibial band. Thirty patients had undergone at least 1 prior surgical procedure on the affected knee, but only 7 patients had previous anterior cruciate ligament reconstruction. All patients were followed for a mean of 47.5 months. The results at final followup demonstrated an average side-to-side arthrometer difference of 1.0 mm. The Lysholm score improved from 65 preoperatively to 89 at the end of the review; the Tegner activity level score improved from 3 to 5. Objectively, 75% of the patients had a negative Lachman test result and 95.1% of the subjects had negative or trace pivot shift results at review. Mild knee pain was still present with day-to-day activity in 87.7% of the patients. Complications occurred in 27.5% of patients, including five who had implant ruptures and two who had their grafts removed. Synovitis was a significant problem. Based on our failure criteria, 47.5% (19) of the subjects had failed results. In this study, radiologic evidence of tracer separation greater than 1 cm was a criterion of failure. With inclusion of tracer separation, the failure rate increased to 60.0% (24). Multiple previous surgeries of any type had an adverse effect on results. Damage to secondary stabilizers in these cases increased failure rate. Based on the high complication and failure rates, and relatively poor end result in this retrospective review, we cannot recommend this procedure.

Beard, D. J., P. J. Kyberd, et al. (1993). "Proprioception after rupture of the anterior cruciate ligament. An objective indication of the need for surgery?" Journal of Bone & Joint Surgery - British Volume 75(2):311-5, 1993 Mar 75(2): 311-5.

Failure of conservative treatment is the usual indication for the reconstruction of a knee with deficiency of the anterior cruciate ligament (ACL) and this depends on subjective judgement. The ability of muscles to protect the subluxing joint by reflex contraction could provide an objective measurement. We have studied 30 patients with unilateral ACL deficiency by measuring the latency of reflex hamstring contraction. We found that the mean latency in the injured leg was nearly twice that in the unaffected limb (99 ms and 53 ms respectively). There was a significant correlation between the differential latency and the frequency of 'giving way' indicating that functional instability may be due, in part, to loss of proprioception. Measures of proprioception, including reflex hamstring latency, may be useful in providing an objective assessment of the efficacy of conservative treatment and the need for surgery.

Benedetto, K. P. F., M.; Lim,T.E.; Passler,J.M.; Schoen,J.L.; Willems,W.J. (2000). "A new bioabsorbable interference screw: preliminary results of a prospective, multicenter, randomized clinical trial." Arthroscopy 16(1): 41-48.

SUMMARY: A randomized clinical trial was conducted to compare a bioabsorbable polyglyconate screw (Endo-Fix; Smith & Nephew, Andover, MA) to a metal screw in anterior cruciate ligament reconstruction. A total of 124 patients were operated on and 113 assessed up to 1 year postoperatively. Assessments included a history and physical examination, the IKDC evaluation, and knee arthrometry measurements. No significant differences were found between the groups with respect to any of the IKDC problem areas at 1 year. The IKDC final evaluation was normal or nearly normal in 92% of polyglyconate patients and 90% of controls. The incidence of postoperative complications was similar in the 2 groups. One polyglyconate patient developed a subcutaneous cyst that may have been related to breakdown of the screw. This resolved without treatment and the patient had an excellent clinical outcome. This study shows that the polyglyconate screw is an effective alternative to metal in endoscopic reconstruction of the ACL

Berg, E. E. (1993). "Parsons' knob (tuberculum intercondylare tertium). A guide to tibial anterior cruciate ligament insertion." Clinical Orthopaedics & Related Research (292):229-31, 1993 Jul(292): 229-31.

In some human autopsy specimens, a bony prominence located anterior to the tibial eminences represents the confluent insertion of the anterior horn medial meniscus and the medial fibers of the anterior cruciate ligament (ACL). The prominence has been called "Parsons' knob" by anatomists and the "tuberculum intercondylare tertium" by radiologists. This article reviews the anatomy and provides the first magnetic resonance image study and perhaps the first roentgenographic depiction of this landmark in the English-speaking orthopedic literature. This structure, if noted preoperatively, can be helpful in identifying the appropriate site of tibial tunnel placement for ACL reconstructive operations performed under arthroscopic or fluoroscopic guidance.

Berg, E. E. (1993). "Comminuted tibial eminence anterior cruciate ligament avulsion fractures: failure of arthroscopic treatment." Arthroscopy 9(4):446-50, 1993 9(4): 446-50.

Multisuture arthroscopic repair of two comminuted tibial eminence anterior cruciate ligament avulsion fractures in adult patients is reported. Lack of rigid fixation and a tentative rehabilitation program resulted in arthrofibrosis and limited knee motion.

Berns, G. S. and S. M. Howell (1993). "Roofplasty requirements in vitro for different tibial hole placements in anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(2):292-8, 1993 Mar-Apr 21(2): 292-8.

In this study we sought both to quantify the forces that result in anterior cruciate ligament graft impingement and the amount of roofplasty necessary to prevent it. The perpendicular force of the intercondylar roof against an anterior cruciate ligament graft was measured in seven fresh-frozen cadaveric knees. Two tibial hole placements were evaluated: an anterior/eccentric hole (26.6% +/- 3.1% of the sagittal depth) and a customized hole aligned 4 to 5 mm posterior and parallel to the slope of the intercondylar roof in the extended knee (42.0% +/- 2.6% of the sagittal depth). A transducer that measured the contact force with the graft was implanted in the roof. An extensive roofplasty was performed so that the sensor would bear all of the roof force. Graft tension was also measured. Extension moments were applied to 20 N-m with a six degree of freedom load application system. Load cycles were repeated with the roof force sensor backed out in 0.8 mm increments. The sensor backout represented a corresponding amount of bone removal in a roofplasty. The flexion angle at roof-graft contact was consistently greater using the anterior tibial hole than the customized one. This held true for all increments of sensor backout. With the anterior hole, the roof sensor (no backout) contacted the graft at 12.8 degrees +/- 6.7 degrees of flexion, whereas the customized hole resulted in contact at 4.1 degrees +/- 4.2 degrees (P = 0.020).(ABSTRACT TRUNCATED AT 250 WORDS)

Beynnon, B. D. P., M.H.; Fleming, B.C.; Howe, J.G.; Johnson, R.J.; Erickson, A.R.; Wertheimer, C.M.; and Nichols, C.E. (1989). "An in-vivo study of the ACL strain biomechanics in the normal knee." Orthop. Res. Soc 14.

Beynnon, B. W., C.; Fleming, B.; Erickson, A.; Pope, M.H.; Howe, J.G.; Johnson, R.J.; and Nichols, C.E. (1990). "An in-vivo study of the anterior cruciate ligament strain biomehanics during functional knee bracing." Trans.Orthop. Res. Soc 15: 223.

Bilko, T. E., L. E. Paulos, et al. (1986). "Current trends in repair and rehabilitation of complete (acute) anterior cruciate ligament injuries. Analysis of 1984 questionnaire completed by ACL Study Group." Am J Sports Med 14(2): 143-7.

Results of a 21 question survey, taken at the ACL Study Group meeting in 1984, present a composite picture of current practices in ACL reconstruction and rehabilitation. Forty-four of the 50 questionnaires were returned. Responses represented views from knee surgeons in the United States, Canada, Australia, Sweden, and Switzerland. These results were compared with a report of a 1980 international survey in which views of 40 knee experts from the United States, Canada, England, France, and Sweden were summarized. Questions on the two surveys were similar, particularly about rehabilitation. Although the time span between the two surveys was only 4 years, we can see both consistencies and changes. Responses about length of time between ACL repair and full range of motion (by 6 months) were essentially the same (88% in 1980, and 86.4% in 1984). However, changes were evident in length of immobilization (longer in 1980) and prescribing isometric contractions of quadriceps 1st week postoperatively (more frequently in 1980). Surgeons allowed patients to return to full activity sooner in 1980 than in 1984. Electrical stimulation was being used more frequently in 1984, and apparently the practice of simultaneous hamstring and quadriceps contraction has come into prominence since 1980 as it was not mentioned in the first survey. In 1984, 50% of the respondents indicated they prescribed it. Since standardized reporting systems are not established, we cannot do reliable statistical analyses on large samples. At the present time, making surveys with responses from similar groups every few years is the best available way to capture trends in treatment of ACL injuries.

Binfield, P. M., N. Maffulli, et al. (1993). "Patterns of meniscal tears associated with anterior cruciate ligament lesions in athletes." Injury 24(8):557-61, 1993 Sep 24(8): 557-61.

In this study, 400 clinically anterior cruciate ligament (ACL) deficient knees were arthroscoped and studied prospectively in the period January 1986 to April 1992. An ACL tear was always confirmed, and 41 per cent of these patients did not have an associated meniscal tear. In 30.25 per cent the lateral meniscus was torn; in 21.25 per cent the ACL tear was associated with a medial meniscus tear, and in the remaining 7 per cent both menisci were torn. The most frequently associated meniscal injury was the bucket handle tear of the medial meniscus (9 per cent), followed by the posterior horn tear of the lateral meniscus, which showed the same frequency as the ragged (or degenerated) tear of the lateral meniscus (6 per cent). The horizontal tear of the posterior part of the lateral meniscus showed a prevalence of 4.3 per cent. This picture is probably dependent on a secondary referral nature of the centre surveyed, in which the average time between injury and arthroscopy was 23.3 months.

Boden, B. P. D., G.S.; Feagin,J.A.; Garrett,W.E. (2000). "Mechanisms of anterior cruciate ligament injury." Orthopedics 23(6): 573-578.

This study examined the mechanisms of anterior cruciate ligament (ACL) injury. In the first part of the study, using a comprehensive, standardized questionnaire, 89 athletes (100 knees) were interviewed about the events surrounding their ACL injury. A noncontact mechanism was reported in 71 (72%) knees and a contact injury in 28 (28%) knees; one patient was unsure if there was any contact. Most of the injuries were sustained at footstrike with the knee close to full extension. Noncontact mechanisms were classified as sudden deceleration prior to a change of direction or landing motion, while contact injuries occurred as a result of valgus collapse of the knee. Hamstring flexibility parameters revealed a statistically higher level of laxity in the injured athletes compared with a matched group of 28 controls. In the second part of the study, videotapes of 27 separate ACL disruptions were reviewed and confirmed that most noncontact injuries occur with the knee close to extension during a sharp deceleration or landing maneuver. Because the knee is in a position to allow the extensor mechanism to strain the ACL and maximum, eccentric muscle force conditions usually apply, the quadriceps may play an important role in ACL disruption. Passive protection of the ACL by the hamstring muscles may be reduced in patients with above-average flexibility

Boel, J. and K. Kirketerp-Moller (1993). "[Clinical result after Leeds-Keio reconstruction of the anterior cruciate ligament]." Ugeskrift for Laeger 155(26):2049-52, 1993 Jun 28 155(26): 2049-52.

Seventeen patients with rupture of the anterior cruciate ligament and chronic instability were treated with the Leeds-Keio Dacron ligament system. The post-operative treatment included 15 weeks of immobilisation (five weeks with fixed knee, five weeks with 30-80 degrees of flexion and five weeks with 0-90 degrees of flexion). Muscular exercise were started after 5 weeks. They were submitted to clinical examination approximately 30 months (13-50) after implantation. The Lysholm-scoring was: excellent-good: 70%, fair: 6%, poor: 24%. These rather disappointing results could be explained by the regime: poor muscular strength and rehabilitation, long preoperative observation period and long post-operative immobilisation. We found a high frequency of rupture of the Leeds-Keio ligament system (18%) and fear, with reference to the literature, that it might increase with time. Rupture and loss of tension result in loss of stability and reactive synovitis. Though the material is small, we conclude that this regime can not be recommended.

Bollen, S. R. (1993). "Comparison of symptomatic versus nonsymptomatic patients with chronic anterior cruciate ligament insufficiency [letter; comment]." American Journal of Sports Medicine 21(5):763, 1993 Sep-Oct 21(5): 763.

Bosch, U. and W. J. Kasperczyk (1993). "[The healing process after cruciate ligament repair in the sheep model]." Orthopade 22(6):366-71, 1993 Nov 22(6): 366-71.

The patellar tendon autograft is widely used in cruciate ligament replacement. Knowledge of the basic processes involved in graft healing and of factors regulating the healing process is still limited. The patellar tendon and cruciate ligament are morphologically and biochemically distinct, which reflects the different mechanical forces acting on them. Based on morphological studies in posterior cruciate ligament replacement in a sheep model, the patellar tendon autograft undergoes a remarkable transformation process during healing. Distinct healing phases similar to those in would healing can be differentiated. During the phase of necrosis and degeneration the graft tissue becomes disorganized and mechanically weak. During the following phase of revitalization, which is characterized by revascularization, cellular proliferation and formation of collagen and other components of the extracellular matrix, the mechanical properties gradually improve. Even after the phase of remodeling the autograft tissue differs structurally and mechanically from a ligament, suggesting that the autograft only heals to a scar-like replacement tissue. The lack of a fascicular structure, the widespread presence of type III collagen and fibronectin, and the predominance of thin collagen fibrils correlate with a maximum stress of 60% and an elastic modulus of 70% compared with control values. In the sheep model cartilage alterations in the treated knees are similar to those in controls even though reconstruction of the posterior cruciate ligament cannot restore joint stability of controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Boszotta, H., W. Helperstorfer, et al. (1993). "[Foreign body synovitis--a limiting factor in use of the Trevira ligament in cruciate ligament surgery?]." Unfallchirurgie 19(3):138-43; discussion 144, 1993 Jun 19(3): 138-43; discussion 144.

In a prospective clinical study on 32 patients with Trevira ligament implants arthroscopic and histological findings were used to assess the articular effects of the synthetic ligament. In group 1 of patients with intact Trevira ligament no changes associated with foreign-body reactions were seen. In group 2 with abrased or frayed synthetic ligaments generalised foreign-body reactions in the suprapatellar recess as well as perivascular, round-cell infiltrates were seen in four out of six patients; four of the six cases also showed fibrotic signs indicative of prearthrotic changes. In group 3 with ruptured Trevira ligament no diffuse foreign-body reactions in the suprapatellar recess were seen in any of the 16 cases. In the intercondylar space foreign-body reactions correlating with the age of the implant were identified (p < 0.03). In 18% of cases with ruptured Trevira ligament generalised foreign-body reactions were seen; however, these changes were not accompanied by chronic inflammatory changes. Cases with technical shortcomings associated with a gradual fraying of the synthetic ligament invariably showed diffuse foreign-body reactions as well as chronic inflammatory infiltrates. In patients with spontaneous ligament rupture due to repeated trauma foreign-body reactions were restricted to the intercondylar space. In spite of the histological evidence of foreign-body granuloma no permanent clinical articular effects could be seen in our patients population within the follow-up time of up to 60 months.

Boynton, M. D. and P. D. Fadale (1993). "The basic science of anterior cruciate ligament surgery." Orthopaedic Review 22(6):673-9, 1993 Jun 22(6): 673-9.

Surgery for ligamentous injuries of the knee continues to be one of the most common procedures performed by orthopaedists. Anterior cruciate ligament (ACL) reconstructions are addressed specifically. Basic science and laboratory research have had a dramatic effect on our understanding of the underlying pathology of the injury, and this information has been used in the development of the clinical procedures most commonly used today. The classic stages of ligament healing are contrasted with the limited potential of the ACL. Surgical options using autografts, allografts, augmentation devices, and primary repair are discussed. Present research is examined for possible future directions in the treatment of ligament injuries.

Brand, J., Jr., A. Weiler, et al. (2000). "Graft fixation in cruciate ligament reconstruction." Am J Sports Med 28(5): 761-74.

Cruciate ligament reconstruction has progressed dramatically in the last 20 years. Anatomic placement of ligament substitutes has fostered rehabilitation efforts that stress immediate and full range of motion, immediate weightbearing, neuromuscular strength and coordination, and early return to athletic competition (3 months). This has placed extreme importance on secure graft fixation at the time of ligament reconstruction. Current ligament substitutes require a bony or soft tissue component to be fixed within a bone tunnel or on the periosteum at a distance from the normal ligament attachment site. Fixation devices have progressed from metal to biodegradable and from far to near-normal native ligament attachment sites. Ideally, the biomechanical properties of the entire graft construct would approach those of the native ligament and facilitate biologic incorporation of the graft. Fixation should be done at the normal anatomic attachment site of the native ligament (aperture fixation) and, over time, allow the biologic return of the histologic transition zone from ligament to fibrocartilage, to calcified fibrocartilage, to bone. The purpose of this article is to review current fixation devices and techniques in cruciate ligament surgery.

Brand, J. C. P., D.; Steenlage,E.; Hamilton,D.; Johnson,D.L.; Caborn,D.N. (2000). "Interference screw fixation strength of a quadrupled hamstring tendon graft is directly related to bone mineral density and insertion torque." Am.J.Sports Med. 28(5): 705-710.

The purpose of this study was to determine whether bone mineral density of the host bone, measured using conventional dual photon absorptiometry techniques, and insertion torque can predict part of the ultimate failure strength of interference screw fixation of quadrupled hamstring tendon grafts. The semitendinosus and gracilis tendons were harvested from 10 human cadaveric knees, mean age 66.5 years (range, 53 to 81). The bone tunnel was sized within 0.5 mm of the graft. The graft was fixed with a biodegradable screw (7 x 25 mm for the femur, and 9 x 25 mm for the tibia) directly against the tendon and at the joint surfaces. Tibial fixation and femoral fixation were tested to failure using a materials testing system. Bone mineral density was measured in the metaphyseal region of the tibia and femur. The results of multiple regression analyses showed that both insertion torque and bone mineral density were related to the maximum load the graft withstood. These two variables explained 77.1% of the maximum load observed. We concluded that bone mineral density measurements of the host bone site are an important determinant of postoperative graft strength and thus have an important, but previously unrecognized, clinical role in establishing individual postsurgery rehabilitation protocols. Insertion torque in this study was a useful predictor of graft fixation strength

Brand, J. W., A.; Caborn,D.N.; Brown,C.H.; Johnson,D.L. (2000). "Graft fixation in cruciate ligament reconstruction." Am.J.Sports Med. 28(5): 761-774.

Brandsson, S. F., E.; Kartus,J.; Jerre,R.; Eriksson,B.I.; Karlsson,J. (2001). "A prospective four- to seven-year follow-up after arthroscopic anterior cruciate ligament reconstruction." Scand.J.Med.Sci.Sports 11(1): 23-27.

The aim of this study was to evaluate the results after arthroscopic anterior cruciate ligament reconstruction using a bone-patellar tendon- bone graft in 99 patients, who were followed up prospectively for four to seven years. The pre-injury Tegner activity level was 7 compared with 5 at the four- to seven-year follow-up (P<0.0001). The preoperative Lysholm score was 74.5 points. At the two-year follow-up, the Lysholm score was 95 points, while it was 90 points at the four- to seven-year follow-up (P<0.0001 preoperative vs two years and preoperative vs four to seven years and P<0.0005 two years vs four to seven years). Using the IKDC evaluation system, 80% of the patients were classified as normal or nearly normal and 20% as abnormal or severely abnormal at the final follow-up. The KT-1000 laxity measurements revealed a side-to-side difference of 2.9 mm preoperatively, 0.6 at two years and 1.0 mm at four to seven years. Twenty-six patients underwent additional surgery during the follow-up period. The results after arthroscopic reconstruction of the anterior cruciate ligament appear to be satisfactory both at the short- and the medium-term follow-ups, but there appears to be some deterioration between the two-year and the four- to seven-year follow-up

Brandsson, S. K., J.; Morberg,P.; Rydgren,B.; Eriksson,B.I.; Hedner,T. (2000). "Intraarticular morphine after arthroscopic ACL reconstruction: a double- blind placebo-controlled study of 40 patients." Acta Orthop.Scand. 71(3): 280-285.

We compared analgesic effects and pharmacokinetics of intraarticular versus intravenous administration of morphine after arthroscopic anterior cruciate ligament surgery. In a double-blind placebo- controlled study, 40 patients were randomly allocated to one of four treatment groups. Group I received 1 mg morphine intraarticularly and saline intravenously; group II received 5 mg morphine intraarticularly and saline intravenously; group III received 5 mg saline intraarticularly and morphine intravenously and group IV, the control group, received saline both intraarticularly and intravenously. The pain scores were significantly lower in groups I and II at 24 hours postoperatively than in group IV, and in group II during the rest of the postoperative period, as compared to groups III and IV. After intraarticular injection of 1 mg and 5 mg morphine, respectively, low concentrations of morphine-6-glucuronide (M6G) were found in the circulation, while morphine-3-glucuronide (M3G) appeared late after the injection in concentrations that considerably exceeded those of morphine in groups I and II. The analgesic effect of intraarticular morphine together with the low levels of morphine and morphine-6- glucuronide in plasma further strengthens the view that opioids have a peripheral mechanism of action

Brandsson, S. K., J.; Larsson,J.; Eriksson,B.I.; Karlsson,J. (2000). "A comparison of results in middle-aged and young patients after anterior cruciate ligament reconstruction." Arthroscopy 16(2): 178-182.

The aim of this retrospective study was to compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction in middle- aged and young patients. From our database (including 604 patients with a follow-up rate of 95%), we extracted all the patients over 40 years of age (group A, n = 30) and compared them with a group of patients from the same material, aged between 20 and 24 years (group B, n = 37). The groups were comparable in terms of the male:female ratio and surgical techniques. The follow-up was performed by independent observers. The median follow-up period was 31 months (range, 22 to 60 months) in group A and 38 months (24 to 60 months) in group B (P =.014). Before injury, the Tegner activity level was 6 (4-9) in group A and 9 (4-9) in group B (P <.001). At follow-up, the Tegner activity level was 5 (3-9) in group A and 6 (3-9) in group B (P =.032). At the follow-up, there was no difference in terms of the Lysholm score, which was 91 (37-100) and 89 (38-100) points in group A and group B, respectively. Using the IKDC evaluation system, 10 patients (33%) were classified as normal, 12 (40%) as nearly normal, 6 (20%) as abnormal, and 2 (7%) as severely abnormal in group A, compared with 8 (22%) normal, 18 (48%) nearly normal, 10 (27%) abnormal, and 1 (3%) severely abnormal in group B (NS). The 1-leg hop quotient was 90% (52-167) in group A and 93% (70-118) in group B (P =.056). The KT-1000 measurement showed an anterior side-to-side laxity difference of 2.0 mm (-4 to 8.5 mm) in group A and 2.0 mm (-2.5 to 8.0 mm) in group B (not significant). The middle-aged patients were subjectively more pleased with the results than the younger patients. There were no differences in either early or late complications between the groups. At the index operation, 11 of 30 patients (37%) in group A and 1 of 37 (3%) in group B had cartilage lesions or degenerative changes (P <.001). Age does not appear to disqualify middle-aged patients with symptomatic ACL tears from undergoing reconstruction

Brief, L. P. (1991). "Anterior cruciate ligament reconstruction without drill holes." Arthroscopy 7(4): 350-7.

Anterior cruciate ligament (ACL) reconstruction in adolescents with open physes remains a difficult problem for the orthopedic surgeon, especially in view of growing teenage participation in contact sports. Traditionally, treatment of ACL tears in adolescents has been conservative; the patient is advised to delay surgery up to several years for fear of damaging physes by drilling holes across them. Unfortunately, this waiting period may inflict irreparable knee damage. This paper suggests an ACL reconstruction technique that utilizes no drill holes, thus causing no harm to physes or other essential knee structures. A graft consisting of semitendinosus and gracilis (SG) tendons is passed under the anterior horn of the medial meniscus through the knee joint, then brought out through the posterior capsule and secured to the lateral femoral metaphysis. The graft is augmented with an iliotibial band tenodesis. Designed primarily but not exclusively for teenagers with open physes, the procedure has produced encouraging results thus far in a small series.

Brown CH (1999). Comparison of Hamstring and Patellar Tendon Femoral Fixation: Cyclic Load. AOSSM, Traverse City Michigan.

Brown, C. H., Jr., A. T. Hecker, et al. (1993). "The biomechanics of interference screw fixation of patellar tendon anterior cruciate ligament grafts." American Journal of Sports Medicine 21(6):880-6, 1993 Nov-Dec 21(6): 880-6.

Twenty-seven paired human cadaveric knee specimens were used to determine the effect of surgical technique and various interference screw parameters on the pullout strength of patellar tendon femoral bone blocks. The study compared the fixation strength of endoscopically inserted and conventional "rear-entry" screws of different diameters and lengths. In all tests the most frequent mode of failure was bone block pullout from the interference screw. There was no significant difference in fixation strength between 9-mm diameter screws inserted through a conventional rear-entry technique and 7-mm diameter screws inserted through an endoscopic technique. There was no significant effect of screw length on fixation strength. The pullout force for 20-mm long screws increased on average 120% when 7-mm diameter screws were compared with 5.5-mm diameter screws. There was no significant effect of increased screw core diameter on fixation strength. There was a weak positive correlation (r2 = 0.45) between screw insertion torque and pullout force. Our measured mean pullout force for the 7-mm endoscopically inserted screws of 362 +/- 198 N represents 20.1% of the failure load of the normal young adult anterior cruciate ligament. Our data indicate that properly inserted 7-mm diameter endoscopic interference screws can provide fixation strengths of patellar tendon anterior cruciate ligament grafts equivalent to those of conventional 9-mm diameter rear-entry, outside-in screws.

Brown, C. H., Jr., M. E. Steiner, et al. (1993). "The use of hamstring tendons for anterior cruciate ligament reconstruction. Technique and results." Clinics in Sports Medicine 12(4):723-56, 1993 Oct 12(4): 723-56.

We feel that some of the current prejudice against use of hamstring tendon grafts for ACL reconstruction has not been justified if one critically reviews the literature. In this article, we have tried to provide the reader with our current indications, present our current surgical technique, and review some of the outcome studies involving use of the hamstring tendons for ACL reconstruction. We also feel that some of the poor results of hamstring tendon ACL reconstructions previously reported resulted from the use of inadequate strength grafts (single-stranded grafts) and lack of rigid fixation on both ends of the graft (usually secondary to inadequate graft length). We feel that the technique described in this article addresses both of these issues. It is our clinical impression that, in appropriately selected patients, this technique produces stability and functional outcome similar to that obtained with patellar tendon grafts but results in less postoperative pain, a quicker return of quadriceps muscle function, and less donor site morbidity.

Brown, C. H. C., E.W. "Revision anterior cruciate ligament surgery." Clin.Sports Med. 18(1): 109-171.

An increasing number of revision ACL reconstructions are being performed each year. Revision ACL surgery is challenging and cannot be approached in the same manner as primary ACL surgery. Successful revision ACL surgery requires a detailed history, a comprehensive physical examination, appropriate radiologic studies, and careful preoperative planning. The results of revision ACL surgery do not equal the results of primary ACL surgery, and this should be explained to the patient prior to surgery. In order to avoid repeating errors that led to failure of the primary reconstruction, the etiology of the primary failure must be clearly understood before proceeding with the revision procedure. Although graft failure is the most common reason for failure of the original reconstruction and revision surgery, other non-graft- related problems, such as loss of motion, extensor mechanism dysfunction, and degenerative arthritis, can also result in an unsatisfactory outcome and residual complaints. Errors in surgical technique, specifically nonanatomic graft placement and failure to address associated ligamentous injuries at the time of the original procedure, are responsible for graft failures in most reported series. Preoperative planning must address the issues of graft selection, skin incisions, hardware removal, tunnel placement, graft fixation, and associated ligamentous injuries. Loss of motion and in some cases enlarged bone tunnels may require a staged approach. Because of the weaker initial graft fixation, laxity of secondary restraints, the potential need to address associated ligamentous injuries, and the presence of more significant articular cartilage changes, an accelerated rehabilitation program is inappropriate in most revision cases. Successful revision ACL surgery requires a motivated and compliant patient, a well thought out plan, and an experienced surgeon who is knowledgeable and proficient with a variety of different surgical techniques, graft sources, and graft fixation techniques

Brown, C. H. S., M.E.; Carson,E.W. (1993). "The use of hamstring tendons for anterior cruciate ligament reconstruction. Technique and results." Clin.Sports Med. 12(4): 723-756.

Bruesch, M. and P. Holzach (1993). "[Epidemiology, treatment and follow-up of acute ligamentous knee injuries in Alpine skiing]." Zeitschrift fur Unfallchirurgie und Versicherungsmedizin Suppl 1:144-55, 1993 Suppl(1): 144-55.

In Switzerland the incidence of sport injuries is twice as high as traffic injuries. Soccer and alpine skiing are the major reasons for such injuries. Nowadays one out of four skiing injuries is an injury of the knee ligaments. Especially in skiing areas favored by beginners, we observed an incidence of knee ligament injuries three times as high compared to other areas. Since 1986 we evaluated 206 patients which were operated for knee ligament injuries. In 44% the direction of instability was unidirectional, most of them in the anterior direction. 115 patients had combined instabilities, 86% of those were anteromedial. 179 patients (87%) were followed up for at least 20 months. The knee was evaluated with the scoring system of the OAK (Orthopadische Arbeitsgruppe Knie der Schweizerischen Gesellschaft fur Orthopadie) and judged by four criterias (pain/swelling; movement/force; stability and function). As expected, unidirectional instabilities show better results than multidirectional. The mean value of the total score for isolated medial collateral injuries was 95.3 of 100, for isolated anterior instabilities 90.4 and for combined antero-medial instabilities 86.7 Altogether 2/3 of the patients showed very good results in stability but, 4/5 showed good results in function, so 4/5 of the patients and their physicians considered the final result as good to very good and 2/3 of those patients are back to sports, only two percent do no more sports at all.

Brulhart, K. B., C. Sartoretti, et al. (1993). "[Rupture of the patellar ligament of the tibial tuberosity as a complication after cruciate ligament-plasty]." Unfallchirurg 96(7):387-9, 1993 Jul 96(7): 387-9.

We report a complication of a rupture of the patellar ligament at the tibial tuberositas following autologous cruciate ligament reconstruction. To our knowledge, this complication has not yet been described.

Buckley, S. L. B., R.L.; and Alexander, A.H. (1989). "The natural history of conservatively treated partial anterior cruciate ligament tears." Am. J. Sports Med 17: 221-225.

Bullis, D. W. and L. E. Paulos (1994). "Reconstruction of the posterior cruciate ligament with allograft." Clin Sports Med 13(3): 581-97.

PCL reconstruction is often a necessary procedure to regain functional knee stability. The procedures used are not able to precisely recreate normal anatomy but are able to provide functional stability to posteriorly destabilized knees when properly performed. Our arthroscopic-assisted procedure limits the soft tissue dissection required and enables the best possible visualization for accurate graft placement. This limits scarring and maximizes the ability of the surgeon to provide posterior knee stability. Allograft tissue, when used as an ACL substitute, was initially believed to be as good as autogenous tissue. It is now believed to be inferior because of slower healing and a tendency to attenuate. PCL allograft reconstructions have not been adequately studied to determine if this same tendency of graft attenuation occurs. In many knees, however, adequate autogenous tissue may not be available, and the only chance to regain stability requires using an allograft. It is in these circumstances that the authors recommend allograft reconstructions.

Burks, R. T., and Leland, R. (1988). "Determination of graft tension before fixation in anterior cruciate ligament reconstruction." Arthroscopy 4: 260-266.

This study was performed to determine the tension needed to be applied on an anterior cruciate ligament graft before fixation to obtain normal anteroposterior translation following an anterior cruciate ligament reconstruction. Ten fresh-frozen cadaver knees underwent arthroscopy and were determined to have intact anterior and posterior cruciate ligaments and both menisci. A knee arthrometer (model KT 1000. MedMetric Corp., San Diego, CA, U.S.A.) was used to determine the anteroposterior translation with a 20 lb load. The anterior cruciate ligament was arthroscopically sectioned, and a repeat arthrometer measurement was made. Isometric points in the femur and tibia were determined using a tension isometer before drilling bony tunnels. The central third patellar tendon (bone-tendon-bone) complex, semitendinosus that was doubled on itself, and an iliotibial band approximately 3 cm wide were harvested. The grafts were separately passed through the knee, the femoral end was secured, and various tensions were applied to the tibial end before fixation. Repeat knee arthrometer measurements were performed after each new tension was applied. Arthrometer testing was continued until the postreconstruction 20 lb anterior drawer equalled the anterior cruciate ligament intact drawer. The patellar tendon returned the knee to its preoperative condition with a mean 3.6 lb of tension, the semitendinosus with 8.5 lb. and the iliotibial band with 13.6 lb. All these differences were statistically significant (p less than 0.01). The tension that needs to be applied to a graft during an anterior cruciate ligament reconstruction appears to be tissue specific. It is hoped that precise intraoperative tensioning of anterior cruciate ligament grafts will lead to more reproducible anterior cruciate reconstruction results.

Buseck, M. S. and F. R. Noyes (1991). "Arthroscopic evaluation of meniscal repairs after anterior cruciate ligament reconstruction and immediate motion." Am J Sports Med 19(5): 489-94.

Sixty-six patients who had meniscal repair at the same time as an ACL reconstruction were followed-up with arthroscopy at an average of 12 months postoperatively. All patients underwent immediate postoperative range of motion from 20 degrees to 90 degrees and began partial weightbearing between the 1st and 3rd postoperative weeks. The rate of meniscal healing was classified as complete, partial, or failed. We statistically analyzed the effect of rim width, length of the tear, type of meniscus, age of patient, length of time between injury and repair, length of time between surgery and follow-up arthroscopy, and open versus arthroscopically assisted surgical procedure on the rate of meniscal healing. The overall results showed that 63 (80%) of the menisci completely healed, 11 (14%) partially healed, and 5 (6%) failed. The only factor that had a statistically significant impact on the rate of healing was rim width. Repairs in the outer one-third region had a higher incidence of healing (98% retained menisci) than those in the central one-third region (79% retained menisci, P less than 0.01). Still, the ability to repair a majority of central one- third meniscus tears that occur in the avascular zone (including flap tears and double longitudinal tears) suggest repair be considered when clinical grounds warrant preserving the meniscus. There were no complications, nor were there any deleterious effects from immediate knee motion or early weightbearing on the meniscal repairs. This allows an aggressive, immediate motion program to be followed with ACL reconstruction when concomitant meniscus repair is performed.

Buss, D. D., R. F. Warren, et al. (1993). "Arthroscopically assisted reconstruction of the anterior cruciate ligament with use of autogenous patellar-ligament grafts. Results after twenty-four to forty-two months." Journal of Bone & Joint Surgery - American Volume 75(9):1346-55, 1993 Sep 75(9): 1346-55.

The results of the first sixty-nine consecutive patients who had had seventy arthroscopically assisted reconstructions of the anterior cruciate ligament with use of an autogenous patellar-ligament graft at our institution were reviewed retrospectively. Sixty-seven patients (sixty-eight knees) were available for evaluation after a minimum of two years. All patients had been managed with early, postoperative range-of-motion exercises and a standardized program of physical therapy. At the time of the most recent follow-up evaluation, the median ligament score, according to the rating system of The Hospital for Special Surgery, was 93 of a possible 100 points. Of the sixty-eight knees, forty-four were rated excellent; fifteen, good; six, fair; and three, poor. Eighteen knees had symptoms related to the patellofemoral joint and sixty-three had a full range of motion; two knees had had manipulation for loss of flexion. At the follow-up evaluation, KT-1000 arthrometric measurements were obtained for both knees of fifty-six patients. Eighty-four per cent of the patients had an increase of three millimeters or less in anterior-posterior displacement of the tibia on the reconstructed side compared with the normal side, while 93 per cent had an increase of four millimeters or less. Postoperatively, there was no apparent association between changes in the Insall-Salvati patellar ligament-to-patella ratios and pain in the patellofemoral joint. The results of the arthroscopically assisted reconstructions combined with use of early range-of-motion exercises were comparable with those reported after open reconstruction and immobilization of the limb in a plaster cast. The frequency of pain in the patellofemoral joint and the need for manipulation because of loss of motion were decreased after the arthroscopically assisted procedures.

Caborn, D. N. and B. M. Johnson (1993). "The natural history of the anterior cruciate ligament-deficient knee. A review." Clinics in Sports Medicine 12(4):625-36, 1993 Oct 12(4): 625-36.

The ACL-deficient knee has been a management dilemma for many years and, to this day, no refutable plan exists for treatment of this injury. No true prospective study has been performed that evaluates all types of individuals at a variety of activity levels, and, in this day of apparently reliable methods of reconstructing the ACL, it is doubtful that one will occur. The ACL injury is no longer a mystery to the general public; it has received extensive publicity because of injuries of professional athletes and the successful reconstruction in many of these athletes. This article has not completely cleared up the issue of the future of an ACL-deficient knee. It has provided, however, convincing evidence that an active individual with a nonfunctional ACL is susceptible to meniscus injury (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). There is also the risk of more tears occurring with time. Bray and Dandy found in their follow-up of patients with ACL repairs that, if the pivot shift returned, these patients had a much higher incidence of meniscus tears. Many of these studies indicate that, if the meniscus cannot be repaired and requires partial meniscectomy or worse, the articular surface will deteriorate (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). Satku et al showed only 11% incidence of radiographic changes in patients with ACL-deficient knees with no evidence of meniscus tears compared with 100% in those having meniscectomy more than 5 years previously. Activity levels in general also change following this injury. This is probably the most difficult area to assess. Even though a substantial number of persons returned to their preinjury level of activity, it is not always possible to determine if they are playing with the same behavior and attitude. In other words, athletes who are involved in sports with cutting and jumping may modify the need for these activities and yet remain relatively competitive depending on their previous level of skill and the position they play. It has also been shown that many athletes return to their preinjury level initially but with time have significant increase in their symptoms and must modify their level of participation. More individuals limited their activities from the beginning than returned to their preinjury level (R. Barrack, J. Bruckner, J. Kneisl, et al, personal communication, 1990). Instability varies in these individuals and, as in Chick and Jackson's patients, those with mild instability (no rotatory instability) may do reasonably well.(ABSTRACT TRUNCATED AT 400 WORD

Cain LE, P. B., Charlebois SJ, Daniels AU, Azar FM. (1999). Effect of Tibial Tunnel Dilation on Pullout Strength of Quadrupled Semitendinosus Gracilus Autografts in ACL Reconstruction Secured with Bioabosorbable Interference Screws. AOSSM, Traverse City Michagan.

Dilation of the tibial tunnel 2 mm improves the pullout by 40%.

Carson, W. G., Jr. (1988). "The role of lateral extra-articular procedures for anterolateral rotatory instability." Clin Sports Med 7(4): 751-72.

The goal of any surgical procedure to correct the instability caused by loss of the ACL is to control the abnormal anterior excursion of the tibia on the femur. Because the main problem is loss of the ACL, it would seem most reasonable to approach this problem by performing an intra-articular reconstruction of the ACL, thus approximating as closely as possible the normal anatomy of the ACL. The classic open intra-articular ACL reconstructions are technically demanding surgical procedures that usually require a significant "learning curve" to achieve a level of technical expertise and confidence. In addition, postoperative complications such as adhesions, loss of motion, prolonged muscle atrophy, and a long rehabilitation period are well known. Thus, it would appear that the extra-articular reconstructive procedures for the anterior cruciate-deficient knee would offer some advantage over these more formidable surgical procedures. Whereas the main problem is certainly the loss of the ACL, the extra-articular procedures are directed more toward the most symptomatic anterior excursion of the tibia on the femur, the pivot shift phenomenon, where the anterolateral portion of the tibia moves anterior in relation to the femur. Thus, the goal of the extra-articular reconstructive procedures for anterolateral rotatory instability is to eliminate functional instability. These goals are most readily achieved by positioning some portion of the iliotibial tract posterior to the transverse center of rotation of the knee to provide a reinforcement for the lateral tibial plateau as the knee approaches terminal extension. All of the extra-articular procedures discussed in this article have been used successfully as reported by the various authors. There are many technical details inherent in each of these surgical procedures, and the reader is referred to the original articles for a more explicit description of these surgical procedures. For the individual surgeon to participate in and view the actual surgical procedure that he or she intends to perform would be the ideal situation. Various workshops where surgical procedures of the knee are actually performed and studied are currently available and are of great value to the surgeon. Of equal importance to the technical demands of the various surgical procedures is selection of the appropriate procedure for each patient. The selection must be based on many factors. The most important factor is the identification of the patient with a high level of athletic activity who is unwilling to modify his or her activity level to compensate for a deficient ACL.(ABSTRACT TRUNCATED AT 400 WORDS)

Cawley, P. W. F., E.P.; and Paulos, L.E. (1991). "The current state of functional knee bracing research. A review of the literature." Am. J. Sports Med 19: 226-233.

Cazenave, A. and J. P. Laboureau (1990). "[Reconstruction of the anterior cruciate ligament. Determination of the pre- and peroperative femoral isometric point]." Rev Chir Orthop Reparatrice Appar Mot 76(4): 288-92.

This study attempted to determine the femoral isometric site by a simple, reliable and easily reproducible technique for the reconstruction of a torn anterior cruciate ligament (A.C.L.). Anatomoradiological studies showed that the posterior border of the lateral condyle corresponded with the third of a circle and that the center of this circle was named the "isometric point" (F). The variations of the intra-articular length of a ligament between the point F and the center of the A.C.L. tibial attachment did not exceed 2 mm. A radiological study on 50 normal patients knees X-Rayed at 0 degree and 90 degrees of flexion showed a length dependence of 1.5 mm in 84% and 2 mm maximum in 98%. Twenty patients with acute or chronic A.C.L. rupture were operated on; the isometric point F was determined by superimposing a template of circles on the posterior border of the condyle. An original guide allowed to drill a bony tunnel with a pin emerging at the exact previous point F. A per-operative X-Ray studied the good reliability of this guide. The measurements of the variations of length of the ligament between 0 degree and 110 degrees of flexion varied less than 5% in 18 patients, which confirms the good isometry of the reconstruction. On the basis of these data, we propose to improve the implantation of autogenous or synthetic ligament in A.C.L. reconstruction by the use of a pre-operative determination of the isometric femoral point and the use of a guide able to drill easily a bony tunnel at this exact pre-determined point.

Cerullo, G. and G. Puddu (1993). "Arthroscopic placement of the interference screw for anterior cruciate ligament reconstruction." Arthroscopy 9(6):712-3, 1993 9(6): 712-3.

This article describes a simple technique to check arthroscopically the position of the interference screw in bone patellar tendon bone reconstruction of the anterior cruciate ligament. With this simple and inexpensive method we can be sure that the bone plug in the tunnel has a rigid fixation and that the screw does not damage that graft.

Chen, C. H. C., W.J.; Shih,C.H. (1999). "Arthroscopic anterior cruciate ligament reconstruction with quadriceps tendon-patellar bone autograft." J.Trauma 46(4): 678-682.

BACKGROUND: Surgical reconstruction of the anterior cruciate ligament (ACL) is indicated in the ACL-deficient knee with symptomatic instability and multiple ligaments injuries. Bone patellar tendon-bone and the hamstring tendon generally have been used. In the present study, we describe an alternative graft, the quadriceps tendon-patellar bone autograft, by using arthroscopic ACL reconstruction. METHODS: From March of 1996 through March of 1997, a quadriceps tendon-patellar bone autograft was used in 12 patients with ACL injuries. RESULTS: After 15 to 24 months of follow-up, the clinical outcome for those patients with this graft have been encouraging. Ten patients could return to the same or a higher level of preinjury sports activity. According to the International Knee Documentation Committee rating system, 10 of the 12 patients had normal or nearly normal ratings. Recovery of quadriceps muscle strength to 80% of the normal knee was achieved in 11 patients in 1 year. CONCLUSION: The advantages of the quadriceps tendon graft include the following: the graft is larger and stronger than the patellar tendon; morbidity of harvest technique and donor site is less than that of patellar tendon graft; there is little quadriceps inhibition after quadriceps harvest; there is quicker return to sports activities with aggressive rehabilitation. A quadriceps tendon-patellar autograft is a reasonable alternative to ACL reconstruction in patients who are not suitable for either a bone-patellar tendon-bone autograft or a hamstring tendon autograft

Chvapil, M., D. P. Speer, et al. (1993). "Collagen fibers as a temporary scaffold for replacement of ACL in goats." Journal of Biomedical Materials Research 27(3):313-25, 1993 Mar 27(3): 313-25.

ACL substitutes made of braided or plied purified collagen fibers and cross-linked with hexamethylenediisocyanate were implanted into a total of 14 adult goats to achieve resorption within 8 to 10 months. Two types of collagen fiber prostheses differing in degree of collagen purification were tested. The implants were harvested 2 to 11 months postimplantation, tested for mechanical strength, and evaluated by morphological methods. In the first group (n = 5), the less purified and less cross-linked collagen fiber ACL implant induced fast connective tissue ingrowth. At 6 months postimplantation, 40 to 60% of the collagen implant was resorbed. No studies on breaking strength were done in this group. In the second group, highly purified and more crosslinked ACL implants were less infiltrated by cells and were resorbed only by 10 to 20%. Still, the breaking strength was decreased to 10% of the original implant strength. In the second group, the fixation of the ACL implant in the bone tunnel with a bone wedge was insufficient (n = 6); however, additional fixation with metal screws was successful (n = 3). We conclude that cross-linked collagen fibers alone cannot be used as a safe ACL substitute as they quickly lose mechanical strength despite limited biodegradation.

Clancy, W. G., Jr.; Nelson, D.A.; Reider, Bruce; and Narechania, R.G. (1982). "Anterior cruciate ligalent reconstruction using one-third of the patellar ligament, augmented by extra-articular tendon transfers." J. Bone and Joint Surg 64A: 352-359.

Clancy, W. G., Jr.; Ray, J.M.; and Zoltan, D.J. (1988). "Acute tears of the anterior cruciate ligament. Surgical versus conservative treatment." J. Bone and Joint Surg 70A: 1483-1488.

Co, F. H., H. B. Skinner, et al. (1993). "Effect of reconstruction of the anterior cruciate ligament on proprioception of the knee and the heel strike transient." Journal of Orthopaedic Research 11(5):696-704, 1993 Sep 11(5): 696-704.

Abnormal proprioception of the knee joint has been documented after rupture of the anterior cruciate ligament (ACL) and may result in the loss of muscular reflexes. Excessive loading from the lack of muscular control may predispose the joint to osteoarthrosis. To investigate this problem, 10 patients were studied at an average of 31.6 months after ACL reconstruction. Three tests of joint proprioception and measurements of the vertical component of heel strike force during normal gait were used. A normal control group also was studied. For two of the proprioception tests (reproduction of passive motion and relative reproduction), there were no statistical differences among the uninjured (control) limbs, the normal contralateral limb of patients with a reconstructed ACL, and the extremity with a reconstructed ACL. In the third test (threshold of detection of motion), which previously has been shown to be adversely affected by ACL injury, the measurements for both extremities of patients with a reconstructed ACL were more accurate than those for the control group. The reconstructed extremity performed less accurately than the contralateral extremity (p < 0.05). The heel strike transient (vertical component of ground reaction force at heel strike) for uninjured and ACL-reconstructed limbs was not significantly different. In fact, the extremity with the reconstructed ACL had a lower transient than the uninjured extremity. Heel strike transients in patients with a reconstructed ACL were higher than those in the controls, but the differences were significant only when corrected for velocity of gait.(ABSTRACT TRUNCATED AT 250 WORDS)

Colville, M. R. and R. R. Bowman (1993). "The significance of isometer measurements and graft position during anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(6):832-5, 1993 Nov-Dec 21(6): 832-5.

Intraoperative isometry measurements are commonly performed before bone tunnel drilling during anterior cruciate ligament reconstruction. The relationship between initial isometer measurements and final graft isometry, however, is unclear. We tested 15 cadaveric knees to determine the relationship between isometer readings and final graft isometry. We found that isometer readings may vary widely from final graft isometry because of eccentric placement of the anterior cruciate ligament graft within bone tunnels. Isometer measurements may be used, however, to predict accurate final graft isometry for specific graft positions within the bone tunnels.

Corry, I. S. W., J.M.; Clingeleffer,A.J.; Pinczewski,L.A. "Arthroscopic reconstruction of the anterior cruciate ligament. A comparison of patellar tendon autograft and four-strand hamstring tendon autograft." Am.J.Sports Med. 27(4): 444-454.

We compared the outcome of anterior cruciate ligament reconstruction using hamstring tendon autograft with outcome using patellar tendon autograft at 2 years after surgery. Patients had an isolated anterior cruciate ligament injury and, apart from the grafts, the arthroscopic surgical technique was identical. Prospective assessment was performed on 90 patients with isolated anterior cruciate ligament injury undergoing reconstruction with a patellar tendon autograft; 82 were available for follow-up. The hamstring tendon autograft group consisted of the next 90 consecutive patients fulfilling the same criteria; 85 were available for follow-up. Clinical review included the Lysholm and International Knee Documentation Committee scores, instrumented testing, thigh atrophy, and kneeling pain. These methods revealed no difference between the groups in terms of ligament stability, range of motion, and general symptoms. Thigh atrophy was significantly less in the hamstring tendon group at 1 year after surgery, a difference that had disappeared by 2 years. The KT-1000 arthrometer testing showed a slightly increased mean laxity in the female patients in the hamstring tendon graft group. Kneeling pain after reconstruction with the hamstring tendon autograft was significantly less common than with the patellar tendon autograft, suggesting lower donor-site morbidity with hamstring tendon harvest

Cosgarea, A. J., M. S. Weng, et al. (1993). "Osgood-Schlatter's disease complicating anterior cruciate ligament reconstruction." Arthroscopy 9(6):700-3, 1993 9(6): 700-3.

Osgood-Schlatter's disease (OSD) is generally felt to be a benign self-limited disorder. In a small number of patients a symptomatic free bone ossicle persists at the tibial insertion of the patellar tendon. We report the case of a collegiate soccer player with a history of OSD who sustained an acute rupture of his anterior cruciate ligament (ACL). The presence of a free bone ossicle in his patellar tendon necessitated modification of our routine approach to ACL reconstruction. Awareness of the potential for patellar tendon graft problems in patients with previous OSD will allow surgeons to plan alternative reconstructive techniques based on the specific needs of the patient.

Cross, M. J., J. R. Wootton, et al. (1993). "Acute repair of injury to the anterior cruciate ligament. A long-term followup." American Journal of Sports Medicine 21(1):128-31, 1993 Jan-Feb 21(1): 128-31.

We reviewed 30 patients at an average of 7.4 years after acute repair of the anterior cruciate ligament augmented with a loop of iliotibial tract. A noncontact twisting had been the mechanism of injury in 18 of these patients, with 28 having been injured in sports. At followup, 25 patients had not experienced symptoms of instability and 23 were able to return to unrestricted athletic activity; only 5 had been unable or unwilling to return to sporting activity at all. There had been no swelling in 23 patients; however, 17 suffered from pain on exertion. The average Lysholm score was 93.2. Joint laxity was assessed and anteroposterior tibial translation quantified with a KT-1000 arthrometer. Eighteen patients had a normal or 1+ Lachman test and 27 had an absent or 1+ pivot shift. When compared with the results of a similar study performed on this group of patients at 2 years after surgery, there had been little subjective change in knee function. However, objectively there had been significant deterioration of the anteroposterior stability of the knees at 7 years, suggesting failure of the integrity of the repaired ligament with time. An associated medial collateral ligament injury had a significant adverse effect both on the integrity of the anterior cruciate ligament repair and the incidence of postoperative stiffness.

Currier, D. P., J. M. Ray, et al. (1993). "Effects of electrical and electromagnetic stimulation after anterior cruciate ligament reconstruction." Journal of Orthopaedic & Sports Physical Therapy 17(4):177-84, 1993 Apr 17(4): 177-84.

A need exists to develop new methods of neuromuscular electrical stimulation (NMES) that are both effective and relatively pain-free. The purpose of this pilot study was to determine the effects of both NMES and a new method of electromagnetic (NMES/PEMF) stimulation for reducing girth loss and for reducing pain and muscle weakness of the knee extensor muscles in patients during the first 6 weeks after reconstructive surgery of the anterior cruciate ligament (ACL). Seventeen patients receiving ACL reconstructive surgery participated as a control group (N = 3), as an NMES group (N = 7), and with combined NMES and magnetic field stimulation (NMES/PEMF) (N = 7). Patients receiving NMES/PEMF rated each type of stimulation for perceived pain and were measured for their torque. Torque results revealed a mean decrease of 13.1% for NMES/PEMF patients. The mean percent of thigh girth decreased 8.3% for controls, 0.5% for NMES, and 2.3% for NMES/PEMF patients. The NMES/PEMF patients rated NMES as causing about twice the pain intensity as NMES/PEMF during treatments. As a result of this data, the authors conclude that both NMES and NMES/PEMF are effective in reducing girth loss and that NMES/PEMF is less painful than NMES alone in treating patients after ACL reconstruction.

D'Agata, S. D., A. W. t. Pearsall, et al. (1993). "An in vitro analysis of patellofemoral contact areas and pressures following procurement of the central one-third patellar tendon." American Journal of Sports Medicine 21(2):212-9, 1993 Mar-Apr 21(2): 212-9.

Patients have complained of pain after the use of the central one-third patellar tendon for reconstruction of the anterior cruciate ligament-deficient knee. This study investigated the effect on patellofemoral contact areas and pressures of harvesting the central 10 mm of the patellar tendon in five cadaveric knees. Isometric quadriceps forces were applied to produce approximately 30% of reported maximum voluntary extension moments at the knee. Using Fuji pressure-sensitive film, measurements were recorded for three states: the normal knee, after the graft removal, and after the tendon was closed. Contact areas and pressures were measured at 20 degrees, 30 degrees, 60 degrees, and 80 degrees of knee flexion in each specimen. Tests of the reproducibility of our methods were performed. Average patellofemoral contact areas for three states ranged from 1.6 cm2 at 20 degrees of knee flexion to 3.0 cm2 at 60 degrees. The average patellofemoral contact pressures ranged from 1.9 MPa at 20 degrees of knee flexion to 3.0 MPa at 30 degrees. At each flexion angle there were no significant differences in average patellar contact area or pressure for the three states (P < 0.05). These results suggest that neither harvesting the central 10 mm of the patellar tendon, nor closing the gap, significantly alters patellofemoral contact area or pressure.

Dahlstedt, L., N. Dalen, et al. (1993). "Cruciate ligament prosthesis vs. augmentation. A randomized, prospective 5-year follow-up of 41 cases." Acta Orthopaedica Scandinavica 64(4):431-3, 1993 Aug 64(4): 431-3.

In a prospective study, 18 patients were randomized to a prosthesis and 23 patients to the Kennedy Ligament Augmentation Device (LAD) because of functional instability due to old anterior cruciate ligament injuries. The operations were performed with use of a modified over-the-top technique. At the last follow-up (5 years), postoperative improvements in scores were maintained for both groups, but LAD-reconstructed patients had better Lysholm and activity scores than the Goretex group. The achieved postoperative improvement in anterior stability (KT-1000) did not deteriorate for either of the groups during the 5-year follow-up. The Goretex patients had more effusion and pain and more secondary operations.

Daniel, D. (1990). Principles of knee ligament surgery. In Knee Ligaments: Structure, Function, Injury, and Repair,. New York, Raven Press.

Danto, M. I. and S. L. Woo (1993). "The mechanical properties of skeletally mature rabbit anterior cruciate ligament and patellar tendon over a range of strain rates." Journal of Orthopaedic Research 11(1):58-67, 1993 Jan 11(1): 58-67.

The effect of strain rate on the mechanical properties of the rabbit anterior cruciate ligament (ACL) and patellar tendon (PT) was evaluated. The medial portion of the ACL was loaded to tensile failure at rates of 0.003, 0.3, and 113 mm/s, and the middle third of the PT was loaded at rates of 0.008, 0.8, and 113 mm/s. The load was recorded with a high-speed measurement plotting system, and each test was videotaped for strain analysis. The nonlinear portion of the stress-strain curve was curve-fit to an exponential function having two nonlinear constants, representing the initial modulus and rate of change of the modulus. The modulus of the rabbit PT was found to be 89% higher than that of the ACL. The initial modulus and rate of change of the modulus also were greater for the PT than for the ACL. The modulus of the PT was shown to be more sensitive to strain rate than that of the ACL; a 94% increase was observed for the PT, and a 31% increase was observed for the ACL. There was no effect of strain rate on the mode of failure of either the ACL or the PT; all but three of the specimens failed at the insertion site.

Davis, T. J. S., K.D.; Klootwyk,T.E. (1999). "Correlation of the intercondylar notch width of the femur to the width of the anterior and posterior cruciate ligaments." Knee.Surg.Sports Traumatol.Arthrosc. 7(4): 209-214.

The purpose of this study was to determine if a correlation exists between the intercondylar notch width (NW) of the femur and the width of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). A study group of 124 consecutive patients (mean age 36.6 +/- 15.2 years; 67 men, 57 women) underwent a magnetic resonance imaging evaluation for knee pain but did not have an ACL or PCL tear or arthrosis. A T2 weighted coronal cut was identified and was located at the middle of the tibial spine, which represented the plane where the ACL and PCL cross each other when the knee is in 10 degrees of flexion. The NW and the width of the ACL and PCL were measured at the level of the middle of the popliteal hiatus on a physician-independent console that allowed for digital measurements in millimeters. Our results showed a statistically significant correlation between NW and ACL width (r = 0.87; P < 0.001) and between NW and PCL width (r = 0.75; P < 0.001). The mean ACL width was 6.4 +/- 1.4 mm (range 3-10 mm). The mean PCL width was 10.2 +/- 2.0 mm (range 6-17 mm). The mean ACL width was 5.7 +/- 1.1 mm for women and 7.1 +/- 1.2 mm for men (P < 0.001). The mean PCL width was 9.5 +/- 1.7 mm for women and 10.9 +/- 2.0 for men (P < 0.001). Our results indicate that NW correlates with ACL and PCL width. In addition, ACL and PCL widths are narrower in women than men

De Carlo, M. S., K.D.; Oneacre,K. (1999). "Rehabilitation program for both knees when the contralateral autogenous patellar tendon graft is used for primary anterior cruciate ligament reconstruction: a case study." J.Orthop.Sports Phys.Ther. 29(3): 144-153.

STUDY DESIGN: Case study of a basketball player who underwent an alternative surgical procedure for anterior (cruciate ligament (ACL) reconstruction and outline of the rehabilitation process designed for this procedure. OBJECTIVES: To describe the surgical procedure, detail the rehabilitation program, and report on this patient's clinical outcome. BACKGROUND: Anterior cruciate ligament injury, its treatment, and rehabilitation continue to be an area of interest to both clinicians and researchers. Surgical procedures have been refined and rehabilitation programs are constantly being evaluated and updated to allow the safest and most predictable return to activity. Currently, the autogenous bone-patellar tendon-bone graft is the graft of choice for ACL reconstruction. Typically the graft is taken from the ipsilateral knee. An alternative procedure is to take the graft from the contralateral, noninvolved knee, allowing 2 separate rehabilitation programs to take place. METHODS AND MEASURES: The patient was followed from the time of injury to 2 years postoperatively. Data collected included range of motion, isokinetic strength scores, ligament stability scores, subjective evaluation, and functional measures. RESULTS: At 3 weeks postoperative the patient had nearly full range of motion in both knees, normal gait, and was beginning sport-specific drills. He was shooting the basketball and jumping by 5 weeks and returned to competitive sports 6 weeks after surgery. He was able to play in all 32 games of the season, starting in 23 of them. CONCLUSIONS: Using the contralateral patellar tendon graft may be appropriate for primary ACL reconstruction of patients, particularly those desiring an early expedient return to athletic competition

Dedrick, D. K., S. A. Goldstein, et al. (1993). "A longitudinal study of subchondral plate and trabecular bone in cruciate-deficient dogs with osteoarthritis followed up for 54 months." Arthritis & Rheumatism 36(10):1460-7, 1993 Oct 36(10): 1460-7.

OBJECTIVE. To evaluate the sequence of changes in articular cartilage, trabecular bone, and subchondral plate in dogs with osteoarthritis (OA), 3 months, 18 months, and 54 months after anterior cruciate ligament transection (ACLT). METHODS. Specimens of the medial tibial plateau were analyzed with microscopic computed tomography (micro-CT) at a resolution of 60 microns, and biochemical and morphologic changes in the femoral articular cartilage were assessed. RESULTS. At 3 months and 18 months after ACLT, the articular cartilage in the unstable knee showed histologic changes typical of early OA and increased water content and uronic acid concentration; by 54 months, full-thickness ulceration had developed. Micro-CT analysis showed a loss of trabecular bone in the unstable knee, compared with the contralateral knee, at all time points. At both 18 and 54 months, the differences in trabecular thickness and surface-to-volume ratio were greater than at 3 months. Although the mean subchondral plate thickness, especially in the medial aspect of the medial tibial plateau, was greater in the OA knee than in the contralateral knee 18 months and 54 months after ACLT, these differences were not statistically significant; however, the difference was significantly greater at 54 months than at 3 months. CONCLUSION. Thickening of the subchondral bone is not required for the development of cartilage changes of OA in this model. The bony changes that develop after ACLT, however, could result in abnormal transmission of stress to the overlying cartilage and thereby contribute to the progression of cartilage degeneration.

Deehan, D. J. S., L.J.; Webb,V.J.; Davies,A.; Pinczewski,L.A. (2000). "Endoscopic reconstruction of the anterior cruciate ligament with an ipsilateral patellar tendon autograft. A prospective longitudinal five- year study." J.Bone Joint Surg.Br. 82(7): 984-991.

A total of 90 patients with an isolated rupture of the anterior cruciate ligament (ACL) had a reconstruction using the ipsilateral patellar tendon secured with round-headed cannulated interference screws. Annual review for five years showed three failures of the graft (two traumatic and one atraumatic); none occurred after two years. Ten patients sustained a rupture of the contralateral ACL. At five years, 69% of those with surviving grafts continued to participate in moderate to strenuous activity. Using the International Knee Documentation Committee assessment, 90% reported their knee as being normal or nearly normal and had a median Lysholm knee score of 96 (64 to 100). Most patients (98%) had a pivot shift of grade 0 with the remaining 2% being grade 1; 90% of the group had a Lachman test of grade 0. The incidence of subsequent meniscectomy was similar in the reconstructed joint to that in the contralateral knee. Radiological examination was normal in 63 of 65 patients. Our study supports the view that reconstruction of the ACL is a reliable technique allowing full rehabilitation of the previously injured knee. In the presence of normal menisci there is a low incidence of osteoarthritic change despite continued participation in sporting activity

Dejour, H., G. Walch, et al. (1987). "[Arthrosis of the knee in chronic anterior laxity]." Rev Chir Orthop Reparatrice Appar Mot 73(3): 157-70.

Arthrosis following rupture of the anterior cruciate ligament has been analysed in two series. The first series was derived from a review of 150 cases of reconstruction of the anterior cruciate ligament with a follow-up of 3 years or more. Arthrosis was seen to have developed in 13.3%. The second series was concerned with 64 cases of unilateral arthrosis treated by upper tibial valgus osteotomy in whom there had been a previous rupture of the anterior cruciate ligament. The "tolerance time"--that is the time between the original ligamentous injury and the time of osteotomy--for the development of arthrosis was very variable, ranging in cases with a "natural history" from 10 to 50 years with a mean of 35 years. It is important to recognise the radiological signs of the onset of arthrosis. These are osteophytosis of the intercondylar notch, osteophyte formation at the posterior part of the medial tibial plateau, and, in particular, narrowing of the medial joint line with posterior subluxation of the medial femoral condyle, well seen in lateral radiographs whilst standing on one lower limb. Early arthroses, appearing after 10 years, may occur as a "natural arthrosis", but it develops much more frequently after surgical treatment that had failed to correct anterior laxity and particularly when it had been performed on knees that were already pre-arthrotic. The main factor in arthrosis is anterior laxity measured radiologically by an "active Lachman" radiograph. Removal of the medial meniscus, which, in itself, is liable to produce arthrosis is even more harmful in anterior cruciate laxity since it doubles the degree of anterior subluxation of the tibia seen on unilateral weight-bearing. The development of varus deformity, which characterises progressive arthrosis, has its origin in wear of the posterior part of the medial tibial plateau caused by anterior cruciate laxity. Other factors play an important part such as associated lateral laxity, constitutional genu varum and weakness of the hamstring muscles which oppose the subluxating action of the quadriceps.

DeLee, J. E., and Curtis, Ralph (1983). "Anterior cruicate ligament insufficiency in children." Clin. Orthop 172: 112-118.

Dempsey, S. M. and R. J. Tregonning (1993). "Nine-year follow-up results of two methods of MacIntosh anterior cruciate ligament reconstructions." Clinical Orthopaedics & Related Research (294):216-22, 1993 Sep(294): 216-22.

Forty-seven MacIntosh anterior cruciate reconstructions using iliotibial band were performed in patients with chronic instability symptoms and positive pivot shift jerk. In 22 knees, a lateral substitution technique alone was used. In 25 knees, the technique was supplemented with an intraarticular component. After an average of follow-up of nine years, 62% of knees had an excellent or good Lysholm score; 83% of patients remained active in sports. Subjectively, there was no deterioration of stability with time, and no return of the jerk on pivot shift testing, although a slide persisted in one third of the patients. The addition of an intraarticular component did not alter the subjective result. Objectively, the trend was toward improvement in functioning. The lateral tenodesis was the major determinant in the improvement of subjective stability and control of pivot shift jerk.

Denti, M. R., P.; Lo,Vetere D.; Moioli,M.; Bagnoli,I.; Cawley,P.W. (2000). "Motor control performance in the lower extremity: normals vs. anterior cruciate ligament reconstructed knees 5-8 years from the index surgery." Knee.Surg.Sports Traumatol.Arthrosc. 8(5): 296-300.

We compared motor control function in 50 patients who had undergone anterior cruciate ligament reconstruction using a bone-tendon-bone graft to that in 50 normal controls. Surgical subjects patients had undergone reconstruction with a one- (n=37) or two-incision (n=13) technique with the same rehabilitation protocol; mean time from the index surgery was 6.1 years (range of 5-8 years). For inclusion patients required an excellent outcome, category A IKDC score, and a KT- 1000 side-to-side difference of 3 mm or less. Motor control evaluations were conducted using the KAT 2000 with static and dynamic tests. Normal controls had substantially better scores than did the surgical patients. There was no statistical difference the single-limb static test between scores of operated and nonoperated limbs. However, the operated limb scores were slightly better overall than those for the nonoperated limb, and the right knee scores tended to be better than those for the left knee. This may be explained by limb dominance. The test method employed in this investigation shows that anterior cruciate ligament reconstructed patients had a clear motor control deficit compared to normal control subjects even after several years

DiStefano, V. (1993). "Anterior cruciate ligament reconstruction. Autograft or allograft?" Clinics in Sports Medicine 12(1):1-11, 1993 Jan 12(1): 1-11.

Refinements in arthroscopic techniques have fostered an upsurge in arthroscopically assisted anterior cruciate ligament reconstruction. This article explores the relative merits of autogenous and allogeneic tissue used for this purpose and describes several important technical points in the author's preferred method of surgery.

Dorchak, J. D., R. L. Barrack, et al. (1993). "Radionuclide imaging of the knee with chronic anterior cruciate ligament tear." Orthopaedic Review 22(11):1233-41, 1993 Nov 22(11): 1233-41.

We studied the results of bone scans in 50 consecutive patients with symptomatic, unilateral, chronic anterior cruciate ligament (ACL) tears. All patients had failed conservative therapy and underwent radionuclide imaging of the knee prior to arthroscopic ACL reconstruction. The scintigraphic activity in each of the three knee compartments was quantitatively scaled from 1 (normal scintigraphic activity) to 4 (marked activity). Quantitative activity in each of the three compartments was correlated with plain radiographic, arthroscopic, and clinical findings. All but four of the scans (92%) showed abnormal scintigraphic activity. The quantitative activity was highest overall in the medial compartment (2.9), followed by the lateral (2.4) and patellofemoral compartments (1.9). In the subgroup of patients with normal menisci (10 patients), most of the abnormal activity was in the lateral compartment (2.9), implying that when the medial meniscus remains competent in the presence of a torn ACL, there is increased stress on the lateral compartment. There was little correlation with scintigraphy and roentgenographic changes, except in the presence of moderate or severe radiographic degenerative arthritis. Similarly, there was little correlation between increased scintigraphic activity and chondromalacia. These results provide a baseline for future studies that use scintigraphic imaging in monitoring restoration of bone homeostasis following ACL reconstruction.

Drez, D. J., Jr., J. DeLee, et al. (1991). "Anterior cruciate ligament reconstruction using bone-patellar tendon- bone allografts. A biological and biomechanical evaluation in goats." Am J Sports Med 19(3): 256-63.

Twenty-eight goats underwent ACL reconstruction with freeze-dried bone- patellar tendon-bone allografts in one knee, the opposite knee serving as a control. One group of 16 knees was evaluated, in groups of four, at 6, 12, 26, and 52 weeks by histologic and vascular injection techniques. The other group of 12 knees was evaluated in two groups of six at 26 and 52 weeks by morphological and biomechanical techniques of analysis. Within the first 12 weeks these allografts were revascularized; in the first 26 weeks they had matured to resemble normal connective tissue. Graft stiffness was 29% of the control value and maximum force to failure was 43% of the control value. The results of this study indicated that freeze-dried bone-patellar tendon-bone allografts are biomechanically and biologically similar to patellar tendon autografts.

Dye, S. F. and M. H. Chew (1993). "Restoration of osseous homeostasis after anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(5):748-50, 1993 Sep-Oct 21(5): 748-50.

Eberhardt, C. K., A.H.; Hailer,N.; Jager,A. (2000). "Revision ACL reconstruction using autogenous patellar tendon graft." Knee.Surg.Sports Traumatol.Arthrosc. 8(5): 290-295.

This retrospective study examined revision anterior cruciate ligament reconstruction using a bone-tendon-bone autograft of the patellar ligament. We followed up 44 patients (mean age 27.9 years) for an average of 41.2 months. Clinical examination with the Lachmann and pivot shift tests showed clearly improved stability; KT-1000 arthrometer measurements had a mean difference of 3.5 mm in side-to- side comparison. The evaluated knee scores were significantly improved (P<0.01); the median Lysholm score was 85 and the median Tegner activity score 5.0 at follow-up. In the IKDC ranking system 75.0% of knees were rated normal or nearly normal (grades A and B). According to a modified Fairbank scale, progression of radiographic signs of osteoarthritis was noted in 36.4%. There was a significant difference (P<0.05) in progression of radiographic signs of osteoarthritis between patients with major (grades III, IV) versus minor (grades I, II) lesions of the articular cartilage surface and between knees with versus without extensive synovitis due to previous synthetic graft reconstruction (P<0.05). Revision anterior cruciate ligament reconstruction using an autogenous patellar tendon graft shows good results with improved knee function compared to the prerevision status and is in line with various operative techniques described in the literature. Progression of osteoarthritis must be expected in patients with major lesions of the articular cartilage surface and knees with long-term extensive synovitis due to previous anterior cruciate ligament reconstruction using synthetic grafts

Edkin, B. S. M., E.C.; Spindler,K.P.; Flanagan,J.F. (1999). "Analgesia with femoral nerve block for anterior cruciate ligament reconstruction." Clin.Orthop.(369): 289-295.

Anterior cruciate ligament reconstruction is performed routinely as an outpatient surgical procedure despite few studies of patient acceptance or postoperative patient analgesia. This study reports the first series of postoperative femoral nerve blocks as analgesia for outpatient anterior cruciate ligament reconstruction. The authors retrospectively reviewed 161 patients undergoing two incision arthroscopically assisted autograft middle 1/3 patellar tendon anterior cruciate ligament reconstruction on an out-patient basis at the authors' institution during a period of 30 months. Hospital and anesthesia records were reviewed, and 83% of patients were contacted retrospectively to survey their perceptions of the procedure and its outcome. Ninety-eight percent of the patients were discharged from the ambulatory surgery center, with 51% discharged the same day as the surgery and 47% discharged by 7:00 AM the next day. As the study progressed, the number of patients staying overnight was reduced by 50%. Ninety-eight percent of patients surveyed found femoral nerve block to be beneficial, and the same percentage thought the discharge time was appropriate. However, 69% of patients staying overnight cited reasons other than pain as factors in their stay. No significant complications were reported. Based on these results, the administration of a femoral nerve block is recommended for patients undergoing outpatient anterior cruciate ligament reconstruction because it is a highly effective form of analgesia with an excellent degree of patient satisfaction

Edwards, K. J., A. B. Goral, et al. (1991). "Functional restoration following anterior cruciate ligament reconstruction in active-duty military personnel." Mil Med 156(3): 118-21.

A retrospective review was conducted of 112 active-duty military patients receiving anterior cruciate ligament reconstruction between 1985 and 1987. Mean age of these patients was 26.4 years, average follow-up was 2.35 years, and the average interval from time of injury to reconstruction was 13.6 months. The three most commonly employed surgical techniques were the Andrews' iliotibial band tenodesis, mid-third patellar tendon autograft, and a combined Andrews' and mid-third patellar tendon reconstruction. Seventy-eight patients (69.6%) returned to full duty and the ultimate disposition was not affected by the reconstructive procedure performed, chronicity of injury, or sex. A statistically higher percentage of patients over 30 years old returned to full unrestricted military service than did patients under 30. Associated posterior cruciate injury and degenerative joint disease resulted in poorer results. Our results demonstrate that functional restoration, based on the occupational criteria of return to full unrestricted duty, is likely following anterior cruciate ligament reconstruction.

Egund, N., T. Friden, et al. (1993). "Radiographic assessment of sagittal knee instability in weight bearing. A study on anterior cruciate-deficient knees." Skeletal Radiology 22(3):177-81, 1993 22(3): 177-81.

In 16 patients with chronic, symptomatic anterior cruciate ligament-deficient knees, sagittal displacement was studied in the standing position using fluoroscopic control and a simple device to support the knee. In slight weight bearing all knees but one had normal femorotibial alignment in the lateral view. During full weight bearing sagittal displacements between 2 mm and 17 mm were recorded in 14 patients. The largest displacements were obtained at different angles of inclination of the leg and flexion of the knee joint and were independent of the point of support of the knee joint. The reproducibility of this new standing technique was within 2 mm. A high correlation with previous methods of radiographic measurements of sagittal laxity was found. By the use of the normal relationship between the tibial eminence and the femoral condyles it is possible to record and measure sagittal displacements on a single lateral radiograph of the standing knee joint.

Emerson, R. J. (1993). "Basketball knee injuries and the anterior cruciate ligament." Clinics in Sports Medicine 12(2):317-28, 1993 Apr 12(2): 317-28.

Basketball arguably may present the greatest risk for anterior cruciate ligament (ACL) injury because it is well known that ACL injuries may occur with external or internal rotation of the tibia with or without hyperextension. All of these mechanical phenomena occur repetitively in a running, jumping, and cutting sport such as basketball. This article discusses the diagnosis and mechanism of injury as well as treatment of ACL injury.

Engebretsen, L., E. Arendt, et al. (1993). "Osteochondral lesions and cruciate ligament injuries. MRI in 18 knees." Acta Orthopaedica Scandinavica 64(4):434-6, 1993 Aug 64(4): 434-6.

Magnetic resonance images were obtained prior to arthroscopy and surgery in 18 knees with acute anterior cruciate ligament injury. The incidence of osseous lesions was assessed and the findings were compared with those at arthroscopy. A total of 28 osseous lesions were detected by MRI in 15 knees, but none of these were detected by radiographs or arthroscopy.

Engebretsen, L., T. Grontvedt, et al. (1993). "[Current principles in the treatment of knee ligament injuries]." Tidsskrift for Den Norske Laegeforening 113(8):952-4, 1993 Mar 20 113(8): 952-4.

Knee ligament injuries are the leading cause of disability from injuries occurring during sports. The incidence of these injuries is increasing in Norway, owing to greater participation in recreational and competitive sports. In Norway, the main contributor to anterior cruciate ligament injuries is European team handball where women who compete at a high level sustain a large number of injuries. This paper describes modern principles of diagnosis and treatment of these injuries, based on personal research and a review of the literature.

Engebretsen, L. R., Pal; and Sundalsvoll, Svein (1989). "Primary suture of the anterior cruciate ligament. A 6-year follow-up of 74 cases." 60: 561-564.

Engstrom, B., J. Gornitzka, et al. (1993). "Knee function after anterior cruciate ligament ruptures treated conservatively." International Orthopaedics 17(4):208-13, 1993 17(4): 208-13.

Thirty-nine patients with ruptures of the anterior cruciate ligament (ACL) were treated conservatively and were subsequently examined at an average of 5.7 years after injury, the uninjured leg acting as a control. The Tegner activity score was significantly lower than the desired activity level. No patients were free of symptoms and only two could take part in sport which involved pivoting. The isokinetic knee extensor and flexor torques, as well as the one-leg-hop and instrumented knee joint laxity tests, were significantly impaired at follow-up. Functional impairment was not related to tests of knee joint laxity. Few patients were pleased with their subjective knee function after an ACL rupture despite thorough initial rehabilitation.

Engstrom, B., T. Wredmark, et al. (1993). "Patellar tendon or Leeds-Keio graft in the surgical treatment of anterior cruciate ligament ruptures. Intermediate results." Clinical Orthopaedics & Related Research (295):190-7, 1993 Oct(295): 190-7.

In a prospective randomized study, 60 patients with unilateral chronic anterior cruciate ligament (ACL) rupture were allocated to surgical reconstruction using an autogenous patellar tendon graft (PT) or a synthetic Leeds-Keio graft (LK). Fifty-five patients (26 PT, 29 LK), 32 men, 23 women, fulfilled the criteria to be further tested. The mean time from surgery to follow up was 28 months. Laxity was tested by pivot shift and an instrumented anterior laxity test. Subjective knee function was classified using the Lysholm score, Tegner activity score, and IKDC grading. Muscle performance was analyzed in 49 patients (23 PT, 26 LK. There was no difference between the two groups in anthropometry, activity levels (before trauma; present; desired activity), time from trauma to surgery, or time from surgery to follow-up evaluation. Neither the concentric and eccentric knee extensor peak torque ratio nor the knee extensor endurance and the one-leg hop test differed between the two groups. However, both the pivotshift and the anterior laxity were significantly greater for the LK group. On the other hand, significantly more patients in the PT group had an extensor lag. Although the results are only intermediate, the Leeds-Keio ligament does not fulfill the requirements for a satisfactory result in ACL reconstructive surgery with regard to knee-joint stability.

Erickson, A. R., K. Yasuda, et al. (1993). "An in vitro dynamic evaluation of prophylactic knee braces during lateral impact loading." American Journal of Sports Medicine 21(1):26-35, 1993 Jan-Feb 21(1): 26-35.

To determine the ability of prophylactic knee braces to reduce or limit medial collateral and anterior cruciate ligament elongation under dynamic loading conditions, we used cadaveric specimens that had a surrogate soft tissue material that matched the tissue compliance of in vivo contracted muscles. Eight cadaveric specimens were fitted with four prophylactic knee braces and instrumented with Hall Effect Strain Transducers on both the medial collateral and anterior cruciate ligament. Each specimen was mounted in a testing frame while a lateral impact was applied to the knee joint by a pendulum at levels below the injury threshold. Legs were tested at 0 degrees and 30 degrees of knee flexion, both with and without an intact anterior cruciate ligament. The maximum elongation for each ligament was calculated as a percentage of the initial measured length. The addition of a prophylactic knee brace significantly reduced the level of impact force at the point of impact, but this did not result in a significant reduction of anterior cruciate ligament elongation for any test. Although not significant, all braces tested were more effective at reducing medial collateral ligament elongation during a lateral impact with the knee flexion at 30 degrees than at 0 degrees.

Eriksson K, A. P., Hamberg P, Lofgren AC, Bredendberg M, Westman I, Wredmark T. (2001). "Prospective and randomized comparison of quadruple semitendinosus and patella tendon graft in anterior cruciate ligament reconstruction." J. Bone and Joint Surg Br.

Eriksson, K. L., H.; Wredmark,T.; Hamberg,P. (1999). "Semitendinosus tendon regeneration after harvesting for ACL reconstruction. A prospective MRI study." Knee.Surg.Sports Traumatol.Arthrosc. 7(4): 220-225.

Utilisation of the semitendinosus and gracilis tendons in reconstruction of the anterior cruciate ligament (ACL) has become more common during the last few years. In recent studies a regeneration potential in the harvested tendons has been observed. In this study, 11 consecutive patients who underwent ACL reconstruction with a quadruple semitendinosus graft were examined 6-12 months postoperatively by MRI. Another two patients were examined within 2 weeks after surgery. The median age of the patients was 24 years and there were 8 males and 3 females. The right knee was involved in six patients and the left knee in five. A low-field 0.2 Tesla Siemens open MRI was used for examinations and T1 and T2 weighted transaxial sequences over the thigh and the knee joint were performed. In some instances, additional sagittal sequences were used. ROI analysis of the pixel value of the signal and area determinations on transaxial sequences was performed for both the involved and the healthy side. In 8 of the 11 patients examined 6-12 months postoperatively, a regeneration of the semitendinosus tendon with normal anatomical topographies to the level of the tibial plateau was found. Three of these eight patients were analysed more distally and fusion of the semitendinosus and gracilis tendons was found approximately 30 mm below the joint line before they inserted as a "conjoined tendon" into the pes anserinus. At the mid- thigh level, the semitendinosus muscle had a smaller area and a higher signal than that on the normal side. However, this difference was smaller in the patients showing normal distal tendon regeneration. This study indicates that the semitendinosus tendon has a strong potential for regeneration and that the muscle atrophy seems to be less in the patients with a more normalised distal insertion of the tendon in the pes anserinus

Faber, K. J. D., J.R.; Amendola,A.; Thain,L.; Spouge,A.; Fowler,P.J. (1999). "Occult osteochondral lesions after anterior cruciate ligament rupture. Six-year magnetic resonance imaging follow-up study." Am.J.Sports Med. 27(4): 489-494.

Twenty-three patients with acute anterior cruciate ligament injuries, normal radiographs, and occult osteochondral lesions revealed by magnetic resonance imaging were reviewed 6 years after initial injury and anterior cruciate ligament hamstring autograft reconstruction. Each patient completed the Mohtadi Quality of Life outcome measure for anterior cruciate ligament deficiency, underwent clinical examination, and had a repeat magnetic resonance imaging scan. The index and follow- up magnetic resonance imaging scans were compared with respect to cartilage thinning and marrow signal. A significant number of patients had evidence of cartilage thinning adjacent to the site of the initial osteochondral lesion. Marrow signal changes persisted in 15 (65%) of the patients. Clinical comparison of patients with normal cartilage with those who had cartilage thinning revealed similar results on both KT-1000 arthrometry and on the Mohtadi outcome measure. This suggests that the initial injury resulted in irreversible changes in the knee. Injuries causing marrow signal changes may result in an alteration in the load-bearing properties of subchondral bone, which in turn allow for changes in the overlying cartilage. Further follow-up will determine the clinical significance of changes detected by magnetic resonance imaging

Feagin, J. A. W., R.P.; Lambert,K.L.; Mott,H.W.; Cunningham,R.R. (1997). "Anterior cruciate ligament reconstruction. Bone-patella tendon-bone versus semitendinosus anatomic reconstruction." Clin.Orthop.(341): 69-72.

In this article, the long term (2-10 years; mean, 4.8 years) followup results of two reconstructive procedures for the anterior cruciate ligament are compared. The bone-patella tendon-bone (with interference fit fixation) was performed on 69 knees, and the semitendinosus anatomic reconstruction was performed on 68 knees, in a population of 76 men and 52 women (age range, 15-60 years; average, 31 years). The patients in the two groups showed no difference in subjective results or activity level and no significant difference to manual testing. The semitendinosus procedure group had a slightly higher KT manual maximum failure rate than the patella tendon group (17% versus 11%). Arthrometric stability did not show deterioration, but patient satisfaction decreased in those patients who had meniscectomies. Both procedures showed satisfactory results during the long term followup. However, if the secondary restraints are compromised, the stiffer bone- patella tendon-bone construct is preferred for reconstruction of the chronic anterior cruciate ligament deficient knee

Feder, S. M., D. L. Butler, et al. (1993). "A technique for the evaluation of the contributions of knee structures to knee mechanics in the knee that has a reconstructed anterior cruciate ligament." Journal of Orthopaedic Research 11(3):448-51, 1993 May 11(3): 448-51.

A technique to quantify the restraining action of specific knee structures during anterior/posterior (A/P) tibial displacement tests in the goat knee that has a reconstructed anterior cruciate ligament (ACL) is described. Joint specimens were mounted in an instrumented test stand to measure both the forces on, and resulting translations of, the tibia in the A/P direction. The intact grafted knee was tested first, after which structures were sequentially cut or removed, or both, and the test was repeated. The ACL graft remained intact in the joint during this process; therefore, subsequent axial failure testing was possible. Analysis of the resulting force-displacement curves allowed the percentage contribution and anterior joint stiffness to be determined for each structure at a fixed anterior displacement in 12 goat knees 6 months after ACL allografting. The allografts were found to provide about 56% of the total restraining force, more than any other structure examined. Studies of this kind will be important in the documentation of the changing role of an autograft or allograft in a reconstructed knee over time.

Fehnel, D. J. J., R. (2000). "Anterior cruciate injuries in the skeletally immature athlete: a review of treatment outcomes." Sports Med. 29(1): 51-63.

The documentation of anterior cruciate ligament (ACL) injuries in the skeletally immature athlete has significantly increased over the past decade, primarily due to increased awareness of these injuries within this younger athletic population. The evaluation of these injuries are similar to that in the adult population. Diagnostic studies such as plain radiographs, as well as magnetic resonance imaging, can delineate the location of the ACL failure. Physical presentation most commonly includes an acute haemarthrosis and ligamentous insufficiency. Several studies have demonstrated that the diagnostic reliability of the physical examination is poor in children, especially in patients less than 12 years old. The site of ACL failure in this adolescent population is most commonly at the tibial insertion. We recommend arthroscopic or arthroscopically assisted open reduction and internal fixation with nonabsorbable sutures for all displaced tibial eminence fractures. Mid-substance ACL failures also occur in this athletic age group. The association of meniscal injuries with these ACL failures appears to be greater than 50%. Historically, poor subjective and objective outcomes have been associated with primary and extra- articular repairs. Intra-articular reconstruction is the gold standard. The issue of placing the graft across open physeal plates is under investigation. Recent animal studies as well as human clinical series have demonstrated safety in placing soft tissue, i.e. hamstring grafts, across open growth plates without subsequent angular or leg length discrepancy. Historically, non-operatively treated ACL failures are associated with poor functional outcomes as well as a high incidence of meniscal re-injury. If the treatment of an adolescent athlete with an ACL failure is to be rehabilitation until skeletal maturity, close follow-up is essential to detect functional instability, which may prompt earlier surgical reconstruction

Feiler, H. E. and C. L. Craig (1993). "Orthopedic aspects of musculoskeletal disease in children." Current Opinion in Rheumatology 5(5):658-62, 1993 Sep 5(5): 658-62.

New information affecting the diagnosis and treatment of a wide variety of musculoskeletal conditions in children was published within the past year. A new etiology for acquired torticollis as well as a test to distinguish ocular and muscular torticollis were described. Familial predisposition for successful nonoperative treatment of interventional disk herniation was reported. Bone scintigraphy was shown to be helpful in defining the cause of occult gait disturbances, and accurate mapping of premature growth plate closure may soon be possible with magnetic resonance scans.

Ferrari JD, F. D. (1991). "The semitendinosus: Anatomic considerations in tendon harvesting." Orthop Rev 20: 1085-1088.

Fetto, J. F., and Marshall, J.L. (1980). "The natural history and diagnosis of anterior cruciate ligament insufficiency." Clin. Orthop 147: 29-38.

Fink, C., C. Hoser, et al. (1993). "[Sports capacity after rupture of the anterior cruciate ligament--surgical versus non-surgical therapy]." Aktuelle Traumatologie 23(8):371-5, 1993 Dec 23(8): 371-5.

Using a new rating system (Innsbruck Knee-Sports Rating Scale) 75 patients 5 to 6 years after ACL-injury have been compared to their sports activity (47 patients with ACL reconstruction and 28 conservative treated patients). Under the viewpoint of knee load and especially the demand on stability sports activities have been divided into 3 categories: High Risk, Low Risk and Non Risk Pivoting Sports. Operative therapy shows an advantage in High Risk Pivoting sports (e.g. soccer, basketball) and in Low Risk Pivoting (e.g. running, hiking) sports, expressed by fewer knee related symptoms and higher participation levels. In the Non Risk Pivoting category (e.g. swimming, cycling) good results could also be achieved by conservative therapy. The careful evaluation of each patient's sports activities is therefore an important factor in the decision for the right therapy on one hand, and for comparing the results of different therapy programs or patient collectives on the other.

Fink, C. B., K.P.; Hackl,W.; Hoser,C.; Freund,M.C.; Rieger,M. (2000). "Bioabsorbable polyglyconate interference screw fixation in anterior cruciate ligament reconstruction: a prospective computed tomography- controlled study." Arthroscopy 16(5): 491-498.

PURPOSE: It was the purpose of the study to evaluate a new polyglyconate bioabsorbable interference screw for graft fixation in anterior cruciate ligament (ACL) reconstruction. TYPE OF STUDY: Prospective randomized. MATERIALS AND METHODS: Forty patients who underwent endoscopic ACL reconstruction were included in the study and randomized intraoperatively. Group A consisted of 20 patients (6 women, 14 men; mean age, 29.6 years) who had femoral bone block fixation with a bioabsorbable interference screw and tibial fixation with a titanium interference screw. Group B included 20 patients (5 women, 15 men; mean age 29.6 years) who had fixation of both femoral and tibial bone blocks with titanium interference screws. There was no significant difference between the groups with regard to age, gender, height, weight, time from injury to surgery, activity level, and concomitant injuries. RESULTS: Clinical results (using IKDC, Lysholm, Tegner scores) of the 2 groups as well as instrumented laxity measurements (KT-1000) did not show significant (P >.05) differences at any stage of follow-up. No complications with respect to graft fixation could be found. Computed tomography scans, performed within the first postoperative week, at 6 weeks, and at 3, 6, 12, and 24 months postoperatively revealed a uniform picture for all patients within the groups, showing completed screw degradation at 12 months in group A. CONCLUSION: Polyglyconate interference screw fixation for patellar tendon grafts has not been found to be associated with increased clinical complications or significant osteolysis. It provided equivalent fixation and clinical results compared with titanium screws. However, replacement of the screw with bone did not take place for up to 3 years postoperatively

Fischer-Rasmussen, T. J., P.E. (2000). "Proprioceptive sensitivity and performance in anterior cruciate ligament-deficient knee joints." Scand.J.Med.Sci.Sports 10(2): 85-89.

We studied the performance and proprioception of the knee joint in a group of non-reconstructed anterior cruciate ligament (ACL)-deficient (n=20) patients and compared them with a group of ACL-reconstructed patients (n=18) and a group of healthy controls (n=20). Each patient was scored according to Lysholm and Tegner and was then asked to subjectively evaluate the performance of the injured knee and the degree of retropatellar discomfort. The knee joint laxity was measured. The performance was assessed based on the performance in a triple jump test and a one-leg one-step leap test. The proprioception in the knee was measured as the threshold when passive movement was detected and as the ability to reproduce a flexion angle from a start position of 60 degrees of flexion or from full extension of the knee. All tests were performed on both legs. The scoring systems and the subjective evaluation showed significant differences between the reconstructed and the non-reconstructed patients. No significant difference in knee joint laxity was found between the two groups. In the triple jump test and the one-step leap test, both groups performed significantly worse on the leg with the injured knee joint than on the non-injured leg. The proprioceptive tests showed decreased ability to recognize and reproduce a prior angle from a start position of 60 degrees. The threshold to detection of passive movement with the injured knee was significantly increased in both groups of patients. No difference was found between the dominant and non-dominant knee in the control group. When reproduction of the same angles started from full extension, the groups did not differ. These data show that decreased performance and changes in the proprioception of the knee joint accompany ACL rupture

Fisher, S. E. and K. D. Shelbourne (1993). "Arthroscopic treatment of symptomatic extension block complicating anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(4):558-64, 1993 Jul-Aug 21(4): 558-64.

Arthrofibrosis resulting in loss of knee extension compromises the results of anterior cruciate ligament reconstructions. We designed a study to clarify the symptoms and to evaluate the results of arthroscopic treatment of this complication. Forty-two patients in a series of 959 consecutive open anterior cruciate ligament reconstructions required further surgical treatment for relief of symptoms related to loss of extension. Arthroscopic examination of these knees confirmed the presence of an extension block caused by hypertrophy of the ligament or abundant tissue formation in the anterior tibiofemoral joint an average of 9 months after anterior cruciate ligament reconstruction. The offending tissues were excised arthroscopically and the patients were followed with an aggressive rehabilitation program. Thirty-five patients were available for followup an average of 28 months after excision of the tissue. Subjective functional status and symptomatic status were scored numerically using identical, patient-completed questionnaires before and after the excision procedure. Range of motion, Cybex, and KT-1000 arthrometer results were also recorded. The results were statistically compared with results from a control group demographically matched and selected at random from the 959 patients. Before excision of the offending tissue, the knee scores of the study group differed significantly from those of the control group. However, after the excision procedure, the knee scores of the 2 groups were nearly identical. Marked improvements in function and symptoms (most notably, activity-related anterior knee pain, crepitus at terminal extension, and knee stiffness) were noted in all patients in the study group after removal of the extension block and resumption of an accelerated rehabilitation program.(ABSTRACT TRUNCATED AT 250 WORDS)

Fitzgerald, S. W., E. M. Remer, et al. (1993). "MR evaluation of the anterior cruciate ligament: value of supplementing sagittal images with coronal and axial images." AJR 160(6):1233-7, 1993 Jun 160(6): 1233-7.

OBJECTIVE. Most studies evaluating the anterior cruciate ligament have focused on sagittal MR images for the diagnosis of injury. Limitations of sagittal images have been reported, however, including nonvisualization and incomplete visualization of the ligament. This study was undertaken to assess the value of adding coronal and axial MR images to sagittal images in the evaluation of the anterior cruciate ligament. MATERIALS AND METHODS. We reviewed oblique sagittal T1-weighted, coronal T2-weighted, and axial T2-weighted images to determine the status of the anterior cruciate ligament in 325 patients. All patients had arthroscopy. Sagittal images were initially interpreted alone and then in combination with coronal and axial images. RESULTS. Sagittal T1-weighted images alone had a 94% sensitivity and an 84% specificity for determining the status of the anterior cruciate ligament. A multiplanar evaluation of the anterior cruciate ligament resulted in a change in MR interpretation in 21 patients (6%), which led to an improved sensitivity of 98% and a specificity of 93%. Diagnostic confidence was improved in an additional 14 patients (4%). CONCLUSION. Our results show that the efficacy of MR imaging for the detection of anterior cruciate ligament tears is greater when axial and coronal images are used in combination with sagittal images than when sagittal images are used alone.

Fleming, B., B. D. Beynnon, et al. (1993). "Isometric versus tension measurements. A comparison for the reconstruction of the anterior cruciate ligament." American Journal of Sports Medicine 21(1):82-8, 1993 Jan-Feb 21(1): 82-8.

This study was designed to compare the displacement patterns of an isometer, used to determine graft placement during reconstruction, with the actual tensions on an anterior cruciate ligament substitute. In cadaveric specimens, a Kevlar anterior cruciate ligament substitute was implanted in three separate femoral sites, each of which was subsequently fixed to two different tibial sites. The initial tension of the Kevlar substitute was set to 22 or 33 N at 20 degrees of knee flexion. The displacement patterns for each position were recorded during passive flexion-extension using the isometer. Using a custom-designed tensiometer, the tensile forces on the substitute after rigid fixation at the tibia and femur were measured. During passive flexion-extension, the maximum change in tension of the anterior cruciate ligament substitute, measured by the tensiometer, was correlated with the maximum change in displacement between attachment sites, measured by the isometer. The coefficient of determination was equal to 0.15, indicating that the isometer may not accurately predict the tensions developed in the substitute.

Fleming, B. C., B. D. Beynnon, et al. (1993). "An in vivo comparison of anterior tibial translation and strain in the anteromedial band of the anterior cruciate ligament." Journal of Biomechanics 26(1):51-8, 1993 Jan 26(1): 51-8.

The objective of this in vivo study was to determine if strain in the anteromedial band (AMB) of the anterior cruciate ligament (ACL) may be predicted by an external measurement of anterior tibial-femoral translation. A Hall effect strain transducer was implanted on the AMB of five human subjects with normal intact ACLs. AMB strain was then measured during anterior shear loading of the tibia relative to the femur, with the knee flexed to 30 and 90 degrees, simulating the loads applied in the Lachman and anterior drawer tests, respectively. The Knee Signature System, a commercially available arthrometer, was used to simultaneously measure anterior tibial translation relative to the femur. The resulting AMB strains and translations during anterior shear loading of the tibia with respect to the femur at 30 and 90 degrees were compared using a regression analysis to determine if AMB strain could be predicted from a measure of anterior tibiofemoral translation at either flexion angle. AMB strain at 150 N anterior shear load at 30 degrees flexion (3.0%) was significantly greater than that at 150 N anterior shear load at 90 degrees flexion (0.9%). During anterior shear loading at 30 degrees flexion, AMB strain correlated with anterior tibial translation (r2 = 0.59). However, there was no significant correlation between AMB strain and anterior tibial translation for anterior shear loading at 90 degrees flexion (r2 = 0.002). Therefore, AMB strain was not accurately predicted from an external measurement of tibial displacement at 90 degrees in this experiment.

Fossier, E., P. Christel, et al. (1993). "[Principles and value of isokinetic evaluation in ruptures of the anterior cruciate ligament]." Revue de Chirurgie Orthopedique et Reparatrice de l Appareil Moteur 79(8):615-24, 1993 79(8): 615-24.

Isokinetic muscular evaluation allows to appreciate the knee joint functional patterns in conditions close to sports activities. Analyzing bilateral symmetry and agonist/antagonist ratios of the lower extremity, this method is a useful index for the objective evaluation of ligament-deficient knees. 106 patients with a chronic ACL deficient knee sustained a presurgery isokinetic evaluation. 94 patients had a post-operative evaluation and 13 a pre and post-surgery evaluation. All patients were simultaneously evaluated by clinical examination and measures of instrumental knee laxity (KT 1000). Results showed that isokinetic performance was not correlated to the objective laxity as measured with the KT 1000 but was correlated to 1) the type of laxity (i.e. associated postero-lateral laxity), 2) the functional level of activity, and 3) the time of disability. Best functional results were obtained in patients whose injured knee hamstring/quadriceps (H/Q) ratio was close to the uninjured knee H/Q ratio. The mean quadriceps deficit was over 15 per cent for 75 per cent of the patients one year after surgery, and for 50 per cent of the patients after two years. The quadriceps deficit was not parallel to the length of the autograft taken from the extensor mechanism. Isokinetic evaluation is a guideline for rehabilitation allowing specific strengthening of the weaker muscular groups.

Fowler, P. J. (1993). "Semitendinosus tendon anterior cruciate ligament reconstruction with LAD augmentation." Orthopedics 16(4):449-53, 1993 Apr 16(4): 449-53.

Freiwald, J., A. Jager, et al. (1993). "[EMG-assisted functional analysis within the scope of follow-up of arthroscopically managed injuries of the anterior cruciate ligament]." Sportverletzung Sportschaden 7(3):122-8, 1993 Sep 7(3): 122-8.

The rehabilitative course of anterior cruciate ligament ruptures was followed up at 16.6 months postoperatively be measuring clinical parameters, isokinetic power values and by means of electromyographic leads. The injured side has significantly looser ligaments than the non-injured one (p = < 0.01). The circumferential measures differ from each other, pointing to a reduction in muscular circumference at the measuring points 10 cm and 20 cm above the medial joint cavity (p = < 0.05). The isokinetic measurements had selective deficits of the knee-joint extensor at 60 degrees W/S (p = < 0.01) and at 180 degrees W/S (p = < 0.05), whereas the flexors did not show any difference, irrespective of the side. EMG measurements after 16.6 months via superficial leads applied to the synergistic compound of the extensors of the knee joint did not confirm any weakness of the m. vastus medialis although such weakness has often been claimed to exist. Laterally changed electromechanical coupling was seen, as well as a changed muscular fatigue pattern. The changed synergistic functional capacity of the m. quadriceps femoris could be of pathogenetic importance for further, e.g. retropatellar, subsequent damage. The author discusses the question whether laterally equal muscular conditions based on traumatically changed conditions in the joints should be treated at all.

Fremerey, R. W. L., P.; Zeichen,J.; Skutek,M.; Bosch,U.; Tscherne,H. (2000). "Proprioception after rehabilitation and reconstruction in knees with deficiency of the anterior cruciate ligament: a prospective, longitudinal study." J.Bone Joint Surg.Br. 82(6): 801-806.

We assessed proprioception in the knee using the angle reproduction test in 20 healthy volunteers, ten patients with acute anterior instability and 20 patients with chronic anterior instability after reconstruction of the anterior cruciate ligament (ACL). In addition, the Lysholm-knee score, ligament laxity and patient satisfaction were determined. Acute trauma causes extensive damage to proprioception which is not restored by rehabilitation alone. Three months after operation, there remained a slight decrease in proprioception compared with the preoperative recordings, but six months after reconstruction, restoration of proprioception was seen near full extension and full flexion. In the mid-range position, proprioception was not restored. At follow-up, 3.7 +/- 0.3 years after reconstruction, there was further improvement of proprioception in the mid-range position. There was no difference between open and arthroscopic techniques. The highest correlation was found between proprioception and patient satisfaction. After reconstruction of the ACL reduced proprioception may explain the poor functional outcome in some patients, despite restoration of mechanical stability

Friden, T., N. Egund, et al. (1993). "Comparison of symptomatic versus nonsymptomatic patients with chronic anterior cruciate ligament insufficiency. Radiographic sagittal displacement during weightbearing [see comments]." American Journal of Sports Medicine 21(3):389-93, 1993 May-Jun 21(3): 389-93.

The sagittal anterior displacement of the tibia, induced by weightbearing, in chronic anterior cruciate ligament-insufficient knees was measured radiographically in 2 groups of patients. All patients in both groups had an increased laxity when assessed with the Lachman and flexion-rotation-drawer test. Sixteen patients were functionally improved and were relatively asymptomatic after a neuromuscular rehabilitation program, while the second group consisted of another 16 patients with persistent functional instability, despite the same rehabilitation program, who eventually had ligament reconstruction. The mean radiographic anterior displacement during weightbearing in the nonsymptomatic group was 4.3 mm, and 8 patients had a displacement < or = 2 mm. In the symptomatic group, the corresponding value was 8.1 mm (P < 0.05), and 3 patients had a displacement < or = 2 mm. No correlations to meniscal injuries, age, or time from injury were found between the patients having a displacement >2 mm and those with < or = 2 mm. The findings should be explained by differences in neuromuscular control of the increased laxity in the injured knee.

Friden, T., A. Jonsson, et al. (1993). "Effect of femoral condyle configuration on disability after an anterior cruciate ligament rupture. 100 patients followed for 5 years." Acta Orthopaedica Scandinavica 64(5):571-4, 1993 Oct 64(5): 571-4.

We measured the configuration of the femoral condyles on lateral radiographs in 100 consecutive, prospectively-studied patients with a complete rupture of the anterior cruciate ligament, with or without associated lesions of the menisci and collateral ligaments. The patients had mainly low-to-moderate activity demands, and in all the patients the cruciate tear was primarily treated non-operatively. A quotient was calculated from the measurements of sagittal depth and axial height in order to describe the geometry of the femoral condyles. Measurements were reproducible with an intra- and interobserver coefficient of correlation of 0.89-0.98. At follow-up, after 5 (3-6) years, 16 patients had developed disability leading to reconstructive surgery. The remaining 84 patients did not have any major functional limitations, but some had reduced their activity level. Individual variations in the articular geometry were found with a more spherical shape of the femoral condyles in the patients where non-operative treatment had failed. Our findings indicate that articular geometry is of importance for function after an anterior ligament lesion.

Fried, B. B., J.A.; Weiker, Garron; and Andrish,J.T. (1985). "Anterior cruciate reconstruction using the Jones-Ellison procedure." J. Bone and Joint Surg 67A: 1029-1033.

Friederich, N. F. (1993). "[Knee joint function and the cruciate ligaments. Biomechanical principles for reconstruction and rehabilitation]." Orthopade 22(6):334-42, 1993 Nov 22(6): 334-42.

Trauma to the knee joint with disruption of one or both cruciate ligaments will start a biological response: inflammatory reactions, neurophysiological changes due to disruption of afferent nerve endings, and biomechanical changes which will ultimately lead to instability (functional and mechanical) as well as to early degenerative changes. Treatment, whether operative or non-operative, has to be based on a sound knowledge of biological and biomechanical principles. Cruciate ligament graft positioning, fixation, pre-tensioning, operative technique for reconstruction, and rehabilitation will all have influence on each other. All these factors therefore have to be balanced to achieve good mid- to long-term results.

Friederich, N. F. and R. M. Biedert (1993). "Role of extra-articular procedure." Clinics in Sports Medicine 12(4):815-24, 1993 Oct 12(4): 815-24.

This article describes the 1993 role of extra-articular procedures in the treatment of anterior cruciate-deficient knees. Twenty years ago, most operative effort was concentrated on elimination of the pivot shift phenomenon. Newer operative reconstructions made most of the advantages attributed to extraarticular procedures (shorter operating room time, less soft tissue injury, shorter postoperative rehabilitation) no longer true.

Friederich, N. F. and W. R. O'Brien (1993). "[Gonarthrosis after injury of the anterior cruciate ligament: a multicenter, long-term study]." Zeitschrift fur Unfallchirurgie und Versicherungsmedizin 86(2):81-9, 1993 86(2): 81-9.

In order to estimate incidence, severity and associated factors in the development of the degenerative arthritis of the knee following a cruciate ligament injury, a multicenter, longterm follow-up study was undertaken. The time interval between injury and follow-up exam was a minimum of 15 years (range 15-52 years). Extensive physical examination and radiographic analyses from four "Knee Centers" (Hospital for Special Surgery, New York; Orthopadische Klinik, Bruderholz; Orthopaedic and Arthritic Hospital, Toronto; Orthopaedic Department Wichita, Kansas) on 328 patients revealed that the best correlation to the degree of osteoarthritis could be found to the time of meniscectomy. All other operations (suture of cruciate ligament, intraarticular or extraarticular reconstruction) showed much less correlation to the severity of the degenerative arthritis found at the follow-up exam. In conclusion: Preservation of as much meniscus tissue as possible at the time of injury seems to be the best warranty for slowing down degenerative arthritis after cruciate ligament injury.

Frobose, I., A. Verdonck, et al. (1993). "[Effects of various load intensities in the framework of postoperative stationary endurance training on performance deficit of the quadriceps muscle of the thigh]." Zeitschrift fur Orthopadie und Ihre Grenzgebiete 131(2):164-7, 1993 Mar-Apr 131(2): 164-7.

The development of a muscular hypertrophy represents one of the most important purpose in a postoperative training. With the example of an isokinetic training the present study was meant to record if the choice of the load intensity is of importance in this connection. 36 patients with an anterior crucial ligament rupture, who were divided into three groups, underwent a stationary training for a period of four weeks. Thereby it could be proved that high intensity mainly influences the intramuscular coordination while the load intensity is far less relevant to the influence on a muscular cross-section. In this connection rather the total extent of practice time makes up the specific stimulus for a hypertrophy.

Fromm, B., B. Schafer, et al. (1993). "[Nerve supply to the anterior cruciate ligament and cruciate ligament allograft]." Sportverletzung Sportschaden 7(3):101-8, 1993 Sep 7(3): 101-8.

To confirm the innervation of the anterior cruciate ligament and anterior cruciate allograft the anterior cruciate ligament was grafted allogenic and deep-freeze preserved, in 12 white New Zealand rabbits. After removal from the donor animal the ligaments and pertaining bone tissue were placed in deep freeze at -90 degrees C for 72 hours. The grafts were fixed in the receiving animal by means of transosseous wire sutures. The non-operated contralateral anterior cruciate ligament served as control. Follow-up examinations were performed after 3, 6, 12, 24, 36 and 52 weeks. Immunohistochemical methods were employed to examine newly ingrown nerve fibres. Monoclonal antibodies against neurofilaments (to identify rapid conducting mechanoreceptive afferent A fibres) were used, as well as substance P (to identify slow conducting nociceptive afferent C fibres) and thyrosine hydroxylase (for the identification of vasomotor efferent C fibres). In the control ligaments we found an abundant amount of nerve fibres of all three kinds, each of these having its own typical distribution pattern. The fibres were mainly subsynovial, in some cases however also localised in the interfascicular connective tissue septae. At specialised end organs we could only identify Ruffini's corpuscles. No nerve fibres were found in the cruciate ligament allografts after 3 weeks, but an initial few fibres showed up after 6 weeks. After 12 weeks individual nerve fibres of all 3 kinds became noticeable, and after 24 weeks all three kinds of fibres were abundantly represented. No specialised end organs were found in the allografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Fruensgaard, S., and Johnannsen, H.V. (1989). "Incomplete ruptures of the anterior cruciate ligament." J. Bone and Joint Surg 71B: 526-530.

Fujikawa, K. K., T.; Sasazaki,Y.; Matsumoto,H.; Seedhom,B.B. (2000). "Anterior cruciate ligament reconstruction with the Leeds-Keio artificial ligament." J.Long.Term.Eff.Med.Implants. 10(4): 225-238.

The Leeds-Keio (L-K) artificial ligament, developed for knee ligament reconstruction, is made of polyester with a maximum tensile strength of 2200 N. This implant works not only as a ligament but also as a scaffold onto which natural tissue grows from synovium. In an animal experiment, each strand of the L-K ligament was covered with new tissue by 2-3 weeks after anterior cruciate ligament reconstruction. Eight weeks postoperatively, abundant fibrous tissue with extensive vascularity covered the implant, which was still histologically immature. After 16 weeks, vascularization and tissue induction began to subside, and histologic analysis showed dense fibers running longitudinally and parallel. By 36 weeks, the new ligament looked like a natural anterior cruciate ligament, although histologically more cells could be seen than in the natural ligament. This maturation was observed only when the substitute was implanted under good tension. Clinically, the surgical procedure has been improved over the past 10 years, to the current practice in which the tape-in-tube double L-K ligament employs a small piece of autogenous tissue to promote early tissue induction and maturation. Using this practice (n = 135), more than 85% of the patients were satisfied subjectively, objectively, and arthroscopically at the 5-year postoperative FU period. Few patients had joint effusion postoperatively. Sacrifice of autogenous tissue is minimal. The patient can return to activities of daily living within 2 weeks, and more than 50% of them to sports within 10 weeks, and the new ligament is expected to keep its function for a long period as ingrowth completes the structure biologically

Fukubayashi, T. I., K. "Follow-up study of Gore-Tex artificial ligament--special emphasis on tunnel osteolysis." J.Long.Term.Eff.Med.Implants. 10(4): 267-277.

The Gore-Tex anterior cruciate ligament has been implanted in 123 patients at our institutions between 1984 and 1993. The Gore-Tex ligaments were totally ruptured in 26 cases. In the remaining 97 cases, 80 were followed up 5-11 years after operation. Graft loosening occurred in half of the cases, and osteoarthritic change was developed in 62% of the cases. Moreover, tibial and tunnel osteolysis was observed in most of the cases. Judging from these follow-up results, the Gore-Tex ligament should not be used for anterior cruciate ligament reconstruction

Gerber, C., and Matter, Peter (1983). "Biomechanical analysis of the knee after rupture of the anterior cruciate ligament and its primary repair. An instant-centre analysis of function." J.Bone and Joint surg 65B: 391-399.

Gertel, T. H., W. D. Lew, et al. (1993). "Effect of anterior cruciate ligament graft tensioning direction, magnitude, and flexion angle on knee biomechanics." American Journal of Sports Medicine 21(4):572-81, 1993 Jul-Aug 21(4): 572-81.

The objective of this study was to determine the biomechanical effect of graft tensioning during reconstruction of the anterior cruciate ligament. We evaluated the magnitude of the tensioning force (22 or 67 N), the flexion angle at which the tension was applied (extension or 30 degrees of flexion), and the direction of application of the tensioning force (proximal, distal, or distal with a posterior force simultaneously applied to the tibia) on 10 fresh cadaveric knees. The anterior cruciate ligament was reconstructed using a bone-patellar tendon-bone graft. The graft was then temporarily fixed during the application of each of 12 combinations of tensioning variables listed above. After each fixation, graft force and joint motion were measured during anterior tibial loads. Tensioning direction and the flexion angle significantly affected graft force and joint motion, while the magnitude of the graft tensioning did not. Graft forces were greater when the tensioning was applied at 30 degrees of flexion. Compared with distal tensioning with and without posterior tibial force, graft forces with proximal tensioning were greater in extension and lower in flexion. The position of the tibia relative to the femur was posterior and externally rotated, compared with normal, for all combinations of tensioning variables in both unloaded and anterior load states.

Gillquist, J. (1993). "Repair and reconstruction of the ACL: is it good enough?" Arthroscopy 9(1):68-71, 1993 9(1): 68-71.

Gillquist, J. (1993). "[Cruciate ligament prostheses. Techniques, results and perspectives]." Orthopade 22(6):381-5, 1993 Nov 22(6): 381-5.

Artificial ligaments have been used as augmentation devices, scaffolds, ingrowth ligaments and even prostheses. The augmentation devices rely entirely on the autologous tissue for their function, whereas each of the other types functions more or less as a prosthesis. These devices can function only for a limited time and they are very sensitive to the implantation technique. Problems involve debris formation, synovitis and finally ligament rupture. There is also a loss of stability in the treated knee over the first 2-3 postoperative years. The clinical results obtained in various studies with the prosthetic devices are not satisfactory. The problem of reconstruction of a knee with ligamentous instability is far greater than that involved in replacing the ligament only.

Gillquist, J. and L. Good (1993). "Load and length changes in an artificial ligament substitute. 10 cases of anterior cruciate ligament reconstruction." Acta Orthopaedica Scandinavica 64(5):575-9, 1993 Oct 64(5): 575-9.

In 10 patients who had reconstruction of the anterior cruciate ligament, the load and length changes in an artificial ligament substitute were measured during passive knee motion. Using a special drill guide, the ligament was placed within +/- 2 mm of the normal anatomic center on the femur. With the femoral end fixed with a bicortical screw the ligament was preloaded to 40 N at the flexion angle with the shortest intraarticular ligament length, usually 45 degrees. The change in load was then registered from 90 degrees of flexion to full extension. In 2/10 cases loads of > 200 N were registered in full extension, but the mean load was 160 N. There was a higher loss of load during the first extension/flexion cycle than during the 4th cycle. The load change correlated to the length change, but the degree of length change could not predict the maximum load level. There was a large variation in load levels between different knees, even with similar ligament placements, but the least change in load and length was obtained by an anatomic placement. Isometer readings did not predict the load level in the ligament substitute, but could indicate the angle of flexion with minimum load. Therefore, the isometer can be used to control the placement of the attachment points for the substitute. After fixation, fiber settling and stretching the ligament, as well as adaptation of the tissues, will tend to reduce the load levels.

Gillquist, J. and M. Odensten (1993). "Reconstruction of old anterior cruciate ligament tears with a Dacron prosthesis. A prospective study." American Journal of Sports Medicine 21(3):358-66, 1993 May-Jun 21(3): 358-66.

Seventy patients with chronic anterior instability underwent anterior cruciate ligament reconstruction with a Dacron prosthesis pretensioned to 60 N. Of these patients, 49% (34%) had combined medial instability, 32% (22) had failed previous anterior cruciate ligament surgery, and 37% (26) had previous meniscectomy. At reconstruction, 12 patients had their medial instability treated; 22 did not. Follow-up intervals were 3, 6, and 12 months and then each year to 5 years. The 5-year followup included 69 patients; the other 1 had the ligament removed because of a synovial fistula at 8 months. Results were 23% prosthesis ruptures, 3% poor, 17% fair, 16% good, and 39% excellent. The 2-year results showed the same distribution, but a lower rupture rate, which was affected by placement of the tibial tunnel within the anterior one-third of the tibia (9 times increase) and coexisting nonrepaired medial instability (5 times increase). Those patients with perfect placement of the ligament who also had good medial stability and no previous ligament surgery had no rupture at 5 years. The stability that was gained at surgery was gradually lost (-11.2% per year). At 5 years, the uninjured knee also had lost 41% of the preoperative stability; the mean laxity difference was within +/- 2 mm. The mean improvement in subjective knee function (Lysholm score 74.5 to 91.9) was maintained during the followup. The mean preoperative activity level improved significantly, but did not reach the preinjury level. These results show that the Dacron prosthesis will not give acceptable results in salvage cases where other instabilities are left untreated.

Giove, T. P. M., S.J.,III; Kent,B.E.; Sanford, T.L.; and Garrick, J.G. (1983). "Non-operative treatment of the torn anterior cruciate ligament." J. Bone and Joint Surg 65A: 184-192.

Giurea, M. Z., P.; Amis,A.A.; Aichroth,P. (1999). "Comparative pull-out and cyclic-loading strength tests of anchorage of hamstring tendon grafts in anterior cruciate ligament reconstruction." Am.J.Sports Med. 27(5): 621-625.

This study examined four devices for anchorage of hamstring tendons used as anterior cruciate ligament grafts: a stirrup, a clawed washer and screw, and "soft" and round-headed interference screws. Ultimate strength tests were performed using bovine tendons and bones. The stirrup was significantly stronger than the other anchorage devices, failing at 898 N. The clawed washer failed at 502 N, the soft screw at 691 N, and the round-headed screw at 445 N. Cyclic loading to 150 N (to simulate walking) caused elongation of 2.1 mm with the stirrup by 1100 cycles, and 6.7 mm with the clawed washer by 300 cycles. Different hole and soft screw diameters and placements (inside-out versus outside-in) allowed 1-to 3-mm slippage (no significant differences) by 1100 cycles. The round-headed screw allowed 6.8-mm slippage by 1100 cycles, and a sharp edge below the screw head caused tendon damage. Cyclic loads to 450 N (to simulate jogging) were then imposed until failure, and all specimens failed rapidly; only stirrup fixation kept all specimens intact after 300 load cycles. We concluded that anterior cruciate ligament reconstructions using hamstring tendons will slacken if rehabilitation is too aggressive, so forces on the reconstructed ligament should be minimized until tendon-to-bone healing occurs

Glasgow, S. G., J. P. Gabriel, et al. (1993). "The effect of early versus late return to vigorous activities on the outcome of anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(2):243-8, 1993 Mar-Apr 21(2): 243-8.

The effect of early (mean, 5 months) versus late (mean, 9 months) return to vigorous cutting activity on the long-term outcome of anterior cruciate ligament reconstruction was evaluated retrospectively. Sixty-four reconstructions, using a distally attached medial one-third patellar tendon, were reviewed on an average of 46 months postoperatively. After surgery, the timing of return to vigorous activity was based on biologic fixation of the graft, a negative Lachman test, absence of effusion, and the patient's desire to return to previous activity. The 64 patients were retrospectively separated into two groups. The early group consisted of 31 patients who returned to activity 2 to 6 months after reconstruction, and the late group consisted of 33 patients who returned to activity 7 to 14 months after reconstruction. By clinical examination, KT-1000 arthrometer measurements, subjective evaluation, and Cybex testing, there were no differences between the early and late return groups except for reestablishment of final range of motion. At an average followup of 46 months, this study indicates that an early return to vigorous physical cutting activities after ACL reconstruction does not predispose patients to reinjury or a less satisfactory longterm result.

Goertzen, M., A. Dellmann, et al. (1993). "[Homologous cruciate ligament transplantation as intra-articular ligament replacement]." Zeitschrift fur Orthopadie und Ihre Grenzgebiete 131(2):179-86, 1993 Mar-Apr 131(2): 179-86.

A multiplicity of surgical operations have been developed in an attempt to achieve satisfactory function after ACL repair. None of these procedures have been able to duplicate the fiber organization, attachment site anatomy, vascularity, or function of the ACL. 29 foxhounds received a deep frozen bone-ACL-bone allograft and a ligament augmentation device (LAD). Biomechanical, microvascular, and histological changes were evaluated 3, 6 and 12 months following implantation. The maximum load of the allograft/LADs were 34.3% (387.2 N) after 3 months, 49.3% (556.6 N) after 6 months and 61.1% (689.8 N) after a year. The maximal load was 69.1% (780 N). In general, after 6 months the allografts showed a normal collagen orientation. The allografts demonstrated no evidence of infection or immune reaction. No bone ingrowth into the LAD was observed. Polarized light microscopy and PAS-staining showed that the new bone/ligament substance interface had intact fiber orientation at the area of ligament insertion. Microvascular examination using Spalteholtz-technique revealed neovascularization and the importance of infrapatellar fat pad for the nourishment of the ACL-allografts.

Goertzen, M., J. Gruber, et al. (1993). "[Neurohistological studies in allogeneic cruciate ligament transplants as intra-articular ligament replacement]." Zeitschrift fur Orthopadie und Ihre Grenzgebiete 131(5):420-4, 1993 Sep-Oct 131(5): 420-4.

A multiplicity of surgical operations have been developed in an attempt to achieve satisfactory function after ACL repair. None of these procedures have been able to duplicate the fiber organization, attachment site anatomy, vascularity, or function of the ACL. 18 foxhounds received a deep frozen bone-ACL-bone allograft and a ligament augmentation device (LAD). Neurohistological changes were evaluated 3, 6, and 12 months following implantation. Modified silver impregnation method and gold chloride technique were used to examine the presence of nerve endings and axons. Two morphological distinct mechanoreceptors were identified, and then were categorized as follows: free nerve-endings golgi-like tendon receptors. Fine nerve endings were frequently ramified freely into ligament collagen bundles. Nerves and blood vessels were commonly associated. Like in normal ACL's both neuroreceptors were mostly located near the surface of the allografts and at both bony attachments. This study demonstrated the first histological evidence of viable mechanoreceptors and free nerve-endings in transplanted ACL-allografts, not previously reported in other ACL-substitutes using for ACL-reconstruction. Particularly important for post-op. rehabilitation, this technique may allow to reconstruct the proprioreceptive functions of normal anterior cruciate ligaments.

Goertzen, M. and K. P. Schulitz (1993). "[Comparison of combined extra- and intra-articular stabilization versus isolated arthroscopic semitendinosus repair after rupture of the anterior cruciate ligament]." Sportverletzung Sportschaden 7(1):7-12, 1993 Mar 7(1): 7-12.

In a prospective study we examined 32 patients with a combined reconstruction of the anterior cruciate ligament, with arthroscopical use of a loop of semitendinosus tendon for the intraarticular portion and an iliotibial band tenodesis for the extraarticular augmentation in comparison to an isolated intraarticular semitendinosus reconstruction in 26 patients. Additionally the importance of a standardized rehabilitation program in this study was evaluated in comparison to a study on 58 athletes without standardized rehabilitation after an arthroscopic ACL-semitendinosus reconstruction. Lysholm-Score, clinical and radiological findings, KT-1000 stability values and isokinetic tests were evaluated monthly over a year. This data suggests that while both procedures under standardized rehabilitation conditions may obtain excellent functional results, adding the iliotibial band tenodesis to an intraarticular reconstruction significant improvement in stability and muscular strength was observed. Patients were able to resume all activities without pivoting.

Gomes JLE, M. L. (1984). "Anterior cruciate ligament reconstruction with a loop or double thickness of semitendinosus tendon." Am J Sports Med 12: 199-203.

Good, L. and J. Gillquist (1993). "The value of intraoperative isometry measurements in anterior cruciate ligament reconstruction: an in vivo correlation between substitute tension and length change." Arthroscopy 9(5):525-32, 1993 9(5): 525-32.

With the objective to evaluate an "isometry" measurement in an anterior cruciate ligament (ACL) substitute, in vivo measurements were taken on 10 patients undergoing reconstruction due to chronic ACL deficiency. Change in intraarticular length of a 1.2-mm test ligament, measured with an isometer, was correlated to the tension created in the same test ligament after fixation, measured with a piezoelectric load cell. The knee was passively moved through the 0-100 degrees range with the patient under general anaesthesia. Good statistical and visual correlations between length change and tension curves were found in individual knees. A correlation between total length change and maximum tension, for all knees grouped, was also found. Individual knees showed large variation in ability of the tissue to absorb load, resulting in a wide range of N/mm ratios between length and tension. Three knees with an isolated ACL injury all showed the least length change, implying a better restoration of kinematics in the absence of associated injuries. In nine of 10 knees the length change pattern could be used to identify the location of the femoral drill channel, as determined on an intraoperative lateral projection of the knee. Intraoperative isometry measurement can be used to predict the tension pattern in the reconstructed knee, but not the magnitude of tension. It will be useful to the surgeon in avoiding an anterior femoral ligament insertion site, which might threaten the integrity of the graft by tension rise in flexion.

Good, L., M. Odensten, et al. (1991). "Intercondylar notch measurements with special reference to anterior cruciate ligament surgery." Clin Orthop(263): 185-9.

The femoral intercondylar notch width was measured in 93 patients with chronic anterior cruciate ligament (ACL) insufficiency (Group 1), in 62 patients with an acute tear of the ACL (Group 2), and in 38 fresh anatomic specimen knees (Group 3). In six of the specimen knees, further anatomic studies of the intercondylar notch were performed after tissue removal. The average intercondylar distance was 16.1 mm in Group 1, 18.1 mm in Group 2, and 20.4 mm in Group 3. All differences were highly significant. The intercondylar notch was wider in the posterior part and had no crossing bony ridges but had generally concave walls, which provided a functional shelf for the ACL to insert on the lateral side. Significant osteophyte formation and stenosis of the anterior outlet of the intercondylar notch occur early in the ACL-deficient knee. A narrow anterior outlet of the intercondylar notch without osteophytes was also found in knees with an acute ACL rupture. At reconstruction of the ACL, notchplasty should be performed concomitantly.

Gorski, Z., K. Tokarczuk, et al. (1993). "[Reconstruction of the anterior cruciate ligament of the knee joint using Eriksson's method]." Polimery W Medycynie 23(1-2):91-3, 1993 23(1-2): 91-3.

The reconstruction of the anterior crucial ligament of the knee joint with the method of Eriksson has been performed in 10 patients of 17 to 42 years. In some patients complicated injuries of joint structures were observed. Control examinations included 7 patients in the period of observation over 6 months after the operation. The results were evaluated according to the 100-point scale of Lysholm-Gilquist. All patients evaluated the results of the treatment as good and obtained from 84 to 91 points.

Graf, B. K., D. A. Cook, et al. (1993). ""Bone bruises" on magnetic resonance imaging evaluation of anterior cruciate ligament injuries." American Journal of Sports Medicine 21(2):220-3, 1993 Mar-Apr 21(2): 220-3.

Magnetic resonance imaging of the knees of 98 consecutive patients with clinically diagnosed anterior cruciate ligament injuries revealed 47 patients (48%) with focal signal abnormalities consistent with the diagnosis of a "bone bruise." Seventy-one percent of the magnetic resonance images taken within 6 weeks of injury demonstrated a bone bruise, whereas no scans done longer than 6 weeks after injury showed a bruise (P < 0.0001). Also significant was the tendency for lesions to be located in the lateral compartment (P < 0.0001). In the sagittal plane, lesions were most likely to be in the middle third of the lateral femoral condyle and the posterior third of the lateral tibial plateau (P < 0.0001). In 31 patients evaluated arthroscopically, there was no correlation between the presence or location of a bone bruise and articular alterations or meniscal tears observed at surgery.

Graf, B. K., J. W. Ott, et al. (1994). "Risk factors for restricted motion after anterior cruciate reconstruction." Orthopedics 17(10): 909-12.

A retrospective review of 373 patients who had undergone anterior cruciate ligament (ACL) reconstruction utilizing the central third of the patellar tendon was undertaken to identify those factors that placed a patient at risk for restricted postoperative motion (flexion < or = 125 degrees or flexion contracture > or = 10 degrees). Stepwise logistic regression analysis determined that the variables most strongly correlated with restricted final range of motion (ROM) were open surgery (P = .0008) and reconstruction performed < or = 7 days after the initial injury (P = .004). Age, associated meniscal repair, or associated collateral ligament injuries did not significantly affect the ROM. A subgroup of 204 patients arthroscopically reconstructed more than 7 days post-injury were significantly less likely to have limited motion when ROM exercises were begun within 2 days of surgery (P = .008). These data support delayed, arthroscopic ACL reconstruction followed by early ROM exercises as useful techniques for avoiding postoperative motion problems.

Grasso, A. and M. Cellerini (1993). "[Partial lesions of the posterior cruciate ligament of the knee: CT findings]." Radiologia Medica 86(6):802-7, 1993 Dec 86(6): 802-7.

Posterior cruciate ligament (PCL) tears are more common than usually reported, especially in athletes. In the acute phase, PCL tears are particularly difficult to diagnose at clinical examination and may go unnoticed even to a skilled clinician because of concomitant lesions to other structures, of hematrhos or of strong muscular defense. The PCL is responsible for 95% of biomechanical knee stability and therefore plays a major role in the maintenance of joint congruence. In the long run, PCL tears cause posterolateral instability and an untimely development of degenerative changes, particularly at the patella. Site and grade of PCL tears must therefore be accurately assessed to plan the most appropriate treatment and to avoid the abuse of arthroscopy, toward improving cost-effectiveness for public health structures. Nowadays, CT of the knee joint is performed more frequently than MRI because the former is more easily available, in agreement with the current Italian economic choices in the field of public health. CT allows the accurate identification of complete and partial PCL tears. In our series (765 patients), PCL tears were more common than reported in the literature (9.5% vs 5%); moreover, PCL tears were always associated with lesions in other structures--e.g., anterior cruciate ligament, menisci. In conclusion, the CT demonstration of the knee joint, together with the knowledge of the physiopathologic relationships among different structures, allows better understanding of painful syndromes of the anterior joint compartment, which are particularly common in athletes. These syndromes are usually caused by a femoro-patellar overload in people suffering from congenital ligament laxity, which may or may not be associated with abnormal knee morphotype--i.e., valgus, recurvatus.

Greis, P. E., D. L. Johnson, et al. (1993). "Revision anterior cruciate ligament surgery: causes of graft failure and technical considerations of revision surgery." Clinics in Sports Medicine 12(4):839-52, 1993 Oct 12(4): 839-52.

The frequency of revision ACL surgery is sure to become more common as the number of primary intraarticular reconstructions increase. Identifying the potential causes of failure through a detailed history, physical examination, and radiographic evaluation is of paramount importance prior to planning a revision surgery if the repetition of errors is to be avoided.

Griffin, L. Y. A., J.; Albohm,M.J.; Arendt,E.A.; Dick,R.W.; Garrett,W.E.; Garrick,J.G.; Hewett,T.E.; Huston,L.; Ireland,M.L.; Johnson,R.J.; Kibler,W.B.; Lephart,S.; Lewis,J.L.; Lindenfeld,T.N.; Mandelbaum,B.R.; Marchak,P.; Teitz,C.C.; Wojtys,E.M. (2000). "Noncontact anterior cruciate ligament injuries: risk factors and prevention strategies." J.Am.Acad.Orthop.Surg. 8(3): 141-150.

An estimated 80,000 anterior cruciate ligament (ACL) tears occur annually in the United States. The highest incidence is in individuals 15 to 25 years old who participate in pivoting sports. With an estimated cost for these injuries of almost a billion dollars per year, the ability to identify risk factors and develop prevention strategies has widespread health and fiscal importance. Seventy percent of ACL injuries occur in noncontact situations. The risk factors for non- contact ACL injuries fall into four distinct categories: environmental, anatomic, hormonal, and biomechanical. Early data on existing neuromuscular training programs suggest that enhancing body control may decrease ACL injuries in women. Further investigation is needed prior to instituting prevention programs related to the other risk factors

Grontvedt, T., Engebretson L, Benum, P, Fasting O, Molster A, Strand, T. (1996). "A prospective randomized study of three operations for acute repair of the anterior cruciate ligament. Five-year follow up of one hundred and thirty-three patients." J. Bone and Joint Surg 78A: 159-168.

Gross, M. T., A. D. Tyson, et al. (1993). "Effect of knee angle and ligament insufficiency on anterior tibial translation during quadriceps muscle contraction: a preliminary report." Journal of Orthopaedic & Sports Physical Therapy 17(3):133-43, 1993 Mar 17(3): 133-43.

Additional information is needed regarding the effects of exercise protocols on the injured or reconstructed anterior cruciate ligament (ACL). The purpose of this investigation was to assess the effects of knee flexion angle and ACL insufficiency on anterior tibial translation (ATT) and patellar ligament insertion angle as subjects performed maximal isometric quadriceps muscle contractions. The subjects were two females and two males between the ages of 18 and 24 who had sustained injuries that resulted in unilateral ACL insufficiency. Each subject performed maximum isometric quadriceps muscle contractions with each leg on a Cybex II dynamometer at each of three positions: 15, 45, and 75 degrees knee flexion. A lateral knee roentgenogram was obtained as each subject maintained each isometric muscle contraction. A roentgenogram also was taken as subjects rested each knee in each of the three target positions. Anterior tibial translation for each isometric muscle contraction was assessed by measuring the anterior displacement of the tibial plateau on the isometric resisted roentgenogram relative to the resting roentgenogram. Patellar ligament insertion angle also was measured for each roentgenogram. Maximum ATT occurred at the 15 degrees knee flexion target angle for two subjects and at the 45 degrees target angle for the other two subjects. Patellar ligament insertion angle decreased as knee flexion angle increased. Appreciable stress may be imposed on the ACL as patients perform maximum quadriceps muscle contractions in positions of terminal knee extension and in midrange positions previously reported as being safe for maximal effort quadriceps exercise. Magnitude of stress imposed on the ACL is discussed as a function of the length-tension relationship of the quadriceps muscle-tendon unit and insertion angle of the patellar ligament. Suggestions are made for additional research regarding appropriate muscle strengthening protocols for patients who have undergone ACL reconstruction.

Guidoin, M. F. M., Y.; Bejui,J.; Poddevin,N.; King,M.W.; Guidoin,R. (200-). "Analysis of retrieved polymer fiber based replacements for the ACL." Biomaterials 21(23): 2461-2474.

The present retrospective analysis of 117 surgically excised anterior cruciate ligament (ACL) prostheses was designed to elucidate the etiology and mechanisms of failure of synthetic ligamentous prostheses. They were harvested from young and active patients (26 +/- 7 yrs) at various orthopaedic centers in France between 1983 and 1993. The average duration of implantation of augmentation and replacement prostheses were 21.5 +/- 12.6 and 33.2 +/- 25.3 months, respectively. The principal causes for their excision were ruptures and synovitis. Each ACL prosthesis was examined macroscopically, histologically, and, after tissue removal, by scanning electron microscopy (SEM) to determine the model, manufacturer, surgical technique used at implantation, the extent of healing, the site of rupture, and the morphology of the damaged fibers. Fourteen types of ACL prostheses were analysed, each fabricated using a different combination of polymers, fibers and textile constructions. Consequently, they generated a variety of healing characteristics and mechanical responses in vivo. SEM observations revealed that abrasion of the textile fibers as a result of yarn-on-yarn and/or yarn-on-bone contact was a common phenomenon to almost all models, and was the primary cause of prosthetic failure. Healing inside the synthetic ACL was poorly organized, incomplete and unpredictable as the extent of collagenous infiltration into the textile structure did not increase with the duration of implantation. In fact, the collagenous infiltration into certain models appeared to be more detrimental than beneficial since it caused deterioration and fraying of the textile structure rather than serving as a reinforcing matrix around the prosthesis. In conclusion, the present study shows that three mechanisms may be involved in the failure of ACL prostheses: (1) inadequate fiber abrasion resistance against osseous surfaces; (2) flexural and rotational fatigue of the fibers, and (3) loss of integrity of the textile structure due to unpredictable tissue infiltration during healing

Hackl, W. B., K.P.; Hoser,C.; Kunzel,K.H.; Fink,C. (2000). "Is screw divergence in femoral bone-tendon-bone graft fixation avoidable in anterior cruciate ligament reconstruction using a single- incision technique? A radiographically controlled cadaver study." Arthroscopy 16(6): 640-647.

Interference screw fixation of patellar tendon bone-tendon-bone grafts for anterior cruciate ligament reconstruction has proven to be a method with high pullout strength if screw divergence is avoided. Twenty-four fresh-frozen cadaveric human knees were used to identify the ideal position for a portal and an optimal knee flexion angle to obtain parallel placement of screw and bone block. On all specimens, anterior cruciate ligament reconstruction was performed using a single-incision technique. In the first part of this study, screw placement was analyzed in the frontal plane. In the second part, screw placement was investigated in the sagittal plane, measuring the additional flexion required between femoral tunnel drilling (at 60 degrees of knee flexion) and screw insertion to obtain parallel screw placement. For both part I and II, image intensification was used. In the third part, femoral screw placement was carried out through a paraligamentous approach and with additional flexion of 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, and 60 degrees. This study shows that screw placement with minimal divergence in the frontal and sagittal planes can be achieved by inserting the screw through a nearly central portal and flexing the knee an additional 35 degrees to 40 degrees

Hackl, W. F., C.; Benedetto,K.P.; Hoser,C. (2000). "Transplant fixation by anterior cruciate ligament reconstruction. Metal vs. bioabsorbable polyglyconate interference screw. A prospective randomized study of 40 patients." Unfallchirurg 103(6): 468-474.

To overcome some of the potential problems (e.g. hardware removal during revision surgery) of metal interference screws used for patellar tendon anterior cruciate ligament reconstruction, bioabsorbable screws have recently been introduced. Forty patients who underwent endoscopic ACL reconstruction using patella tendon autograft were included in the study, they were randomized intraoperatively to either Group A (femoral bone block fixation: polyglyconate screw; tibial: metal screw) or Group B (both bone blocks fixed with metal interference screws). The patients were evaluated clinically preoperatively as well as 6 weeks, 3 months 12 months and 24 months post op. Lysholm Score at 24 months was 98.1 +/- 2.3 for Group A and 97.7 +/- 3.0 for Group B. Tegner Score was 7.4 +/- 1.1 for Group A and 7.5 +/- 0.8 for Group B. Two years post op overall IKDC-Score for group A was 5.6% normal, 88.8% nearly normal and 5.6% abnormal. The result for group B was 11.1%, 77.8% and 11.1%, respectively. KT-1000 (at 89 N) at two years revealed a side to side difference of 1.5 +/- 0.3 mm (Group A) and 1.6 +/- 0.7 (Group B). The results of the two groups did not show significant differences at any stage of follow up. In our study polyglyconate interference screw fixation for patellar tendon grafts has not found to be associated with increased clinical complications. It provided equivalent fixation and clinical results compared to metal screws

Halbrecht, J. and I. M. Levy (1993). "Fluoroscopic assist in anterior cruciate ligament reconstruction." Arthroscopy 9(5):533-5, 1993 9(5): 533-5.

When creating the femoral tunnel during endoscopic anterior cruciate ligament reconstruction, the potential exists for penetration of the posterior femoral cortex. In addition, during placement of the proximal fixation screw, the screw can deviate from its intended path. We have used an image intensifier intraoperatively to obtain a lateral view of the knee to enable the assessment of tunnel placement and screw alignment. This technique assures the accurate placement of the tibial and femoral tunnels and helps avoid screw divergence from the graft.

Halling, A. H., M. E. Howard, et al. (1993). "Rehabilitation of anterior cruciate ligament injuries." Clinics in Sports Medicine 12(2):329-48, 1993 Apr 12(2): 329-48.

Rehabilitation of the anterior cruciate ligament absent or reconstructed knee is becoming a true artform. Accelerated, but controlled rehabilitation, is becoming more commonplace. Scientific-based data along with clinical experiences are the basis of the rehabilitation guidelines brought forth in this article. Anterior cruciate ligament strain and implications for exercise, continuous passive motion, proprioceptive exercise, and the role of knee bracing are all discussed in relation to the overall rehabilitation program.

Hamner, D. L. B., C.H.; Steiner,M.E.; Hecker,A.T.; Hayes,W.C. (1999). "Hamstring tendon grafts for reconstruction of the anterior cruciate ligament: biomechanical evaluation of the use of multiple strands and tensioning techniques." J.Bone Joint Surg.Am. 81(4): 549-557.

Hanley, S. T., and Warren,R.F. (1987). "Arthroscopic menisectomy in the anterior cruciate ligament-deficient knee." Arthroscopy 3.

Harilainen, A., J. Sandelin, et al. (1993). "Prospective preoperative evaluation of anterior cruciate ligament instability of the knee joint and results of reconstruction with patellar ligament." Clinical Orthopaedics & Related Research (297):17-22, 1993 Dec(297): 17-22.

Of 54 patients with chronic (n = 49) or acute (n = 5) anterior cruciate ligament instability, 52 were evaluated after mean 16 months' follow-up interval after open (n = 18) or arthroscopic assisted (n = 36) bone-tendon-bone patellar ligament reconstruction. Preoperative Knee Signature System side-to-side difference in anterior displacement decreased from 7.9 mm to 3.5 min at follow-up evaluation (p < 0.0001). An objectively satisfactory limit of 5 mm in side-to-side difference was achieved in 73% of the patients. At follow-up evaluation, there was a positive pivot shift sign in eight knees (one definite and seven trace). Average Lysholm knee scores improved from 69 to 83. The only significant difference between the arthroscopic assisted and open groups was smaller side-to-side anterior displacement difference in the arthroscopic group (2.2 mm versus 4.8 mm, p = 0.002). Results suggest that more accurate and isometric placement of the graft is possible with the arthroscopic-assisted technique.

Harmon, K. G. I., M.L. "Gender differences in noncontact anterior cruciate ligament injuries." Clin.Sports Med. 19(2): 287-302.

Female athletes have an increased incidence of ACL rupture. The cause of this increased injury rate is unclear, but it is most likely from a complex interplay between multiple variables. The relative risk of incurring an ACL injury is still low. The increased risk of ACL injury in women compared with men should not discourage female participation in sports. Instead, the focus should be on strategies to prevent injuries. Intrinsic factors are difficult or impossible to change; modifiable risk factors need to identified and prevention strategies should be employed

Harter, R. A. O., L.R.; Singer,K.M.;James,S.L.; Larson, R.L.; and Jones, D.C. (1988). "Long-term evaluation of knee stability and function following surgical reconstruction for anterior cruciate ligament insufficiency." Am. J. Sports Med., 16: 434-443.

Hasler, C. and F. Hardegger (1993). "[Proximal intra-articular tibial fracture in skiers]." Zeitschrift fur Unfallchirurgie und Versicherungsmedizin 86(3):169-77, 1993 86(3): 169-77.

56 cases of proximal intraarticular tibia fractures over a 4-year period are reviewed. In every case the patients described a preceding valgus-compression trauma of their knee. Clinically we always found a hemarthrosis combined with a tenderness on pressure at the fractured condyle. Roentgenograms should be performed in 4 projections, eventually followed by conventional tomograms or computed tomography. Frequency of the several fracture types is demonstrated following the classification of the AO working group for osteosynthesis. The Eminentia intercondylaris was concerned in 13 cases as avulsion fracture of the anterior cruciate ligament (ACL) with a double peak distribution in the under 20-years- and over 40-years-age group. In the remaining cases we observed split- and/or compression fractures of the lateral tibial plateau of the 40 to 60 year old skier, in 20% communitive fractures. In 85% of the ACL-avulsion fractures we applied a cast brace as a conservative measure, whereas 75% of the tibia plateau fractures were treated operatively by mean of open reconstruction of the articular surface and internal fixation based on the AO-principles as well as bone graft buttressing in two third of the cases.

Hawkins, R. J. M., G.W.; and Merritt,T.R. (1986). "Followup of the acute nonoperated isolated anterior cruciate ligament tear." Am. J. Sports Med 14: 205-210.

Hay Groves, E. (1917). "Operation for the repair of the crucial ligaments." Lancet 2: 674-675.

Hazel, W. A., Jr., J. A. Rand, et al. (1993). "Results of meniscectomy in the knee with anterior cruciate ligament deficiency." Clinical Orthopaedics & Related Research (292):232-8, 1993 Jul(292): 232-8.

Sixty-three knees in 62 patients with insufficiency of the anterior cruciate ligament (ACL) were treated by arthroscopic partial or total meniscectomy without ligament reconstruction. The implications of this sequence of treatment with this combination of pathologies was documented. At 4.5 years after meniscectomy, 84% of the knees were subjectively improved and 10% were subjectively worse. Sixty-eight percent of the patients had persistent knee pain and 52% had episodes of giving way. Roentgenographic evidence of osteoarthrosis was present in 65% of 34 knees at 4.4 years after operation. Additional surgery was required in 24% of the knees. Meniscectomy without a stabilization procedure should be performed only infrequently in knees with deficient ACL.

Hefti, F. and W. Muller (1993). "[Current state of evaluation of knee ligament lesions. The new IKDC knee evaluation form ]." Orthopade 22(6):351-62, 1993 Nov 22(6): 351-62.

Various scoring systems have been proposed for quantification of the disability caused by knee ligament injuries and to evaluation of the results of their treatment. None of them was found worldwide acceptance, mainly because all scoring systems attribute numerical values to factors that are not quantifiable, after which the arbitrary scores for parameters that are not comparable with each other are added together. For these reasons a group of knee surgeons from Europe and America met in 1987 and founded the International Knee Documentation Committee. A common terminology and an evaluation form were created. This form is the standard form for use in all publications on results of treatment of knee ligament injuries. It is a concise one-page form and includes a documentation section, a qualification section and a evaluation section. For evaluation there are four problem areas (subjective assessment, symptoms, range of motion and ligament examination). These are supplemented by four additional areas that are documented but are not included in the evaluation (compartmental findings, donor site pathology, X-ray findings and functional tests). The form can be used pre- and postoperatively and at follow-up. The Committee also laid down that in a publication the minimum follow-up time for short-term results should be 2 years, for medium-term results, 5 years, and for long-term results, 10 years. Most of the sheet is devoted to the qualification section. It is called "qualification" and not "scoring" section because no scores are given. Each parameter is qualified as "normal", "nearly normal", "abnormal" or "severely abnormal". This qualification is less subjective and emotional than "very good", "good", "fair" and "poor". No knee and no knee function can be better than normal, and it is rather doubtful whether any knee that has been operated on can ever be "normal" again. For evaluation, the parameters of the four problem areas "subjective assessment", "symptoms", "range of motion" and "ligament examination" are qualified for the group qualification. The worst qualification within the group is taken as the group qualification. The worst group qualification is taken as the final evaluation. If the knee is abnormal in any of the problem areas it cannot be entered as normal knee. For knees with chronic pathology it is also possible to evaluate the sum of levels of improvement or deterioration of all groups compared with the preoperative evaluation. The committee also recommends that terms describing knee ligament problems should be used according to the definitions published by Noyes et al.(ABSTRACT TRUNCATED AT 400 WORDS)

Hefzy, M. D. G., E.S.;and Noyes,F.R. (1989). "Factors affecting the region of most isometric femoral attachments. Part II:the anterior cruciate ligament." Am. J. Sports Med: 208-216.

Hernandez, A. J. and A. Hernandes (1993). "Universal coupled isometric guide for ligament reconstruction of the knee ("G.U.I.A.") [published erratum appears in Rev Paul Med 1993 Nov-Dec;111(6):455]." Revista Paulista de Medicina 111(3):422-6, 1993 May-Jun 111(3): 422-6.

The author presents a new drill guide for reconstruction of the knee ligament called "Guia Universal Isometrico Acoplado--G.U.I.A." (Universal Coupled Isometric Guide). The guides uses the posterior region of the intercondylar notch to obtain the femoral tunnel for the anterior cruciate ligament (ACL). Based on biomechanics, literature and cadaver knee studies, the guide has proved to be practical, to facilitate the preparation of isometric tunnels and to avoid iatrogenic injuries.

Hertel, P. (2000). "Improperly placed anterior cruciate ligament grafts: correlation between radiological parameters and clinical results." Unfallchirurg 103(12): 1128-1129.

Hiemstra, L. A. W., S.; MacDonald,P.B.; Kriellaars,D.J. (2000). "Knee strength deficits after hamstring tendon and patellar tendon anterior cruciate ligament reconstruction." Med.Sci.Sports Exerc. 32(8): 1472-1479.

PURPOSE: The purpose of this study was to examine the strength of the knee flexors and knee extensors after two surgical techniques of ACL reconstruction and compare them to an age and activity level matched control group. METHODS: Twenty-four subjects who had undergone ACL reconstruction greater than 1 yr previously were placed into one of two groups according to autograft donor site: patellar tendon (BPB; N = 8) and hamstring (H; N = 16), and compared with an active, control group (N = 30). Knee flexor and extensor strength was evaluated using isovelocity dynamometry (5 speeds, eccentric and concentric, 5-95 degrees ROM). Strength maps were used to graphically analyze strength over a broad operational domain of the neuromuscular system. Average strength maps were determined for each autograft group and compared with controls. A difference map (control minus graft group) and confidence (t-test) maps were used to quantitatively identify strength deficits. RESULTS: The combined ACL group (N = 24) revealed a global 25.5% extensor strength deficit, with eccentric regional (angle and velocity matched) deficits up to 50% of control. Strength deficits covered over 86% of the sampled strength map area (P < 0.01). These knee extensor strength deficits are greater than previously reported. In addition, the BPB group demonstrated a concentric, low velocity, knee extensor strength deficit at 60-95 degrees that was not observed in the H group. Significant graft site dependent, regional knee flexor deficits of up to 50% of control were observed for the H group. CONCLUSIONS: Strength deficits localized to specific contraction types and ranges of motion were demonstrated between the ACL and control groups that were dependent upon autograft donor site. Postoperative rehabilitation protocols specific to these deficits should be devised

Hirokawa, S. (1993). "Biomechanics of the knee joint: a critical review." Critical Reviews in Biomedical Engineering 21(2):79-135, 1993 21(2): 79-135.

The literature concerning kinematic and kinetic studies on the knee joint is comprehensively reviewed in this article. Also reviewed are studies of etiology and operative treatment of injury, as well as chronic disease such as dislocation, arthritis, and ligamentous rupture. This paper formulates experimental study and mathematical model analysis of the tibio-femoral and patello-femoral joints, respectively. The sections on experimental study cover the following: the tibio-femoral joint including load bearing capacity, knee laxity, ligamentous strain, articular geometry, and multiaxial movement; the patello-femoral joint including forces and stresses and patellar tracking patterns. Further, three items, considered as future problems, are discussed briefly: individual variations in material properties of the soft tissue and biphasic cartilage-bone structures, quantitative description of bone geometry, and quantitative determination of extreme tensions and distortions in connective tissues surrounding the knee.

Hirshman, H. P. D., D.M.; and Miyasaka,K. (1990). The fate of unoperated knee ligament injuries. Knee Ligaments:Structure, Function, Injury, and Repair,. W. H. A. a. J. J. O. D.M. Daniel. New York, Raven Press: 481-503.

Hodler, J., E. Buess, et al. (1993). "[Magnetic resonance tomography (MRT) of the knee joint: meniscus, cruciate ligaments and hyaline cartilage]." Rofo 159(2):107-12, 1993 Aug 159(2): 107-12.

The use of MRT for diagnosing injury to the meniscus, the cruciate ligaments and hyaline cartilage was evaluated retrospectively in 82 knee joints without any knowledge of operative findings. In 49 cases the results were verified by arthroscopy and in 33 cases by arthrotomy. Sensitivity, specificity and diagnostic accuracy of MRT for meniscus lesions was 73.9%, 96.9%, and 94.6%. Corresponding values for lesions of the anterior cruciate ligament were 88.9%, 96.6%, and 94.7%, and for lesions of the hyaline cartilage 62.6%, 96.1%, and 87.9%, respectively. In addition to its high specificity, MRT proved accurate in excluding lesions of the meniscus (97.1%) of the anterior cruciate ligament (96.6%) and of hyaline cartilage (88.8%). A negative finding on MRT therefore makes the presence of a lesion of the meniscus, cruciate ligaments of cartilage unlikely. In such cases one is justified in delaying the use of arthroscopy or arthrotomy.

Hoffmann, M. W., J. V. Wening, et al. (1993). "Repair and reconstruction of the anterior cruciate ligament by the "Sandwich technique". A comparative microangiographic and histological study in the rabbit." Archives of Orthopaedic & Trauma Surgery 112(3):113-20, 1993 112(3): 113-20.

The effect of complete ensheathment of the repaired or reconstructed anterior cruciate ligament (ACL) in the infrapatellar fat pad was studied in a rabbit model. Four to 16 weeks after repair of a transected ACL or insertion of an autologous tendon graft these tissues were evaluated by histology and microangiography. Following ACL repair a high incidence of ligament atrophy was evident in both the ensheathed (43%) and the non-ensheathed control (54%) group. In functional ligaments a similar sequence of remodelling events was evident in both the ensheathed and the non-ensheathed group: infiltration of the transected area by mesenchymal cells, maturation of these cells to fibroblasts, and increasing organization of newly formed collagen fibres. An initial hypervascular reaction was followed by a decrease in the number and an increase in the longitudinal orientation of blood vessels. Despite a similar sequence of remodelling events, however, this process was considerably accelerated in repaired ligaments ensheathed with infrapatellar fat pad compared with non-ensheathed controls. At 16 weeks only the ensheathed repaired ACL resembled the normal ACL morphologically, even though it was still hypercellular. The tendon autograft followed a similar course from an initially avascular and acellular tissue towards a structure similar to the normal ACL. In the ensheathed ligaments and tendon grafts vascular and cellular ingrowth as well as subsequent maturation were again accelerated. This effect may be attributable to improved revascularization and cell repopulation, as well as protection from synovial fluid by the surrounding fat pad.(ABSTRACT TRUNCATED AT 250 WORDS)

Hoffmann, R. F., R. Peine, et al. (1999). "Initial fixation strength of modified patellar tendon grafts for anatomic fixation in anterior cruciate ligament reconstruction." Arthroscopy 15(4): 392-9.

Recently it has been shown that anatomic tibial graft fixation in anterior cruciate ligament (ACL) reconstruction is preferable in order to increase isometry and knee stability. To facilitate anatomic patellar tendon graft fixation, customized graft length shortening is necessary. The purpose of this study was to compare the initial fixation strength of four different shortened patellar tendon grafts including three bone plug flip techniques and direct patellar tendon-to- bone interference fit fixation in a model with standardized bone density. Ninety calf tibial plateaus (22 to 24 weeks old) with adjacent patella and extensor ligaments were used. Tendon grafts were shortened by flipping the bone plug over the tendon leaving a tendon-tendon-bone (TTB) construct and, as the first modification in the opposite direction resulting in a tendon-bone-tendon (TBT) construct. The second modification consisted of the TBT construct with interference screw position at the lateral aspect of the bone plug (TBTlat). As the fourth modification the tendon graft was directly fixed (Tdirect) with an interference screw. In addition, a round-threaded titanium (RCI; Smith & Nephew DonJoy, Carlsbad, CA), a round-threaded biodegradable screw (Sysorb; Sulzer Orthopedics, Munsingen, Switzerland), and a conventional titanium interference screw (Arthrex Inc, Naples, FL) were compared. We found that TTB (mean 441 N for biodegradable screw, 357 N for RCI screw, 384 N for conventional screw) and TBT (mean 407 N for biodegradable screw, 204 N for RCI screw, 392 N for conventional screw) construct fixation achieves comparable fixation strength, although failure in the TTB was due to tendon strip off at its ligamentous insertion. The highest failure load was found in TBTlat fixation (mean 610 N for biodegradable screw, 479 N for RCI screw). Therefore, this technique should be recommended when using a tendon flip technique. The failure load for Tdirect fixation (mean 437 N for biodegradable screw, 364 N for RCI screw) was similar to that of TTB and TBT fixation, which may indicate that a patellar-tendon graft harvested without its patellar bone plug and directly fixed with an interference screw is equivalent to a flipped graft. This may additionally reduce harvest site morbidity and eliminates the risk of patellar fracture. The fixation strength of round-threaded biodegradable and conventional titanium interference screws was similar, whereas that of round- threaded titanium screws was significantly lower in the patellar tendon flip-techniques. However, it should be taken into consideration that round-threaded titanium screws are proposed for direct tendon-to-bone fixation.

Hogervorst, T. v. d. H., C.P.; Pels Rijcken,T.H.; Taconis,W.K. (2000). "Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length." Knee.Surg.Sports Traumatol.Arthrosc. 8(6): 332-328.

Tibial bone tunnels were examined with bone scans 2 years after patella ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r = 0.64, P < 0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r = 0.59 P < 0.001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation is more than 14 mm below the joint

Hoher, J. S., S.U.; Withrow,J.D.; Livesay,G.A.; Debski,R.E.; Fu,F.H.; Woo,S.L. (2000). "Mechanical behavior of two hamstring graft constructs for reconstruction of the anterior cruciate ligament." J.Orthop.Res. 18(3): 456-461.

We compared the mechanical behavior of two common hamstring graft constructs that are frequently used for reconstruction of the anterior cruciate ligament-Graft A: quadrupled semitendinosus tendon fixed with titanium button/polyester tape and suture/screw post, and Graft B: a double semitendinosus and double gracilis tendon fixed with a cross pin and two screws over washers. The experimental protocol used to evaluate each graft construct included stress relaxation (with and without preconditioning), cyclic loading, and a tensile load-to-failure test. The amount of stress relaxation without preconditioning was 60.6% for Graft A and 53.8% for Graft B. With preconditioning, it significantly decreased (p < 0.05) to 48.7 and 42.3%, respectively. Elongation of the graft construct in response to 100 cycles of loading (20-150 N) was 1.8 and 0.6% of the original length for Grafts A and B, respectively. However, after a series of five cyclic loading tests, the residual permanent elongation for each construct was 3.8 +/- 1.2 and 0.3 +/- 0.2 mm, a significant difference (p < 0.05) between the two graft constructs. Further analysis found more than 90% of the permanent elongation in the proximal and distal regions of Graft A, which consisted of polyester tape tied to a titanium button (proximal) and sutures tied around a screw post (distal). The tensile load-to-failure tests also revealed significant differences (p < 0.05) between the two graft constructs. Linear stiffness was 32 +/- 1 and 119 +/- 19 Nmm and ultimate load was 415 +/- 36 and 658 +/- 128 N for Grafts A and B, respectively. For Graft A, the polyester tape consistently failed; for Graft B, slippage or tearing from the washers was the mode of failure. We conclude that a quadruple-hamstring graft fixed over a cross pin proximally and with metal washers distally (Graft B) has less permanent elongation in response to cyclic loading and has structural properties superior to those of a graft construct that includes suture and tape material (Graft A). The large permanent elongation following repetitive loading of a graft construct with tape and suture material during the early postoperative period is of concern

Hoher, J. T., T. (2000). "Differential transplant selection in cruciate ligament surgery." Chirurg 71(9): 1045-1054.

Over the past century numerous graft materials have been used for the reconstruction of the cruciate ligament of the knee. Among the autologous tissues that are currently recommended as graft materials, the central bone patellar tendon bone graft, a quadrupled hamstring graft and the central quadriceps tendon graft have the greatest clinical significance. With some limitations, allograft materials can also be used. Each of the three mentioned grafts has specific features regarding morphological and structural properties, graft fixation and graft incorporation. Clinical studies have failed to identify any of the three grafts as superior to the others. When choosing the graft for surgery the different anatomy and function of the anterior and posterior cruciate ligaments have to be considered. For the treatment of multiple ligament injuries and for revision cases, thorough preoperative planning is necessary and modified graft selection may be required

Holland, J. P. (1992). "A modified repair for the anterior cruciate ligament deficient knee." Br J Sports Med 26(4): 249-52.

A retrospective analysis of 48 sportsmen and women from an original series of 76 consecutive patients who had undergone a modified McIntosh repair was carried out to establish whether or not the procedure could provide a satisfactory recovery and return to previous ability. The type and level of sport before injury was compared with that after operation. Symptoms of pain and giving way, and examination findings of pivot shift, and Lachman's test were compared before and after operation. Of the 48 patients assessed, 28 (58%) returned to full sporting capacity; 17 (35%) patients were participating in different sports or lower levels of their previous sports, and three patients did not participate in any sport. The more severely symptomatic knees did not perform so well after operation. The degree of preoperative anterior draw and Lachman's test did not influence the final result and the pivot shift, present in all before operation, was abolished in all but one case, which remained badly symptomatic. Concurrent meniscal injury or medial or lateral laxity did not influence return to sport once a full postoperative recovery was made. No deterioration was noticed in the level of sporting ability achieved thereafter. In this study it has been shown that the modified McIntosh repair is a swift extra-articular reconstruction for the anterior cruciate ligament deficient knee, which is less elaborate than previously described Ellison and McIntosh procedures, and which has produced a comparable result.

Hollis, J. M. P., A.W.; Niciforos,P.G. (2000). "Change in meniscal strain with anterior cruciate ligament injury and after reconstruction." Am.J.Sports Med. 28(5): 700-704.

Meniscal injury has been well documented in association with injury to the anterior cruciate ligament. The purpose of this study was to evaluate the effect of anterior cruciate ligament transection and reconstruction on meniscal strain. Four differential variable reluctance transducer strain gauges were placed in the medial and lateral menisci of nine cadaveric knees. Each specimen was mounted to a six-degree-of-freedom knee testing device. Testing was conducted with the knee fully extended and at 45 degrees and 90 degrees of flexion, both with and without applied axial load. At each angle of flexion, an anterior and posterior tibial load was applied. Next, the anterior cruciate ligament was transected and the testing sequence was repeated. Finally, the ligament was reconstructed using a central one-third patellar tendon graft and the testing sequence was repeated. The results demonstrated statistically significant increases in meniscal strain in ligament-transected knees compared with intact specimens. A reduction in meniscal strain to a level similar to that detected in the ligament-intact knees was observed after anterior cruciate ligament reconstruction. These results have important clinical implications regarding the potentially deleterious effect of the anterior cruciate ligament-deficient knee on meniscal strain and the potential benefit of anterior cruciate ligament reconstruction

Holmes PF, J. S., Larson RL, et al (1987). "Retrospective direct comparison of three intra-articular anterior cruciate ligament reconstructions." Am J Sports Med 19: 596-600.

Hooper, J. R., O.P.; Krepski,B.; Johnson,D.H. (1999). "Tourniquet inflation during arthroscopic knee ligament surgery does not increase postoperative pain." Can.J.Anaesth. 46(10): 925-929.

PURPOSE: A double-blind clinical trial was conducted to determine the effect of inflation of a thigh tourniquet during anterior cruciate ligament repair on arthroscopic visibility, duration of procedure, postoperative pain and opioid consumption. METHODS: Thirty patients were randomly allocated into two groups; Group I had the thigh tourniquet inflated during surgery whereas the tourniquet was not inflated in Group II patients. All patients received standardized general anesthesia and postoperative pain management. Supplemental analgesia was provided with i.v. morphine via a patient-controlled analgesia (PCA) apparatus. Verbal pain rating scores (0-10) were obtained after surgery. RESULTS: Arthroscopic visibility was impaired in Group II patients (P < 0.0001), but this was ameliorated by increased irrigation flow or addition of epinephrine. Duration of surgery was similar in both groups. There was no difference between groups in postoperative morphine consumption (9.8 +/- 7.1 mg in Group I vs 11.4 +/- 10.2 mg in Group II) or in postoperative pain scores between groups. CONCLUSION: Inflation of a thigh tourniquet did not result in increased pain or opioid consumption after arthroscopic ACL surgery. Arthroscopic visibility was somewhat impaired in some patients without the use of tourniquet. Finally, the duration of the surgical procedure was not increased in patients where the tourniquet was not inflated during the ACL repair

Horster, G. and O. Kedziora (1993). "[Loss of strength and regeneration of knee extensor musculature after operations of the knee ligaments. EMG studies of the effect of the injury pattern, surgical procedure and after-care with special reference to electromyostimulation]." Aktuelle Traumatologie 23(5):244-54, 1993 Aug 23(5): 244-54.

Clinically relevant losses of the capacity of the extensor muscles of the thigh to contract voluntarily are usual after open knee joint operations and are known to lead frequently to a major delay in healing. In the present paper, a randomized prospective comparative study is presented in which the negative effect of the injury and surgical trauma on the extensor musculature of the thigh is compared between open and arthroscopically controlled cruciate ligament operations. The surface electromyogram is measured. The values found make it evident that an equally pronounced loss of strength amounting to more than 90% results after injuries in the region of the cruciate ligament apparatus and in open as well as arthroscopically controlled reconstruction operations. The alterations are mainly attributable to the surgical trauma. The injury on its own only leads to a roughly 25% loss of strength in the preoperative investigation. With an appropriate programme of follow-up treatment, the strength values are only partially restored after about six weeks. In the follow-up treatment, electromyostimulation has a significantly positive effect on the rectus femoris muscle, but not on the vastus lateralis muscle. According to our investigations, it is of preeminent importance to consider how to avoid the negative effect of the operation (with particular consideration of the arthroscopic procedure) on the function of the thigh musculature.

Horstman, J. K., F. Ahmadu-Suka, et al. (1993). "Anterior cruciate ligament fascia lata allograft reconstruction: progressive histologic changes toward maturity." Arthroscopy 9(5):509-18, 1993 9(5): 509-18.

Biopsy samples were obtained arthroscopically from 21 patients who had undergone anterior cruciate ligament (ACL) reconstruction using rolled, freeze-dried fascia lata allograft in order to evaluate progressive histologic changes toward maturation. The study period was 3-20 months postoperation. The mean age (+/- SEM) was 31.9 +/- 10.3. Histomorphometry was used for quantitative evaluation. Arthroscopic examination showed fully synovialized allografts in all patients. Varying degrees of degenerative tissues were observed histologically. There was a significant, direct correlation between the percentage of polarized tissue and the maturity of the biopsy specimen (r = 0.9; p < 0.04). The mean area of polarization in the postrehabilitation period (10-20 months) was significantly higher (p < 0.01) than in the rehabilitation period (3-20 months). Overall, there was a progressive decrease in cellularity and vascularity as the allograft matured. Compared with the biopsy samples of normal ACLs, the allograft was still undergoing maturation 20 months postoperatively.

Howe, J. G. J., R.J.; Kaplan,M.J.; Fleming, Braden; and Jarvinen, Markku (1991). "Anterior cruciate ligament reconstruction using quadriceps patellar tendon graft. Part I. Long-term followup." Am.J. Sports Med., 19: 447-457.

Howell, S. M. (1993). "Comparison of closed and open kinetic chain exercise in the anterior cruciate ligament-deficient knee [letter; comment] [see comments]." American Journal of Sports Medicine 21(4):632; discussion 632-3, 1993 Jul-Aug 21(4): 632; discussion 632-3.

Howell, S. M. and M. A. Taylor (1993). "Failure of reconstruction of the anterior cruciate ligament due to impingement by the intercondylar roof." Journal of Bone & Joint Surgery - American Volume 75(7):1044-55, 1993 Jul 75(7): 1044-55.

The relationship between impingement of the roof of the intercondylar notch on a reconstructed anterior cruciate ligament, and the subsequent stability and range of extension of the joint, was analyzed in forty-seven knees. The extent of the impingement was determined by analysis of the relationship of the tibial tunnel to the intersection of the line of slope of the intercondylar roof with the plane of the subchondral bone of the articular surface of the tibial plateau. These lines were drawn on a lateral roentgenogram that was made with the knee in maximum extension, two years after the operation. In all four knees in which the entire articular opening of the tibial tunnel was anterior to the slope of the intercondylar roof, there was severe impingement on the graft, and all four grafts failed. In the fourteen knees in which a portion of the articular opening of the tibial tunnel was anterior to the slope of the intercondylar roof, there was moderate impingement on the graft, and four grafts failed (an unacceptable rate of failure). There was no impingement in the knees in which the entire articular opening of the tibial tunnel was posterior to the slope of the intercondylar roof, and these knees were associated with the lowest rate of failure of the grafts (three of twenty-nine). Knees that had an impinged graft and regained a complete range of extension became unstable.

Howell, S. M. D., M.L. (1999). "Comparison of endoscopic and two-incision techniques for reconstructing a torn anterior cruciate ligament using hamstring tendons." Arthroscopy 15(6): 594-606.

This study compared the differences in clinical outcome between an endoscopic (67 of 70) and two-incision (41 of 49) technique used to reconstruct tom anterior cruciate ligaments (ACL) using a double-looped semitendinosus and gracilis (DLSTG) graft. In both techniques, the graft was placed without roof impingement, the looped end of the graft was fixed around a post with bone compaction, and the free ends were fixed with either double staples or a soft tissue washer(s). No graft required suture fixation. The postoperative treatment featured an aggressive rehabilitation protocol without a brace, and allowed unrestricted sports participation 4 months after reconstruction. Age, sex distribution, duration from injury to surgery, and preoperative laxity were not significantly different between treatment groups. The operative time for the endoscopic technique averaged 48 minutes less than the two-incision technique. There were no significant differences in thigh circumference, knee extension, stability, and the single leg hop test between the two treatment groups at 4 and 24 months. Ninety- one percent of the knees in the endoscopic group and 90% in the two- incision group had less than a 3 mm increase in anterior translation compared with the normal knee using the manual maximum test (KT-1000) and had either a normal or near normal knee (IKDC score) at 2 years. A second surgery for removal of painful, prominent hardware was required in 21% of the subjects in the endoscopic group and 12% of the subjects in the two-incision treatment group. Patients preferred the endoscopic technique because the result was more cosmetic and aggressive rehabilitation could be accomplished without the assistance of a physical therapist. Unfortunately, objective stability could not be restored in about 10% of knees with either technique. Reoperation for removal of prominent staples and washers continues to be the primary source of postoperative morbidity

Hughston, J. C. (1994). "The importance of the posterior oblique ligament in repairs of acute tears of the medial ligaments in knees with and without an associated rupture of the anterior cruciate ligament. Results of long-term follow-up." J Bone Joint Surg Am 76(9): 1328-44.

Forty-one of fifty patients (fifty knees) who had had a repair of an acute tear of the medial ligaments, a procedure in which repair of the posterior oblique ligament and the semimembranosus complex was emphasized, were re-evaluated after an average duration of follow-up of twenty-two years (range, eighteen to thirty years). The ages of the patients at the time of the injury had ranged from fifteen to twenty-one years. In twenty-four of the forty-one knees, the anterior cruciate ligament had been torn. In seventeen of these knees, the torn ligament had been debrided; in six others, which had had avulsion of a bone fragment or a terminal tear, the ligament had been repaired with absorbable sutures; and in the remaining knee, the repaired anterior cruciate ligament had been augmented. Four patients had had a pes anserinus transfer to supplement the medial repair. The medial meniscus had been intact or repaired in twenty-five of the forty-one knees and had been removed from the remaining sixteen. The lateral meniscus had been retained in thirty-nine knees and removed from two. Postoperatively, all knees had been immobilized for six weeks in 60 degrees of flexion by means of a plaster cast. This had not caused lasting loss of motion, persistent muscle atrophy, or clinically demonstrable deterioration of the articular cartilage. In the twenty-four knees that had had a tear of the anterior cruciate ligament, the rates of instability, meniscal injury, and deterioration of the joint had not increased since the time of treatment, compared with those in the knees with an intact ligament, even though repair and augmentation of this ligament had not been performed (except in one patient, in whom it was unsuccessful). Thirty-eight patients had good stability and a normal range of motion, as well as little or no muscle atrophy. Radiographic changes were slight or absent in all but four knees. Most patients had maintained a high level of physical fitness and recreational athletic activity. There were three failures of treatment (7 per cent). This previously described treatment of acute tears of the medial ligaments, with or without an associated tear of the anterior cruciate ligament, provides good long-term results and is still recommended.

Hulstyn, M., P. D. Fadale, et al. (1993). "Biomechanical evaluation of interference screw fixation in a bovine patellar bone-tendon-bone autograft complex for anterior cruciate ligament reconstruction." Arthroscopy 9(4):417-24, 1993 9(4): 417-24.

A bovine model was developed for biomechanical evaluation of anterior cruciate ligament (ACL) reconstruction using patellar bone-tendon-bone (b-t-b) autograft to examine the differences in time zero fixation mechanical properties of different interference screw lengths and diameters. The surgical technique of interference screw fixation of the b-t-b complex performed clinically was reproduced in a controlled animal model. The femur-patellar tendon graft-tibia complex was tested with anterior displacement of the tibia in 30 degrees of knee flexion to allow examination of the femoral and tibial fixation properties simultaneously. The statistical model concurrently explored differences between screw length and diameter while accounting for variations between graft properties. No statistically significant differences were found between the 7- and 9-mm screws with respect to peak load or energy to failure when using a 10-mm triangular graft in a 10-mm tunnel. The 7- and 9-mm screws were superior to the 5.5-mm screws with respect to these same parameters. Based on our results, the 7-mm interference screws can be used with equal confidence as the 9-mm screw, and the 20-mm length can be similarly exchanged for 30-mm length for patellar b-t-b graft fixation.

Hunter, R. E. L., J.L.; Kowalczyk,C.; and Settle,W. (1990). "Graft force-setting technique in reconstruction of the anterior cruciate ligament." Am. J. Sports Med 18: 12-19.

Huston, L. J. G., M.L.; Wojtys,E.M. (2000). "Anterior cruciate ligament injuries in the female athlete. Potential risk factors." Clin.Orthop.(372): 50-63.

In the general population, an estimated one in 3000 individuals sustains an anterior cruciate ligament injury per year in the United States, corresponding to an overall injury rate of approximately 100,000 injuries annually. This national estimate is low for women because anterior cruciate ligament injury rates are reported to be two to eight times higher in women than in men participating in the same sports, presenting a sizable health problem. With the growing participation of women in athletics and the debilitating nature of anterior cruciate ligament injuries, a better understanding of mechanisms of injury in women sustaining anterior cruciate ligament injuries is essential. Published studies strongly support noncontact mechanisms for anterior cruciate ligament tears in women, which make these injuries even more perplexing. Speculation on the possible etiology of anterior cruciate ligament injuries in women has centered on anatomic differences, joint laxity, hormones, and training techniques. Investigators have not agreed on causal factors for this injury, but they have started to profile the type of athlete who is at risk. In the current study the most recent scientific studies of intrinsic and extrinsic risk factors thought to be contributing to the high rate of female anterior cruciate ligament injuries will be reviewed, important differences will be highlighted, and recommendations proposed to alleviate or minimize these risk factors among female athletes will be reported where appropriate

Ikeda, H. (1993). "[Isokinetic torque of quadriceps in patients with untreated anterior cruciate ligament injury of the knee joint]." Nippon Seikeigeka Gakkai Zasshi - Journal of the Japanese Orthopaedic Association 67(9):826-35, 1993 Sep 67(9): 826-35.

In order to study the role of muscle strength in patients with untreated anterior cruciate ligament (ACL) injury of the knee joint, the torque of the quadriceps was isokinetically measured during concentric contraction (CC) and passive eccentric contraction (PEC). The results were compared with those in normal individuals and sports players. Ninety patients with untreated ACL injury were subjected for the study. There were 50 men and 40 women. The normal group consisted of 20 students and the sports player group consisted of 20 soccer players. The peak torque and the torque at 30 degrees flexion of the quadriceps were isokinetically measured during CC and PEC by using a BIODEX machine. Results: In patients with ACL injury, the peak torque was smaller in the injured side as compared with the uninjured side. At the same angle velocity, decrease of PEC in the injured side was larger than that of CC. These results were compared with the normal group and the sports player group. There was significant difference in the peak torque per body weight among each groups. But, the torque per body weight at 30 degrees flexion was almost consistent in these three groups. Discussion: A considerable quadriceps atrophy occurs following ACL injury. In our experience, patients with functional absence of ACL are much more difficult to return to vigorous sports which require explosive eccentric contraction than to return to endurance sports which require repetitive concentric contractile efforts of the quadriceps. In the present study, decrease of the passive eccentric contraction in the injured side was more pronounced than that of the concentric contraction. From these results, the significantly decreased passive eccentric torque in the patients with untreated ACL injury can be a factor to cause instability of the knee joint in active daily life as well as in sports activities.

Imhoff, A. (1993). "[Anterior cruciate ligament-plasty with the Insall iliotibial tract transfer. Long-term results after 5 years]." Sportverletzung Sportschaden 7(1):1-6, 1993 Mar 7(1): 1-6.

For the reconstruction of the anterior cruciate ligament we performed the bone block iliotibial tract transfer in 56 patients from May 1984 until December 1987. The results were followed up for 2 to 6 1/2 years (average 53 months). The clinical results showed a positive Lachman test in 20 degrees flexion (3-5 mm) in 50% of the knees. There was no Lachman test ++ or and no sign of pivot shift. At the time of follow-up, the Lysholm-score was very high with 98.67 points. Subjectively, 91.3% of the knees were rated excellent, 4.3% good and 4.3% poor. 93% of the patients were engaged in some kind of sport before their accident, 87% of all patients were able to practice their sport at the same level after the operation. Long-term results after 5 years are consistent with the physiological aspects of this transfer. The immediate fixation of bone allows early motion of the knee and the rehabilitation time is much shorter.

Indelicato, P. A. and E. S. Bittar (1985). "A perspective of lesions associated with ACL insufficiency of the knee. A review of 100 cases." Clin Orthop(198): 77-80.

A retrospective study was conducted to survey the extent of intracapsular damage associated with ACL insufficient knees in both the acute and chronic situation. Previously unoperated knees were studied to assess the effect that reinjury had on the knee joint. One hundred patients with confirmed anterior cruciate ligament damage, both clinically and under general anesthesia, were examined arthroscopically and the findings recorded on video tape. Both anterolateral and posteromedial approaches were used to well visualize the entire intra-articular structures of the knee joint. The incidence of meniscal tears increased from 77% in the acute injury to 91% in the chronically reinjured knee (p less than .06). Furthermore, articular surface disease increased from 23% in the acute injury to 54% in the chronically ACL lax knee (p less than .002). The majority of meniscal tears were medial and amenable to peripheral suture repair (63%). Irrespective of how one approaches ACL insufficiency of the knee acutely, one cannot ignore the likelihood of finding these significant associated lesions. Reinjury to the knee will likely enhance the incidence of meniscal tears and articular changes.

Ireland, J. and E. L. Trickey (1980). "Macintosh tenodesis for anterolateral instability of the knee." J Bone Joint Surg Br 62(3): 340-5.

Fifty patients who underwent a MacIntosh repair for anterolateral instability of the knee have been reviewed after a mean follow-up of two and a quarter years. The repair abolished a positive anterolateral jerk test in 42 out of 50 knees and at the time of review 37 patients (74 per cent) were involved in some form of active sport, having regained functional and clinical stability. The MacIntosh repair is described in detail and the importance of excluding meniscal lesions as the main cause of instability is emphasised.

Irrgang, J. J. (1993). "Modern trends in anterior cruciate ligament rehabilitation: nonoperative and postoperative management." Clinics in Sports Medicine 12(4):797-813, 1993 Oct 12(4): 797-813.

Rehabilitation following ACL injury or reconstruction should be based on sound scientific and rehabilitation principles. Basic science principles related to rehabilitation following ACL injury and reconstruction have been reviewed. Guidelines incorporating these basic science principles as well as clinical experience were presented for rehabilitation following ACL injury and reconstruction.

Ishibashi, Y., T. W. Rudy, et al. (1997). "The effect of anterior cruciate ligament graft fixation site at the tibia on knee stability: evaluation using a robotic testing system." Arthroscopy 13(2): 177-82.

Despite its current popularity and relative success, endoscopic reconstruction of the anterior cruciate ligament (ACL) using a bone-patellar tendon-bone (BPTB) graft has not yet been perfected. Using a recently developed robotic/UFS testing system, we assessed the overall stability of porcine knees following ACL reconstruction with different sites of tibial graft fixation--proximal, central, and distal. Testing of the intact knee was performed first to determine the normal anterior-posterior (A-P) displacements and in situ forces of the ACL under 110 N of anterior tibial loading of 30 degrees, 60 degrees, and 90 degrees of knee flexion. The knee was then reconstructed with a BPTB autograft, and the distal end of the graft was fixed sequentially at three different locations in each specimen--proximal, central, distal. A-P testing was repeated for each fixation site, and the resulting knee kinematics and the in situ forces of the grafts were compared to the intact case. The site of tibial fixation was demonstrated to have a significant effect on the resulting anterior displacement and internal rotation of the tibia as well as the in situ forces of the graft. Proximal fixation produced the most stable knee (A-P displacements reduced to 120% of intact at 30 degrees and 170% at 90 degrees), becoming significantly less stable with more distal fixation. These results suggest that proximal graft fixation may provide the most acute stability of the reconstructed knee.

Iwasa, J. O., M.; Adachi,N.; Tobita,M.; Katsube,K.; Uchio,Y. (2000). "Proprioceptive improvement in knees with anterior cruciate ligament reconstruction." Clin.Orthop.(381): 168-176.

The correlation between the prospective course of proprioceptive improvement and knee stability after anterior cruciate ligament reconstruction was investigated in 38 patients. Proprioception, on the basis of the patient's capacity to reposition the limb accurately, was evaluated at 3-month intervals for 24 months after hamstring graft anterior cruciate ligament surgery. Knee stability was evaluated concurrently with a KT-2000 knee arthrometer. Thirty patients experienced improvement in postoperative position sense in at least one of the examinations, although eight patients had no improvement at any time. Of the 30 patients who had improvement, 28 maintained improved position sense from 18 months to the final followup. Thirty patients maintained significantly better knee stability for a postoperative period of at least 24 months. These results indicated that a minimum of 18 months after anterior cruciate ligament reconstruction may be needed for complete restoration of the proprioceptive function in knees, although the mean position sense in all patients gradually improved from 9 months. Improvement in postoperative knee stability may have facilitated recovery of proprioception

Jackson, D. W., E. S. Grood, et al. (1993). "A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model." American Journal of Sports Medicine 21(2):176-85, 1993 Mar-Apr 21(2): 176-85.

Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile failure tests, measurement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament reconstruction, the autografts demonstrated a smaller increase in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance. More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorporation, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.

Jackson, D. W., R. Kenna, et al. (1993). "Endoscopic ACL reconstruction." Orthopedics 16(9):951-8, 1993 Sep 16(9): 951-8.

The endoscopic technique offers the advantage of one incision and a femoral osseous tunnel trajectory that is more in line with the collagen fibers of the graft. Technically, it is more demanding to reproducibly obtain the interference fixation than using the two-incision technique. There is a tendency for screw and graft divergence in the femoral tunnel. The exact clinical significance of this screw and bone plug divergence has yet to be clarified. Surgeons must assess their ability to obtain the best results for the patient. There is a definite learning curve for the endoscopic technique. We believe that, with further advances in instrumentation, fixation, and alternative grafts, it will eventually be the approach of preference for ACL reconstructions.

Jackson, D. W. C., J.; Simon,T.M. (1996). "Biologic incorporation of allograft anterior cruciate ligament replacements." Clin.Orthop.(324): 126-133.

Soft tissue allografts allow the orthopaedic surgeon to reconstruct ligaments without having to harvest additional tissue from the patient, which can eliminate donor tissue site morbidity and reduce surgical time. There is still much to be learned about the biologic aspects of the remodeling and incorporation of allografts in comparison with autografts. The interaction of cells, matrix, and biomolecules, such as growth factors, plays an important role that can potentially modulate, enhance, or impede the healing response in allografts. The authors have shown that, in the short term, allografts used in anterior cruciate ligament reconstruction are not as rapidly remodeled and incorporated into host tissue as are autografts. The long-term implications of this slower allograft incorporation in anterior cruciate ligament reconstruction are still unknown. The cells that repopulate allografts and autografts favor production of smaller diameter collagen fibrils, which in sufficient numbers can provide significant strength. Use of allografts raises other issues and potential disadvantages, including scarcity, immunogenicity, the potential for disease transmission, and cost-effectiveness in anterior cruciate ligament reconstruction

Jackson, D. W. W., G.E.; and Simon,T.M. (1990). "Intraarticular reaction associated with the use of freeze-dried, ethylene oxide-sterilized bone-patella tendon-bone allografts in the reconstruction of the anterior cruciate ligament." Am.J. Sports Med., 18: 1-10.

Jackson, R. W. (1988). The torn ACL: natural history of untreated lesions and rationale for selective treatment. the Crucial Ligaments. J. A. Feagin. New York, Churchill Livingstone.

Jansson, K. A. H., A.; Sandelin,J.; Karjalainen,P.T.; Aronen,H.J.; Tallroth,K. (1999). "Bone tunnel enlargement after anterior cruciate ligament reconstruction with the hamstring autograft and endobutton fixation technique. A clinical, radiographic and magnetic resonance imaging study with 2 years follow-up." Knee.Surg.Sports Traumatol.Arthrosc. 7(5): 290-295.

The aim of this study was to describe the contrast-enhanced magnetic resonance imaging (MRI) appearance of bone tunnel enlargement detected on radiography after anterior cruciate ligament (ACL) reconstruction with semitendinosus and gracilis tendon endobutton (STG-endobutton) fixation technique. Fourteen patients with a STG-endobutton ACL reconstruction were examined 3 months (n = 1), 1 year (n = 1) and 2 years (n = 12) postoperatively. An age- and sex-matched group with a bone-patellar tendon-bone (BTB) autograft ACL reconstruction with similar follow-up was taken as control. Data on clinical examination, laxity and isokinetic muscle torque measurements, anteroposterior and lateral view radiography were obtained, and knee scores (Lysholm and Tegner) were collected. Contrast-enhanced MRI was performed in the STG- endobutton group with a 1.5-T imager. There were no statistical differences between the groups with respect to clinical findings, stability tests, or knee scores. In the STG-endobutton group the average femoral and tibial bone tunnel diameter detected on anteroposterior view radiography had increased at 2-year follow-up by 33% and 23%, respectively. On MRI the ligamentous graft itself was not enhanced by the contrast medium whereas periligamentous tissue within and around the STG graft bundles showed mild contrast enhancement. In conclusion, the MRI results suggest that enhancing periligamentous tissue accumulated in and around the STG graft associated with the tunnel expansion. In spite of the significant bone tunnel enlargement observed on the follow-up radiography the STG-endobutton knees were stable and the patients satisfied

Johnson, D. L. and F. H. Fu (1993). "Total quadriceps sparing, endoscopic single-incision anterior cruciate ligament reconstruction using fresh frozen allograft tissue: surgical technique and potential pitfalls." Iowa Orthopaedic Journal 13:115-20, 1993 13: 115-20.

Johnson, D. L., M. D. Miller, et al. (1993). "The arthroscopic "impingement test" during anterior cruciate ligament reconstruction." Arthroscopy 9(6):714-7, 1993 9(6): 714-7.

A primary goal of ACL reconstruction is to avoid graft impingement, which may lead to loss of motion and/or an increased incidence of instability. Although surgeons are cognizant of this potential problem, the intraoperative correction of graft impingement is technically demanding because the graft-notch relationship is obscured by the trochlea articulating with the tibial plateau during the final 10 degrees of extension. We present a simple impingement test that is performed before graft insertion and fixation to help avoid this potential pitfall.

Johnson, D. L. and J. J. Warner (1993). "Diagnosis for anterior cruciate ligament surgery." Clinics in Sports Medicine 12(4):671-84, 1993 Oct 12(4): 671-84.

We have reviewed the important aspects of the history, physical examination, and other diagnostic tools available to help diagnose ACL injuries. We feel that, in the hands of an experienced clinician, greater than 90% of ACL disruptions can be diagnosed at the time of injury. Appropriate evaluation will enable the clinician to advise the appropriate treatment, whether it be operative or nonoperative. We have also briefly outlined the variables that we consider to be the most important in the decision-making process of treatment options after ACL disruption.

Johnson, D. L. B., D.P.; Brand,J.C.; Nyland,J.; Caborn,D.N. (2000). "The effect of a geographic lateral bone bruise on knee inflammation after acute anterior cruciate ligament rupture." Am.J.Sports Med. 28(2): 152-155.

We prospectively evaluated 40 patients who had knee inflammation after isolated anterior cruciate ligament rupture with or without an associated "geographic" bone bruise/subchondral fracture of the lateral femoral condyle. All patients with acute ruptures documented by magnetic resonance imaging within 1 week of injury were evaluated for a geographic bone bruise/subchondral fracture of the lateral femoral condyle. Two groups of 20 patients each (bone bruise versus no bone bruise) were then enrolled. Variables measured at 1, 2, 3, and 4 weeks after injury included pain, range of motion, effusion, and number of days with an antalgic gait. Patients with a bone bruise had increased size and duration of effusion, increased number of days required to nonantalgic gait without external aids, increased days to achieve normal range of motion, and increased pain scores at measured time intervals. This study confirms results of previous clinical and histologic studies showing an associated articular cartilage lesion, otherwise known as bone bruise/subchondral fracture, is clinically significant. There appears to be an association between a geographic bone bruise and increased disability in patients with acute anterior cruciate ligament ruptures. Patients with a geographic bone bruise may require longer to reach normal homeostasis (range of motion, pain, neuromuscular control) before undergoing anterior cruciate ligament reconstruction

Johnson, L. L. (1993). "The outcome of a free autogenous semitendinosus tendon graft in human anterior cruciate reconstructive surgery: a histological study." Arthroscopy 9(2):131-42, 1993 9(2): 131-42.

This report illustrates the outcome of a free human autogenous semitendinosus tendon graft placed in the knee under arthroscopic control for anterior cruciate ligament reconstruction. The tendon graft showed signs of injury by localized loss of normal histochemical staining properties. The cellularity was not diminished in an early (3-week) specimen. The resultant composite anterior cruciate ligament consisted of two distinct areas: tendon graft and surrounding fibrous tissue. The tendon maintained gross and microscopic characteristics of the original tendon. The tissue surrounding the tendon graft had a disorganized cellular pattern and hypervascularity. The tendon graft in this study did not show gross or microscopic evidence of death and reorganization. Previous reports have led to erroneous conclusions concerning the outcome of a free tendon graft due to inaccurate biopsy site of the reorganizing fibrous tissue surrounding the tendon graft.

Johnson, R. J. (1988). Anatomy and biomechanics of the knee. Philadelphia, J.B. Lippincott.

Johnson, R. J. B., B.D.; Nichols,C.E.; Renstrom,P.A. (1992). "The treatment of injuries of the anterior cruciate ligament." J.Bone Joint Surg.Am. 74(1): 140-151.

Johnson, W. L. and R. D. Corzatt (1993). "Ganglion cyst of the anterior cruciate ligament. A case report of an unusual cause of mechanical knee symptoms." American Journal of Sports Medicine 21(6):893-4, 1993 Nov-Dec 21(6): 893-4.

Jomha, N. M., V. J. Raso, et al. (1993). "Effect of varying angles on the pullout strength of interference screw fixation." Arthroscopy 9(5):580-3, 1993 9(5): 580-3.

Arthroscopically assisted reconstruction of the anterior cruciate ligament-deficient knee using a bone-patellar tendon-bone graft is a new and evolving technique. One technically demanding aspect involves the placement under arthroscopic visualization of the femoral interference screw. The effect on pullout strength of changing the angle of the interference screw from 0 degree to 10 degrees, 20 degrees, or 30 degrees with respect to the bone plug was examined. The mean pullout strengths were 621 +/- 82, 594 +/- 48, 508 +/- 66, and 485 +/- 62 N, respectively. We concluded that there was no significant difference in the tensile strength provided by interference screw fixation for angles up to 10 degrees, but that there was a significant (p = 0.0010) weakening of fixation for screw angles > or = 20 degrees.

Jomha, N. M. B., D.C.; Clingeleffer,A.J.; Pinczewski,L.A. (1999). "Long-term osteoarthritic changes in anterior cruciate ligament reconstructed knees." Clin.Orthop.(358): 188-193.

To consolidate the indications for anterior cruciate ligament reconstruction and clarify the long-term prognosis associated with current surgical and rehabilitation techniques, the incidence of osteoarthritis in arthroscopically anterior cruciate ligament reconstructed knees requires investigation. Seventy-two patients with anterior cruciate ligament ruptures who were active in sports requiring sidestepping and pivoting, or who had recurrent episodes of giving way, underwent arthroscopic bone-patellar tendon-bone anterior cruciate ligament reconstruction. These patients were evaluated for meniscal damage and osteoarthritic changes at the time of surgery and followed up for 7 years. Fifty-three patients underwent radiographic evaluation at 7 years, which included anteroposterior, lateral, skyline, and 30 degrees posteroanterior weightbearing views. Radiographic evaluation was performed by three independent surgeons and graded as per International Knee Documentation Committee criteria. Results revealed that knees with chronic anterior cruciate ligament deficiency, even those with intact menisci before reconstruction, suffered early osteoarthritic changes. More severe changes were seen with meniscectomy. Acute anterior cruciate ligament reconstruction with meniscal preservation was shown to have the lowest incidence of degenerative change. Controversy exists regarding the timing of anterior cruciate ligament reconstruction. This study supports early reconstruction of anterior cruciate ligament deficient knees before episodes of giving way occur in individuals intent on continuing activities that involve sidestepping and pivoting

Jomha, N. M. C., A.; Pinczewski,L. (2000). "Intra-articular mechanical blocks and full extension in patients undergoing anterior cruciate ligament reconstruction." Arthroscopy 16(2): 156-159.

Patients with acute anterior cruciate ligament (ACL) rupture frequently present with a lack of full extension. Current literature is unclear whether arthroscopic debridement is necessary before reconstruction to achieve full extension postoperatively. This study examined the postoperative extension achieved in 153 knees that underwent ACL reconstruction within 12 weeks of index injury. All patients performed preoperative physical therapy to increase range of motion and control pain/swelling, regardless of presenting range of motion without prior aspiration or arthroscopy. Of the 153 knees, 103 had meniscal pathology, of which 73 were peripheral vertical tears; 96 of the 153 knees lacked >/=3 degrees extension preoperatively. Five of 96 knees had an intra-articular mechanical block to extension and all regained full extension after ACL reconstruction. This study documented that a true intra-articular mechanical block is unusual in primary ACL ruptures. Lack of full extension can be adequately dealt with during surgical reconstruction without a detrimental effect on knee extension postoperatively

Jomha, N. M. P., L.A.; Clingeleffer,A.; Otto,D.D. (1999). "Arthroscopic reconstruction of the anterior cruciate ligament with patellar-tendon autograft and interference screw fixation. The results at seven years." J.Bone Joint Surg.Br. 81(5): 775-779.

Deficiency of the anterior cruciate ligament (ACL) is a common disorder which can lead to changes in lifestyle. We followed 59 patients who had had arthroscopic reconstruction of the ACL using a central-third patellar-tendon autograft for seven years to assess the long-term effectiveness of recent advances in reconstruction of the ACL. The standard criteria for evaluation of the International Knee Documentation Committee, the Lysholm knee score and measurements using the KT 1000 arthrometer all showed satisfactory results. Deterioration in the clinical performance after seven years was associated with osteoarthritic changes and correlated with chronic ligament injuries and meniscectomy. There were three traumatic and three spontaneous ruptures. We believe that the procedure can be successful, but remain concerned about failure of the graft and osteoarthritis. The results raise questions about the best time to operate and suggest that early surgery may reduce the risk of osteoarthritis

Jones, A. R., D. B. Finlay, et al. (1993). "A deep lateral femoral notch as a sign of acutely torn anterior cruciate ligament." Injury 24(9):601-2, 1993 Oct 24(9): 601-2.

Anterior cruciate ligament (ACL) tears are frequently associated with abnormalities of the lateral femoral condyle as shown by magnetic resonance imaging. The mechanism of injury has been described as due to bone compression during knee trauma. This may lead to compression of the lateral condylopatellar notch (sulcus). It has been suggested that detection of a deep notch on the plain lateral radiograph is a useful indirect sign of ACL tear. Depth of this notch was measured in 34 consecutive prospective patients assessed as having acute ACL tear clinically and proven at arthroscopy. In no patient was the notch deep, suggesting that this is not a useful sign in acute tears of the anterior cruciate ligament.

Jones, M. (1993). "Arthroscopic anterior cruciate ligament repair using patella tendon graft." British Journal of Theatre Nursing 3(9):6-8, 1993 Dec 3(9): 6-8.

Jonsson, H., J. Karrholm, et al. (1993). "Laxity after cruciate ligament injury in 94 knees. The KT-1000 arthrometer versus roentgen stereophotogrammetry." Acta Orthopaedica Scandinavica 64(5):567-70, 1993 Oct 64(5): 567-70.

We examined 94 knees with chronic anterior cruciate ligament injuries, 55 of which had been operated with ligament reconstruction, using the KT-1000 arthrometer (89 N anterior force) and roentgen stereophotogrammetry (RSA, 150 N anterior, 80 N posterior force). In intact knees the tibial displacement did not differ between the methods. In injured knees, operated or not, the KT-1000 recorded smaller AP translations and side-differences than RSA. Thus, the stabilizing effect of reconstructive surgery may be overrated, if evaluated with the standard KT-1000 technique.

Joshi, G. P., S. M. McCarroll, et al. (1993). "Intra-articular morphine for pain relief after anterior cruciate ligament repair [see comments]." British Journal of Anaesthesia 70(1):87-8, 1993 Jan 70(1): 87-8.

We have performed a randomized, double-blind controlled study in patients undergoing elective anterior cruciate ligament repair, to assess the effect of intra-articular morphine on postoperative pain. The morphine group (n = 11) received morphine 5 mg in saline 25 ml and the control group (n = 9), saline 25 ml intra-articularly. Patients in the morphine group had significantly smaller pain scores throughout the 24-h postoperative period compared with those in the control group (P < 0.05). There was less requirement for supplementary analgesics in the morphine group.

Joshi, G. P., S. M. McCarroll, et al. (1993). "Effects of intraarticular morphine on analgesic requirements after anterior cruciate ligament repair." Regional Anesthesia 18(4):254-7, 1993 Jul-Aug 18(4): 254-7.

BACKGROUND AND OBJECTIVES. Intraarticular morphine has been shown to provide postoperative pain relief after knee arthroscopy. The analgesia results from local action within the knee joint. This study was conducted to assess the efficacy of intraarticular morphine as a treatment for postoperative pain after anterior cruciate ligament repair. METHODS. A randomized double blind-study was conducted in patients undergoing elective anterior cruciate ligament repair. Patients in the study group (n = 10) received intraarticularly 5 mg of morphine in a 25 ml dilution. Those in the control group (n = 10) received 25 ml of saline by the same route. Intravenous morphine with patient-controlled analgesia was used in the postoperative period in both the groups. Visual analog scores were recorded at 1, 2, 4, 8, and 24 hours after the operation. The amount of morphine used over the 24-hour postoperative period was documented. RESULTS. The total consumption of morphine over the 24-hour period was significantly lower (p < 0.01) in the study group compared to the control group. The postoperative pain scores were lower in the study group throughout the study period, but this did not reach statistical significance. CONCLUSIONS. Intraarticular morphine reduces analgesic requirements after anterior cruciate ligament repair and is an effective method of providing postoperative analgesia.

Kanai, H. (1993). "[Dynamic analysis in the knees with chronic anterior cruciate ligament insufficiency--an evaluation of antero-posterior instability, leg rotation and ground reaction force]." Nippon Seikeigeka Gakkai Zasshi - Journal of the Japanese Orthopaedic Association 67(7):617-30, 1993 Jul 67(7): 617-30.

A dynamic analysis was made on the knees with chronic anterior cruciate ligament (ACL) insufficiency for antero-posterior instability and abnormal rotation, also evaluating them for ground reaction force and muscle strength of knee extension. Studies were carried out on 51 patients with chronic unilateral ACL insufficiency and 80 knees of 40 healthy male and female young adults as controls. Using a knee motion analyser, an apparatus designed to analyse three dimensional knee motion, the gait was studied on a force plate. At the same time, the muscle strength of knee extension was measured with a Kinetic-Communicator (KIN-COM). In the dynamic analysis of the knee motion anterior instability was notable at a small angle of flexion. Qualitative evaluation of the knee motion revealed three patterns of rotation. The evaluation of ground reaction force showed that the rise from the heel strike was slow, its slope was gentle and the effect of weight removal was unclear. The evaluation of the muscle strength of knee extension revealed a decrease in torque of muscular contraction at 20 degrees of knee flexion.

Kaneko, K., E. H. De Mouy, et al. (1993). "Distribution of joint effusion in patients with traumatic knee joint disorders: MRI assessment." Clinical Imaging 17(3):176-8, 1993 Jul-Sep 17(3): 176-8.

One hundred forty-five knee magnetic resonance imaging examinations with joint effusions were reviewed to clarify the usual distribution of joint fluids in patients with traumatic knee joint disorders. Almost all knees (99%) had effusions in the central portion, and most knees (76%) had effusions in the suprapatellar pouch. Effusions were rarely found in the posterior femoral recess (9%) or subpopliteal recess (2%). However, this difference was considered to be only a reflection of anatomic communications. Effusions were occasionally found around posterior cruciate ligaments (36%), but were less frequently seen around anterior cruciate ligaments (18%).Kaneko, K., E. H. Demouy, et al. (1993). "Correlation between occult bone lesions and meniscoligamentous injuries in patients with traumatic knee joint disease." Clinical Imaging 17(4):253-7, 1993 Oct-Dec 17(4): 253-7.

To identify any correlation between the distribution of occult bone lesions and meniscoligamentous injuries, magnetic resonance images of 333 patients with traumatic knee joint disease were reviewed. Bone lesions of the knee were commonly associated with medial meniscal injuries and/or anterior cruciate ligament injuries. While knees with bone lesions showed a higher incidence (P < 0.05) of anterior cruciate ligament injury than knees without bone lesions, the presence of a lateral femoral condylar lesion resulted in a significantly higher incidence of anterior cruciate ligament injuries (P < 0.01). However, no significant positive correlation was found between other occult bone lesions and meniscoligamentous injuries.

Kannus, P., and Jarvinen, Markku (1987). "Conservatively treated tears of the anterior cruciate ligament. Long-term results." J.Bone and Joint Surg 69A: 1007-1012.

Karageanes, S. J. B., K.; Vangelos,Z.A. (2000). "The association of the menstrual cycle with the laxity of the anterior cruciate ligament in adolescent female athletes." Clin.J.Sport Med. 10(3): 162-168.

OBJECTIVE: To identify a significant change in the laxity of the anterior cruciate ligament (ACL) in the competitive adolescent female athlete throughout the different phases of the menstrual cycle. DESIGN: Prospective, single-blinded 8-week study set during a winter sports season. SETTING: Suburban Ohio Division I high school. PARTICIPANTS: 26 members of gymnastics, soccer, track, tennis, and basketball teams. All participants were screened for normal menstrual cycles (26-30 days, menses 4-7 days long). MAIN OUTCOME MEASURES: KT-1000 arthrometer was used to measure laxity by performing repeated measures throughout an 8- week period. Measurements were taken before the athletes' workouts. The athlete charted the menstrual periods on a monthly calendar. The measurements were then grouped into the three phases of the menstrual cycle (follicular, ovulatory, and luteal) and averaged. RESULTS: Right knee laxity measured 4.98 mm follicular phase, 5.24 mm ovulatory, and 5.09 mm luteal. Left knee laxity measured 4.51 mm follicular, 4.43 mm ovulatory, and 4.62 mm luteal. There was no statistical difference among the three phases in the left (p = 0.9) and right (p = 0.7977). Additionally, left ACL laxity was significantly less in all three phases. We found no statistically significant variability in laxity among the five sports sampled (p > 0.63 to 0.10) and different ages (p = 0.404). CONCLUSIONS: We found an insignificant change in ACL laxity from follicular to luteal phases of the menstrual cycle. This indicates that no single phase of the menstrual cycle clinically affects the ACL more than the next. Although the presence of sex hormones-particularly estrogen-may indeed predispose females to higher ACL injury rates, we did not find any evidence that hormonal level changes equate with significant ACL laxity changes. We conclude that the menstrual cycle does not significantly affect ACL laxity in the competitive adolescent female athlete

Kartus, J. E., L.; Sernert,N.; Brandsson,S.; Karlsson,J. (2000). "Comparison of traditional and subcutaneous patellar tendon harvest. A prospective study of donor site-related problems after anterior cruciate ligament reconstruction using different graft harvesting techniques." Am.J.Sports Med. 28(3): 328-335.

Our goal was to compare the results after anterior cruciate ligament reconstruction using either the traditional one-incision or the subcutaneous two-incision technique to harvest the central third of the patellar tendon, particularly concerning disturbances in anterior knee sensitivity and the patient's ability to walk on his or her knees. One surgeon performed anterior cruciate ligament reconstruction on 124 patients with unilateral ruptures and no history of previous incisions in the anterior knee region. The traditional one-incision graft harvesting technique was used in 58 patients and the subcutaneous two- incision technique was used in 66 patients. At 2 years, the International Knee Documentation Committee classification, Lysholm score, arthrometry side-to-side difference, and single-legged hop test showed no significant differences between groups. The area of insensitivity was a median of 24 cm2 in the traditional harvest group and 0 cm2 in the subcutaneous harvest group. The patients with subcutaneous harvest had a tendency toward fewer problems during walking on their knees than did the patients with traditional harvest. Our conclusion is that the subcutaneous two-incision graft harvesting technique caused less disturbance in anterior knee sensitivity and a tendency of less discomfort during walking on one's knees than the traditional one-incision technique

Kartus, J. M., L.; Stener,S.; Brandsson,S.; Eriksson,B.I.; Karlsson,J. (1999). "Complications following arthroscopic anterior cruciate ligament reconstruction. A 2-5-year follow-up of 604 patients with special emphasis on anterior knee pain." Knee.Surg.Sports Traumatol.Arthrosc. 7(1): 2-8.

The aim of the study was to assess knee function after arthroscopic anterior cruciate ligament reconstruction and to analyse complications impeding rehabilitation, additional surgery until the final follow-up, as well as residual patellofemoral pain and donor-site problems. Between 1991 and 1994, 635 patients were operated on using patellar tendon autografts and interference screw fixation. Of these, 604 (95.1%) patients (403 male and 201 female) were re-examined by independent observers at the final follow-up 38 (range 21-68) months post-operatively. The Lysholm score was 85 (range 14-100) points and the Tegner activity level was 6 (range 1-10). Using the IKDC score, 206 patients (34.1%) were classified as normal, 244 (40.4%) as nearly normal, 122 (20.2%) as abnormal and 32 (5.3%) as severely abnormal. In patients with an uninjured contralateral knee (n = 527), the KT-1000 revealed a total side-to-side difference of 1.5 (range -7-11) mm, and 384/527 (72.9%) had a side-to-side difference of < or = 3 mm. The one- leg-hop test was 95% (range 0%-167%). One or more complications impeding rehabilitation were recorded in 184/604 patients (30.5%). The most common was an extension deficit (> 5 degrees), in 81 patients (13.4%). During the period until the final follow-up, 196 re-operations were performed in 161/604 (26.7%) patients. More than one re-operation was required in 27 patients. Shaving and anterior scar resection due to extension deficit were the most common procedures performed (on 65 occasions). Moderate to severe subjective anterior knee pain related to activity, walking up and down stairs, and sitting with the knee flexed was found in 203/604 patients (33.6%). The median loss of anterior knee sensitivity was 16 (range 0-288) cm2. Patients with a full range of motion had less anterior knee pain than patients with isolated flexion or extension deficits, or combined flexion and extension deficits (P < 0.05, P = 0.08 and P < 0.001, respectively). Patients with a full range of motion had less anterior knee pain than patients with extension deficits (with and without flexion deficits) (P < 0.001). Patients with a full range of motion and a minimal loss (< or = 4 cm2) of anterior knee sensitivity had significantly (P < 0.01) less subjective anterior knee pain than patients who did not fulfil these criteria. A considerable number of complications hindering the rehabilitation and conditions requiring additional surgery until the final follow-up were recorded. Anterior knee pain and problems with knee-walking were correlated with the loss of range of motion and anterior knee sensitivity

Kdolsky, R., O. Kwasny, et al. (1993). "Synthetic augmented repair of proximal ruptures of the anterior cruciate ligament. Long-term results of 66 patients." Clinical Orthopaedics & Related Research (295):183-9, 1993 Oct(295): 183-9.

The long-term results (five-to eight-year follow-up evaluation) of 66 patients with high proximal ruptures of the anterior cruciate ligament (ACL) who were treated operatively are presented in a retrospective and uncontrolled study. Technique of surgery was the reinsertion of the ACL in a multiple suture loop technique, augmented with Kennedy-LAD (ligament augmentation device) on over the top route in temporary double-end fixation. This technique was used in patients with proximal rupture of the anterior cruciate ligament found at arthroscopy. In the follow-up as well as in instrumented measurement, 97% of the knee joints have normal joint laxity. According to the evaluation sheet designed by the Orthopadische Arbeitsgemeinschaft Knie (OAK), excellent or good results were found in 86% of the patients. Nine percent had limited range of motion. The ACL reconstruction technique allowed 75% of the patients to regain their preinjury sports activity level. The potential advantages of synthetic augmented reinsertion of the ACL are anatomic reconstruction without destruction of other anatomic structures as grafts; securing early rehabilitation with weight bearing of the operated limb depending on individual pain tolerance; and presenting excellent long-term results of normal joint laxity.

Keene, G. (2000). "Arthroscopic reconstruction of the anterior cruciate ligament. A comparison of patellar tendon autograft and four-strand hamstring tendon autograft." Am.J.Sports Med. 28(3): 438.

Keene, G. C., D. Bickerstaff, et al. (1993). "The natural history of meniscal tears in anterior cruciate ligament insufficiency." American Journal of Sports Medicine 21(5):672-9, 1993 Sep-Oct 21(5): 672-9.

We reviewed the meniscal status of 176 consecutive patients undergoing anterior cruciate ligament reconstruction acutely (less than 6 weeks from injury), subchronically (6 weeks to 12 months from injury), and chronically (more than 12 months from injury). The commonest tear was the single longitudinal vertical split of the medial meniscus. There was an increasing incidence of meniscal tears as the injury became more chronic, with a significant (P < 0.001) increase in medial meniscal tears; the incidence of lateral meniscal tears remained relatively constant. Seventy-five (43%) of the patients had one or both menisci repaired. Acutely, repair was performed more frequently on the medial meniscus than the lateral (80% versus 24%, respectively). All repaired menisci had single longitudinal tears unstable to probing. The incidence of repair dropped to 46% in the medial meniscus and 14% in the lateral meniscus in the chronic stage. Nineteen (25%) of these 75 patients (26 menisci) underwent a check arthroscopy at a minimum of 6 months from repair. All 21 medial menisci and all 5 lateral meniscal tears had healed; however, 1 lateral meniscus had torn along the line of the sutures. At an average followup of 40 months, 92% of the repaired menisci were still in situ and 8% that had required resection were related to the recurrence of anterior cruciate ligament instability. This study highlights the increasing incidence of meniscal injury in chronic anterior cruciate ligament insufficiency with the meniscal tears becoming more complex and therefore less amenable to suture.(ABSTRACT TRUNCATED AT 250 WORDS)

Kenna, B., T. M. Simon, et al. (1993). "Endoscopic ACL reconstruction: a technical note on tunnel length for interference fixation." Arthroscopy 9(2):228-30, 1993 9(2): 228-30.

The total length of bone-patella tendon-bone autografts can vary significantly between individuals. Grafts that are "too long" may protrude from the tibial tunnel site, precluding interference screw fixation. A simple calculation can be used to estimate the length of the tibial tunnel required to accommodate the graft. An intraoperative final check can be made with a calibrated drill. This distance should accommodate the total graft length. If necessary, minor adjustments that include trimming the bone plugs or deepening the femoral osseous tunnel can be made to prevent graft protrusion.

Kerboull, L., P. Christel, et al. (1993). "[Influence of the suture technique and material on the mechanical behavior of a reinforced Mac Intosh graft]." Revue de Chirurgie Orthopedique et Reparatrice de l Appareil Moteur 79(3):185-93, 1993 79(3): 185-93.

The anterior cruciate ligament reconstruction by a biological graft augmented by a synthetic device allows theoretically to increase the strength of the composite graft during the remodeling period. The technical realization of the reinforcement is still controversial because it is difficult to obtain a mechanical compromise between a real effect of protection of the graft and a load sharing to favour the remodeling. When the graft and the augmentation device are tied together the ligature between them plays a fundamental mechanical role. The first goal of the present study was to define by calculation and experimentation the influence of the suturing method on the strength of the graft-device ligature. The second goal was to appreciate the possibility of using absorbable suture in such an application. Calculation allowed to show that the weakest area of the composite graft was the junction between the augmented and unaugmented parts of the graft. When increasing number and anchorage of sutures in this critical area it was possible to double the resistance of the ligature. To define the outcome of absorbable suture the strength decrease was measured during the resorption period. Two threads were tested: the polyglactin 910 (Vicryl) and the polydioxanon (PDS). The strength decrease was sudden and rapid for the Vicryl (50 p. cent in 3 weeks). For the PDS the strength loss was more gradual (50 p. cent in 8 weeks). With these two threads the strength duration appeared as incompetent to allow the augmentation to protect the graft during all the remodeling period.

Kitsuda, M. (1993). "[An experimental study on the replacement of the anterior cruciate ligament of the rabbit's knee using an augmented substitute]." Nippon Ika Daigaku Zasshi - Journal of the Nippon Medical School 60(2):95-104, 1993 Apr 60(2): 95-104.

The mechanical properties of a reconstruction of the anterior cruciate ligament (ACL) using an augmented substitute were investigated in rabbits' knees. After total resection of the ACL, 25 knees were reconstructed with a patellar tendon alone (nonaugmented group) and 25 with a patella tendon augmented by a Leeds-Keio artificial ligament (augmented group). The rabbits were sacrificed for biomechanical testing at 0, 4, 8, 12 and 24 weeks, respectively, after operation. In the augmented group, the mean ultimate load was 48.8% of the original ACL load at 4 weeks, and this gradually increased to 65.6% at 8 weeks. That of the twenty-four-week specimens was restored to 71% of the original ACL load. In the nonaugmented group, the mean ultimate load decreased to 9.3% at 8 weeks, but increased to 37.5% at 24 weeks. The mean static stiffness in the augmented group was higher than in the nonaugmented group at all time periods. The differences between the augmented and nonaugmented groups were statistically significant in the 8 to 12 week period (p < 0.01). Tan delta values, exhibiting the magnitude of viscosity in a viscoelastic material, in the augmented group were significantly higher than those in the nonaugmented group at 8 weeks (p < 0.05) and 12 weeks (p < 0.01). The mean tan delta in the augmented group decreased to 0.08 +/- 0.04 at 24 weeks, but the values were higher than those of the original ACL. The mean dynamic elastic modulus in the augmented group was higher than in the nonaugmented group at all time periods. The difference between the augmented and nonaugmented groups was statistically significant in the 8th week (p < 0.05). The values of dynamic elastic modulus in both groups were increased at 24 weeks: 96.4 MPa in the augmented group, and 77.5 MPa in the nonaugmented group. It was demonstrated that the augmented ligaments used for anterior cruciate ligament reconstruction had greater strength and static stiffness than the patellar tendon autograft. As for dynamic properties, the augmented group showed higher viscosity group than ACL.

Klos, T. V. H., M.K.; Habets,R.J.; Devilee,R.J.; Banks,S.A. (2000). "Locating femoral graft placement from lateral radiographs in anterior cruciate ligament reconstruction: a comparison of 3 methods of measuring radiographic images." Arthroscopy 16(5): 499-504.

Graft positioning in anterior cruciate ligament (ACL) reconstruction is usually documented from lateral postoperative radiographs. The purpose of this study was to compare 3 measurement methods for femoral graft placement in 50 patients with ACL reconstruction. Intraoperative radiographic images were obtained and divided into 2 groups. The first group showed suboptimal projections, with out-of-plane rotations causing the femoral condyles to not be perfectly overlapped. The second group showed good projection, with optimal rotation and fully overlapped femoral condyles. In our study, only the measurement technique described by Amis produced data with the least measurement error when multiple observers assessed both groups. It is recommended that Amis' method be used to measure femoral ACL graft position so that reliable data are available for comparison between medical centers

Kobayashi, S. and K. Terayama (1993). "Quantitative stress radiography for diagnosis of anterior cruciate ligament deficiency. Comparison between manual and instrumental techniques and between methods with knee flexed at 20 degrees and at 90 degrees." Archives of Orthopaedic & Trauma Surgery 112(3):109-12, 1993 112(3): 109-12.

A portable stress-applying device for stress radiography was developed for daily clinical use. Using this device, stress radiography for the diagnosis of the anterior cruciate ligament (ACL) deficiency was performed with the knee flexed at 20 degrees and at 90 degrees. A 100-N force was chosen as a standardized stress. The subjects were classified into four groups: the manually tested ACL-deficient group (32 knees), the manually tested control group (80 knees), the instrumentally tested ACL-deficient group (14 knees), and the instrumentally tested control group (34 knees). There was no statistical difference in the reliability (sensitivity, specificity, and accuracy) of stress radiography between the manual technique and the instrumental technique. When stress radiography with the knee flexed at 20 degrees and that at 90 degrees were compared, the former was more reliable than the latter. As the manual technique is compromised by a lack of standardization in applied force, a mechanical device is required in quantitative stress radiography. The reliability of stress radiography with the knee flexed at 20 degrees is considered high enough to warrant dispensing with further stress radiography with the knee flexed at 90 degrees for diagnosing ACL deficiency.

Kohn, D. R., S. (2000). "Strategies for interventional revisions in failed anterior cruciate ligament reconstruction." Chirurg 71(9): 1055-1065.

Anterior cruciate revision reconstruction is gaining more and more importance. Postoperative infection, a painful knee, limited range of motion and instability may make a second operation necessary. Results after revision ACL reconstruction are worse than results after primary ACL reconstruction. Analysis of the causes of failure and a therapeutic concept that is tailored to the individual case are preconditions for a successful reintervention. Revision ACL reconstruction has to be performed by an experienced knee surgeon who masters all the necessary techniques, from arthroscopy to arthrotomy and should be carefully planned

Kramer, J., D. Nusca, et al. (1993). "Knee flexor and extensor strength during concentric and eccentric muscle actions after anterior cruciate ligament reconstruction using the semitendinosus tendon and ligament augmentation device." American Journal of Sports Medicine 21(2):285-91, 1993 Mar-Apr 21(2): 285-91.

The purposes of this study were to compare operated and nonoperated knees after anterior cruciate ligament reconstruction using the semitendinosus tendon and a polypropylene ligament augmentation device, and to determine the interrelationships among strength, knee stability, and current activity levels. Isokinetic tests for knee flexion (prone position) and extension (sitting position) strength during concentric-eccentric muscle action cycles were completed at 60 and 180 deg/sec angular velocities, and passive anterior displacement were determined for 15 male and 15 female patients (mean age, 27 +/- 8 years; mean time since surgery, 21 +/- 3 months). With the exception of eccentric muscle actions during knee extension, peak torque and work done were significantly greater on the nonoperated leg (P < 0.05). Passive anterior displacement was significantly greater in the operated than the nonoperated knee (P < 0.01). Strength measurements tended to be modestly related to current activity level (R > 0.40 in 24 of 32 correlations; P < 0.05), whereas anterior displacement was not related to current activity level (R = -0.19, operated knee; R = -0.09, nonoperated knee; P > 0.05). Greater emphasis should be directed toward strengthening the knee flexors and knee extensors after this surgery. Although joint-specific tests (completed actively via isokinetic dynameter) are more related to activity levels than are knee laxity tests (completed passively via knee arthrometer), neither test should be relied on as the only predictor of activity level in this patient population.

Kuhne, J. H. and H. J. Refior (1993). "[Primary suture of the anterior cruciate ligament. A critical analysis]." Unfallchirurg 96(9):451-6, 1993 Sep 96(9): 451-6.

Recently some authors have claimed that primary repair of an acute tear in the anterior cruciate ligament will fail in the long run. A review of the literature reveals that this opinion is mainly based on an American study in 1976. However, the poor results presented in this study were never reproduced. The study is critically analyzed, and 14 more papers presenting successful primary reconstructions of the anterior cruciate ligament are discussed. Preserving proprioceptive structures may be an important advantage of this technique, as it is hypothesized that the anterior cruciate ligament functions as a significant sensory organ, not only providing proprioceptive information, but also initiating protective and stabilizing muscular reflexes. In conclusion, it is recommended that primary suture be used combined with intra-articular semitendinosus tendon augmentation for rapid rehabilitation in cases of acute tears in the anterior cruciate ligament.

Kumar, V. P. and K. Satku (1993). "The false positive Lachman test." Singapore Medical Journal 34(6):551-2, 1993 Dec 34(6): 551-2.

Five patients with isolated rupture of the posterior cruciate injury following road traffic accidents were noted to demonstrate a "positive Lachman test". Stress radiographs while performing the Lachman manoeuvre confirmed that all 5 patients had only a posterior cruciate injury. Attention is drawn to the "false positive Lachman test" that indicates a posterior cruciate injury. The presence of a sag sign also establishes a diagnosis of posterior cruciate rupture and a positive Lachman test in this situation must be interpreted with caution.

Kurosaka, M. Y., S.; and Andrish,J.T. (1987). "A biomechanical comparison of different surgical techniques of graft fixation in anterior cruciate ligament reconstruction." Am. J. Sports Med 15: 225-229.

Kurzweil, P. R. (1999). "Formula to calculate the length of the tibial tunnel with endoscopic ACL reconstruction to avoid graft-tunnel mismatch." Arthroscopy 15(1): 115-117.

Kwan, M. K., T. H. Lin, et al. (1993). "On the viscoelastic properties of the anteromedial bundle of the anterior cruciate ligament." Journal of Biomechanics 26(4-5):447-52, 1993 Apr-May 26(4-5): 447-52.

The nonlinear viscoelastic properties of the anteromedial (AM) bundle of porcine anterior cruciate ligament (ACL) were characterized by using a new analytical approach based on the quasi-linear viscoelastic theory. Stress relaxation and cyclic tensile tests were performed. Using the solution derived from this approach, we curve-fitted data from the stress relaxation test to determine the viscoelastic coefficients for the ligament bundles. The coefficients were verified by comparison of the predicted and the experimental results from the cyclic tensile test. The ACL AM bundle exhibited significant stress relaxation with time; a reduction of more than 50% of the peak value occurred during the 2-h experiment. Also, the reduced relaxation function for the ACL AM bundle was not a linear function of logarithmic time, as is commonly assumed for many soft tissues. The new approach, which takes into account the finite strain rate of the ramp function used in the stress relaxation test, provides an accurate description of this nonlinear stress relaxation behavior.

Lahoda, L. U. (1993). "[Comparison of parallel and divergent augmented reconstructions of the anterior cruciate ligament]." Wiener Klinische Wochenschrift 105(19):558-9, 1993 105(19): 558-9.

Laitinen, O., T. Pohjonen, et al. (1993). "Mechanical properties of biodegradable poly-L-lactide ligament augmentation device in experimental anterior cruciate ligament reconstruction." Archives of Orthopaedic & Trauma Surgery 112(6):270-4, 1993 112(6): 270-4.

The mechanical properties, including maximum load, elongation, and axial rigidity, of the biodegradable poly-L-lactic acid (PLLA) ligament augmentation device were investigated, 6, 12, 24, and 48 weeks after experimental anterior cruciate ligament (ACL) repair in 32 sheep. In 16 sheep the cut ACL was removed and reconstructed with the fascia lata augmented with a braided PLLA implant 3.2 mm in diameter. In 16 sheep the ACL was cut from its midportion, sutured, and then augmented with a PLLA implant. The contralateral knee served as a control. At 6 weeks the maximum loads of the reconstructed ACL in the fascia lata-PLLA and primary suture-PLLA groups were 9% and 6%, respectively, of the contralateral ACL, but they increased with time and at 48 weeks were 21% and 12%, respectively, of the control. In the fascia lata-PLLA group the increase in maximum load was evident (P < 0.05) during the follow-up period. During the first 12 weeks the axial rigidity (expressing the elasticity of the reconstruction) was poor, especially in the high-stress region corresponding to the tensile load close to the maximum load. Thereafter the axial rigidity increased, being 48% of the control in the fascia lata-PLLA group and 29% in the primary suture-PLLA group at 48 weeks. In the low-stress region between 10 N and 100 N the increase in axial rigidity in the fascia lata-PLLA group was apparent (P < 0.05) throughout the follow-up, with values of 72% of the control in the fascia lata-PLLA and 47% in the primary suture-PLLA grou

Lam, J. J., A. K. Poon, et al. (2001). "Modified cross-pin femoral fixation using long needles, polydioxanone suture, and traction suture for hamstring anterior cruciate ligament reconstruction." Arthroscopy 17(3): 324-328.

The use of cross-pin femoral fixation in anterior cruciate ligament (ACL) reconstruction using semitendinosus and gracilis (ST/G) tendons has been shown to be biomechanically sound. As a result of some technical problems that we encountered, we modified the technique of the DePuy OrthoTech Xact ACL Graft Fixation System (DePuy, Warsaw, IN) using No. 2/0 polydioxanone suture (PDS) with long needles normally used for inside-out meniscal repair. In addition, a No. 5 Ethibond suture loop (Ethicon, Somerville, NJ) is used for traction of the ST/G graft up the femoral tunnel. Using a 2-suture loops technique, the traction suture loop offers a more effective in-line pull for the graft and it pulls the ST/G loops slightly higher than the alignment PDS. By so doing, it lessens the chance of kinking the alignment guidewire or even amputating the graft. Although not reported in literature, this type of graft complication is possible in other single-alignment suture or guidewire techniques.

Lane, J. G., P. McFadden, et al. (1993). "The ligamentization process: a 4 year case study following ACL reconstruction with a semitendinosis graft." Arthroscopy 9(2):149-53, 1993 9(2): 149-53.

This study evaluates the histological and biochemical changes that occurred in a semitendinosis autograft 4 years after intraarticular placement as an anterior cruciate ligament (ACL) substitute in a human patient. The graft was harvested during total knee replacement. Comparison to harvested ACL and hamstring tendon was made. Changes in collagen crimp pattern, cell type, glycosaminoglycan composition, and collagen crosslinking were present between the ACL autograft and the hamstring tendon. The appearance and biochemical properties of the semitendinosis autograft and the native ACL were similar 4 years following intraarticular placement. These observed phenomena could be attributed to functional adaptation, supporting the concept of ligamentization.

Lazovic, D. and K. Messner (1993). "Collagen repair not improved by fibrin adhesive. Cruciate ligament ruptures studied in dogs." Acta Orthopaedica Scandinavica 64(5):583-6, 1993 Oct 64(5): 583-6.

The anterior cruciate ligament in 30 dogs was transected and repaired by simple suture. In every other dog, fibrin adhesive (Tisseel Kit, Immuno AG, Vienna, Austria) was applied to the transection area before suturing. The proportion of organized versus unorganized and inflammatory tissue formation was assessed histologically. At 3 weeks, the amount of normal organized collagenous tissue was reduced to 20 percent both without and with fibrin adhesive. After 6 weeks, a substantial increase of organized collagenous tissue was observed after suture only, which at 12 weeks reached about 70 percent of the total area. In contrast, repair with fibrin adhesive had at 12 weeks only 30 percent of normal collagenous tissue.

Le Vot, J., J. C. Solacroup, et al. (1993). "[Correlations between the clinical test/MRI/arthroscopy in acute knee injuries]." Journal de Radiologie 74(10):483-92, 1993 Oct 74(10): 483-92.

Authors study retrospectively 81 cases of isolated recent (less than three months) knee traumas. These include clinical aspects, NMR, arthroscopy. Clinical examinations have been graded: 1. possible lesion; 2. likely lesions; 3. confirmed lesions. Clinical examinations and NMR results are compared to arthroscopy considered as reference. Clinical examination of acute traumatic knee is essential. Nevertheless, its value for detecting precise lesions is poor, except for knee locking well correlated with meniscal tears. Results show that NMR provide better results than clinical examination. NMR is reliable for detecting tears of posterior cruciate ligament, tears of posterior horn of menisci (sensibility: 93%; specificity: 80%). Its results are less effective for appreciation of lesion of anterior cruciate ligament (sensibility: 88%; specificity: 78%) because of partial tears and functional but not morphologic damage. It is the only method able to evidence osteochondral injuries and soft-tissues associated lesions in traumatic knees. Emergency NMR scans show results no differences in results compared with routine examinations. However, one should keep in mind that negative NMR cannot exclude small cartilaginous lesions and partial tears of anterior cruciate ligament. According to these results and the known qualities of NMR (non invasive), we propose that this type of investigation should be more largely included in diagnostic attitude for acute injured knee. Emergency diagnostic arthroscopy could be efficiently replaced by NMR knee examination.

Lehnert, M., A. Eisenschenk, et al. (1993). "Results of conservative treatment of partial tears of the anterior cruciate ligament." International Orthopaedics 17(4):219-23, 1993 17(4): 219-23.

The diagnosis of an acute partial tear of the anterior cruciate ligament was made in 56 patients who did not undergo surgical repair. After a period of up to 5 years, 39 returned for follow up evaluation. They were divided into three groups according to clinical analysis of the knee and the Lysholm-Gillquist score. Our aim was to determine their long term functional limitations. 56% had progressed to anterior cruciate ligament deficiency at the time of follow up. This came about not only after resuming sporting activities, but also occurred in those who were not so active. Our results suggests that a partial tear leaves an irreversible defect which may progress to a complete tear, especially in young athletes engaged in active sport.

Lemos, M. J., J. Albert, et al. (1993). "Radiographic analysis of femoral interference screw placement during ACL reconstruction: endoscopic versus open technique." Arthroscopy 9(2):154-8, 1993 9(2): 154-8.

Fifty patients with anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft performed by two techniques were evaluated roentgenographically to compare the position of the femoral interference screws. Group I consisted of 25 patients in whom the screw was placed using a distal lateral femoral incision (the two-incision technique). Group II patients underwent arthroscopically assisted intraarticular placement of the screw. These patients were then evaluated with anterior-posterior (AP) and lateral roentgenograms. We observed that the AP and lateral screw angles were significantly different with the two techniques. In addition, the endoscopic placement of the femoral screw had an associated divergence of the screw relative to the bone plug in nine of 25 patients compared with zero of 25 in the open group. In conclusion, radiographic differences do exist between femoral interference screws placed for fixation of an ACL graft using the open approach and those placed endoscopically. Although the clinical significance of these differences is not known, we raise the question of greater divergence in femoral interference screw placement with the newer intraarticular femoral interference screw placement techniques.

Lephart, S. M., M. S. Kocher, et al. (1993). "Quadriceps strength and functional capacity after anterior cruciate ligament reconstruction. Patellar tendon autograft versus allograft." American Journal of Sports Medicine 21(5):738-43, 1993 Sep-Oct 21(5): 738-43.

Harvesting the central third of the patellar tendon for autograft anterior cruciate ligament reconstruction is thought to compromise quadriceps strength and functional capacity. We compared objective measurements of quadriceps strength and functional capacity in athletes after patellar tendon autograft or allograft anterior cruciate ligament reconstruction. We looked at 33 active male patients (mean age, 24.3 years) who had anterior cruciate ligament reconstructions 12 to 24 months earlier using patellar tendon autograft (N = 15) or allograft (N = 18) techniques. All patients underwent an intensive rehabilitation program. Quadriceps strength and power were assessed by measuring peak torque at 60 and 240 deg/sec, torque acceleration energy at 240 deg/sec, and the quadriceps index using a Cybex II isokinetic testing device. Functional capacity was evaluated based on the results of 3 specially designed functional performance tests and the hop test. Results revealed no significant difference between autograft and allograft groups with respect to any of these parameters. These findings indicate that harvesting the central third of the patellar tendon for autograft anterior cruciate ligament reconstruction does not diminish quadriceps strength or functional capacity in highly active patients who have intensive rehabilitation. Thus, the recommendation to avoid patellar tendon autograft anterior cruciate ligament reconstruction to preserve quadriceps strength and functional capacity may be unnecessary.

Lerat, J. L., B. Moyen, et al. (1993). "[Anterior laxity and internal arthritis of the knee. Results of the reconstruction of the anterior cruciate ligament associated with tibial osteotomy]." Revue de Chirurgie Orthopedique et Reparatrice de l Appareil Moteur 79(5):365-74, 1993 79(5): 365-74.

Fifty-one knees were reviewed out of 53 which had been operated on (between 1981 and 1991) for instability due to a long-standing rupture of the anterior cruciate ligament (A.C.L.), associated with medial arthritis related to a varus deformity. They had undergone a reconstruction of the cruciate ligament using the patellar tendon (5 cases had received an artificial ligament) and a high tibial osteotomy. In 80 per cent of cases this was an opening osteotomy with interposition of a heterologous bone graft, and in 39 cases it was a closing osteotomy. The average age was 37 +/- 6 years. The oldest patient was 58 years old. 80 per cent of cases were men and 88 per cent of the patients practised sport on a regular basis at the time of the accident. The average delay before surgery was 9.5 years. Almost all the patients has already undergone a medial meniscectomy and there were deep cartilaginous lesions and the bone was exposed in 50 per cent of cases. 28 knees were reexamined after a follow-up of over 4 years. Based on the ARPEGE score the results on pain and stability were good. Return to sport has been possible for 43 per cent of patients. Pivot shift, which was constant before surgery (grade 2 or 3), disappeared in 20 cases and was estimated at grade 1 in 8 cases (of which 6 had suffered a rupture of the graft). For the 20 cases in which the reconstruction of the A.C.L. had held, the average anterior radiological subluxation was 4.3 +/- 3.2 mm (from 2 to 14 mm) and the average gain after surgery was 6.7 +/- 3.7 mm (from 2.5 to 18 mm). The femoro-tibial angle went from an average of 6 degrees of varus to 3 degrees of valgus. The opening osteotomy was more precise for correction in the frontal plane. A large valgus (over 3 degrees) was not desirable and a hypercorrection was occasionally difficult to accept by relatively young patients who are likely to take up sport again. The osteotomy often involuntarily modified the normal posterior tibial plateau slope (especially closing osteotomy). A backwards increase of the tibial plateau slope is a factor which increases the anterior subluxation of the femur on the tibia. This is confirmed before and after surgery. It seems preferable to decrease the tibial slope during the osteotomy in order to protect the A.C.L. reconstruction.(ABSTRACT TRUNCATED AT 400 WORDS)

Letsch, R. and J. M. Garcia-Schurmann (1993). "[Experimental evaluation of various anchoring techniques for synthetic ligaments]." Unfallchirurgie 19(2):74-80, 1993 Apr 19(2): 74-80.

One of the weak points of augmentation or replacement of cruciate ligaments by synthetic material is the fixation of these artificial ligaments to the bone. The present investigation examines the mechanical properties of a newly developed anchoring technique (ligament fixation device = LFD) in regard to linear and maximum load, stiffness, creep, and long-term durability compared to single staples, double staples in belt buckle technique, and passing the ligament through an additional bone tunnel. The tests are carried out on cadaver knees and plastic bones under standardized conditions with the same artificial ligament in all experiments (Trevira hochfest). The LFD shows a linear load of 1866 N in cadaver knees and 1874 N in plastic bones. The stiffness is 68.3 N/mm respectively 51.9 N/mm, the elongation at 500 N load 12.7 mm respectively 10.9 mm. In the hysteresis tests with submaximum loads the ligament/LFD-unit lasts 8515 cycles in the plastic bone and 4431 cycles in the cadaver knee. These results are significantly superior to all other fixation techniques concerning linear load, stiffness and long-term durability. They permit aggressive functional treatment and immediate postoperative weight bearing of the operated knee.

Letsch, R., K. M. Sturmer, et al. (1993). "[Suture protection of acute ruptured anterior cruciate ligament by the Pet-band (Trevira extra strong). Indications, technique results of a five-year study]." Unfallchirurg 96(10):499-507, 1993 Oct 96(10): 499-507.

In a prospective clinical study 56 acute tears of the anterior cruciate ligament (ACL) were treated between 1986 and 1991 by reinsertion and protection of the suture by means of a PET ligament (Trevira hochfest). The patients concerned were 31 men and 23 women (1 man and 1 woman had both knees operated on), with an average age of 39.7 years; 28 left and 28 right knees were affected. In 19 cases the ACL tear occurred in isolation, while in 37 concomitant intraarticular lesions were present. Nine patients had suffered multiple injury, and 3 had additional fractures distant from the knee. Haemarthrosis was encountered in 34 cases, and a clear effusion in 3 cases. The main causes of ACL rupture were sports injuries (n = 32), followed by traffic accidents (n = 14), activities of daily life (n = 6), and work accidents (n = 4). The preoperative diagnosis of ACL rupture was made correctly in 54 cases. After injury, 37 knees were operated on within the first 2 weeks, and 19 between the 3 and the 8 week. After arthroscopic repair of the concomitant lesions the alloplastic ligament was implanted isometrically by arthrotomy or miniarthrotomy through two bone tunnels and fixed to the bone with staples. Postoperative treatment included immediate continuous passive motion (CPM) and early weight-bearing with the protection of a brace. The patients were followed up at yearly intervals. At the last follow up, 6 years after the beginning of the study, 50 patients were examined clinically and radiologically, and the mean follow-up interval in these 50 was 40.2 months (12-79 months).(ABSTRACT TRUNCATED AT 250 WORDS)

Li, C. K., K. M. Chan, et al. (1993). "The Johnson antishear device and standard shin pad in the isokinetic assessment of the knee." British Journal of Sports Medicine 27(1):49-52, 1993 Mar 27(1): 49-52.

Isokinetic training and assessment of the knee joint has been the mainstay of rehabilitation, especially in patients with anterior cruciate ligament deficiency. Besides the original shin pad used, the antishear device was introduced by Johnson in 1982. This device has been shown biomechanically to prevent excessive anterior translation of force on the tibia during training. However, there is a need to compare the antishear device and the standard shin pad in the isokinetic assessment. Hence, the major objective of this study is to define, if any, the difference in patient assessment between the new double pad device and the old single shin pad. Ten subjects with no previous history of injury on either knee were tested with the Cybex Isokinetic Dynamometer. There were four men and six women and the mean age was 25.2 years. They were randomized into different test sequences with different shin pads at different speeds. Correlation and paired t tests (P) were performed to find out the correlation and difference between the two devices. There was significant difference in performance assessment between the two devices in knee extension (P < 0.05) but no significant difference in knee flexion (P > 0.05). There was also a high correlation (r > 0.75) between the two devices. It is concluded that because of the significant difference of data generated between the two devices, it is important to select one single device with each patient during a series of testings.

Linn, R. M., D. A. Fischer, et al. (1993). "Achilles tendon allograft reconstruction of the anterior cruciate ligament-deficient knee." American Journal of Sports Medicine 21(6):825-31, 1993 Nov-Dec 21(6): 825-31.

Thirty-five patients had reconstruction of the anterior cruciate ligament with intraarticular fresh-frozen Achilles tendon allograft and extraarticular tibial band tenodesis. Patients were followed 2 to 4 years (mean, 2.5). Evaluation included clinical and functional examinations, measurement of tibiofemoral displacement, and anteroposterior and lateral radiographs. Clinical results were considered satisfactory in 85% of the patients; 16 had arthroscopic examination after the allograft; allograft biopsies in 9 at this time showed cellular and vascular tissue without evidence of immune reaction. Clinical, arthroscopic, and biopsy results were favorable, but radiologic results were not. In most patients there was a significant size increase in femoral and tibial bone tunnels, as measured from radiographs. In the 6 most extreme cases, bone tunnels measured 20 mm or more in diameter, twice the initial size. Etiology and clinical significance of these bone tunnel changes remain unknown. Enlargement appears to occur early after operation; it stabilizes within 2 years. No statistical correlation was seen between tunnel enlargement and results of clinical and functional examinations; nevertheless, unexplained tunnel enlargement is cause for concern, and allograft replacement of the anterior cruciate ligament with fresh-frozen Achilles tendon allograft should be considered a salvage procedure.

Lipscomb, A. B. J., R.K.; Snyder,R.B.; Warburton,M.J.; and Gilbert, P.P. (1982). "Evaluation of hamstring strength following use of semitendinosus and gracilis tendons to reconstruct the anterior cruciate ligament." Am.J. Sports Med., 10: 340-342.

Liu, S. H. A. S., R.A.; Panossian,V.; Finerman,G.A.; Lane,J.M. (1997). "Estrogen affects the cellular metabolism of the anterior cruciate ligament. A potential explanation for female athletic injury." Am.J.Sports Med. 25(5): 704-709.

Investigations from this laboratory have established the presence of estrogen receptors in the human anterior cruciate ligament. This study further investigates the effects of 17 beta-estradiol on the cellular proliferation and collagen synthesis of fibroblasts derived from the rabbit anterior cruciate ligament. Fibroblast proliferation and collagen synthesis in response to near log concentrations of 17 beta- estradiol (at 0.0029, 0.025, 0.25, 2.5, and 25 ng/ml) were assessed by measuring [3H]thymidine and [14C]hydroxyproline incorporation, respectively. Collagen synthesis was significantly reduced with increasing local estradiol concentration (P < 0.001). Declining collagen synthesis was first noted at a 17 beta-estradiol concentration of 0.025 ng/ml. Within normal physiologic levels of estrogen (0.025 to 0.25 ng/ml), collagen synthesis was reduced by more than 40% of control, and at pharmacologic levels of 2.5 and 25 ng/ml, by more than 50% of control. A significant reduction of fibroblast proliferation was also observed with increasing estradiol concentrations (P = 0.023). Clinically, alterations in anterior cruciate ligament cellular metabolism caused by estrogen fluctuations may change the composition of the ligament, rendering it more susceptible to injury

Lo, I. K., D. M. Bell, et al. (1998). "Anterior cruciate ligament injuries in the skeletally immature patient." Instr Course Lect 47: 351-9.

Anterior cruciate ligament injury in the skeletally immature is becoming increasingly recognized and reported. History taking and physical examination based on the principles of ACL injuries in adults, with adjuncts such as arthroscopy and MRI, are effective in diagnosing ACL injury in the young patient. Evaluation of the young patient's true level of skeletal immaturity by comparison with family growth history, examination for signs of sexual maturity, and radiographic evaluation is critical. The risk of physeal damage with surgical treatment is related to the immaturity of the distal femoral and proximal tibial physes. The functional results of nonsurgical treatment of ACL injury, either as an attempt at definitive treatment or as a temporizing plan until skeletal maturity occurs, are poor and the risks of reinjury and further meniscal and cartilage damage are significant. Surgical treatment for primary repair or extra-articular reconstruction alone has not proven to be efficacious. In the adolescent patient who is approaching skeletal maturity, risk of physeal injury is low and intra-articular reconstruction can be performed as in the adult patient. Results with respect to decreased laxity and return to athletic activities mirror those described in adults. In patients with significant growth remaining, however, surgical treatment carries much higher risks of physeal damage and subsequent deformity. Yet, as noted above, intra-articular reconstruction in truly skeletally immature patients using a soft-tissue graft through a transphyseal tibial tunnel of moderate or small diameter and the over-the-top position on the femur has not been shown to cause early physeal closure, limb-length discrepancy, or angular deformity. In humans, the maximum diameter of graft tunnel that will not cause physeal closure has not been determined Animal studies have shown that the tibial physis can be very sensitive to drilling. Therefore it is wise to use moderate tunnel diameters. Bone-patellar tendon-bone grafts have been used with success in patients closer to skeletal maturity. Their use has not been reported in the very skeletally immature knee and cannot be recommended because of the presumed high risk of physeal closure with a bone plug traversing the physis. It is hoped that improved understanding of the ACL injury in the skeletally immature patient will provide treatment options that will restore enduring knee function and prevent early arthrosis.

Lobenhoffer, P., A. Gogus, et al. (1993). "[Therapy of arthrofibrosis after ligament reconstruction of the knee joint]." Orthopade 22(6):392-8, 1993 Nov 22(6): 392-8.

The development of arthrofibrosis in a serious complication of knee ligament injury or knee ligament surgery. The fibrosis is caused by a pathologic quantity or quality of collagen fiber formation in the knee or in the capsular structures, causing irreversible loss of range of motion, restricted patellar motion and finally patella baja with frank osteoarthritis of the patella. The major factors inducing fibrosis are notch impingement, development of a cyclops on an anterior cruciate ligament graft, scarring of the fat pad and the retinacula and adhesions in the recesses of the joint. Our therapeutic concept includes aggressive physiotherapy and an early arthroscopic procedure if conservative measures fail. A posterior capsulotomy is performed from a posteromedial arthrotomy in cases with flexion contracture persisting over a number of years. In 16 patients reviewed 17 months after arthroscopic treatment of arthrofibrosis the average improvement in range of motion was 13 degrees for extension and 25 degrees for flexion. A further 7 patients with chronic flexion contractures persisting for 1 year or more were treated with a posterior capsulotomy and reviewed 18 months after surgery. The average gain for extension was 15 degrees in these patients at follow-up.

Lobenhoffer, P. and H. Tscherne (1993). "[Rupture of the anterior cruciate ligament. Current status of treatment]." Unfallchirurg 96(3):150-68, 1993 Mar 96(3): 150-68.

This article summarizes the present knowledge on the diagnosis of and treatment rationales for ruptures of the anterior cruciate ligament (ACL) of the knee. There is an increasing incidence of this injury due to the high number of persons involved in dynamic sports. The most significant diagnostic criterion is a positive pivot shift associated with a pathological anterior translation of the tibia in slight flexion of the knee. Instrumented testing of the knee is becoming increasing important and is standard in follow-up studies. A survey of the literature at present delineates very clearly the importance of an intact ACL for homeostasis of the knee. Loss of this structure leads to a high incidence of secondary meniscus tears with consecutive osteoarthritis of the knee. All valid studies also indicate an involuntary decrease of activity in the patients after loss of the ACL. Risk factors for early decompensation of the knee are a young age, high activity level, rupture of the collateral ligaments, congenital laxity, varus morphotype and high initial laxity. Primary repair of the ACL is possible, but results in stable ligament healing in only a limited percentage of cases. Reconstruction of the ACL with a free patellar tendon graft has become the standard procedure for many surgeons. ACL reconstruction can be performed either arthroscopically or through a "miniarthrotomy" with comparable results. Augmented repair or reconstruction using autologous flexor tendons is an alternative in certain cases. Augmentation with allogeneic material and the use of tendon allografts are still experimental and should be restricted to centers that can perform strict follow-up studies. The rehabilitation program after implantation of a patellar tendon graft can be accelerated markedly without endangering joint stability. Crutches are necessary only for the first 2-3 weeks. The success rate in terms of objective stability with an autologous patellar tendon graft is high, although specific disadvantages such as chronic patellar pain and a risk for loss of motion must be considered.

Lobenhoffer, P. and H. Tscherne (1993). "[Indications for anterior cruciate ligament reconstruction--current surgical techniques, choice of transplant]." Orthopade 22(6):372-80, 1993 Nov 22(6): 372-80.

At present there is still a great deal of uncertainty about the natural history of ruptures of the ACL. The literature reveals that a significant number of secondary meniscus lesions and chondral damage results, when a high activity level is maintained. Reconstruction of the ACL now improves objective stability and decreases the meniscectomy rate in a large number of cases. Replacement with a patellar tendon or semitendinosus graft and augmented repair give better results than primary suture of the ligament. A limited arthrotomy or an arthroscopic technique should be used for reconstruction of the ACL. Two tunnel techniques with a lateral incision and single incision techniques with a femoral half tunnel are used. There is no consensus at present on the optimal graft source and surgical technique for ACL reconstruction.

Long, A. J., F. P. Monsell, et al. (1993). "A method for the kinematic evaluation of the knee following anterior cruciate ligament injury and reconstruction." Proceedings of the Institution of Mechanical Engineers 207(2):73-7, 1993 207(2): 73-7.

A quantitative method for assessing the kinematics of the knee in the sagittal plane has been developed in order to evaluate the role of the anterior cruciate ligament following injury and reconstruction. Measurements were made on a series of lateral radiographs obtained at different angles of flexion with the limb weight-bearing and the foot and ankle rotated so that the condyles of the femur overlapped. The kinematics of the joint were then defined by recording the path of the tip of the medial tibial spine as flexion proceeded, using a coordinate system based on the femur. This method overcomes the problems inherent in quantifying knee kinematics by using the pathway of the centre of rotation. In an amputated knee, tibial positions could be specified to within approximately 1.2 mm. There were no significant differences between results obtained at the beginning and end of a six month period for the normal knees of two patients; the standard deviation of the measured tibial positions was approximately 1.6 mm.

Lubowitz, J. H. and J. D. Grauer (1993). "Arthroscopic treatment of anterior cruciate ligament avulsion." Clinical Orthopaedics & Related Research (294):242-6, 1993 Sep(294): 242-6.

A new technique is described for arthroscopic reduction and internal fixation (ARIF) of avulsion fractures involving the insertion of the anterior cruciate ligament (ACL). Conventional methods of treatment of ACL avulsion in adults may lead to suboptimal results owing to stiffness from either prolonged immobilization or the morbidity of arthrotomy. Contemporary techniques of arthroscopic reduction and percutaneous pinning do not achieve rigid fixation and thus still require cast immobilization. The placement of cannulated screws through the anteromedial arthroscopic portal provides rigid fixation while avoiding arthrotomy, allowing early mobilization and return to activity. The possibility of interstitial damage to the ACL and implications regarding tensioning of the ligament are considered A typical case illustrates ARIF of ACL avulsion. The technique minimizes morbidity and optimizes function.

Maffulli, N., P. M. Binfield, et al. (1993). "Isolated ganglions of the anterior cruciate ligament." Medicine & Science in Sports & Exercise 25(5):550-3, 1993 May 25(5): 550-3.

We report three athletes with symptomatic isolated ganglion of the anterior cruciate ligament. The symptoms consisted of anteromedial knee pain, worse when changing direction while running, and on squatting. All gave a history of repeated minor knee trauma without a single episode of serious injury. At day-case arthroscopy, a unilobulated cystic mass arising from a clinically and arthroscopically intact anterior cruciate ligament was noted and removed in each case. No further intra- or extra-articular knee lesion was seen. Histology revealed a cystic ganglion in each case. With early physiotherapy, the patients could start gentle training 3 wk after arthroscopy, and, at 6-month review, were fully asymptomatic. A review of the literature shows that an isolated ganglion arising from the anterior cruciate ligament is exceedingly rare, with only three such ganglia having been previously reported.

Maffulli, N., P. M. Binfield, et al. (1993). "Acute haemarthrosis of the knee in athletes. A prospective study of 106 cases." Journal of Bone & Joint Surgery - British Volume 75(6):945-9, 1993 Nov 75(6): 945-9.

We made a prospective arthroscopic study of 106 skeletally mature male sportsmen with an average age of 28.35 years (16.8 to 44) who presented with an acute haemarthrosis of the knee due to sporting activities. We excluded those with patellar dislocations, radiographic bone injuries, extra-articular ligamentous lesions or a previous injury to the same joint. The anterior cruciate ligament (ACL) was intact in 35 patients, partially disrupted in 28 and completely ruptured in 43. In the patients with an ACL lesion, associated injuries included meniscal tears (17 patients), cartilaginous loose bodies (6), and minimal osteochondral fractures of the patella (2), the tibial plateau (3) or the femoral condyle (9). We found no age-related trend in the pattern of ACL injuries. Isolated injuries included one small osteochondral fracture of the patella, and one partial and one total disruption of the posterior cruciate ligament. Three patients had cartilaginous loose bodies, and no injury was detected in five. Acute traumatic haemarthrosis indicates a serious ligament injury until proved otherwise, and arthroscopy is needed to complement careful history and clinical examination. All cases with a tense effusion developing within 12 hours of injury should have an aspiration. If haemarthrosis is confirmed, urgent admission and arthroscopy are indicated.

Magen, H. E. H., S.M.; Hull,M.L. (1999). "Structural properties of six tibial fixation methods for anterior cruciate ligament soft tissue grafts." Am.J.Sports Med. 27(1): 35-43.

This study compared the stiffness (K), yield load (YL), and slippage (SL) of six tibial fixation methods. These properties were determined from load-to-failure and cyclic tests of double-looped tendon grafts fixed to both animal and young human tissue. Tandem washers (K = 259 N/mm, YL = 1159 N, SL = 0.5 mm) and the Washerloc (K = 248 N/mm, YL = 905 N, SL = 2.0 mm) were the two best fixations. At 500 N of load, which is the estimated daily tension of an anterior cruciate ligament graft during intensive rehabilitation, slippage was significantly greater in either of the other two methods for sutures tied to a post (4.9 mm), double staples (3.3 mm), and a 20-mm spiked metal washer (3.5 mm). Interference screw fixation performed well in animal tissue (YL = 776 N), but was significantly worse in young human tissue (YL = 350 N), with 57% of the fixations failing before 500 N of load. Animal tissue should not be used to estimate the performance of interference screw fixation in human tissue. Because 57% of the interference screw fixations using human tissue failed at loads below 500 N, their ability to provide adequate fixation during intensive rehabilitation should be questioned. However, both the Washerloc and tandem washers and screws provide fixation structural properties in young human tibia that should be appropriate for intensive rehabilitation

Maitland, M. E., R. Lowe, et al. (1993). "Does Cybex testing increase knee laxity after anterior cruciate ligament reconstructions?" American Journal of Sports Medicine 21(5):690-5, 1993 Sep-Oct 21(5): 690-5.

Long-term stability of the knee after anterior cruciate ligament reconstruction is imperative. Testing protocols that use isokinetic systems are commonly performed despite controversies as to their safety. The purpose of this study was to test whether one episode of isokinetic testing would cause an increase in anterior tibial translation. Twenty-four subjects who had anterior cruciate ligament reconstructions 153 to 300 days earlier volunteered for the study. Initially, subjects walked on a treadmill at 5 km/hr for 10 minutes to test the effect of exercise on displacement measurements. One week later, subjects performed a maximal knee flexion-extension test on the Cybex dynamometer at 60, 150, and 240 deg/sec. Anterior tibial displacement at 133.5 N was obtained from force-displacement curves produced by KT-2000 arthrometer testing at nine intervals: before exercise on the treadmill, at four intervals after treadmill exercise, and at four intervals after Cybex testing. Repeated measures analysis of variance did not show a significant exercise effect, interaction between type of exercise and time interval, or change after Cybex testing for the reconstructed knee displacement, the contralateral knee displacement, or side-to-side difference. The average difference before and after Cybex testing was 0.1 mm for the reconstructed knee. In conclusion, a single Cybex test, performed at least 6 months after surgery, did not affect anterior tibial displacement in this study sample.

Maletius, W. and K. Messner (1999). "Eighteen- to twenty-four-year follow-up after complete rupture of the anterior cruciate ligament." Am J Sports Med 27(6): 711-7.

A unilateral, complete rupture of the anterior cruciate ligament was diagnosed in 60 consecutive patients by arthroscopy within 1 week of trauma. Most ruptured ligaments were treated by acute nonaugmented repair immediately after the arthroscopy. Fifty-five and 56 patients were reevaluated after 12 years and 20 years, respectively. Twenty-five patients (45%) had at least one reoperation during the follow-up period of 20 years, primarily for meniscal problems. Seven patients (13%) had repeat anterior cruciate ligament surgery. The overall Lysholm knee function score remained at a median of 90 points from 12 to 20 years, but patients had decreased their sporting activities from team sports at full rehabilitation to physical fitness activities at the late follow-up. Patients who had repeat surgery had a worse knee function score, were less satisfied with their knees, and also had to change activities and change work more often than patients without reoperation. The majority of patients had, at both follow-up periods, unstable knees. At 20 years, weightbearing radiographs showed slight-to-moderate changes equivalent to osteoarthrosis in 84% (47) of patients and a 32% increase in osteoarthrosis since the 12-year evaluation.

Mangine, R. E., F. R. Noyes, et al. (1992). "Minimal protection program: advanced weight bearing and range of motion after ACL reconstruction--weeks 1 to 5." Orthopedics 15(4): 504-15.

Markolf, K. L., D. C. Wascher, et al. (1993). "Direct in vitro measurement of forces in the cruciate ligaments. Part II: The effect of section of the posterolateral structures." Journal of Bone & Joint Surgery - American Volume 75(3):387-94, 1993 Mar 75(3): 387-94.

Specially designed load-transducers were applied to eight fresh-frozen cadaveric knee specimens in order to measure resultant forces in both cruciate ligaments as the knees were subjected to straight varus-valgus bending moment and to tibial torque (with and without a superimposed posterior tibial force). The forces in the ligaments and tibial rotation were recorded at seven angles of flexion of the knee, between 0 and 90 degrees, before and after section of the posterolateral structures. Ligamentous section increased angulation of the tibia when varus moment was applied to the knee; the large increases in lateral opening of the knee joint were accompanied by increases in the force in the anterior cruciate ligament at all angles of flexion and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. When valgus moment was applied, there were no significant changes in valgus angulation or the resultant force in either cruciate ligament after ligamentous section. Ligamentous section increased rotation of the tibia when external torque was applied to the knee. The increased external rotation was accompanied by decreases in the force in the anterior cruciate ligament between 0 and 20 degrees of flexion of the knee and increases in the force in the posterior cruciate ligament between 45 and 90 degrees of flexion. In the studies involving applied internal tibial torque, after ligamentous section, rotation of the tibia increased slightly between 60 and 90 degrees of flexion. The force in the anterior cruciate ligament increased between 0 and 20 degrees of flexion, while the force in the posterior cruciate ligament was unaffected.(ABSTRACT TRUNCATED AT 250 WORDS)

Marks, P. and P. J. Fowler (1993). "Imaging modalities for assessing the anterior cruciate ligament deficient knee." Orthopedics 16(4):417-24, 1993 Apr 16(4): 417-24.

Marks, P. H., M. Cameron, et al. (1993). "[Reconstruction of the cruciate ligaments with allogeneic transplants. Techniques, results and perspectives]." Orthopade 22(6):386-91, 1993 Nov 22(6): 386-91.

The authors have used allografts for reconstruction of the cruciate ligaments in over 600 cases since 1985. Advantages are the reduced operative trauma and the unlimited availability of high-quality grafts even in multiple ligament reconstructions. Arthroscopic techniques are available for reconstruction of the anterior and the posterior cruciate ligament, which makes arthrotomies and large skin incisions unnecessary. The grafts of choice are the bone-patellar tendon-bone preparation and the Achilles tendon with bone bloc. No specific complications were observed with the use of allograft material in this series. Results show a high subjective acceptance of the procedure among the patients, with a high rate of return to pre-injury sports activities following ACL reconstruction. Objective stability was restored in over 70% of these cases. All cases with posterior instability had 3+ posterior drawer preoperatively. At follow-up, almost normal stability had been restored in 50%. Further research must focus on the biological processes that take place during incorporation of these tissues and on better techniques of graft processing and sterilisation. At present, the risk of disease transmission must be considered and discussed with the patient.

Marder, R. A. R., J.R.; Carroll,M. (1991). "Prospective evaluation of arthroscopically assisted anterior cruciate ligament reconstruction. Patellar tendon versus semitendinosus and gracilis tendons." Am.J.Sports Med. 19(5): 478-484.

Eighty consecutive patients with chronic laxity due to a torn ACL underwent arthroscopically assisted reconstruction with either autogenous patellar tendon or doubled semitendinosus and gracilis tendons. Reconstructions were performed on a one-to-one alternating basis. Preoperatively, no significant differences between the two groups were noted with respect to age, sex, level of activity, and degree of laxity (chi square analysis). A standard rehabilitation regimen was used for all patients after surgery including immediate passive knee extension, early stationary cycling, protected weightbearing for 6 weeks, avoidance of resisted terminal knee extension until 6 months, and return to activity at 10 to 12 months postoperatively. Seventy-two patients were evaluated at a minimum of 24 months postoperatively (range, 24 to 40 months). No significant differences were noted between groups with respect to subjective complaints, functional level, or objective laxity evaluation, including KT-1000 measurements. Seventeen of 72 patients (24%) experienced anterior knee pain after ACL reconstruction. Overall, 46 of 72 patients (64%) returned to their preinjury level of activity. Mean KT-1000 scores were 1.6 +/- 1.4 mm for the patellar tendon group and 1.9 +/- 1.3 mm for the semitendinosus and gracilis tendons group. This study did find a statistically significant weakness in peak hamstrings torque at 60 deg/sec when reconstruction was performed with double-looped semitendinosus and gracilis tendons

Marks, P. H. and C. D. Harner (1993). "The anterior cruciate ligament in the multiple ligament-injured knee." Clinics in Sports Medicine 12(4):825-38, 1993 Oct 12(4): 825-38.

The ACL may be associated with concomitant injury to the posterior cruciate ligament, collateral structures, bone or cartilage. An approach to the multiligament injured knee is discussed including evaluation, treatment, graft selection, operative techniques, graft placement, tensioning, fixation, impingement, postoperative care, and complications.

Marois, Y., R. Roy, et al. (1993). "Histopathological and immunological investigations of synthetic fibres and structures used in three prosthetic anterior cruciate ligaments: in vivo study in the rat." Biomaterials 14(4):255-62, 1993 14(4): 255-62.

Three types of prosthetic anterior cruciate ligaments were investigated by enzymatic and histological analysis of the tissue surrounding each implant and immunologically by a cytofluorometric analysis of T-cell populations in the peripheral blood of rats. Two of the prostheses had a braided construction, one made from polyester and the other from high performance polyethylene fibres. The third type also contained high performance polyethylene fibres, but had been manufactured in a knitted construction (Raschel high performance polyethylene). Five specimens from each prosthesis were implanted intraperitoneally in rats by a trocar for different periods of time up to 4 wk. A control group of rats underwent the surgery, but not the implant. No modification in peripheral T-cell populations was induced by the presence of any implant. Whilst the levels of acid phosphatase and esterase activity appeared to have increased slightly following implantation of any of the prostheses, such increases were not highly significant. Histologically, all three materials induced an intense acute inflammatory reaction at 3 d which gave way to a typical chronic response after 4 wk. The only major difference between the prostheses was that after 4 wk the polyester fibres exhibited less inflammation, and the surrounding tissue was more mature, more vascularized and more densely infiltrated with collagen than with the two high performance polyethylene implants. In conclusion, all three devices provided satisfactory biocompatibility in terms of cellular and healing response.

Marshall, J. L., R. F. Warren, et al. (1982). "Primary surgical treatment of anterior cruciate ligament lesions." Am J Sports Med 10(2): 103-7.

Seventy patients who underwent primary repair of the anterior cruciate ligament are reviewed in follow-up. The surgical technique consisted of multiple loop-varying depth sutures in both cruciate stumps in 61 patients. Nine patients had additional fascial augmentation done primarily. follow-up was from 12 to 90 months, the average being 29 months. All patients were scored on a 50-point normal knee score sheet. Average score at follow-up was 42.7. No patient was bothered by giving way, which is defined as an unpredictable instability. No patient has required subsequent meniscal surgery. Ninety-three percent of the patients were active in sports. Anterior drawer sign at 90 degrees showed increased excursion compared to the unaffected leg in all patients. However, Lachman's test showed a firm end point to excursion in all knees tested, and, in addition, 52% were rated as normal compared to the unaffected knee. We conclude that primary repairs of mid-substance tears are technically possible and recommended in an athlete.

Martinek, V., R. Seil, et al. (2001). "The fate of the poly-L-lactic acid interference screw after anterior cruciate ligament reconstruction." Arthroscopy 17(1): 73-6.

We report the persistence of a poly-L-lactic acid (PLLA) interference screw 2.5 years after anterior cruciate ligament (ACL) reconstruction with Achilles tendon allograft. The arthroscopy was performed because the patient sustained a reinjury of the ACL graft, making ACL revision surgery necessary. At the time of arthroscopy, both PLLA screws were macroscopically still intact but could not be removed in 1 piece. No inflammation could be observed either macroscopically or in the histologic analysis. The biopsy specimen from the femoral insertion of the graft showed parts of the PLLA material surrounded by scar tissue. This case shows that biodegradation of PLLA material in the knee joint causes no irritation and can take several years, even if the material is in contact with the synovial fluid.

Martinek, V., G. Steinbacher, et al. (2000). "Operative treatment of combined anterior and posterior cruciate ligament injuries in complex knee trauma: can the cruciate ligaments be preserved?" Am J Knee Surg 13(2): 74-82.

A retrospective study was performed focusing on operative treatment after combined anterior cruciate ligament (ACL)/posterior cruciate ligament (PCL) injuries. The operative treatment included the preservation of one or both cruciate ligaments. Twenty-eight patients, average age 30 years (range: 12-55 years), were evaluated 5.4 years (range: 1-14 years) postoperatively. Twenty-two operations were performed in patients with acute injuries (<30 days after trauma) and 6 operations in patients with chronic instabilities (>30 days after trauma). Both cruciate ligaments were preserved by suture or refixation in 16 patients. Suture of one and reconstruction of the other cruciate ligament with autologous tendon graft was performed in 12 cases. In addition, 61 procedures (meniscal suture/resection, medial/lateral reconstruction, tendon suture, and open reduction and internal fixation were performed. Postoperative treatment included continuous passive motion and protected weight bearing. Eleven (27% acute, 83% chronic) patients required revision (ACL/PCL reconstruction, osteotomy, and meniscal repair). At follow-up, 43% of the patients were very satisfied and 46% were satisfied. Seventy-one percent (89% preinjury) of the patients were able to maintain intensive and moderate International Knee Documentation Committee (IKDC) activity levels. The IKDC evaluation of the patients (acute %/chronic cases %) was graded for symptoms: A 39% (45/17), B 35% (27/67), C 15% (18/0), and D 11% (9/17); for range of motion: A 42% (36/67), B 42% (50/17), C 16% (14/17), and D 0%; and for ligaments: A 21% (18/17), B 33% (45/0), C 42% (32/83), and D 4% (5/0). Radiographic findings were A 18%, B 41%, and C 41%. Primary repair of acute injuries was superior to the delayed repair of chronic instabilities. Preservation of cruciate ligaments in acute combined ACL/PCL tears results in a satisfying knee function despite distinct residual ligament instability. Although suture of the cruciate ligaments in open technique is a therapeutic option in acute multiligamentous knee injuries, it is not recommended for the treatment of chronic instabilities.

Martinek, V. F., N.F. (1999). "To brace or not to brace? How effective are knee braces in rehabilitation?]." Orthopade 28(6): 565-570.

Since the clinical benefit of knee braces has yet to be defined, discussion about braces after reconstructive surgery of the anterior cruciate ligament remains controversial. The use of prophylactic braces in sport did not prove to be effective. In ACL insufficient knee joints, the operative treatment is preferred over the use of functional knee braces. Therefore, the postoperative rehabilitation presents the main application of braces. Modern operative techniques with an initial strong fixation of the ACL graft make a functional postoperative treatment without external fixation possible. In the presented meta- analysis of the literature about knee braces, results from clinical and experimental studies are compared. No published clinical data have shown that braces have any effect on postoperative outcome after ACL- reconstruction. Also, no evidence of a significant bracing effect could be demonstrated in the experimental in vivo or in vitro studies, except a limited stabilizing function for lower shear stress below the physiological loads. Consequently, the systematic use of braces in the rehabilitation after ACL reconstruction cannot be recommended

Marumo, K. K., Y.; Tanaka,T.; Fujii,K. (2000). "Long-term results of anterior cruciate ligament reconstruction using semitendinosus and gracilis tendons with Kennedy ligament augmentation device compared with patellar tendon autografts." J.Long.Term.Eff.Med.Implants. 10(4): 251-265.

ACL reconstructions were postoperatively evaluated in 102 patients who underwent surgery using an arthroscopically assisted double-incision technique. Augmentation of the distally based semitendinosus and gracilis tendons was done either with the Kennedy ligament augmentation device (LAD) (Group 1 patients, mean follow-up of 108 months) or bone- patellar-tendon-bone graft (Group 2 patients, mean follow-up of 109 months). At follow-up, serial KT-1000 measurements showed < or = 5 mm side-to-side differences in 70% of Group 1 and 90% of Group 2 patients. No differences were found among patients regarding postreconstruction complications such as loss in motion range, patellofemoral crepitus, osteoarthritis, and muscle disfunction

Matheny, J. M., G. A. Hanks, et al. (1993). "A comparison of patient-controlled analgesia and continuous lumbar plexus block after anterior cruciate ligament reconstruction." Arthroscopy 9(1):87-90, 1993 9(1): 87-90.

Anterior cruciate ligament (ACL) reconstruction is often a painful operation. Fifty-eight patients who underwent ACL reconstruction using patellar tendon autograft received either a lumbar plexus block (LPB) or patient-controlled analgesia (PCA) for pain relief during the first 24 h after surgery. The average total dose of narcotic used was dramatically less for the LPB group (10.1 mg) than for the PCA group (91.9 mg). The common narcotic analgesic side effects of nausea, pruritus, sedation, and urinary retention were significantly less in the LPB group. The LPB is a safe and effective alternative analgesia after ACL reconstruction.

Matsumoto, H. and B. B. Seedhom (1993). "Three-dimensional analysis of knee joint movement with biplanar photography, with special reference to the analysis of 'dynamic' knee instabilities." Proceedings of the Institution of Mechanical Engineers 207(3):163-73, 1993 207(3): 163-73.

An apparatus was developed by means of which it was possible to move a cadaveric knee joint under a constant external force and to measure its movement in three dimensions using biplanar photography, to investigate mechanisms of 'dynamic' knee instabilities, such as the 'pivot shift' phenomenon. Two wire frameworks, one attached to the femur, the other to the tibia, defined a system of three mutually orthogonal axes. While the knee joint was moved under a given force, a series of biplanar photographs of the two frameworks were taken. This procedure was repeated after sectioning different ligaments simulating different injuries. The joint was finally fully disarticulated, but leaving the reference wire frameworks still attached to their respective bone. Another series of biplanar photographs of the femur and tibia were taken. From these two series of measurements, movements of the tibia with respect to the femur were calculated. With this two-step method, knee movements could be measured without damaging the knee structures before or during the actual measurement (which could change the knee movement itself). On validating the system, it was concluded that knee movement could be measured with sufficient accuracy for the analysis of knee instability.

Matsumoto, H. and B. B. Seedhom (1993). "Rotation of the tibia in the normal and ligament-deficient knee. A study using biplanar photography." Proceedings of the Institution of Mechanical Engineers 207(3):175-84, 1993 207(3): 175-84.

The difference between physiological tibial rotation and rotatory instability of the knee, particularly the 'pivot shift' phenomenon, was investigated by analysing knee movements under both rotatory and valgus torques using 29 fresh cadaveric knees. The knee movements were measured in three dimensions using biplanar photography, when all ligaments were intact, and then after the ligaments were sequentially sectioned. The axis of the physiological tibial rotation was shown to be located about the centre of the tibial plateaux, while that of the pivot shift is located about the medial collateral ligament (MCL). When the anterior cruciate ligament (ACL) was sectioned, little or no significant change in physiological tibial rotation was observed under rotary torques, while a significant rotatory instability, including the 'pivot shift' phenomenon, was observed under a valgus torque. It was thus concluded that the rotatory instability is not simply an increase in the magnitude of the physiological rotation of the tibia, but is an abnormal tibial rotation which occurs with a different mechanism.

Matsusue, Y., T. Yamamuro, et al. (1993). "Arthroscopic multiple osteochondral transplantation to the chondral defect in the knee associated with anterior cruciate ligament disruption." Arthroscopy 9(3):318-21, 1993 9(3): 318-21.

Treatment of a chondral lesion in the knee, associated with anterior cruciate ligament disruption, is known to be difficult and controversial. This article presents an arthroscopic technique for transplantation of multiple osteochondral fragments, harvested from the same knee, to this chondral lesion. A 3-year follow-up shows excellent results with good cartilage repair confirmed by second-look arthroscopy.

Matthews, L. S., S. J. Lawrence, et al. (1993). "Fixation strengths of patellar tendon-bone grafts." Arthroscopy 9(1):76-81, 1993 9(1): 76-81.

Secure fixation of bone-patellar tendon-bone grafts is essential to allow early joint mobilization after anterior cruciate ligament (ACL) reconstruction surgery. This study was designed to evaluate four fixation methods of patellar tendon-bone grafts in cadaveric knees. Fifty-one fresh cadaveric patellar tendon-bone specimens were anchored in tibial or femoral metaphyseal bone tunnels. Group I grafts were fixed with Kurosaka interference screws. In Group II the grafts were initially fixed as in Group I, but the screws were then removed, the bone plugs repositioned, and the grafts resecured with screws. In Group III the grafts were anchored with three no. 2 nonabsorbable sutures tied over a screw and washer, whereas in Group IV no. 5 nonabsorbable sutures were used. Each bone specimen was mounted in the biomechanical testing machine, and a vertical tensile load was applied at a strain rate of 51 cm/min until failure of fixation, bone plug fracture, or tendon disruption occurred. The mean force to failure in Groups I, II, III, and IV were 435.0 N, 458.2 N, 454.2 N, and 415.8 N, respectively. There was no significant difference in the force to failure among the four methods of fixation. However, the modes of failure were diverse. In three specimens the Kurosaka screws diverged from the plugs and failed to achieve fixation. These specimens were excluded and will be discussed separately. Although technique-related difficulties may arise, interference screw fixation of patellar tendon-bone grafts affords strong graft fixation--often stronger than the graft itself. Secondary screw fixation appears to be equal in strength to primary screw fixation.(ABSTRACT TRUNCATED AT 250 WORDS)

Matthews, L. S., D. F. Martin, et al. (1990). "Tips of the trade #28. Accurate tunnel placement using drill guides in knee ligament reconstruction." Orthop Rev 19(9): 822-4.

Knee ligament reconstruction is optimized when intra-articular grafts are placed isometrically. Several drill guides have been designed to facilitate accurate tunnel placement. The use of an intra-articular keying hole, made with a burr, enhances proper and secure drill guide placement. Sterile mineral oil lubrication of the drill guide components will help prevent their distortion and will eliminate improper tunnel placement.

Maywood, R. M., B. J. Murphy, et al. (1993). "Evaluation of arthroscopic anterior cruciate ligament reconstruction using magnetic resonance imaging." American Journal of Sports Medicine 21(4):523-7, 1993 Jul-Aug 21(4): 523-7.

Thirty-two patients who had arthroscopic anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft underwent subsequent magnetic resonance imaging of the knee. A total of 32 magnetic resonance imaging examinations were performed from 10 days to 39 months postoperatively. The anatomic plane of the autograft was determined by obtaining a coronal pilot scan of the graft fixation screws or screw and staple. T1-weighted, T2-weighted, proton density, and gradient-echo imaging sequences were then obtained in the anatomic plane, as well as T1-weighted coronal images. The autograft was defined on the basis of visualization of fiber continuity on T2-weighted images as follows: 1) intact; 2) having a partial tear; or 3) having a complete tear. These results were then correlated with clinical examination and, in 10 cases, subsequent arthroscopy. Magnetic resonance imaging correlated with clinical findings in 31 of 32 patients. In addition, of the 10 patients who underwent subsequent arthroscopy, magnetic resonance scanning correlated in all cases with arthroscopic findings. T2-weighted and, in some cases, proton density images were most useful in visualizing the autograft. T2-weighted magnetic resonance imaging in the anatomic plane of the anterior cruciate ligament autograft can be a useful diagnostic tool in the evaluation of patients with patellar tendon anterior cruciate ligament reconstructions when graft integrity is in question.

McAllister, D. R., R. D. Parker, et al. (1999). "Outcomes of postoperative septic arthritis after anterior cruciate ligament reconstruction." Am J Sports Med 27(5): 562-70.

Arthroscopically guided reconstruction of the anterior cruciate ligament is a common orthopaedic procedure. While many associated complications have been described in the literature, postoperative septic arthritis has received little attention. Although rare after anterior cruciate ligament reconstruction, septic arthritis can have devastating consequences. From a group of 831 consecutive patients, we report 4 (0.48%) who sustained septic arthritis. All patients had similar symptoms and were treated by the same surgeon in the same manner. All underwent immediate arthroscopic lavage, open incision, drainage of associated wounds, debridement with graft retention, and treatment with intravenous and then oral antibiotics. The patients underwent an average of 2.75 procedures after the diagnosis to eradicate the infection and restore knee motion. All patients were evaluated at an average of 3 years after surgery. We found that previous knee surgery and meniscal repair were risk factors for the development of postoperative septic arthritis. The infection was successfully eradicated, the ligament graft was preserved, and knee stability and mobility were adequately restored in all patients. However, the clinical outcome of these patients appeared to be inferior to that of patients who had undergone uncomplicated anterior cruciate ligament reconstruction. This inferior outcome appeared to be secondary to damage to the articular cartilage from the infection.

McCarthy, M. R., C. K. Yates, et al. (1993). "The effects of immediate continuous passive motion on pain during the inflammatory phase of soft tissue healing following anterior cruciate ligament reconstruction." Journal of Orthopaedic & Sports Physical Therapy 17(2):96-101, 1993 Feb 17(2): 96-101.

Continuous passive motion (CPM) may have potential application as a physical modality in decreasing acute pain. The purpose of this study was to examine the effects of CPM immediately following an arthroscopically-assisted anterior cruciate ligament (ACL) reconstruction utilizing bone-patella-bone autograft on acute pain during the inflammatory phase of soft tissue healing. Acute pain was measured by assessing the amount of pain medication (amount of narcotic delivered from the patient-controlled analgesia (PCA) pump during the first postoperative 24 hours and the total intake of oral medication during the second and third postoperative days), the need for pain medication (number of times the patient pushed the PCA button during the first postoperative 24 hours), and perceived pain (graphic pain scale measuring antalgic sensation). Thirty patients (15-45 years old) participated in this study. The patients were prospectively randomized into two groups, CPM and non-CPM. Both groups followed an identical postoperative rehabilitation program except for the CPM groups using a CPM device. The design of this study included the collection of data during the inflammatory phase of soft tissue healing. The results indicated that the initiation of CPM immediately following an ACL reconstruction had a significant (p < .05) effect on decreasing the amount of medication consumed by the patient and a significant (p < .05) decrease in the patient's need for medication during the inflammatory phase. There was no statistical significance in the level of perceived pain between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

McConville, O. R., J. M. Kipnis, et al. (1993). "The effect of meniscal status on knee stability and function after anterior cruciate ligament reconstruction." Arthroscopy 9(4):431-9, 1993 9(4): 431-9.

The purpose of this study was to examine the relationship of meniscal status at the time of anterior cruciate ligament (ACL) reconstruction with the ultimate function and stability of the knee joint. Seventy-one patients were studied prospectively following bone-patellar tendon-bone ACL reconstruction. Subjects were divided into six subgroups relative to the integrity (intact, partial meniscectomy, complete meniscectomy) of the two menisci. After a minimum of 2 years of follow-up (range 2-4.1 years), 56 subjects were available for subjective, objective, and radiographic assessment. Meniscal status at the time of ACL reconstruction proved to have no significant bearing on the ultimate stability of the knee. However, individuals who had undergone meniscal excision reported subjective complaints and activity limitations more commonly than those with intact menisci (p < 0.05). Radiographic changes also were more common in the meniscectomized subset.

McDaniel, W. J., Jr.; and Dameron,T.B., Jr. (1980). "Untreated ruptures of the anterior cruciate ligament. A follow-up study." J. Bone and Joint Surg 62A: J. Bone and Joint Surg.

McFarland, E. G. (1993). "The biology of anterior cruciate ligament reconstructions." Orthopedics 16(4):403-10, 1993 Apr 16(4): 403-10.

Ligaments, including the anterior cruciate ligament (ACL), have a limited biological response to injury. The same healing process affects graft tissues used to reconstruct the ACL. These biological processes interact with mechanical forces to transform the grafts into tissues, which are expected to functionally replace the ACL. Although these grafts may undergo "ligamentization," they may not undergo "ACL-ization." Further study of the important relationship between these biological and biomechanical interactions is warranted.

McGuire, D. A., S. D. Hendricks, et al. (1996). "Use of an endoscopic aimer for femoral tunnel placement in anterior cruciate ligament reconstruction." Arthroscopy 12(1): 26-31.

Accurate placement of the femoral tunnel is a technically difficult aspect of anterior cruciate ligament reconstruction. Various drill guides have been developed to aid in the selection of this site. The purpose of this article is to describe a new drill guide designed to ensure anatomic placement of the femoral tunnel. The guide is used as part of a single-incision arthroscopic anterior cruciate ligament reconstruction technique with a bone-patellar tendon-bone graft secured with interference screws. An intraoperative check of the "pretunnel footprint" can be made to verify correct placement by the remaining cortical margins measurement within an acceptable 1 to 2 mm range before drilling the tunnel to depth. If necessary, minor adjustments to the guidepin location can be made to prevent posterior tunnel margin dimensions of less than 1 mm (troughing) or greater than 2 mm.

McGuire, D. A., S. D. Hendricks, et al. (1997). "The relationship between anterior cruciate ligament reconstruction tibial tunnel location and the anterior aspect of the posterior cruciate ligament insertion." Arthroscopy 13(4): 465-73.

A retrospective study of arthroscopic anterior cruciate ligament reconstruction in 20 patients was conducted. These patients underwent computed tomography (CT) scans on the involved knee postoperatively to determine sagittal placement of the proximal end of the tibial tunnel (TTp) based on a distance from a specific anatomic reference known as the over-the-back (OTB) ridge. The distance from the posterior aspect of the TTp to the OTB ridge, defined as the backset, was measured from the CT scans. The mean backset was 6.2 mm. The anterior to posterior (AP) tibial plateau diameter was measured from the CT and by plain view radiograph. The mean AP diameter by CT scan was 55.1 mm and the mean AP diameter by radiograph was 55.4 mm. A Pearson correlation coefficient of r = .633 comparing backset versus AP diameter suggests a moderately significant positive relationship. For the AP diameter comparing measurement method, CT versus radiograph, r = .985, representing a highly significant positive relationship, confirming AP diameter sizing accuracy by inexpensive radiography versus CT scan. A proposed backset model based on these data uses three fixed distances, derived by ratio, within a 2-mm range. This model is defined by 5-, 6-, and 7-mm backset intervals for < 50 mm, 50 to 60 mm, and > 60 mm AP diameters respectively, and is currently under prospective clinical investigation.

McGuire, D. A., K. Sanders, et al. (1993). "Comparison of ketorolac and opioid analgesics in postoperative ACL reconstruction outpatient pain control." Arthroscopy 9(6):653-61, 1993 9(6): 653-61.

Pain control is an important postoperative consideration with any surgical procedure. Technological and procedural improvements have contributed to the reduction in both the degree of surgical difficulty and the postsurgical complications associated with intricate surgeries. As a result, certain surgeries have potential for being performed on an outpatient basis, dependent upon appropriate pain-management regimens and the degree of potential for postoperative complications. Arthroscopic anterior cruciate ligament (ACL) reconstruction is a common procedure. Because of the reduction in invasiveness that arthroscopy provides, outpatient surgery is now routinely employed for ACL patients. The arguments against ACL outpatient surgery have included the reluctance to use ambulatory, indwelling, intravenous pain-pump delivery systems for opioid pain medication. The purpose of this study was to determine the efficacy of a ketorolac tromethamine used for the management of the postoperative pain produced as a result of outpatient ACL reconstruction. When the ketorolac pain management regimen is compared in this setting with meperidine or morphine, pain control is as good as, or in some cases better than, either of the opioid drugs. Additionally, the adverse side effects associated with opioid drugs are significantly reduced at a substantially lower direct cost to the patient.

McGuire, D. A. and J. W. Wolchok (1998). "The footprint: a method for checking femoral tunnel placement." Arthroscopy 14(7): 777-8.

Anterior placement of the femoral tunnel during anterior cruciate ligament reconstruction results in nonisometric placement, and posterior placement can lead to posterior tunnel blow out or troughing. Creating a pretunnel footprint before final placement and drilling allows the surgeon to visually verify that proper femoral tunnel placement has been obtained.

McGuire, D. A. B., F.A.; Elrod,B.F.; Paulos,L.E. (1999). "Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction." Arthroscopy 15(5): 463-473.

The central one third of the patellar tendon autograft is popular because the bone-tendon-bone (BTB) construct provides several graft fixation options, robust graft incorporation, and a mechanically sufficient substitute. Interference screw fixation is one method used to secure the graft. Bioabsorbable interference screws may offer advantages over metal interference screws. Bioabsorbable screws are made from poly L-lactic acid (PLLA) and are absorbed by the body. This prospective, randomized study compared the safety and efficacy of the PLLA screw with that of the metal cannulated interference screw for anterior cruciate ligament reconstruction. There were 204 patients randomly assigned to the Bioscrew (Linvatec, Largo, FL) (n = 103) or the metal interference screw (n = 101) groups at four sites. The mean age was 30 years. There were 66 women and 138 men. Mean follow-up was 30 months for Bioscrews and 28 months for metal screws; the average follow-up interval was 2.4 years. The Lysholm mean scores at 4 years for the 32 patients seen at this interval were 95.0 and 97.2 for the Bioscrew and metal screw group, respectively. Ligament laxity comparisons made with an instrumented arthrometer at manual maximum force resulted in side-to-side mean score differences of B = 1.8mm and M = 1.6mm. The Tegner activity level score means were B = 6.1 and M = 5.8. Other variables examined included pain, thigh size, meniscal tests, Lachman's test, range of motion, anterior drawer, pivot shift, patellofemoral crepitus and tenderness, and joint effusion. None of these variables showed a statistically significant difference between groups. No radiographic evidence of osteolytic change or bone resorption around the Bioscrews was observed. There were no complications related to loss of fixation, toxicity, allergenicity, or other evidence of osteolytic or inflammatory reaction. In every assessment between groups there was no difference found. There were 12 PLLA screws that broke during insertion without any adverse effects. The PLLA headless cannulated interference fit screws produce equal results to similarly designed metal screws

McGuire, D. A. W., J.C. (2000). "Extra-articular lateral reconstruction technique." Arthroscopy 16(5): 553-557.

This article describes an anterolateral reconstruction procedure that, when used in combination with an intra-articular anterior cruciate ligament (ACL) reconstruction, restores rotary and anterior knee stability. We believe that failing to recognize lateral instabilities and to perform an extra-articular reconstruction is an under-recognized cause of failure of ACL reconstruction. We also describe the indications, medical histories, and physical examination tests used to determine when an anterolateral reconstruction is needed. One should suspect a compromise of the lateral structures when presented with a failed ACL reconstruction in which the tunnels, the graft, and the rehabilitation all seem to have been done properly, or when a prior lateral procedure has been attempted and failed. In our experience, if a second ACL reconstruction is undertaken without the benefit of a lateral reconstruction, it may fail as well

McMahon, P. J. D., J.R.; Yocum,L.A.; Glousman,R.E. (1999). "The cyclops lesion: a cause of diminished knee extension after rupture of the anterior cruciate ligament." Arthroscopy 15(7): 757-761.

Four patients presented with persistent diminution of knee motion after rupture of the anterior cruciate ligament with a novel lesion as the cause. Each had participated in an aggressive rehabilitation program for a minimum of 2 months with emphasis on regaining full range of knee motion. Because chronic impairment of knee extension can be disabling, in those who did not regain full range of motion, arthroscopy of the knee ensued. All had a lesion in the intercondylar notch near the tibial insertion of the anterior cruciate ligament that acted as a mechanical obstruction to full knee extension. Grossly and histologically, these were similar to the cyclops lesion that also has been shown to cause loss of knee extension after anterior cruciate ligament reconstruction. Arthroscopic debridement of the cyclops lesion and manual manipulation of the knee under anesthesia lead to restoration of full knee extension in all knees. In 1 other knee with chronic instability after anterior cruciate ligament rupture, the cyclops lesion was present but was very small and was not associated with diminished knee extension. When loss of full extension persists for 2 months after anterior cruciate ligament disruption despite aggressive rehabilitation, the presence of a cyclops lesion should be considered

McNair, P. J. and G. A. Wood (1993). "Frequency analysis of the EMG from the quadriceps of anterior cruciate ligament deficient individuals." Electromyography & Clinical Neurophysiology 33(1):43-8, 1993 Jan-Feb 33(1): 43-8.

A bilateral comparison of the peak torque generated by the quadriceps muscles during isokinetic muscle action at a joint angular velocity of 180 deg/sec was undertaken in 17 subjects with chronic anterior cruciate ligament (ACL) deficiency. The results allowed subjects to be separated into minimal and maximal deficit groups. A frequency analysis of the electromyographic signals of the vasti lateralis obtained during the peak torque tests was then undertaken. The results showed that the median frequency of the ACL deficient limb in the maximal deficit group was significantly (p < 0.05) decreased compared to the median frequency of the uninvolved limb and both limbs of the minimal deficit group. These results suggested that type II muscle fibre atrophy had occurred. The frequency analysis of EMG may provide a noninvasive technique of measuring relative fibre atrophy differences between legs.

Meisterling, R. C., T. Wadsworth, et al. (1993). "Morphologic changes in the human patellar tendon after bone-tendon-bone anterior cruciate ligament reconstruction." Clinical Orthopaedics & Related Research (289):208-12, 1993 Apr(289): 208-12.

Magnetic resonance imaging (MRI) was performed on 15 patients, an average of 2.5 years after arthroscopically assisted bone-tendon-bone (BTB) anterior cruciate ligament (ACL) reconstruction, to evaluate the patellar tendon donor site. Five patients who had arthroscopically assisted ACL reconstruction using the semitendinosus tendon as a graft also were scanned bilaterally and evaluated. The mean difference between the involved and uninvolved patellar tendon length was -0.2 mm for the BTB patients and -2.6 mm for the semitendinosus patients. The mean difference between patellar tendon width for the BTB patients was 1.1 mm and 1.9 mm for the semitendinosus patients. The mean difference between patellar tendon thickness was 0.4 mm for the BTB surgery group and 0.02 mm for the semitendinosus surgery group. None of the differences were statistically significant. Results indicate that harvesting the central one third of the patellar tendon does not significantly affect the length, width, or thickness of the tendon at least 22 months after arthroscopically assisted BTB-ACL.

Menetrey, J., C. Kasemkijwattana, et al. (1999). "Direct-, fibroblast- and myoblast-mediated gene transfer to the anterior cruciate ligament." Tissue Eng 5(5): 435-42.

The anterior cruciate ligament (ACL) has poor capabilities of healing. Maturation or "ligamentization" of the ACL following autograft or allograft reconstruction has been found slow and remains under investigation. In vitro and in vivo studies have shown that platelet-derived growth factor (PDGF), transforming growth factor-beta (TGF-beta), and epidermal growth factor (EGF) have the potential to improve ligament healing. Gene therapy approaches may represent a new alternative in delivering these specific growth factors to the ACL. The aim of this study was to investigate the feasibility of three different gene therapy approaches (direct-, fibroblast-, and myoblast-mediated gene transfer) to the ACL. Rabbit myoblasts and ACL-fibroblasts were transduced with 5 x 10(7) recombinant adenoviral particles carrying the LacZ reporter gene (MOI = 50). Myoblasts and fibroblasts (1 x 10(6)) were each injected into the right ACL of 10 adult rabbits; direct injection of 5 x 10(7) adenoviral particles was performed in 10 other rabbits. The left side was used as sham. The beta-galactosidase production was revealed using the LacZ histochemical technique. The transduced fibroblasts and myoblasts were found in the ligament tissue and in the synovial tissue surrounding the ACL at 4, 7, 14, and 21 days postinjection. The myoblasts fused and formed myotubes in the ligament. The direct approach also allowed the transfer of the marker gene in the ligament at 4, 7, 21, and 42 days postinjection. X-gal staining revealed no expression of beta-galactosidase in the sham ligament. The presence of cells expressing the marker gene in the ACL opens up the possibility of delivering proteins (i.e., PDGF, TGF-beta, and EGF) capable of improving ACL healing and graft maturation. Furthermore, engineered myoblasts may mediate and accelerate the intraligament neovascularization. This new technology based on gene therapy and tissue engineering may allow a persistent expression of selected growth factors to enhance ACL healing following injury.

Menigaux, C. F., D.; Dupont,X.; Guignard,B.; Guirimand,F.; Chauvin,M. (2000). "The benefits of intraoperative small-dose ketamine on postoperative pain after anterior cruciate ligament repair." Anesth.Analg. 90(1): 129-135.

In a randomized, double-blinded study with three parallel groups, we assessed the analgesic effect of intraoperative ketamine administration in 45 ASA physical status I or II patients undergoing elective arthroscopic anterior ligament repair under general anesthesia. The patients received either IV ketamine 0.15 mg/kg after the induction of anesthesia and before surgical incision and normal saline at the end of surgery (PRE group); normal saline after the induction of anesthesia and before surgical incision and IV ketamine at the end of surgery (POST group); or normal saline at the beginning and the end of surgery (CONT group). Anesthesia was performed with propofol (2 mg/kg for induction, 60-200 microg x kg(-1) x min(-1) for maintenance), sufentanil (0.2 microg/kg 10 min after surgical incision, followed by an infusion of 0.25 microg x kg(-1) x h(-1) stopped 30 min before skinclosure), vecuronium (0.1 mg/kg), and 60% N2O in O2 via a laryngeal mask airway. Postoperative analgesia was initially provided with IV morphine in the postanesthesia care unit, then with IV patient- controlled analgesia started before discharge from the postanesthesia care unit. Pain scores, morphine consumption, side effects, and degree of knee flexion were recorded over 48 h and during the first and second physiotherapy periods, performed on Days 1 and 2. Patients in the ketamine groups required significantly less morphine than those in the CONT group over 48 h postoperatively (CONT group 67.7+/-38.3 mg versus PRE group 34.3+/-23.2 mg and POST group 29.5+/-21.5 mg; P < 0.01). Better first knee flexion (CONT group 35+/-10 degrees versus PRE group 46+/-12 degrees and POST group 47+/-13 degrees; P < 0.05) and lower morphine consumption (CONT group 3.8+/-1.7 mg versus PRE group 1.2+/- 0.4 mg and POST group 1.4+/-0.4 mg; P < 0.05) were noted at first knee mobilization. No differences were seen between the PRE and POST groups, except for an increase in morphine demand in the PRE versus the POST group (P < 0.05) in the second hour postoperatively. IMPLICATIONS: We found that intraoperative small-dose ketamine reduced postoperative morphine requirements and improved mobilization 24 h after arthroscopic anterior ligament repair. No differences were observed in the timing of administration. Intraoperative small-dose ketamine may therefore be a useful adjuvant to perioperative analgesic management

Micheli, L. J. R., B.; Gerberg,L. (1999). "Anterior cruciate ligament reconstruction in patients who are prepubescent." Clin.Orthop.(364): 40-47.

Between 1980 and 1996, 17 children who were prepubescent have had a combined intraarticular and extraarticular reconstruction of the anterior cruciate ligament using the iliotibial band that does not violate the physes. The average chronological age of the patients was 11 years (range, 2-14 years) and the average skeletal age of the patients was 10 years (range, 2-13 years). Eight of the 10 patients who had attained skeletal maturity were evaluated at an average of 66.5 months postoperatively (range, 25-168 months). All knees were stable subjectively by history and objectively by KT1000 testing. The average Lysholm score at assessment was 97.4. No child with a traumatic disruption had leg length discrepancy develop

Mikkelsen, C. W., S.; Eriksson,E. (2000). "Closed kinetic chain alone compared to combined open and closed kinetic chain exercises for quadriceps strengthening after anterior cruciate ligament reconstruction with respect to return to sports: a prospective matched follow-up study." Knee.Surg.Sports Traumatol.Arthrosc. 8(6): 337-342.

Rehabilitation after anterior cruciate ligament (ACL) reconstruction has focused over the past decade on closed kinetic chain (CKC) exercises due to presumably less strain on the graft than with isokinetic open kinetic chain exercises (OKC); however, recent reports suggest that there are only minor differences in ACL strain values between some CKC and OKC exercises. We studied anterior knee laxity, thigh muscle torque, and return to preinjury sports level in 44 patients with unilateral ACL; group 1 carried out quadriceps strengthening only with CKC while group 2 trained with CKC plus OKC exercises starting from week 6 after surgery. Anterior knee laxity was determined with a KT-1000 arthrometer; isokinetic concentric and eccentric quadriceps and hamstring muscle torque were studied with a Kin-Com dynamometer before and 6 months after surgery. At an average of 31 months after surgery the patients answered a questionnaire regarding their current knee function and physical activity/sports to determine the extent and timing of their recovery. No significant differences in anterior knee laxity were noted between the groups 6 months postsurgery. Patients in group 2 increased their quadriceps torque significantly more than those in group 1, but no differences were found in hamstring torque between the groups. A significantly higher number of patients in group 2 (n = 12) than in group 1 (n = 5) returned to sports at the same level as before the injury (P < 0.05). Patients from group 2 who returned to sports at the same level did so 2 months earlier than those in group 1. Thus the addition of OKC quadriceps training after ACL reconstruction results in a significantly better improvement in quadriceps torque without reducing knee joint stability at 6 months and also leads to a significantly higher number of athletes returning to their previous activity earlier and at the same level as before injury

Miller, M. D. and F. H. Fu (1993). "The role of osteotomy in the anterior cruciate ligament-deficient knee." Clinics in Sports Medicine 12(4):697-708, 1993 Oct 12(4): 697-708.

Whether the ACL-deficient knee actually causes osteoarthritis is unclear. What is clear is that the two conditions can exist simultaneously. Treatment of these patients must be individualized based on their activities, symptoms, and findings. In the unusual patient with significant instability and moderate medial compartment osteoarthritis, a combined valgus osteotomy and ACL reconstruction may be appropriate. The authors emphasize that this is a salvage procedure, not intended to return the athlete to competition. Although the short-term results are promising, the long-term results of this treatment are unknown.

Miller, M. D. and C. D. Harner (1993). "The use of allograft. Techniques and results." Clinics in Sports Medicine 12(4):757-70, 1993 Oct 12(4): 757-70.

There are several advantages to allograft use for ACL reconstruction. Bone-patella, tendon-bone, and achilles tendon allografts are routinely used. The one-incision endoscopic technique is described. Very few comparative studies exist in the current literature, but clinical results with allograft tissues appear to be similar to those of autograft use.

Miller, M. D. N., T.; Butler,C.A. (1999). "Patella fracture and proximal patellar tendon rupture following arthroscopic anterior cruciate ligament reconstruction." Arthroscopy 15(6): 640-643.

The central one-third bone-patella tendon-bone graft is a popular choice for arthroscopic anterior cruciate ligament reconstruction. Complications following graft harvesting are unusual, but several reports have been published. We report an unusual case involving a simultaneous patella fracture and patellar tendon rupture that occurred 6 weeks postoperatively

Miller, M. D. N., T.; Butler,C.A. (1999). "Patella fracture and proximal patellar tendon rupture following arthroscopic anterior cruciate ligament reconstruction." Arthroscopy 15(6): 640-643.

Miller, M. D. S., R.T. (2001). "Anterior cruciate ligament reconstruction in an 84-year-old man." Arthroscopy 17(1): 70-72.

Anterior cruciate ligament (ACL) reconstruction is typically reserved for younger patients. Several recent articles have reported expanding traditional age barriers for ACL reconstruction in patients up to 62 years old. We report a case of a successful ACL reconstruction in an active 84-year-old rancher. Physiologic age is more important than chronologic age when considering ACL reconstruction

Millett, P. J. W., R.J.; Wickiewicz,T.L. (1999). "Open debridement and soft tissue release as a salvage procedure for the severely arthrofibrotic knee." Am.J.Sports Med. 27(5): 552-561.

Postoperative loss of knee motion is a well-recognized phenomenon. This paper reports our results with open debridement and soft tissue release as a salvage procedure in the treatment of patients with severe arthrofibrosis on whom arthroscopic surgical techniques had failed. Eight knees (eight patients) were identified retrospectively. There were four men and four women; mean age was 29 years. All had severely restricted motion with extensive intraarticular and periarticular fibrosis. Range of motion averaged 62.5 degrees preoperatively (flexion 81 degrees, loss of extension 18.8 degrees). Patients underwent open debridement and soft tissue release to restore motion. There were no complications. Motion improved to an average of 124 degrees after surgery. Average flexion improved from 81 degrees to 125 degrees . Loss of extension improved from 18.8 degrees to 1.25 degrees. Functional outcome was good, with Lysholm II scores averaging 79. Patient satisfaction was high. There was a high incidence of patellofemoral arthritis at follow-up. Furthermore, the patellar tendon shortened approximately 6 mm over time. While we do not advocate open debridement and soft tissue release as a first-line treatment for arthrofibrosis, we do conclude

Mills, C. A. and I. J. Henderson (1993). "The rubber fat pad retractor: use in arthroscopic anterior cruciate ligament reconstruction." Arthroscopy 9(3):332-3, 1993 9(3): 332-3.

Arthroscopic anterior cruciate ligament (ACL) reconstruction surgery requires adequate visualization of the anterior intercondylar area. Described is a quick, inexpensive, safe, and easily learned technique. Secondary benefits of the improved visualization provided by the technique include increased ease of the portal entry, facility for dry intraarticular arthroscopy, and harvest of drilled bone for later grafting of donor sites. The technique is described for use in arthroscopic knee surgery, but can be adapted for use in other joints and procedures.

Mitsou, A., P. Vallianatos, et al. (1990). "Anterior cruciate ligament reconstruction by over-the-top repair combined with popliteus tendon plasty." J Bone Joint Surg Br 72(3): 398-404.

We used the MacIntosh over-the-top repair combined with a popliteal tendon plasty in 273 athletically active patients with chronic incapacitating functional instability due to anterior cruciate ligament rupture; 244 were reviewed at three to nine years after operation. We describe the technique and its results, with functional evaluation by the Tegner and Lysholm system. Excellent or good results were obtained in 71%; most of the 29% fair or poor results were due to extensive meniscal and degenerative changes. In a group of 11 patients with excellent results arthroscopic and histological findings were encouraging, showing good incorporation of the graft.

Mittlmeier, T., A. Weiler, et al. (1999). "novel Award Second Prize Paper. Functional monitoring during rehabilitation following anterior cruciate ligament reconstruction." Clin Biomech (Bristol, Avon) 14(8): 576-84.

OBJECTIVE: It was hypothesized that testing of ambulatory function and more demanding activities were more appropriate predictors of dynamic knee function before and after reconstruction of the anterior cruciate ligament than conventional measures of functional evaluation. It was assumed that assessment of dynamic plantar pressure distribution would represent a practical tool for guidance of the rehabilitation process after anterior cruciate ligament reconstruction. DESIGN: In a prospective study, 10 patients with isolated anterior cruciate deficiency were examined before and after replacement of the anterior cruciate (6, 12, 24 weeks) in a standardized technique. BACKGROUND: Today, functional assessment following anterior cruciate ligament reconstruction relies on clinical examination supplemented by instrumented testing of knee laxity and on isokinetic evaluation of muscle performance. Gait analysis has not been used as a quantitative measure of rehabilitation progress after surgery. METHODS: All patients were subjected to the same physiotherapy protocol. The clinical results were documented using the International Knee Documentation Committee (IKDC) protocol and the degree of knee laxity by an instrumented anterior drawer test. Muscular performance was evaluated by isokinetic testing. Dynamic pedography (EMED-SF 4) was performed to compare the non-injured and the operated leg during level walking and while descending stairs. RESULTS: Gait performance six weeks after surgery tended to be inferior to preoperative and late postoperative values. While the slight increase of maximum knee extensor torque in the operated leg and the improvement of the IKDC score during the rehabilitation period were not statistically significant, a significantly decreased gait asymmetry could be observed 12 weeks after surgery. The descending stairs test revealed functional deficits better than level walking. The latter test exhibited a strong correlation with the preoperative IKDC level and the maximum knee extensor deficit at 60 degrees /s. CONCLUSIONS: Dynamic pedography during level walking and while descending stairs is a valuable tool for monitoring the rehabilitation process after anterior cruciate ligament reconstruction. RELEVANCE: Due to the better resolution of functional deficits compared with indirect measures of function (isokinetic testing) assessment of the plantar pressure distribution may provide a more individualized adaptation for the rehabilitation program.

Miyatsu, M., Y. Atsuta, et al. (1993). "The physiology of mechanoreceptors in the anterior cruciate ligament. An experimental study in decerebrate-spinalised animals." Journal of Bone & Joint Surgery - British Volume 75(4):653-7, 1993 Jul 75(4): 653-7.

The physiological role of mechanoreceptors in the anterior cruciate ligament (ACL) was studied in unanaesthetised decerebrate-spinalised cats and dogs. Tonic activity in the quadriceps and the hamstring increased in response to physiological loading of the ACL. Evoked potentials in the posterior articular nerve (PAN) were elicited by electrical stimulation of the surface of the ligament. ACL loading also induced significant discharges from the PAN. The results suggest that ACL loading has an excitatory effect on the thigh muscles through a multimotor neurone output, and that the PAN is one of the afferent routes from the mechanoreceptors of the ACL. The ACL-muscle reflex may therefore play a physiological role in maintaining knee kinematics.

Mody, B. S., L. Howard, et al. (1993). "The ABC carbon and polyester prosthetic ligament for ACL-deficient knees. Early results in 31 cases." Journal of Bone & Joint Surgery - British Volume 75(5):818-21, 1993 Sep 75(5): 818-21.

We treated 39 knees with chronic deficiency of the anterior cruciate ligament by reconstruction using the ABC carbon and polyester prosthetic ligament; 31 (79.5%) were reviewed at an average follow-up of 34 months. There had been four complete failures requiring revision. The remaining 27 were studied in detail. On the Lysholm rating, only 11 knees (41%) had good results with a score of over 76. The mean anterior drawer movement was reduced from 7.6 mm before operation to 5.8 mm at review. The mean difference from the opposite uninjured knee was 3.9 mm before operation, 1 mm (in 21 patients) at mean follow-up of 7.4 months and 2.5 mm (in 27 patients) at 34 months, indicating progressive loss of effect. In our opinion the results are unsatisfactory: we do not recommend the use of this prosthetic ligament.

Mohtadi, N. G., S. Webster-Bogaert, et al. (1991). "Limitation of motion following anterior cruciate ligament reconstruction. A case-control study." Am J Sports Med 19(6): 620-4; discussion 624-5.

Limitation of motion following ACL reconstruction is a well-recognized and disturbing complication. The purposes of this study were to identify and characterize those patients who developed this complication from a series of 527 ACL reconstructions, determine etiologic factors, and make recommendations regarding prevention and management. The case group included 37 patients who required a manipulation under anesthesia because of failure to gain a satisfactory range of motion after an ACL reconstruction. Unsatisfactory motion was defined as a flexion deformity of 10 degrees or more and/or limitation of flexion to less than 120 degrees by 3 months following ACL reconstruction. The control group of patients were selected randomly from the overall series and all had a satisfactory range of motion. The cases and controls were then compared by analyzing these variables: age, sex, knee, time from injury to reconstruction, type of tissue used, meniscal abnormalities or surgery, repair of the medical collateral ligament, and postoperative immobilization and rehabilitation. The cases were followed up to assess the range of motion compared to the opposite knee at an average of 26 months postmanipulation. Thirty-seven patients (7%) underwent a manipulation under anesthesia, 9 of these (24.3%) also had an arthroscopic arthrolysis. Reconstructions done less than 2 weeks postinjury showed a statistically significant higher rate of knee stiffness. The same trend was also present for those reconstructed 2 to 6 weeks postinjury. All other variables failed to show a significant statistical difference. At followup, the average loss of extension was 4 degrees and loss of flexion 5 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Mok, D. W. and G. S. Dowd (1993). "Long-term results of anterior cruciate reconstruction with the patellar tendon." Injury 24(6):385-8, 1993 Jul 24(6): 385-8.

Thirty patients who had an anterior cruciate reconstruction with a patellar tendon autograph were reviewed at an average of 7.5 years (range 5-11 years) after operation. In all, 27 patients maintained their good/excellent results based on the Lysholm and Gillquist scoring system compared with the review at 2 years; two patients remained fair and one reconstruction failed at an early stage. There was no apparent deterioration of knee function at 7.5 years when compared with those at 2 years. None of the patients had symptoms related to the patellofemoral joint.

Molina, M. E. N., D.E.; Evans,J.A.; Delee,J.C. (2000). "Contaminated anterior cruciate ligament grafts: the efficacy of 3 sterilization agents." Arthroscopy 16(4): 373-378.

PURPOSE: A study was undertaken to determine the incidence of positive cultures resulting from an anterior cruciate ligament (ACL) specimen dropped on the operating room floor and the efficacy of sterilizing the specimen by soaking in 1 of 3 antimicrobial solutions: an antibiotic solution of neomycin and polymyxin B, 10% providone-iodine solution, and standard chlorhexidine gluconate solution. TYPE OF STUDY: Randomized trial. MATERIALS AND METHODS: Fifty ACL specimens removed from patients undergoing total knee arthroplasty were used as the test group. The specimens were longitudinally sectioned into 4 equal pieces. The 4 pieces were dropped on the floor and left for a period of 15 seconds. Cultures were taken from each specimen after immersion in 1 of the 3 sterilization solutions for a period of 90 seconds. One of the 4 specimens was cultured without being exposed to any solution, thereby establishing these specimens as the control group. Cultures of a floor swab were taken at the same time and place that the ACL was dropped. RESULTS: The floor swab cultures were positive in 48 of the 50 specimens (96%). The ACL control group (untreated dropped grafts) had 29 of 50 specimens positive (58%). The grafts soaked in antibiotic solution had 3 of 50 specimens positive (6%). The grafts soaked in providone-iodine solution had 12 of 50 specimens positive (24%). The grafts soaked in chlorhexidine gluconate solution had 1 of 50 specimens positive (in broth only) (2%). CONCLUSION: This study shows that significant contamination occurs when dropping specimens on the floor, as 58% of the dropped grafts had positive cultures. Of the 3 sterilization techniques used, chlorhexidine gluconate seems to be the most efficient with only a single broth culture (2%) found to be positive. The antibiotic solution was second best (6%), although there is no statistically significant difference between these 2 groups. The 10% providone-iodine solution under these test conditions was the least effective of all the 3 sterilization agents with 24% cultures positive after immersion

More, R. C., B. T. Karras, et al. (1993). "Hamstrings--an anterior cruciate ligament protagonist. An in vitro study." American Journal of Sports Medicine 21(2):231-7, 1993 Mar-Apr 21(2): 231-7.

A cadaveric model that incorporated quadriceps and hamstrings muscle loads was developed to simulate the squat exercise. The addition of hamstrings load affected knee kinematics in two ways. First, anterior tibial translation during flexion ("femoral roll-back") was significantly reduced (P = 0.003) and second, internal tibial rotation during flexion was reduced (P = 0.008). However, quadriceps force was unaffected by the addition of hamstrings load. Thus, it seems likely that hamstrings muscle activity that has been observed in vivo during a squat probably functions synergistically with the anterior cruciate ligament to provide anterior knee stability. After the ACL was sectioned, anterior tibial translation was significantly increased during the squat (P = 0.04). The anterior cruciate ligament was then reconstructed using a graft instrumented with a load cell. During passive motion, maximal graft tension was at full extension. During simulated squat exercise, the addition of hamstrings caused a significant decrease in graft load (P = 0.006). During the squat, maximal graft tension was at full extension, and was equal to the graft tension at full passive extension. Thus, the squat exercise may be useful in the early stages of anterior cruciate ligament rehabilitation.

Morrissey, M. C. H., Z.L.; Drechsler,W.I.; Coutts,F.J.; Knight,P.R.; King,J.B. (2000). "Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction." Knee.Surg.Sports Traumatol.Arthrosc. 8(6): 343-348.

Knee extensor resistance training using open kinetic chain (OKC) exercise for patients recovering from anterior cruciate ligament reconstruction (ACLR) surgery has lost favour mainly because of research indicating that OKC exercise causes greater ACL strain than closed kinetic chain (CKC) exercise. In this prospective, randomized clinical trial the effects of these two regimes on knee laxity were compared in the early period after ACLR surgery. Thirty-six patients recovering from ACLR surgery (29 males, 7 females; age mean = 30) were tested at 2 and 6 weeks after ACLR with knee laxity measured using the Knee Signature System arthrometer. Between tests subjects trained using either OKC or CKC resistance of their knee and hip extensors in formal physical therapy sessions three times per week. Following adjustment for site of treatment, pretraining injured knee laxity, and untreated knee laxity at post-training, the use of OKC exercise, when compared to CKC exercise, was found to lead to a 9% increase in looseness with a 95% confidence interval of -8% to +29%. These results indicate that the great concern about the safety of OKC knee extensor training in the early period after ACLR surgery may not be well founded

Mott, H. (1983). "Semitendinosus anatomic reconstruction for cruciate ligament insufficiency." Clin Orthop(172): 90-92.

Muller, B. R., S.; Kohn,D.; Seil,R. (2000). "Donor site problems after anterior cruciate ligament reconstruction with the middle third of the patellar ligament." Unfallchirurg 103(8): 662-667.

In a retrospective study we examined the clinical and sonographic changes after anterior cruciate ligament reconstruction with lig. patellae. 51 patients were evaluated clinically and sonographically after arthroscopically assisted ACL-reconstruction with a bone-patella tendon 3-6 years (mean 4.3 years) postoperatively. Certainly 18 patients (35%) reported about an anterior knee pain, but only 2 patients (4%) complained about pain during activities of daily living and 3 patients (6%) about pain during slight sports activities. Retropatellar crepitations was found in 24 patients (47%) on the operated side and at 11 patients (22%) on the non operated side. Twenty nine patients (57%) complained about a discomfort or pain when kneeling on the operated side. In 13 patients (26%) sonography showed a shortening of the patella ligament by 4 mm or more. Only few patients are strongly limited in their activity by the anterior knee pain. Neither our results nor the literature give evidence, that the tendon defect is the underlying cause of this pain syndrome. However, the number of patients with pain during kneeling on the operated side was relatively high. The semitendinosus gracilis graft should be considered for patients who have to knee during working or recreational activities

Muller, M. (1993). "The relationship between the rotation possibilities between femur and tibia and the lengths of the cruciate ligaments." Journal of Theoretical Biology 161(2):199-220, 1993 Mar 21 161(2): 199-220.

The system of the anterior (a) and posterior (p) cruciate ligaments and their distances between attachments to the femur (f) and tibia (t), respectively, as found in the knee joint of tetrapods is considered as a crossed four-bar linkage. Starting from a flat or curved tibial articulating surface the shape of the femoral articulating surfaces in principle can be derived (Huson, 1974; Menschik, 1974). The point of intersection (S) of the cruciate ligaments is the instantaneous centre of rotation and describes a curve during knee angulation; the centrode. Two centrodes are distinguished: S1 with the tibia stationary and S2 with the femur stationary. During leg bending the centrodes roll over each other, without sliding. Four series of knee-joint simulations were made. In series A, the femoral bar (distance between cruciate ligaments) was varied, in series B, the anterior cruciate ligament (so the length of a ligament). In series C and D, combinations of bar lengths were varied. The maximum leg rotation range was calculated from the lengths of the bars of the cruciate ligament system for each of the series A ... D. Also the leg rotation range for which the knee joint is mechanically stabilized by the cruciate ligaments was calculated. The stabilization criterium chosen was that a cruciate ligament may not become perpendicular (> 78.5 degrees) to the articulating surfaces. It was found that the cruciate ligaments alone cannot stabilize the knee joint adequately over the whole required range of leg movement. External structures are required to obtain full stabilization. As the femoral and tibial articulating surfaces never lie at the centrodes, considerable sliding occurs between them. It is suggested that a uniformly distributed sliding is essential for lubrication and so for a proper knee-joint functioning.

Muneta, T., H. Yamamoto, et al. (1993). "Relationship between changes in length and force in in vitro reconstructed anterior cruciate ligament." American Journal of Sports Medicine 21(2):299-304, 1993 Mar-Apr 21(2): 299-304.

The effect of tibial and femoral attachment site on the length change and force of an anterior cruciate ligament graft during unloaded flexion in eight cadaver specimens was examined. Two tibial sites (anteromedial and central portion of the anterior cruciate ligament attachment) and three femoral sites (anterior and central portions of the anterior cruciate ligament attachment, and over-the-top) were evaluated. Graft length changes between all combinations of attachment sites were measured from full extension to 150 degrees of passive flexion at 15 degrees intervals using the displacement of a 2-mm inextensible cord. The anterior cruciate ligament was then reconstructed using a Kennedy Ligament Augmentation Device, and graft forces at the same angles of passive flexion were measured with a buckle transducer. Graft length change and force were more affected by the femoral attachment site than the tibial site. There was a close correlation between length change and force measurements in flexion, but not near extension. The pattern of force and length change versus flexion angle for a given combination of attachment sites sometimes varied over the knees tested. Our results suggest that intraoperative isometry measurements are worthwhile for indicating an overloaded graft in flexion; however, length changes near extension may not adequately reflect graft force, creating the possibility that a graft may be more highly loaded than realized.

Muneta, T., H. Yamamoto, et al. (1993). "Effects of postoperative immobilization on the reconstructed anterior cruciate ligament. An experimental study in rabbits." American Journal of Sports Medicine 21(2):305-13, 1993 Mar-Apr 21(2): 305-13.

To investigate the effects of postoperative immobilization and limited motion on reconstructed anterior cruciate ligaments, 28 rabbits received an anterior cruciate ligament reconstruction using autogenous Achilles tendon and were then divided into three groups: fully immobilized, 4 weeks immobilized, and limited motion. Two rabbits from each group were evaluated macroscopically, histologically and microangiographically at 4-week intervals until 12 weeks postoperatively. An additional six rabbits in the 4 weeks immobilized and limited motion groups were studied biomechanically at 12 weeks postoperatively. Macroscopically, both immobilized groups showed more proliferation of the infrapatellar fat pad, which was adherent to the reconstructed anterior cruciate ligament. Histology revealed more rapid regeneration of reconstructed anterior cruciate ligaments in the limited motion group, with no findings of necrosis in the mid-substance. Microangiography indicated faster normalization of vascularity in the limited motion group. The biomechanical study showed no significant difference in laxity between the 4 weeks immobilized and limited motion groups. The graft stiffness and maximum load to failure were greater for the limited motion group, although the increase was not statistically significant. The histologic and microangiographic results from the limited number of animals in this study support limited postoperative motion in the anterior cruciate ligament reconstructed knee. However, there were no differences in terms of the biomechanical parameters at 12 weeks postoperatively between the immobilized and limited motion treatment modes.

Musgrove, T. P. S., L.J.; Burt,C.F.; Pinczewski,L.A. (2000). "The influence of reverse-thread screw femoral fixation on laxity measurements after anterior cruciate ligament reconstruction with hamstring tendon." Am.J.Sports Med. 28(5): 695-699.

In arthroscopically assisted anterior cruciate ligament reconstruction using hamstring tendon graft, the graft rotates slightly as the femoral screw is inserted. Its final position tends to be in the anterior half of the tunnel in right knees, resulting in clinical laxity. To perform identical procedures on left and right knees, a reverse-thread screw was designed for femoral fixation in right knees. We prospectively studied 80 patients undergoing right-knee anterior cruciate ligament reconstruction with hamstring tendon autograft. Thirty-six patients underwent reconstruction with a standard screw and 44 underwent reconstruction with a reverse-thread screw. The same technique, performed by the same surgeon, was used on all patients. At 12 months' follow-up, the average side-to-side differences on arthrometry testing were 2.00 mm for the standard screw group and 0.95 mm for the reverse- thread screw group using a manual maximum test, and 1.66 mm and 1.00 mm, respectively, using the 20-pound test. Both differences were statistically significant. Of the standard group, 23% had a manual maximum difference of 3 mm or more, compared with 8% of the reverse- thread group. A significant difference was found between these two groups for Lachman test (77% with grade 0 for the standard group compared with 92% for the reverse group) but pivot shift and Lysholm knee score were not significantly different. The use of a reverse- thread screw for femoral fixation in right-knee anterior cruciate ligament reconstructions in men significantly decreased laxity at 12 months after surgery compared with standard screw fixation

Mylle, J., P. Reynders, et al. (1993). "Transepiphysial fixation of anterior cruciate avulsion in a child. Report of a complication and review of the literature." Archives of Orthopaedic & Trauma Surgery 112(2):101-3, 1993 112(2): 101-3.

An avulsion of the anterior cruciate of an 11 year old girl was internally fixed with a transepiphysial screw. Two years later, anterior epiphysiodesis was evident, causing hyperextension of the knee. To avoid this complication, we recommend early removal of transepiphysial metalwork in children. Arthroscopical intrafocal fixation is proposed as a safe alternative.

Nawata, K., R. Teshima, et al. (1993). "Osseous lesions associated with anterior cruciate ligament injuries. Assessment by magnetic resonance imaging at various periods after injuries." Archives of Orthopaedic & Trauma Surgery 113(1):1-4, 1993 113(1): 1-4.

In 56 patients with anterior cruciate ligament (ACL) rupture, we retrospectively examined osseous lesions secondary to the rupture using magnetic resonance imaging (MRI). Depending on the time from their ligamentous injury to the performance of MRI, the patients were divided into three groups: the acute group (less than 1 month, n = 20), the subacute group (between 1 and 12 months, n = 16), and the chronic group (12 months or more, n = 20). Occult osseous lesions which were not detected by roentgenography were revealed by MRI in 14 patients in the acute group (70.0%), 5 in the subacute group (31.3%), and 1 in the chronic group (5%). The detection rate of osseous lesions by MRI was significantly higher in the acute group than in the other groups (P < 0.001). Osseous lesions were always detected in the same locations of the lateral compartment of the knee joint. When examined by arthroscopy, these lesions were often found to be accompanied by articular cartilage injuries. In the acute group, osseous lesions were visible in the high signal intensity area of T2-weighted images and in the low signal intensity area of proton density images. They were interpreted as representing hemorrhage and edema within the bone marrow. In the subacute and chronic groups, the osseous lesions were smaller, and their signal intensity on T2-weighted images was lower than that in the acute group, probably reflecting the ongoing resorption of the hemorrhage and healing of the lesions. These results suggest that osseous lesions develop following injury to the ACL.

Neurath, M. (1993). "[Expression of tenascin, laminin and fibronectin following traumatic rupture of the anterior cruciate ligament]." Zeitschrift fur Orthopadie und Ihre Grenzgebiete 131(2):168-72, 1993 Mar-Apr 131(2): 168-72.

In the present study, the pattern of some extracellular matrix glycoproteins was determined in traumatic anterior cruciate ligament ruptures (n = 17) and in normal ligaments (n = 11). 6 microns cryo-sections were incubated with monoclonal antibodies recognizing tenascin, laminin, and fibronectin, and FITC-labeled secondary antibodies. Immunohistochemistry revealed that tenascin, fibronectin and laminin are sparsely distributed in normal anterior cruciate ligaments, but strongly expressed in ruptured ligaments with a time-restricted pattern. The de novo-expression of tenascin appeared before laminin but later than fibronectin. The data suggest that fibronectin and tenascin are important, partially antagonistic components during healing processes after anterior cruciate ligament ruptures.

Neuschwander, D. C., D. Drez, Jr., et al. (1993). "Simultaneous high tibial osteotomy and ACL reconstruction for combined genu varum and symptomatic ACL tear." Orthopedics 16(6):679-84, 1993 Jun 16(6): 679-84.

This article reviews the subjective, objective, functional, and radiographic results of five patients with symptomatic anterior cruciate instability, genu varum, and varus rotational instability treated by sequential high tibial osteotomy and anterior cruciate ligament reconstruction at one operative procedure. The average patient age was 27 years (range: 21 to 35), and the average follow up was 2.5 years (range: 2 to 3). All patients had symptomatic instability with anterior tibia subluxation, which was documented by KT-1000 testing. All patients also had a varus alignment clinically and radiographically with medial compartment pain. Postoperatively, the medial compartment pain was improved, and instability episodes were eliminated. Side to side differences (KT-1000--manual maximum) were reduced to 3.1 mm. There were no complications. The instability episodes were eliminated, and functional levels were improved in all patients. We concluded that, for this select group of patients, simultaneous extremity realignment and ligament stabilization will effectively manage both conditions without compromising the results of either procedure.

Neusel, E., S. Maibaum, et al. (1993). "[Results of follow-up of conservatively treated isolated fresh anterior cruciate ligament rupture]." Aktuelle Traumatologie 23(4):200-6, 1993 Jun 23(4): 200-6.

35 patients with an arthroscopically confirmed isolated fresh anterior cruciate ligament rupture were subjected to follow-up examination after an average period of four years. In all the 35 patients a conservative treatment schedule had been followed post-arthroscopically, with a physiotherapy on a neurophysiological basis. Of the 35 isolated anterior cruciate ligament ruptures, 24 were complete and 11 partial ruptures. The follow-up examination results are based on subjective scores (O'Donoghue Score, Lysholm Score) and on one objective score (objective ODonaghue Score), as well as on the Lachman Test and the Pivot Shift Sign. In the partial anterior cruciate ligament ruptures we obtained mostly good to satisfactory results with the subjective and objective scores and a lower incidence of surgery; the original performance ratings at sports were largely maintained. On the other hand, the complete isolated anterior cruciate ligament ruptures yielded mainly satisfactory to poor results with the objective scores and a high rate of repeat surgery especially in the case of meniscus tears, and a major setback in the original sports performance ratings.

Neyret, P., S. T. Donell, et al. (1993). "Partial meniscectomy and anterior cruciate ligament rupture in soccer players. A study with a minimum 20-year followup." American Journal of Sports Medicine 21(3):455-60, 1993 May-Jun 21(3): 455-60.

A retrospective review of 77 soccer players with 91 affected knees that had undergone the same operation, a rim-preserving meniscectomy, was made with a minimum followup of 20 years and an average followup of 27 years. The patients were divided into groups based on the presence of an intact (Group 1) or ruptured (Group 2) anterior cruciate ligament. At 5 years after meniscectomy, 75% of Group 1 and 52% of Group 2 were still playing soccer, and 13% in Group 1 as opposed to 28% in Group 2 had given up sports. The sporting class assessment was good in 80% of the Group 1 knees and 62% in the Group 2 knees. By followup, 5% of Group 1 and 32% of Group 2 required further meniscectomies, and 2% of Group 1 and 16% of Group 2 required operations for osteoarthritis. Radiologically diagnosed osteoarthritis was present in 24% of Group 1 knees compared with 77% of Group 2. Functionally, 60% of the Group 1 knees were excellent at followup as opposed to 9% in Group 2 knees. In Group 1, 49% were still involved in sports compared with 22% in Group 2. However, 97% of Group 1 were satisfied with their knees compared with 74% of Group 2. All of these differences were statistically significant.

Neyret, P., S. T. Donell, et al. (1993). "Results of partial meniscectomy related to the state of the anterior cruciate ligament. Review at 20 to 35 years." Journal of Bone & Joint Surgery - British Volume 75(1):36-40, 1993 Jan 75(1): 36-40.

We reviewed 195 knees in 167 patients at least 20 years after a rim-preserving meniscectomy. They were considered in two groups: 102 knees had had an intact anterior cruciate ligament (ACL), and 93 had had an unrepaired rupture. More patients with a ruptured ACL had downgraded their sport activity by five years after meniscectomy. The incidence of radiographic osteoarthritis was about 65% at 27 years in patients with a ruptured ligament, and 86% in those followed up for over 30 years. In the ligament-deficient group 10% had had operations for osteoarthritis, and another 28% had had other operations, mainly further meniscectomies. Only 6% of those with an intact ligament had needed a second operation after meniscectomy and at long-term follow-up 92% of them were satisfied or very satisfied. Only 74% of the ligament-deficient patients were satisfied with their result. The long-term outcome after rim-preserving meniscectomy depends mainly upon the state of the anterior cruciate ligament.

Nikolaou, P. K. S., A.V.; Glisson,R.R.; Ribbeck,B.M.; and Bassett, F.H.III (1986). "Anterior cruciate ligament allograft transplantation. Long-term function, histology, revascularization, and operative technique." Am.J. Sports Med., 14: 348-360.

Nogalski, M. P. and B. R. Bach, Jr. (1993). "A review of early anterior cruciate ligament surgical repair or reconstruction. Results and caveats." Orthopaedic Review 22(11):1213-23, 1993 Nov 22(11): 1213-23.

Earlier diagnosis and knowledge of the natural history of anterior cruciate ligament (ACL) injuries has made consideration of early operative treatment more important in the active patient at risk for further instability episodes. In a review of early operative treatment options, ACL repair alone has been disappointing for many patients, with long-term follow-up suggesting that the reinjury rate is high. Early repair with augmentation or reconstruction with hamstring or central third bone-tendon-bone graft yielded better results, but long-term follow-up is still needed, especially in the early reconstruction groups. Early ACL reconstruction, especially in patients with medial collateral ligament injury and/or extra-articular surgery, is associated with an increased incidence of arthrofibrosis. The methods of reporting data in these studies have also presented problems in interpreting and comparing data from one study with those of another. Further standardization will be needed if literature regarding ACL surgery can be easily compared from series to series.

Nonweiler, D. E., R. C. Schenck, Jr., et al. (1993). "The incomplete bicruciate knee injury. A report of two cases." Orthopaedic Review 22(11):1249-52, 1993 Nov 22(11): 1249-52.

Two patients suffered similar knee injuries due to valgus stress and hyperextension. Examination under anesthesia and arthroscopic evaluation revealed a previously unreported ligament injury pattern. Both patients had a complete tear of the anterior cruciate ligament and a partial tear of the posterior cruciate ligament; neither was noted to have a dislocation. The descriptive term identifying this injury pattern is "incomplete bicruciate knee injury." The purpose of this report is to identify this knee-injury complex, which appears to be part of the sequence that leads to complete tears of both cruciate ligaments--the classic knee dislocation.

Noyes, F. R. and S. D. Barber (1991). "The effect of an extra-articular procedure on allograft reconstructions for chronic ruptures of the anterior cruciate ligament." J Bone Joint Surg Am 73(6): 882-92.

A study was performed on the effect of the addition of an extra-articular procedure involving tenodesis of the iliotibial band to a reconstruction with a bone-patellar ligament-bone allograft for the treatment of chronic rupture of the anterior cruciate ligament. One hundred and four patients were divided into two groups for comparison: Group 1 (sixty-four patients) was treated with only an intra-articular replacement with an allograft and Group 2 (forty patients), with both an intra-articular replacement with an allograft and the extra-articular procedure. Preoperatively, there were no statistically significant differences between the two groups in terms of twenty variables, including body weight, level of activity, anterior-posterior displacements, number of previous operations, and duration of follow-up. All of the patients returned for follow-up evaluation twenty-three to fifty-four months (mean, thirty-five months) postoperatively. All were treated with the same postoperative program of immediate motion of the knee and rehabilitation. The results were evaluated with the use of a comprehensive subjective and objective system that rated the twenty factors. Both procedures proved to be effective in decreasing functional limitations and symptoms and in improving the level of sports activity and the over-all scores. The results in Group 2 were significantly better than those in Group 1, as measured with tests done with the KT-1000 arthrometer (p less than 0.01) and with regard to the level of sports activity (p less than 0.05) and the over-all scores (p less than 0.01). There was no postoperative difference between the two groups in terms of the results on pivot-shift or isokinetic testing, patellofemoral crepitus, functional limitations, or symptoms. The program of rehabilitation effectively restored 0 to 135 degrees of motion to all but four knees, which lacked 5 degrees of extension at the most recent follow-up. The over-all rate of failure for both groups was 11 per cent. However, the rate of failure was 16 per cent (ten of sixty-four knees) in Group 1 and only 3 per cent (one of forty knees) in Group 2. This difference was significant (p less than 0.05). The extra-articular procedure appeared to provide support to the healing intra-articular allograft by reducing deleterious forces and tibial displacements, and to restore the secondary restraints provided by the lateral iliotibial band. The results suggest that the combination of the procedures is of value in young, athletically active people who have chronic rupture of the anterior cruciate ligament.(ABSTRACT TRUNCATED AT 400 WORDS)

Noyes, F. R. and S. D. Barber (1993). "Allograft reconstruction of the anterior and posterior cruciate ligaments: report of ten-year experience and results." Instructional Course Lectures 42:381-96, 1993 42: 381-96.

Noyes, F. R., S. D. Barber, et al. (1990). "Bone-patellar ligament-bone and fascia lata allografts for reconstruction of the anterior cruciate ligament." J Bone Joint Surg Am 72(8): 1125-36.

A prospective study was performed of the first forty-seven consecutive patients who had repair of a ruptured anterior cruciate ligament and replacement with an allograft. Patients who had a rupture of another ligament were excluded, to provide a homogeneous group. Twenty-two patients received a fascia lata allograft and twenty-five patients received a bone-patellar ligament-bone allograft. All patients were enrolled in an exercise program to facilitate motion of the knee immediately after the operation, and all patients returned for postoperative evaluation (mean, forty months; range, twenty-five to sixty-seven months). The results were based on a comprehensive subjective and objective rating system, which assessed twenty factors. On testing with the KT-1000 arthrometer, 69 per cent of the patients had less than three millimeters of increased anterior-posterior displacement of the knee that had been operated on compared with the contralateral knee, 26 per cent had three to five millimeters, and 5 per cent had more than five millimeters. The knees that had a bone-patellar ligament-bone allograft had significantly lower values for anterior-posterior displacement than did those that had a fascia lata allograft (p less than 0.05). Just one patient, the only one in whom the fascia lata graft failed, had giving-way. There were no infections, and there was no evidence of rejection of the allograft or documented transmission of disease at the time of writing. A strict rating system was used. Eighteen patients (38 per cent) had an excellent result, twenty-four (51 per cent) had a good result, and five (11 per cent) had a fair or poor result. Motion of the knee immediately postoperatively was not deleterious to the allograft, and, because limitations of motion were identified and treated in the early postoperative period, full motion (0 to 135 degrees) was restored in all knees.

Noyes, F. R., S. D. Barber, et al. (1993). "High tibial osteotomy and ligament reconstruction in varus angulated, anterior cruciate ligament-deficient knees. A two- to seven-year follow-up study." American Journal of Sports Medicine 21(1):2-12, 1993 Jan-Feb 21(1): 2-12.

We assessed short-term treatment results of younger patients with varus malalignment and chronic anterior cruciate ligament deficiency. Forty-one patients (mean, 32 years; range, 16 to 47) underwent a high tibial osteotomy. Because of giving way symptoms, 14 also had a lateral iliotibial band extraarticular procedure at the time of the osteotomy and 16 had an intraarticular anterior cruciate ligament allograft reconstruction after the osteotomy. All returned for followup (mean, 58 months; range, 23 to 86), which included KT-1000 arthrometer testing and evaluation by our knee rating system. Statistically significant (P < 0.05) improvements were found in the mean overall rating scores for pain, swelling, and giving way. Preoperatively, 30 (73%) had pain with activities of daily living or with any sports activity; 11 (27%) could perform only light sports activities without pain. At followup, 32 patients (78%) had no pain with activities of daily living or light sports. Ten of 15 patients with advanced medial tibiofemoral arthrosis (subchondral bone exposure) had significant improvements in symptoms. Patient satisfaction was high: 88% stated they would undergo the procedure again and 78% felt their knee condition was improved. Patients who had the allograft reconstruction had significantly lower (P < 0.05) anterior-posterior displacements at followup than those who had the extraarticular procedure. We concluded that osteotomy should be performed early in the disease process for younger athletes who experience symptoms with activity. It may be unrealistic, however, to expect continuation of sports beyond light recreational, given the joint arthrosis that is usually present and the high in vivo joint loadings with athletes. Anterior cruciate ligament reconstruction should be considered when giving way previously occurred and the patient plans to resume athletics. However, patients with advanced arthrosis can avoid anterior cruciate ligament surgery by reducing athletic activities.

Noyes, F. R. and S. D. Barber-Westin (1997). "Arthroscopic-assisted allograft anterior cruciate ligament reconstruction in patients with symptomatic arthrosis." Arthroscopy 13(1): 24-32.

We reviewed the results of arthroscopic-assisted anterior cruciate ligament (ACL) allograft reconstruction in 40 patients who had advanced articular cartilage deterioration documented by arthroscopy during the reconstruction. A mean of 7 years had elapsed between the original injury and the reconstruction, and 102 prior operative procedures had been done in 34 of the 40 patients. A total of 64 articular cartilage lesions were noted; 34 knees had lesions in the medial or lateral tibiofemoral compartment. Postoperatively, all had immediate motion and early functional rehabilitation. The results were assessed using the Cincinnati Knee Rating System. At follow-up (mean, 37 months), significant improvements were found for pain, giving-way, and functional limitations with daily and sports activities (P < .01). Fifty-five percent had returned to mostly light athletics (avoiding high impact sports) based on our advice and were asymptomatic. The mean overall rating scores significantly improved (P < .0001, mean improvement 22 points). We concluded that the majority of patients in this study with chronic ACL rupture and post-traumatic arthrosis benefited short-term from arthroscopic-assisted ACL reconstruction.

Noyes, F. R. and S. D. Barber-Westin (1997). "A comparison of results in acute and chronic anterior cruciate ligament ruptures of arthroscopically assisted autogenous patellar tendon reconstruction." Am J Sports Med 25(4): 460-71.

We conducted a prospective study of 94 consecutive patients who received a patellar tendon autograft for anterior cruciate ligament rupture. Eighty-seven patients (93%) returned for followup a mean of 28 months postoperatively; 57 had chronic and 30 had acute or subacute ruptures. There were no significant differences between the subgroups for age, sex, articular cartilage lesions, or months of followup. Forty-six meniscal tears were repaired; 27 of these extended into the central avascular region. Rehabilitation emphasized immediate knee motion, but strenuous activity was delayed for at least 4 months. Only one patient had a knee motion complication, and stability (<3 mm, KT-2000 arthrometer, 134 N) was restored in 85% of knees with chronic ruptures and 92% of knees with acute ruptures. Earlier reconstruction should be considered in active persons as symptoms and limitations continued postoperatively in knees with chronic ruptures, leading to overall less satisfactory results. In patient rating of the overall knee condition, 69% of knees with chronic ruptures and 100% of knees with acute ruptures scored in the normal or very good range. Repair of meniscal tears that extend into the central avascular region should be considered, as 24 of the 27 (89%) menisci repaired showed clinical evidence of healing and did not require reoperation.

Noyes, F. R. and S. D. Barber-Westin (2001). "Revision anterior cruciate surgery with use of bone-patellar tendon-bone autogenous grafts." J Bone Joint Surg Am 83-A(8): 1131-43.

BACKGROUND: A prospective study was done to determine the functional results, patient satisfaction, and graft failure rate after fifty-seven consecutive revision replacements of the anterior cruciate ligament with use of a bone-patellar tendon-bone autogenous graft. METHODS: Fifty-four patients (fifty-five operations) were followed in this study. Concurrent operative procedures were performed during the revision procedure in thirty-seven knees (67%). These procedures included repair of a meniscal tear in twenty knees (36%) and reconstruction of deficient posterolateral or medial ligament structures in seventeen knees (31%). Nine knees (16%) had a high tibial osteotomy to correct varus malalignment before the revision operation. The results were evaluated with the Cincinnati Knee Rating System. RESULTS: There were significant improvements in the scores for pain (p < 0.0001), activities of daily living (p < 0.01), sports participation (p < 0.001), patient satisfaction (p < 0.0001), and overall rating of the knee (p < 0.0001). Thirty-three (60%) of the replaced ligaments were functional, nine (16%) were partially functional, and thirteen (24%) had failed. CONCLUSIONS: Many knees (93%) had compounding problems, including articular cartilage damage, prior meniscectomy, loss of secondary ligament restraints, varus malalignment, and concomitant ligament replacement or meniscal repair. Therefore, the results were generally less favorable than those following primary operations. The rate of graft failure was three times higher than our previously reported failure rate after primary replacements of the anterior cruciate ligament with a bone-patellar tendon-bone autogenous graft. Even so, symptoms and functional limitations with regard to daily and sports activities were found to have decreased and patient satisfaction improved. We advocate correction of varus malalignment prior to anterior cruciate procedures. Associated posterolateral ligament deficiencies should be surgically corrected during anterior cruciate procedures to prevent excessive loading on the graft from abnormal lateral tibiofemoral joint opening. Meniscal tears, including complex tears that extend into the avascular zone, can be concurrently repaired successfully during the revision.

Noyes, F. R., D. L. Butler, et al. (1983). "Intra-articular cruciate reconstruction. I: Perspectives on graft strength, vascularization, and immediate motion after replacement." Clin Orthop(172): 71-7.

All of the factors discussed here hopefully will increase the success rate of future intra-articular grafts. But it should not be supposed that the ideal ACL substitution answer is immediately forthcoming. Past experience points to the inherent difficulty of any potential solution and the need to progress in a rigorous scientific manner in the evaluation of the next wave of ligament substitutes. This article reports the utilization of an immediate protective motion program to avoid the problems of postoperative stiffness and lack of knee extension. It can not be stated with certainly whether the same program can be applied to free grafts or to those obtained from other sites. However, the avoidance of these problems will significantly lessen the morbidity of intra-articular reconstruction. The utilization of a vascularized patellar tendon hopefully will add another dimension to ACL replacement.

Noyes, F. R., R. E. Mangine, et al. (1987). "Early knee motion after open and arthroscopic anterior cruciate ligament reconstruction." Am J Sports Med 15(2): 149-60.

The hypothesis proposed in this study was that the initiation of active and passive knee motion within 48 hours of major intraarticular knee ligament surgery would not have the deleterious effects of increasing knee effusion, hemarthrosis, periarticular soft tissue edema, and swelling. We conducted a prospective study with randomized assignment of 18 patients into two groups: 9 patients in the "motion" group began 10 hours of daily continuous passive motion (CPM) on the 2nd postoperative day, while the remaining 9 in the "delayed motion" group used a soft hinged knee brace with knee hinges locked at 10 degrees of flexion and entered into the motion program on the 7th postoperative day. All knees were allowed full 0 degrees to 90 degrees of motion except for a total of seven knees with concomitant mensicus repairs and extraarticular reconstructions where 20 degrees to 90 degrees of motion was allowed, limiting the last 20 degrees of knee extension for the first 4 postoperative weeks to protect the repair. In all other respects, the rehabilitation program after surgery was the same for the two groups, including postoperative compression dressings, exercises, and weight-bearing status. Ten of the eighteen patients had acute ACL disruptions and 8 had chronic ACL insufficiencies. There was an even distribution of acute and chronic knee cases and of open and arthroscopic ligament procedures in the early and delayed motion groups. Associated surgery included four meniscus repairs, three medial collateral ligament repairs, and one lateral collateral ligament repair. Special suturing and fixation techniques were used at surgery to maintain the integrity of ligament and meniscus structures, allowing the surgeon to feel safe in subjecting the joint to early postoperative motion. The objective parameters measured were KT-1000 arthrometer measurements, Cybex isokinetic testing, girth measurements at four lower limb locations, range of motion goniometer measurements, postoperative pain medications, and days of hospitalization. Starting intermittent passive motion on the 2nd postoperative day did not increase joint effusion, hemarthrosis, or soft tissue swelling. In both motion groups, postoperative joint effusions were absent after the 14th postoperative day. There was no statistically significant difference in knee extension or flexion limits, pain medication used, or hospital stay in comparing the two knee motion programs. An important finding of this study was the significant decreases in thigh circumference that occurred within the first few weeks of surgery, which progressed despite a closely supervised inpatient and outpatient rehabilitation program.(ABSTRACT TRUNCATED AT 400 WORDS)

Noyes, F. R., R. E. Mangine, et al. (1992). "The early treatment of motion complications after reconstruction of the anterior cruciate ligament." Clin Orthop(277): 217-28.

The use of active and passive knee motion in the immediate postoperative period and a treatment plan for early postoperative limitations in knee motion has proven highly effective in restoring motion after anterior cruciate ligament (ACL) reconstruction. Of 207 knees, 189 (91%) regained a full range of motion of 0 degrees-135 degrees. The remaining 18 knees (9%) did not regain motion as rapidly as the others and were placed in an early postoperative phased treatment program. Six knees had serial extension casts, nine had early gentle manipulation under anesthesia, and three had arthroscopic lysis of intraarticular adhesions and scar tissue. Fourteen of these 18 knees regained a full range of knee motion. Two of the remaining four knees lacked 5 degrees of full extension, whereas the other two, in patients who had failed to follow medical advice and the rehabilitation program, had permanent and significant limitation of motion. The incidence of postoperative motion problems was related to the extent of the surgical procedure. The incidence was 4% in patients who had only ACL reconstruction, 10% in cases in which added lateral extraarticular procedure had been done, 12% where a meniscus repair had been done, and 23% where a medial collateral ligament repair was done.

Noyes, F. R. B.-W., S.D.; Roberts,C.S. "Use of allografts after failed treatment of rupture of the anterior cruciate ligament." J.Bone Joint Surg.Am. 76(7): 1019-1031.

A prospective study was done of the use of allogeneic tissue to reconstruct the anterior cruciate ligament in knees in which an intra- articular or an extra-articular operation had failed. Sixty-six consecutive patients (sixty-six knees) had such an operation with use of bone-patellar ligament-bone allografts; all but one returned for follow-up evaluation twenty-three to seventy-eight months (mean, forty- two months) after the operation. A total of 235 previous operations had been performed in these sixty-six knees, including eighty-one procedures for rupture of the anterior cruciate ligament. The results of the allograft procedure were evaluated with a subjective and objective system that rated twenty factors. The anterior-posterior displacement was substantially improved in most of the patients. According to data derived from arthrometric studies and pivot-shift tests of the fifty-seven patients who were so evaluated and in whom the condition was unilateral, 53 per cent (thirty) of the reconstructed ligaments were determined to be functional; 21 per cent (twelve ligaments), partially functional; and 26 per cent (fifteen ligaments), a failure. When we calculated the rate of failure by including ten failures that had occurred within two years after the operation with the fifteen that occurred in patients who had been followed for at least two years, the over-all rate of failure was 33 per cent (twenty- five of seventy-five operations). There was significant improvement in the subjective ratings of functional limitations and symptoms (p < 0.01) and in the over-all rating score (p < 0.0001). However, there was a significant difference between the scores of the patients in whom the surfaces of the articular cartilage had appeared normal at the index operation and those of the patients in whom there had been noteworthy fissuring and fragmentation or exposure of subchondral bone. After the program of rehabilitation, which included immediate motion of the knee, a range of motion of 0 to 135 degrees was restored in all but five knees, four of which lacked only 5 degrees of this extent of flexion or extension. The results demonstrate that bone-patellar ligament-bone allografts may be used when proper autogenous tissues are not available and that symptoms and abnormal displacement were reduced in most of our patients

Noyes, F. R. B.-W., S.D. (1997). "Arthroscopic-assisted allograft anterior cruciate ligament reconstruction in patients with symptomatic arthrosis." Arthroscopy 13(1): 24-32.

Noyes, F. R. B.-T., S.; Barber-Westin,S.D.; Heckmann,T.P. (2000). "Prevention of permanent arthrofibrosis after anterior cruciate ligament reconstruction alone or combined with associated procedures: a prospective study in 443 knees." Knee.Surg.Sports Traumatol.Arthrosc. 8(4): 196-206.

We prospectively determined the effectiveness of an immediate knee motion and early intervention program to prevent permanent motion limitations in a consecutive series of patients who had anterior cruciate ligament autogenous patellar tendon reconstruction for isolated rupture (219 knees) or combined with other procedures (224 knees). The subjects were placed into either a progressive or delayed rehabilitation program and were followed for at least 12 months postoperatively. At follow-up a normal range of motion (0 degrees to at least 135 degrees) was found in 436 knees (98%), and mild losses of extension (-5 degrees) were found in 7 knees. Twenty-three knees (5%) required interventions; 9 had extension casts, 9 had gentle manipulations under anesthesia, 3 had arthroscopic debridements, and 2 had continuous epidural anesthetic and inpatient therapy. All of these 23 knees regained full motion. The 7 patients with mild losses of extension had refused treatment intervention. The 0% incidence rate of permanent arthrofibrosis, and 0.7% reoperation rate for knee motion limitations, demonstrated the effectiveness of our program

Noyes, F. R. B., S.D.; Simon,R. "High tibial osteotomy and ligament reconstruction in varus angulated, anterior cruciate ligament-deficient knees. A two- to seven-year follow- up study." Am.J.Sports Med. 21(1): 2-12.

We assessed short-term treatment results of younger patients with varus malalignment and chronic anterior cruciate ligament deficiency. Forty- one patients (mean, 32 years; range, 16 to 47) underwent a high tibial osteotomy. Because of giving way symptoms, 14 also had a lateral iliotibial band extraarticular procedure at the time of the osteotomy and 16 had an intraarticular anterior cruciate ligament allograft reconstruction after the osteotomy. All returned for followup (mean, 58 months; range, 23 to 86), which included KT-1000 arthrometer testing and evaluation by our knee rating system. Statistically significant (P < 0.05) improvements were found in the mean overall rating scores for pain, swelling, and giving way. Preoperatively, 30 (73%) had pain with activities of daily living or with any sports activity; 11 (27%) could perform only light sports activities without pain. At followup, 32 patients (78%) had no pain with activities of daily living or light sports. Ten of 15 patients with advanced medial tibiofemoral arthrosis (subchondral bone exposure) had significant improvements in symptoms. Patient satisfaction was high: 88% stated they would undergo the procedure again and 78% felt their knee condition was improved. Patients who had the allograft reconstruction had significantly lower (P < 0.05) anterior-posterior displacements at followup than those who had the extraarticular procedure. We concluded that osteotomy should be performed early in the disease process for younger athletes who experience symptoms with activity. It may be unrealistic, however, to expect continuation of sports beyond light recreational, given the joint arthrosis that is usually present and the high in vivo joint loadings with athletes. Anterior cruciate ligament reconstruction should be considered when giving way previously occurred and the patient plans to resume athletics. However, patients with advanced arthrosis can avoid anterior cruciate ligament surgery by reducing athletic activities

Noyes, F. R. B., D.L.; Grood,E.S.; Zernicke,R.F.; and Hefzy,M.S. (1984). "Biomechanical analysis of human ligament grafts used in knee-ligament repairs and reconstruction." J.Bone and Joint Surg 66A: 344-352.

Noyes, F. R. B., S.D.; and Mangine,R.E. (1990). "Bone-patellar ligament-bone and fascia lata allografts for reconstruction of the anterior cruciate ligament." J.Bone and Joint Surg 72A: 1125-1136.

Noyes, F. R. B., S.D. (1993). "Allograft reconstruction of the anterior and posterior cruciate ligaments: report of ten-year experience and results." Instr.Course Lect. 42: 381-396.

Noyes, F. R. M., P.A.; Matthews,D.S.; and Butler,D.L. (1983). "The symptomatic anterior cruciate-deficient knee. Part I: the long-term functional disability in athletically active individuals." J. Bone and Joint Surg 65A: 154-162.

Noyes, F. R. M., R.E.; and Barber,S. (1987). "Early knee motion after open and arthroscopic anterior cruciate ligament reconstruction." Am.J. Sports Med., 15: 149-160.

Noyes, F. R. M., L.A.; Moorman,C.T., III; and McGinniss,G.H. (1989). "Partial tears of the anterior cruciate ligament. Progression to complete ligament deficiency." J.Bone and Joint Surg., 71B: 825-833.

Oates, K. M. V. E., D.P.; Briggs,K.; Homa,K.; Sterett,W.I. (1999). "Comparative injury rates of uninjured, anterior cruciate ligament- deficient, and reconstructed knees in a skiing population." Am.J.Sports Med. 27(5): 606-610.

To evaluate the risks of skiing after anterior cruciate ligament injury with or without reconstruction, we performed a 3-year study of 5646 skiers employed by a large ski resort. All skiers underwent knee ligament examinations before entering the study. The participants were divided into three groups based on whether they had never had an anterior cruciate ligament injury (N = 4748), were unilaterally deficient of the ligament (N = 138), or had undergone a unilateral reconstruction of the ligament at least 1 year before (N = 274). The rates of knee injuries requiring evaluation by a physician or time off work were calculated. The results of the reconstructed knees were further evaluated to determine whether ligament repair with semitendinosus/gracilis or patellar tendon autograft had a higher injury rate. Compared with knees with intact anterior cruciate ligaments, ligament-deficient knees had a 6.2-times higher rate of injuries, and knees in which the ligament had been reconstructed had a 3.1-times higher rate. The differences between each of the three groups were significant. Injuries to ligament-intact knees were less severe, with 13% requiring surgery, while 39% of the injuries in the ligament- deficient and 41% of the injuries in the reconstructed-ligament knees required surgery. The rates of injury for the graft types were not significantly different, but skiers with a semitendinosus/gracilis tendon autograft were significantly more likely to rupture their graft than skiers with a patellar tendon autograft

Oberlander, M. A., R. M. Shalvoy, et al. (1993). "The accuracy of the clinical knee examination documented by arthroscopy. A prospective study." American Journal of Sports Medicine 21(6):773-8, 1993 Nov-Dec 21(6): 773-8.

The diagnostic accuracy of the clinical examination for intraarticular injuries of the knee was documented by arthroscopy over a 6-month period. Two-hundred ninety patients (296 knees) were evaluated by history, physical examination, and standard radiographs. Supplemental diagnostic studies included 41 magnetic resonance images, 2 arthrograms, and 1 previous arthroscopy that had been recently performed. Overall, the correct diagnosis was made in 165 knees (56%), an incomplete diagnosis in 92 (31%), and an incorrect diagnosis in 39 (13%). There were only 2 knees (0.07%) with no discernable lesions. When a single lesion was present in the knee, the diagnosis was made correctly in 72% of cases. When more than 2 were discovered, the diagnosis was correct in only 30%. However, all individual lesions were diagnosed with an accuracy of greater than 90%. The lesions most difficult to diagnose were chondral fractures, fibrotic fat pads, tears in the anterior cruciate ligament, and loose bodies. Knees with acute lesions and those with a single diagnosis proved to be significantly easier to diagnose (P < 0.01). The variables that proved to be insignificant were age, sex, magnetic resonance imaging, surgeon, workers' compensation, or pending litigation.

OBrien, S. J. W., R.F.; Pavlov, Helene; Panariello, Robert; and Wickiewicz,T.L. (1991). "Reconstruction of the chronically insufficient anterior cruciate ligament with the central third of the patellar ligament." J. Bone and Joint Surg., 73A: 278-286.

Ochi, M., T. Yamanaka, et al. (1993). "Arthroscopic and histologic evaluation of anterior cruciate ligaments reconstructed with the Leeds-Keio ligament." Arthroscopy 9(4):387-93, 1993 9(4): 387-93.

In 62 of the patients who underwent anterior cruciate ligament (ACL) reconstruction with the Leeds-Keio (L-K) artificial ligament, we performed an arthroscopic second look and biopsy of the reconstructed ACL at 8-36 months postoperatively. Arthroscopic findings were classified into two groups according to the tautness of the ligament and the coverage of the implanted L-K ligament with synovial tissue. Histologic results were classified into three groups according to the orientation of the collagen fibers around the L-K ligament, and the arrangement and morphology of the cells. Although our results demonstrated that the implanted L-K ligament had the capacity for tissue induction, no statistically significant correlation was observed between any two results among the arthroscopic, histologic, and clinical data. Therefore, within the time span of our experiment, we could not conclude that the L-K ligament functioned as a scaffold type of artificial ligament. More convincing results must be attained before any firm recommendation can be made for the use of the L-K ligament as a substitute ACL over the autograft or allograft.

O'Connor, J. J. (1993). "Can muscle co-contraction protect knee ligaments after injury or repair?" Journal of Bone & Joint Surgery - British Volume 75(1):41-8, 1993 Jan 75(1): 41-8.

A computer-based model of the knee was used to study forces in the cruciate ligaments induced by co-contraction of the extensor and flexor muscles, in the absence of external loads. Ligament forces are required whenever the components of the muscle forces parallel to the tibial plateau do not balance. When the extending effect of quadriceps exactly balances the flexing effect of hamstrings, the horizontal components of the two muscle forces also balance only at the critical flexion angle of 22 degrees. The calculations show that co-contraction of the quadriceps and hamstring muscles loads the anterior cruciate ligament from full extension to 22 degrees of flexion and loads the posterior cruciate at higher flexion angles. In these two regions of flexion, the forward pull of the patellar tendon on the tibia is, respectively, greater than or less than the backward pull of hamstrings. Simultaneous quadriceps and gastrocnemius contraction loads the anterior cruciate over the entire flexion range. Simultaneous contraction of all three muscle groups can unload the cruciate ligaments entirely at flexion angles above 22 degrees. These results may help the design of rational regimes of rehabilitation after ligament injury or repair.

Odensten, M. L., J.; and Gillquist,J. (1985). "The course of partial anterior cruciate ligament ruptures." Am.J. Sports Med., 13: 183-186.

Ohkoshi, Y. O., M.; Nagasaki,S.; Ono,A.; Hashimoto,T.; Yamane,S. (1999). "The effect of cryotherapy on intraarticular temperature and postoperative care after anterior cruciate ligament reconstruction." Am.J.Sports Med. 27(3): 357-362.

The objective of this study was to elucidate how cryotherapy after anterior cruciate ligament reconstruction affects intraarticular temperature and clinical results. A prospective and randomized study was performed on 21 knees of 21 patients. The ligament reconstruction was performed by single-incision arthroscopy using autogenous hamstring tendon. On completion of the surgery, thermosensors were implanted in the suprapatellar pouch and the intracondylar notch, and the intraarticular temperature was monitored while the joint was cooled. Cooling was performed in one group at 5 degrees C (N = 7) and in another at 10 degrees C (N = 7), for 48 hours. A control group (N = 7) did not undergo cryotherapy. The cooled groups showed three temperature phases: a low-temperature phase immediately after the ligament reconstruction, followed by a temperature-rising phase and a thermostatic phase. The control group had no low-temperature phase and immediately entered a thermostatic phase. During the low-temperature phase in the treated groups, the temperature of the suprapatellar pouch and of the intercondylar notch were significantly lower than the body temperature. The pain score and the number of times an analgesic had to be administered were both significantly lower in the 10 degrees C group than in the control group. Blood loss was significantly less in the 5 degrees C group than in the control group

O'Meara, P. M. (1993). "Rehabilitation following reconstruction of the anterior cruciate ligament." Orthopedics 16(3):301-6, 1993 Mar 16(3): 301-6.

A closely supervised rehabilitation program is mandatory if maximum benefit is to be derived from anterior cruciate ligament (ACL) reconstruction. The author describes a postoperative rehabilitation protocol based on kinesiologic, histologic, and biomechanical factors affecting the ACL.

O'Neill, D. B. (1996). "Arthroscopically assisted reconstruction of the anterior cruciate ligament. A prospective randomized analysis of three techniques." J.Bone Joint Surg.Am. 78(6): 806-813.

One hundred and twenty-seven patients who had a rupture of the anterior cruciate ligament agreed to participate in a prospective, randomized study of three arthroscopically assisted reconstruction techniques. One hundred and twenty-five patients (125 reconstructions) were evaluated after a mean duration of follow-up of forty-two months (range, two to five years). Group I included forty patients who had a two-incision reconstruction with use of an autogenous semitendinosus-gracilis graft, group II consisted of forty patients who had a two-incision reconstruction with use of an autogenous patellar-ligament graft, and group III included forty-five patients who had a single-incision reconstruction (endoscopic technique) with use of an autogenous patellar-ligament graft. The male-female ratio, age range, level of athletic activity, interval between the injury and the reconstruction, previous operative procedures, and associated injuries were similar in all three groups. The same postoperative rehabilitation protocol was followed for all patients. Testing with a KT-2000 arthrometer at maximum manual force was done at the follow-up evaluation; the difference in laxity between the involved knee and the contralateral knee was three millimeters or less in thirty-three patients (83 per cent) in group I, thirty-seven patients (93 per cent) in group II, and thirty-nine patients (87 per cent) in group III. A difference of two millimeters or less was found in thirty patients (75 per cent) in group I, thirty-one patients (78 per cent) in group II, and thirty-five patients (78 per cent) in group III. Thirty-five patients (88 per cent) in group I, thirty-eight patients (95 per cent) in group II, and forty patients (89 per cent) in group III returned to at least the same level of athletic activity. Four grafts (two in group I and two in group II) failed as a result of trauma. There was one additional failure in groups I and III, as evidenced by a difference of nine and seven millimeters, respectively, on instrumented testing of laxity. The significant findings were that no knee was rated D according to the system of the International Knee Documentation Committee (p < 0.002, 94 per cent confidence level) and that fewer additional operative procedures were done on patients in group III (p < 0.08). Also, it was found that the patients in group II returned to a greater level of athletic activity (p < 0.02) and that a higher percentage of the patients in this group had a difference of three millimeters or less on testing with the KT-2000 arthrometer than in the other two groups (p < 0.08). However, with the numbers available, there were no significant differences in the over-all outcome among the three groups (p > 0.1). Importantly, the rate of failure was not greater and the outcomes were not less satisfactory for the late reconstructions than they were for the acute reconstructions (those performed less than three weeks after the injury), including those done with an autogenous semitendinosus- gracilis graft in a chronically unstable knee

Osterman, K., U. M. Kujala, et al. (1993). "The MacIntosh lateral substitution reconstruction for anterior cruciate deficiency." International Orthopaedics 17(4):224-7, 1993 17(4): 224-7.

Twenty-five patients who had anterior cruciate deficient knees treated by the MacIntosh reconstruction operation were reviewed after 5 years, with particular reference to any changes occurring over time. Subjectively, the knees were improved and the results were even better after 5 years than after one year. This was considered to be due to a decrease in the restriction of flexion, and to the psychological and functional adaptation to the injured knee. In the knees operated on, the anterolateral instability increased significantly during the follow up from one year (mean 1.9 mm) to 5 years (3.0 mm), but the numerical value was still as good as in the intact knees (3.5 mm).

Otero, A. L. and L. Hutcheson (1993). "A comparison of the doubled semitendinosus/gracilis and central third of the patellar tendon autografts in arthroscopic anterior cruciate ligament reconstruction." Arthroscopy 9(2):143-8, 1993 9(2): 143-8.

The purpose of this study was to compare the postoperative success and stability of two different autografts used to reconstruct the anterior cruciate ligament (ACL): doubled semitendinosus/gracilis (DST&G) and bone-patellar tendon-bone (PAT). Ninety-one young (x = 25.4 years), active patients were available for an average follow-up of 36.4 months and included 55 patients in the PAT group and 36 in the DST&G group. No patients had previously undergone ACL reconstruction. Knee stability data were obtained yearly and included scores from the Lysholm questionnaire, Lachman exam, and KT-1000 arthrometer at 30 pounds (KT30) and maximum pull (KTMAX). Both autografts were of comparable size, tension, and isometricity. Two separate factorial multivariate analyses of variance (MANOVA) were used to compare the two series for 3 follow-up years in the categories acute and chronic (A versus C) and meniscectomy and no meniscectomy (M versus NM). Results indicated that in all categories and follow-up years, PAT patients had consistently greater knee stability compared with the DST&G group. Overall MANOVA results showed significantly lower (p < 0.01) Lachman scores in PAT versus DST&G in each of the 3 follow-up years. Significantly lower (p < 0.05) KT30 and KTMAX values were also observed for PAT compared with DST&G in year 1. MANOVA results also showed lower (p < 0.01) Lachman scores in PAT-A versus DST&G-A for 3 follow-up years. Lachman scores in PAT-NM patients were lower (p < 0.01) for postop years 1 and 2 compared with DST&G-NM.(ABSTRACT TRUNCATED AT 250 WORDS)

Paavolainen, P., S. Makisalo, et al. (1993). "Biologic anchorage of cruciate ligament prosthesis. Bone ingrowth and fixation of the Gore-Tex ligament in sheep." Acta Orthopaedica Scandinavica 64(3):323-8, 1993 Jun 64(3): 323-8.

The biologic fixation and strength of fixation of the polytetrafluoroethylene (PTFE) Gore-Tex ligament prosthesis was investigated in sheep knees. The device was inserted to replace the anterior cruciate ligament according to the recommended technique. Histological bone tunnel evaluation together with mechanical tensile studies were done at 6, 12, and 18 months. Already at 6 months the pull-out load of the prosthesis exceeded that of the normal ligament, and this finding persisted up to 18 months postoperatively. At 6 months there was marked fibrous tissue ingrowth into the prosthesis, and at 12 months trabecular bone had replaced the fibrous tissue between the interstices of the filaments; at 18 months bone even penetrated into the individual porous fibers of the prosthesis. The intra-articular part of the prosthesis was surrounded and partly invaded by undifferentiated connective tissue, with no recognizable macrophages or other inflammatory cells. In this experiment, the biocompatibility and porosity of the Gore-Tex prosthesis seemed optimal to permit ingrowth from surrounding fibrous and osseous tissues and firm anchorage into the bone tunnels.

Pagnani MJ, W. J., OBrien DJ, Warren RF (1983). "Anatomic considerations in harvesting the semitendinosus and gracilus tendons and a technique of harvest." Am J Sports Med 21: 565-571.

Palmer, I. (1938). "On Injuries to the Knee Joint. A Clinical Study." Acta Orthop.Scand. LXXXI(Suppl 53).

Papadopoulos, D., P. Efstathiou, et al. (1996). "Anterior cruciate ligament replacement using part of the patellar tendon as a free graft." Bull Hosp Jt Dis 55(1): 33-5.

The operative result in 91 patients who had a repair of a ruptured anterior cruciate ligament and replacement with a bone-patellar ligament-bone autogenous graft are analyzed. The average time between initial injury and operation was 2 years. Instability of the knee had been present for 6 months to 6 years and the mean follow up was 4 years. Indications for the intraarticular repair were a positive Pivot shift test and Lachman test and a positive anterior drawer sign at the preoperative examinations while under anesthesia. Seventy percent of the injuries were sports related and the remaining thirty percent injured their knee during work-related activities. Forty-eight percent (44 patients) had an associated meniscal lesion, the majority of which were on the medial side. Eighty percent of the meniscal lesions required partial meniscectomy and 20% were repaired. Eleven percent (10 patients) had an associated chondral lesion while 2 patients had a second degree of chondromalacia of the patella. The results were assessed using the Clancy criteria. Sixty eight percent (62 patients) had an excellent result, 28% (25 patients) very good, and 4 patients fair or good. The Lachman test was negative in 70% of out patients and mildly positive with a firm end point in 30%. The pivot shift test was negative in 71% and mildly positive in 29% of our patients.

Papadopoulos, D., P. Efstathiou, et al. (1996). "Anterior cruciate ligament replacement using part of the patellar tendon as a free graft." Bull Hosp Jt Dis 55(1): 33-5.

Papandrea, P. V., M.C.; Ferretti,A.; Conteduca,F. (2000). "Regeneration of the semitendinosus tendon harvested for anterior cruciate ligament reconstruction. Evaluation using ultrasonography." Am.J.Sports Med. 28(4): 556-561.

In a prospective study, 40 consecutive patients who underwent anterior cruciate ligament reconstruction with doubled semitendinosus and gracilis tendon autografts were examined pre- and postoperatively by ultrasound to investigate the anatomy of the donor site before and after the harvest of the tendons. The patients underwent ultrasonography at 2 weeks and 1, 2, 3, 6, 12, 18, and 24 months postoperatively. A total of 298 postoperative sonographic evaluations were performed. The semitendinosus tendon was imaged in the sagittal and axial planes: structure and margins were evaluated with the sagittal views; thickness and width were measured with the axial views. In all cases the following sequence of healing was documented: 2 weeks after surgery the semitendinosus tendon site was occupied by an area of increased thickness and decreased echogenicity, suggesting the presence of traumatic edema of the soft tissue surrounding the tenotomy. At 1 month, an irregular hypoechoic structure appeared in a near-anatomic position; at 2 months after surgery, thickness, width, and cross- sectional area of this structure were significantly greater than preoperatively. The amount of regenerated tissue increased up to that seen in the tissue of the 6-month examinations, which also showed a more uniform echostructure. The scans performed at 1 year showed distinct edges and reduction in thickness and width. At 18 and 24 months the echogenicity of the structure occupying the donor site was very similar to that of the normal semitendinosus tendon. However, this structure was clearly identified about 4 cm proximal to the pes anserinus, revealing a more proximal insertion of the regenerated semitendinosus tendon

Passler, H. H. and K. D. Shelbourne (1993). "[Biological, biomechanical and clinical concepts of after-care following knee ligament surgery]." Orthopade 22(6):421-35, 1993 Nov 22(6): 421-35.

Rehabilitation of the anterior cruciate ligament (ACL) continues to be a topic of intense interest among surgeons and therapists. Numerous experimental studies have demonstrated that motion and a certain amount of stress are necessary for ligament healing. In experimental and clinical studies closed kinetic chain exercises have been proven to be safe already in the early phase of rehabilitation. Since 1987, over 2900 patients who have undergone ACL reconstruction using the central one-third of the bone patellar tendon bone graft have followed our accelerated rehabilitation protocol. Follow-up of the patients reveals early return to athletic activity and maintenance of long-term stability. Our 1987 accelerated rehabilitation program continues to be modified, with less constraints placed on the postoperative patient in our present rehabilitation protocol. Past patient non-compliance to previously established protocols still yielded excellent results that demanded further investigation. Gradually we developed a four-phase rehabilitation protocol. The initial phase encompasses the preoperative period with the goal of resolving swelling and regaining full motion. The second phase involves the initial two weeks post ACL reconstruction and focuses primarily on wound healing, full extension, control of swelling, and leg control. The third phase (two to five weeks) involves increasing flexion, developing a functional gait, and resuming activities of daily living. The fourth phase (> five weeks) identifies a safe return to competitive athletics. With this accelerated rehabilitation protocol a decreased postoperative morbidity was noted without jeopardizing the long term stability of the ACL reconstructed knee.

Patel, J. V. C., J.S.; Hall,A.J. (2000). "Central third bone-patellar tendon-bone anterior cruciate ligament reconstruction: a 5-year follow-up." Arthroscopy 16(1): 67-70.

SUMMARY: Arthroscopically assisted anterior cruciate ligament (ACL) reconstruction using the central third bone-patellar tendon-bone as a free autologous graft is now a widely used procedure. However, little has been published regarding its long-term success. In this retrospective study, we report on the results of 32 patients who were followed-up over 5 years after their reconstruction. Twenty-five patients had improved on their prereconstruction Lysholm and Tegner Activity scores and the same number denied having any symptoms of instability. The mean Lysholm knee score was 88.5. All patients had within 10 degrees of full flexion and 28 had KT-1000 arthrometer readings within 3 mm of their uninjured knee. Only 3 patients had clinical evidence of failure of the graft. We conclude that this technique compares favorably with other alternatives in the long-term treatment of ACL rupture

Paulos, L. E., J. Cherf, et al. (1991). "Anterior cruciate ligament reconstruction with autografts." Clin Sports Med 10(3): 469-85.

Arthroscopically assisted ACL reconstruction has undergone rapid development in recent years. Although achievement of stability has been well-documented in open ACL reconstructive procedures, improved results may be obtained by reducing operative morbidity. Arthroscopically assisted ACL reconstruction appears to offer significantly diminished morbidity and thus offers more predictable rehabilitation, at least initially, after surgery. Improvements in instrumentation continue to refine the precision of this technique. Proper graft selection is an important issue that is paramount to the evolution of ligament reconstruction surgery. Although the central third patellar tendon is presently the operation by which all new techniques must be compared, the use of nonautogenous grafts may complement arthroscopic reconstruction by allowing further reduction in surgical morbidity. In this article we have expanded on some of the advantages of arthroscopic ACL reconstruction, given an overview of arthroscopic techniques, and described the techniques we prefer.

Paulos, L. E., T. D. Rosenberg, et al. (1987). "Infrapatellar contracture syndrome. An unrecognized cause of knee stiffness with patella entrapment and patella infera." Am J Sports Med 15(4): 331-41.

Infrapatellar Contracture Syndrome (IPCS) is an infrequently recognized cause of posttraumatic knee morbidity. Unique to this group of patients is the combination of restricted knee extension and flexion associated with patella entrapment. IPCS can occur primarily as an exaggerated pathologic fibrous hyperplasia of the anterior soft tissues of the knee beyond that associated with normal healing. It can also occur secondarily to prolonged immobility and lack of extension associated with knee surgery, particularly intraarticular ACL reconstruction. IPCS follows a predictable natural history which is divided into three stages. Symptoms, diagnostic findings, and recommended treatment are determined by the stage at presentation. Once beyond its early presentation, IPCS is best treated by an anterior intraarticular and extraarticular capsular debridement and release, followed by extensive rehabilitation. The authors review 28 consecutive cases of IPCS. At followup 3 months to 4 years postoperation, the patients had averaged 2.3 additional surgical procedures following their index procedure or injury. The average increase in extension at followup was 12 degrees with the average increase flexion 35 degrees. Eighty percent of patients demonstrated signs and symptoms consistent with patellofemoral arthrosis; 16% of the patients demonstrated patella infera. The authors conclude that prevention or early detection and aggressive treatment are the only ways of avoiding complication in these problem cases.

Peterson, R. K. S., W.R.; Bomboy,A.L. (2001). "Allograft versus autograft patellar tendon anterior cruciate ligament reconstruction: A 5-year follow-up." Arthroscopy 17(1): 9-13.

PURPOSE: To compare the long-term results of allograft versus autograft central one-third bone-patellar tendon-bone reconstruction of the anterior cruciate ligament (ACL), 2 groups of 30 patients were evaluated subjectively and objectively at an average follow-up of 63 months (range, 55 to 78 months). TYPE OF STUDY: A prospective nonrandomized study. METHODS: All surgeries were performed endoscopically by a single surgeon using metal interference screw fixation between May 1991 and November 1992. Early aggressive rehabilitation was employed and follow-up visits at 3, 6, 12, 24, and 60 months noted swelling, pain, range of motion, and patellofemoral crepitus, and Lachman test, pivot shift test, and side-to-side arthrometer differences. RESULTS: Results were analyzed using 2-sample t test and chi-square analysis. Average age at surgery for autografts was 25 years (range, 14 to 49) and for allografts was 28 years (range, 14 to 53). The presence of meniscal tears were similar (allografts, 23 tears; autografts, 19 tears). At follow-up, no statistically significant difference was found for the presence of pain, giving way, effusion, Lachman and pivot shift results, or arthrometer measurements. Two patients, 1 allograft and 1 autograft had complete rupture of their grafts. There was no late stretching out of either graft and patients stable at 2 years were stable at 5 years, with the exception of the 1 ruptured graft in each group. CONCLUSIONS: A trend toward a greater incidence of glide on pivot testing was seen in the allografts (4 allografts v 2 autografts) but was present at 2 years and did not change at 5 years. A trend toward greater loss of extension in autografts (2.47 degrees ) than allografts (1.07 degrees ) was seen at 5-year follow-up, not seen at 2 years

Puddu, G. (1980). "Method for reconstruction of the anterior cruciate ligament using the semitendinosus tendon." Am J Sports Med 8: 402-404.

Puddu, G., A. Ferretti, et al. (1988). "Reconstruction of the anterior cruciate ligament by semitendinosus transfer in chronic anterior instability of the knee." Ital J Orthop Traumatol 14(2): 187-93.

Between 1979 and 1983, 127 chronic anteromedial or anterolateral instabilities of the knee were submitted to surgical treatment (Hughston et al., 1976; Imbert, 1984). The central pivot was reconstructed by the semitendinosus tendon, using our own modification of the original Hughston technique (Puddu et al., 1986). On the medial side we advanced the posterior oblique ligament and reflex tendon of semimembranosus in cases submitted to medial meniscectomy at the same time. Laterally, we always advanced the biceps. As this method produced excellent results very quickly, it was later improved by associating the gracilis tendon with the semitendinosus. Assessment of the results was based on an average follow-up of 5 years (minimum 4, maximum 7). Of the 127 patients we personally interviewed 108 and clinically evaluated 88 professional sportsmen. The results in the latter group were excellent or good in 76.

Raab, D. J., D. A. Fischer, et al. (1993). "Comparison of arthroscopic and open reconstruction of the anterior cruciate ligament. Early results." American Journal of Sports Medicine 21(5):680-3; discussion 683-4, 1993 Sep-Oct 21(5): 680-3; discussion 683-4.

The purpose of this study was to determine in a prospective, randomized, blinded design whether arthroscopically assisted anterior cruciate ligament reconstruction offered any significant immediate or short-term advantages over traditional open reconstruction through a limited arthrotomy. Patients with a diagnosis of deficiency of the anterior cruciate ligament were randomly assigned to one of two treatment groups: the open group (limited open reconstruction) or the arthroscopic group (fully arthroscopic reconstruction). Postoperatively, both groups were treated identically. Intra- and postoperative observations included length of surgery, duration of hospitalization, and amount of pain medication. Follow-up evaluations were performed at 1, 6, 12, 16, 20, and 24 weeks to record crepitus, swelling, range of motion, ligament laxity, and thigh atrophy. Lysholm scores were obtained at the 16 and 24 week follow-ups. At 24 weeks, 86% of the open group and 89% of the arthroscopic group had good-to-excellent results. Intraoperative, postoperative, and follow-up findings indicated no statistically significant differences or relationships between the two groups in any of the variables measured, except that operative time was 13 minutes longer in the arthroscopic group (P < 0.001). The results do not substantiate a clinical advantage for either technique.

Ramsey, D. K. L., M.; Wretenberg,P.F.; Valentin,A.; Engstrom,B.; Nemeth,G. (2001). "Assessment of functional knee bracing: an in vivo three-dimensional kinematic analysis of the anterior cruciate deficient." Clin.Biomech 16(1): 61-70.

OBJECTIVE: To describe three-dimensional tibial and femoral movements in vivo and examine the effect of a brace on knee kinematics during moderate to intense activity. DESIGN: Skeletal kinematics of anterior cruciate ligament deficient knees was measured with and without braces during moderate to intense activity. BACKGROUND: Invasive markers implanted into the tibia and femur are the most accurate means to directly measure skeletal motion and may provide a more sensitive measure of the differences between brace conditions. METHODS: Steinmann traction pins were implanted into the femur and tibia of four subjects having a partial or complete anterior cruciate ligament rupture. Non- braced and braced conditions were randomly assigned and subjects jumped for maximal horizontal distance to sufficiently stress the anterior cruciate ligament. RESULTS: Intra-subject peak vertical force and posterior shear force were generally consistent between conditions. Intra-subject kinematics was repeatable but linear displacements between brace conditions were small. Differences in angular and linear skeletal motion were observed across subjects. Bracing the anterior cruciate ligament deficient knee resulted in only minor kinematic changes in tibiofemoral joint motion. CONCLUSION: In this study, no consistent reductions in anterior tibial translations were observed as a function of the knee brace tested. Relevance. Investigations have reported that knee braces fail when high loads are encountered or when load is applied in an unpredictable manner. Questions remain regarding tibiofemoral joint motion, in particular linear displacements. The pin technique is a means for direct skeletal measurement and may provide a more sensitive measure of the differences between brace conditions

Randall, R. L. W., E.M.; Heilmann,M.R.; Lotz,J. (1999). "Comparison of bone-patellar tendon-bone interference screw fixation and hamstring transfemoral screw fixation in anterior cruciate ligament reconstruction." Orthopedics 22(6): 587-591.

While bone-patellar tendon-bone (BPTB) interference screw anterior cruciate ligament (ACL) reconstruction is a biomechanically sound construct, alternative techniques have been developed secondary to potential donor site morbidity. This study evaluates a system designed to address this problem that involves a transfemoral screw fixation device and stapling of hamstring tendons. Seven pairs of cadaveric knees underwent ACL reconstruction using either BPTB interference screw technique or semitendinosus gracilis (STG) transfemoral screw fixation and stapling. Tensile testing was performed. There was no significant difference between the two fixation types with regard to stiffness, maximum load to failure, elongation, energy to failure and yield load, displacement, and energy

Richter, A. and W. K. Krudwig (1993). "[Technical, material and biomechanical requirements for alloplastic replacement of the anterior cruciate ligament surgical technic]." Polimery W Medycynie 23(1-2):39-54, 1993 23(1-2): 39-54.

Chronically instable knee-joints progressively draw to an arthrosis as a result of the irregular kinematic. Different operative techniques to replace the anterior cruciate ligament using exclusively autologous, homologous or heterologous grafts in all cases of chronic instabilities, but the primary sole suture of acute ACL injuries, too, didn't show long-term stable results in many cases. Recurrent ruptures were found first of all at the intraarticular edge of the femoral tunnel caused by permanent abrasions of the replacement. The reason why is the large angle of the ACL and each replacement respectively under motion. The question of what tissue could or should be used for renewed autogenous reconstructions in case of re-instabilities and after using bone-tendon-bone-mid-third patellar-tendon-grafts isn't yet been discussed to the end. Because of the fact that there is no isometric behaviour of the complete ACL but of a few fibres only depending on the position of the knee the complete reconstruction of the ACL is absolutely impossible, but only a partial substitute. The anatomically limited intraarticular joint-space (notch) confines the replacements in their dimension and endangers voluminous reconstructions by an impending impingement especially as a result of the immediately postoperative swelling of the transplants. The use of the mid-third-patellar-tendon-graft destroys a lot of proprioceptors and causes a partly loss of the neuromuscular balance previously impaired by the loss of the ACL including its receptors. In addition to this the still existing proprioceptors of the ligamentous stumps can be definitively destroyed by big tunnels. Each autologous graft passes a long-term transformation and at best achieves to 50% of the maximum stress capacity of an original ACL after two years. Resulting from these reasons synthetic and unlimited-ly available ligaments presented themselves to be used for ACL replacements. The Trevira-ligament of polyethylenetherephthalat (= TRE-VIRA HOCHFEST 730R) seems to be best qualified therefore at the present. It meets the material and technical requirements and makes allowance for all biomechanical knowledge. A modified over-the-top technique by arthroscopy or mini-arthrotomy (minimized operative trauma) enables the preservation of still existing ligamentous tissue on the one hand and guarantees the immediate postoperative functional therapy on the other hand. A recurrent instability independent of cause doesn't bring about a worse starting position for the following renewed stabilization and enables corrective operative techniques including the substitute of a ruptured synthetic ligament if required.

Risberg, M. A. H., I.; Steen,H.; Eriksson,J.; Ekeland,A. (1999). "The effect of knee bracing after anterior cruciate ligament reconstruction. A prospective, randomized study with two years' follow- up." Am.J.Sports Med. 27176-83.

The purpose of this prospective, randomized, clinical trial was to evaluate the effect of knee bracing after anterior cruciate ligament reconstruction. Sixty patients were randomized into one of two groups: Patients in the braced group wore rehabilitative braces for 2 weeks, followed by functional braces for 10 weeks, and patients in the nonbraced group did not wear braces. Data were recorded preoperatively, and postoperatively after 6 weeks, 3 and 6 months, and 1 and 2 years. The following outcome measures were used: KT-1000 arthrometry, the Cincinnati knee score, goniometry to record range of motion, computed tomography to determine thigh atrophy, Cybex 6000 isokinetic testing to evaluate muscle strength, three functional knee tests, and a visual analog scale to evaluate pain. At all follow-up times there were no significant differences between the two groups with regard to knee joint laxity, range of motion, muscle strength, functional knee tests, or pain. However, the Cincinnati knee score showed that patients in the braced group had significantly improved knee function compared with patients in the nonbraced group at the 3-month follow-up, even though the braced group showed significantly increased thigh atrophy compared with the nonbraced group at 3 months

Rispoli, D. M. S., T.G.; Miller,M.D.; Morrison,W.B. (2001). "Magnetic resonance imaging at different time periods following hamstring harvest for anterior cruciate ligament reconstruction." Arthroscopy 17(1): 2-8.

PURPOSE: The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hamstring graft harvest site after harvesting the hamstring tendons to reconstruct a torn anterior cruciate ligament (ACL). TYPE OF STUDY: Case series. METHODS: We performed MRI on 21 patients who had previously undergone hamstring harvest and ACL reconstruction. Twenty of the patients (7 female and 13 male; mean age, 37 years; range, 16 to 84 years), all volunteers, were selected from a series of 45 ACL reconstructions performed by the senior author during a 20-month period. Another patient, a 32-year-old man, underwent ACL reconstruction elsewhere 32 months before. Both the semitendinosus and gracilis tendons were harvested in all cases. All MRIs were obtained on a 1.5-T magnet and were prospectively evaluated by 2 experienced musculoskeletal radiologists who were blinded to the time interval between graft harvest and MRI. RESULTS: Two weeks after graft harvest, MRI showed ill-defined intermediate signal on T1- weighted images and increased signal on T2-weighted images, consistent with fluid in the harvest site, with no discernable tendon. At 6 weeks, structures were seen at the level of the superior pole of the patella that had morphology and signal characteristics similar to native tendon. By 3 months, structures with normal morphology and signal characteristics were seen to the level of the joint line, and by 12 months, to the level of 1 to 3 cm above that of the tibial attachment. At 32 months, the tendons appeared on MRI to normalize to a level of 1 to 2 cm above their tibial attachment. CONCLUSION: Following hamstring tendon harvest, MRI demonstrates an apparent regeneration of tendons beginning proximally and extending distally over time

Roberts, T. S. D., David,Jr.; McCarthy,William; and Paine,Russell (1991). "Anterior cruciate ligament reconstruction using freeze-dried, ethylene oxide-sterilized, bone-patellar tendon-bone allografts." Am.J. Sports Med 19: 35-41.

Robertson, D. B. D., D.M; and Biden,E. (1986). "Soft tissue fixation to bone." Am.J. Sports Med., 14: 398-403.

Robins, A. J., A. P. Newman, et al. (1993). "Postoperative return of motion in anterior cruciate ligament and medial collateral ligament injuries. The effect of medial collateral ligament rupture location." American Journal of Sports Medicine 21(1):20-5, 1993 Jan-Feb 21(1): 20-5.

Twenty consecutive patients with combined anterior cruciate/medial collateral ligament injuries were analyzed to determine if a correlation exists between the location of medial collateral ligament disruption and postoperative return of motion. All patients were treated operatively by autogenous patellar tendon anterior cruciate ligament reconstruction and primary medial collateral ligament repair. The mean followup was 379 days. The patients (12 men and 8 women; mean age, 23 years) were divided into two groups based on the location of superficial medial collateral ligament rupture. Group P consisted of 13 patients with lesions at or proximal to the joint line; Group D consisted of 7 patients with disruptions distal to the joint line. Group D patients had a more rapid return of motion for both flexion and extension. At the conclusion of followup, patients from Group D also achieved 8 degrees more flexion and 3 degrees more extension. There were eight additional procedures performed on five patients, all from Group P, required to treat difficulty regaining motion. Among these patients with anterior cruciate/medial collateral ligament injuries there are two distinct groups, each with different prognoses related to return of motion based on the location of the medial collateral ligament disruption. We suggest that patients with double-ligament injuries, where the medial collateral ligament lesion is proximal, should be managed very aggressively to regain motion.

Rodeo, S. A., S. P. Arnoczky, et al. (1993). "Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog." J Bone Joint Surg Am 75(12): 1795-803.

Our study evaluated tendon-to-bone healing in a dog model. Twenty adult mongrel dogs had a transplantation of the long digital extensor tendon into a 4.8-millimeter drill-hole in the proximal tibial metaphysis. Four dogs were killed at each of five time-periods (two, four, eight, twelve, and twenty-six weeks after the transplantation), and the histological and biomechanical characteristics of the tendon-bone interface were evaluated. Serial histological analysis revealed progressive reestablishment of collagen-fiber continuity between the bone and the tendon. A layer of cellular, fibrous tissue was noted between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganized during the healing process. The collagen fibers that attached the tendon to the bone resembled Sharpey fibers. High-resolution radiographs showed remodeling of the trabecular bone that surrounded the tendon. At the two, four, and eight-week time-periods, all specimens had failed by pull-out of the tendon from the bone tunnel. The strength of the interface was noted to have significantly and progressively increased between the second and the twelfth week after the transplantation. At the twelve and twenty-six-week time-periods, all specimens had failed by pull-out of the tendon from the clamp or by mid-substance rupture of the tendon. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralization, and maturation of the healing tissue, noted histologically.

Roeddecker, K., G. D. Giebel, et al. (1993). "Arthroscopic repair of traumatic longitudinal meniscal tears. A 3 to 5-year follow-up." Surgical Endoscopy 7(1):46-51, 1993 Jan-Feb 7(1): 46-51.

The healing potential of the meniscal tissue has been known for a century but has only been broadly introduced into surgical treatment during the last years. Open surgical suture of the meniscus has increasingly been replaced by arthroscopic refixation. We report 34 meniscal refixations with a minimal follow-up of at least 3 years and a mean of 4 years. Using our own simple and economic surgical technique, 34 refixations were performed in 32 patients from January 1987 to December 1988. All patients had traumatic meniscal tears close to the capsule. Frequently the injury was associated with a fresh or old rupture of the anterior cruciate ligament. Without additional trauma, one meniscus had to be partially resected after 4 months; a second one was partially resected in an unstable knee. Both the clinical examination and the satisfaction of the patient demonstrate that meniscal refixation is feasible and appropriate with a correct indication.

Romano, V. M., B. K. Graf, et al. (1993). "Anterior cruciate ligament reconstruction. The effect of tibial tunnel placement on range of motion." American Journal of Sports Medicine 21(3):415-8, 1993 May-Jun 21(3): 415-8.

In 111 patients who had anterior cruciate ligament reconstructions, postoperative radiographic measurements of anterior to posterior and medial to lateral location of the tibial tunnels were correlated with the final range of motion achieved. In the 25 patients with extension deficits of 10 degrees or more, placement of the tibial tunnel was more anterior (average, anterior 23% of the tibia) than in the remaining 86 patients with extension deficits of < 10 degrees (average, anterior 29% of tibia). This difference was statistically significant with P < 0.001. Logistic regression analysis revealed that the more anterior the placement of the tibial tunnel, the greater the loss of both flexion (P = 0.01) and extension (P = 0.002). In the 21 patients with full extension but flexion < 130 degrees, placement of the tibial tunnel tended to be more medial (average, medial 40% of the tibia) than in the 65 patients without flexion deficit (average, medial 45% of the tibia). We conclude that placement of the tibial tunnel in the "eccentric," anteromedial position may contribute to the development of flexion and extension deficits after anterior cruciate ligament reconstruction.

Roolker, W. P., T.W.; van Dijk,C.N.; Vegter,M.; Marti,R.K. (2000). "The Gore-Tex prosthetic ligament as a salvage procedure in deficient knees." Knee.Surg.Sports Traumatol.Arthrosc. 8(1): 20-25.

The purpose of this study was to evaluate the results of prosthetic ligament replacement of the anterior cruciate ligament (ACL) or posterior cruciate ligament (PCL) with the Gore-Tex polytetrafluorethyene prosthesis (W.L.Gore and Co., Flagstaff, Ariz. ) in 52 patients (54 knees). All patients sustained multiple (failed) knee operations or had knees with gross instability. Twenty-eight (29 knees) of the 52 patients (54%) in whom the Goretex prosthesis was still in situ were available at a minimum follow-up of 5 years (mean 9 years, range 5-11 years). The mean age at examination was 39 years (range 30-57 years); there were 15 men and 13 women. The results of the procedure were compared with the results of the same patients at a mean follow-up of 3 years. Eighty-one percent of the patients of the whole group complained about pain. This was 78% for the patients with an ACL reconstruction and 75% for the patients with a PCL reconstruction. The Tegner activity score and the Lysholm knee score showed a statistically significant difference over time. The anterior instability pattern improved in only 43% of the knees and the posterior instability in 41% of the knees. The Lachman test showed also a significant difference over time. In all patients X-ray showed an increase in degenerative changes. In conclusion, the PTFE prosthetic ligament in the reconstruction of the ACL and the PCL in the (chronically) unstable knee seems to deteriorate over time

Rosen, M. A., D. W. Jackson, et al. (1992). "The efficacy of continuous passive motion in the rehabilitation of anterior cruciate ligament reconstructions." Am J Sports Med 20(2): 122-7.

Seventy-five patients undergoing arthroscopically-assisted anterior cruciate ligament reconstruction by the same surgeon were divided into three random subgroups. All of the anterior cruciate ligament reconstructions used the middle third of the ipsilateral patellar tendon autograft. Patients undergoing meniscal repair, extraarticular procedures, or repair of other ligaments were excluded. The 75 patients were divided into subgroups to assess the benefits or disadvantages of early active motion (25 patients), continuous passive motion (25 patients), and a combination of both (25 patients) during the first 30 days after surgery. All patients were evaluated at specific intervals for 6 months after surgery. Data recorded included drain output, medication usage, tourniquet time, leg involved, hospital stay length, KT-1000 testing (before surgery in the anesthetized patient, after the procedure was completed, and 2 and 6 months after surgery), and range of motion. Radiographs and the International Knee Evaluation Form were also used to evaluate the results. No statistically significant differences were found between the three groups. Side-to-side anterior-posterior differences, stability, and restoration of full range of motion were similar in each subgroup at each evaluated interval. In this prospective study of motion, started immediately after anterior cruciate ligament reconstruction, passive and active methods were shown to have identical results. A supervised active and passive motion program during the 1st month had the same results as either one used individually.

Rosen, M. A. J., D.W.; and Berger,P.E. (1991). "Occult osseous lesions documented by magnetic resonance imaging associated with anterior cruciate ligament ruptures." Arthroscopy 7: 45-51.

Rougraff, B., K. D. Shelbourne, et al. (1993). "Arthroscopic and histologic analysis of human patellar tendon autografts used for anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(2):277-84, 1993 Mar-Apr 21(2): 277-84.

To evaluate the fate of patellar tendon autografts in humans, the knees of 23 patients who had undergone anterior cruciate ligament reconstruction were examined 3 weeks to 6.5 years postoperatively. Arthroscopy and biopsy were performed on all patients. The patellar tendon autografts progressed through four stages of ligamentization after reconstruction. The first stage of repopulation occurred during the first 2 months and was evidenced by a viable 3-week specimen with an increasing fibroblast number and active nuclear morphology. Over the next 10 months, the graft went through a stage of rapid remodeling in which the fibroblast count increased markedly, the active nuclear morphology and neovascularity remained increased, and more areas of degeneration were present as the percentage of mature collagen decreased. The third stage or "maturation" stage occurred over the next 2 years and was characterized by a slow decline in the nuclei and the maturation of the collagen matrix. By 3 years the grafts were ligamentous by all histologic criteria examined. The authors conclude that human autogenous patellar tendon grafts are viable as early as 3 weeks postoperatively and may not go through a necrotic stage. They then progress through a prolonged process of ligamentization that takes as long as 3 years to complete.

Runkel, M., J. Blum, et al. (1993). "[The value of the radiologic Lachman test in anterior cruciate ligament ruptures]." Aktuelle Traumatologie 23(6):297-301, 1993 Oct 23(6): 297-301.

A radiologic Lachman test of both knees was performed in 35 patients with surgically verified tears of the anterior cruciate ligament (ACL). We found a mean anterior drawer of 3.2 mm for uninjured joints, 4.5 mm for isolated ACL-tears and 10.8 mm for complex ACL-injuries. Sensitivity of the radiological Lachman test was 95% for complex ACL-injuries as only 23% in case of isolated ACL-ruptures. Failure of diagnosis due to clinical investigation in case of ACL-ruptures could not be proved by means of radiological Lachman-test. Technical requirements and radiation exposure are further disadvantages. Clinically doubtful cases of acute knee injuries should therefore be investigated with other diagnostic procedures.

Rupp, S. S., R.; Schneider,A.; Kohn,D.M. (1999). "Ligament graft initial fixation strength using biodegradable interference screws." J.Biomed.Mater.Res. 48(1): 70-74.

The objective of this study was to evaluate the initial fixation strength of three types of biodegradable interference screws [an Endo Fix, 7 x 25 mm polyglycolic acid, non-self-tapping (Acufex); a biodegradable interference screw, 7 x 23 mm poly-L-lactic acid, self- tapping (Arthrex); a Bioscrew, 7 x 25 mm poly-L-lactic acid, self- tapping (Linvatec)] in comparison to a titanium interference screw (Linvatec, 7 x 25 mm) in anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft. Porcine lower limbs were used. To control for specimen related bias, bone mineral density of each tibia was measured. All specimens were loaded to failure. Failure mode was determined by visual analysis. The maximum load to failure [mean (SD)] was 785 (87) N (titanium screw), 555 (60) N (Acufex), 592 (211) N (Arthrex), and 844 N (Linvatec). The primary fixation strength of the titanium screw and the Linvatec screw was significantly higher (p < 0.05) than the primary fixation strength of the Arthrex screw and the Acufex screw. There was no difference in bone mineral density between the groups. With respect to primary fixation strength, all biodegradable screws were strong enough to allow accelerated rehabilitation. From this point of view the biodegradable screws may be a reasonable alternative to titanium interference screws

Sachs, R. A. D., D.M.; Stone,M.L.; and Garfein,R.F. (1989). "Patellofemoral problems after anterior cruciate ligament reconstruction. Am. J. Sports Med.,." Am. J. Sports Med 17: 760-765.

Saddemi, S. R., A. D. Frogameni, et al. (1993). "Comparison of perioperative morbidity of anterior cruciate ligament autografts versus allografts." Arthroscopy 9(5):519-24, 1993 9(5): 519-24.

We present a retrospective report of 50 patients (31 autograft and 19 allograft patients) who underwent arthroscopic bone-patellar tendon-bone anterior cruciate ligament (ACL) reconstructions between August 1988 and September 1990. All patients were followed for a minimum of 2 years. The purpose of this study was to analyze each group regarding hospital stay, swelling, thigh atrophy, laxity, strength, endurance, range of motion, patellofemoral symptoms, and complications. We found no statistical difference between autograft or allograft ACL reconstructions with regard to perioperative morbidity.

Sanberg, R. B., Bengt; Nilsson, Bo; and Weslin, Nils (1987). "Operative versus non-operative treatment of recent injuries to the ligaments of the knee. A prospective randomized study." J. Bone and Joint Surg., 69A: 1120-1126.

Sanchis-Alfonso, V., V. Martinez-Sanjuan, et al. (1993). "The value of MRI in the evaluation of the ACL deficient knee and in the post-operative evaluation after ACL reconstruction [published erratum appears in Eur J Radiol 1993 Apr;16(3):255]." European Journal of Radiology 16(2):126-30, 1993 Feb 16(2): 126-30.

To evaluate the usefulness of magnetic resonance imaging (MRI) in the exploration of the anterior cruciate ligament (ACL) deficient-knee, a total of twenty-five patients with chronic instability of the knee joint and who underwent both MRI and arthroscopy were studied prospectively. Twenty-three of these patients underwent an intra-articular reconstruction of the ACL with bone-patellar tendon-bone autografts. For the ACL lesions MRI had a sensitivity of 95.8%, a specificity of 100% and a diagnostic accuracy of 97.7%. Associated bowing of the PCL was seen in 20 cases of the study group. For the associated meniscal lesions MRI had a sensitivity of 77.7%, a specificity of 94.7% and a diagnostic accuracy of 91.5%. In no case did MRI allow to detect the minimal cartilage irregularities observed in the arthroscopy. MRI had great accuracy for the evaluation of the anchoring points, direction of the tunnels and the state of the autografts at intra-articular level. It is concluded that MRI is a useful imaging diagnostic modality for evaluation of the ACL deficient-knee and the intra-articular reconstruction of the ACL, thereby MRI affords the surgeon better preoperative planning.

Sapega, A. A., R. A. Moyer, et al. (1990). "Testing for isometry during reconstruction of the anterior cruciate ligament. Anatomical and biomechanical considerations." J Bone Joint Surg Am 72(2): 259-67.

Instrumented tibiofemoral (bone-to-bone) excursion wires were implanted in the mid-substance of the anteromedial, central, and posterior fiber-regions of the anterior cruciate ligament through limited anterior and posterior arthrotomies in eight fresh knees from cadavera. The change in the distance of linear separation between each pair of osseous fiber-insertion sites was measured and was plotted against the angle of flexion of the knee as the knee was cycled through a 120-degree range of motion. Testing conditions likely to be present during intraoperative testing for isometry were used (anterior cruciate fibers transected, quadriceps relaxed, femur stabilized with the patient in the supine position and the leg freely dependent, and motion of the knee induced in neutral rotation by force applied at the level of the foot). In no instance did the insertion-site centers of any fiber-region exhibit isometric behavior (change in the distance of linear separation of 1.0 millimeter or less). The least deviations from isometry (range, 1.4 to 3.1 millimeters) were observed for the anteromedial sites, under conditions when the gravitational dependency of the lower leg was constrained. When the leg hung in a dependent manner during passive motion, the deviation from isometry of the anteromedial sites of insertion increased significantly (range, 2.8 to 5.6 millimeters). The central sites of insertion were generally less isometric than the anteromedial sites, and the posterior sites were the least isometric, regardless of testing conditions.

Saragaglia, D., S. Plawecki, et al. (1988). "[Meniscal lesions in so-called "isolated" ruptures of the anterior cruciate ligament. Apropos of 59 cases]." J Chir (Paris) 125(10): 571-4.

Between December 1984 and March 1987, i.e. a period of 27 months, the authors operated on 59 "isolated" fresh ruptures of the ACL with routine evaluation of the posterior horns of the medial and lateral menisci. Lesions were investigated either by arthroscopy (23 cases) or by anterior arthrotomy with routine medial and lateral retro-ligamentous counter-incision (36 cases). This revealed 21 lesions of the medial meniscus (i.e. 35.5%) and 38 lesions of the lateral meniscus (i.e. 64.5%). Lesions of both menisci were present in 16 knees (27%) and only 16 knees (27%) were found to be free of any meniscal lesion. The majority of meniscal lesions were viable and could be sutured in 86% of cases for the medial meniscus and 87% of cases for the lateral meniscus. From the standpoint of operative technique, posterior lesions are relatively poorly visualized by arthroscopy (notably concerning the posterior horn of the medial meniscus though it is easier to assess the stability of the meniscus by this technique using the palpating hook. Lesions are well visualized by medial and lateral retroligamentous counter-incisions, but it is difficult to assess meniscus stability. Finally it should be noted that all of these ruptures of the ACL were dealt with by reconstruction of the central pivot either by suture and a strengthening procedure (semitendinous) or by ligament plasty from the outset.

Scavenius, M. B., K.; Hansen,S.; Norring,K.; Jensen,K.H.; Jorgensen,U. (1999). "Isolated total ruptures of the anterior cruciate ligament--a clinical study with long-term follow-up of 7 years." Scand.J.Med.Sci.Sports 9(2): 114-119.

Seventy patients met our inclusion criteria in this retrospective study, all with an arthroscopic/arthrotomic-verified isolated total anterior cruciate ligament (ACL)-rupture and a minimum follow-up period of 3 years and no associated lesions. Due to emigration/death, 3 patients were not available for follow-up. Of the remaining 67, 25 patients underwent secondary ACL-reconstruction, equivalent to a failure rate of the initial non-operative treatment of 37%. All patients were initially treated conservatively. This left 42 patients for follow-up--9 answered a questionnare and 33 went through follow-up examination after a median of 7.1 years (range 3.3 14.6) including IKDC- evaluation form, Lysholm & Tegner score, ES-SKA-score, clinical examination and Stryker Laxity test. In the present study all values represent the 33 patients available for follow-up. Soccer, handball and alpine skiing were most frequently responsible for the injury. We observed in the 33 patients a decline in median Lysholm score from 100 (90-100) pretraumatic to 86 (42-100) at follow-up, and a decrease in median Tegner values from 7 (3-9) pretraumatic to 5 (2-7) at follow-up. All but 2 patients demonstrated a decline in Lysholm score, and only 3 patients returned to their preinjury level. According to the ESSKA- classification, the number of "cutting-sports performers" declined dramatically from 24 to 2. All but one patient ascribed their decline in activity to their knee status. The Stryker-measured AP- translocations were significantly higher on the injured knee (7.27) compared to the healthy knee (4.80) (P < 0.05). Intermittant rest pain was suffered by 63% of the patients. During the time from inclusion until follow-up, 13 (39%) patients sustained an additional ipsilateral knee lesion, most commonly a tear of the medial meniscus. The overall outcome was expressed in a low frequency of return to unrestricted preinjury level of function, and a high level of instability complaints resulting in many secondary ACL-reconstructions. Naturally some have adapted to their ultimate functional disability, but only through modification of activities, and the overall outcome after conservative therapy of these ACL-ruptures was not satisfactory

Schaefer, R. A., R. E. Eilert, et al. (1993). "Disruption of the anterior cruciate ligament in a 4-year-old child." Orthopaedic Review 22(6):725-7, 1993 Jun 22(6): 725-7.

Anterior cruciate ligament (ACL) injuries in children are rare. Thus, the natural history of ACL injuries in skeletally immature patients is unknown. This case represents the longest follow-up (11 years) reported in the literature of an ACL injury in a child of less than 5 years old.

Scherer, M. A., H. J. Fruh, et al. (1993). "[Biomechanical studies of change in the patellar tendon after transplant removal]." Aktuelle Traumatologie 23(3):129-32, 1993 May 23(3): 129-32.

The reconstruction of the anterior cruciate ligament deficient knee with the patellar tendon is the "gold standard". Dislocation of the patella, rupture of the patellar tendon and fracture of the patella were reported to occur. In this biomechanical investigation on the changes of the patellar tendon following harvesting of a graft, 51 sheep knee underwent destructive testing at t0 (n = 11), 4 weeks p.op. (n = 5), 3 months p.op. (n = 14), 6 months p.op. (n = 15), and 12 months p.op. (n = 6). Harvesting of a graft produces a stiffness and strength of the patellar tendon of 50-70% of normal. There was no significant change of free patellar tendon length up to 12 months p.op. The cross-sectional area is definitely increased (p < 0.05). The tensile stress is always above normal, nevertheless the strength shows a massive decline until 6 months p.op. and does not regain normal strength by one year p.op. Stiffness shows comparable biomechanical pattern like tensile stress. There are time-dependent changes, the structural weakness is compensated by an increase of cross-sectional area. There is no restitution of the patellar tendon ad integrum, the remainder is a defect with scar tissue and alterated biomechanical properties. Revision surgery using the same host patellar tendon cannot be recommended.

Scherer, M. A., M. Kraus, et al. (1993). "[Importance of ultrasound in postoperative follow-up after reconstruction of the anterior cruciate ligament]." Unfallchirurg 96(1):47-54, 1993 Jan 96(1): 47-54.

Eighty-eight male patients following reconstruction of the anterior cruciate ligament (ACL; mean 24 months since operation) had a thorough clinical examination including instrumented measurement of laxity using the KT 1000. These results were correlated with an ultrasound (US) grading that evaluates the reconstruction itself as well as its functional behaviour during the anterior drawer test. Thirty-four magnetic resonance (MR) studies of 33 patients were available. Undoubtedly postoperative visualization of the reconstructed ACL is superior to that of both normal control ACL and acute trauma cases. Especially operative procedures which use the patellar or semitendinosus tendon lend themselves to accurate evaluation of the intraarticular reconstruction. The sensitivity, specificity, positive and negative predictive values and overall accuracy of US/MR versus the clinical laxity measurement are calculated to be 66.7%/96.0%, 71.2%%/23.8%, 59.5%/60.0%, 77.1%/83.3% and 69.4%/63.0% respectively. US has a satisfactory diagnostic value and performs similarly well on all these parameters. MR, on the other hand, correctly diagnoses nearly all unstable knees but is associated with a high number of false positives. There is no statistically significant, linear correlation between MR and US; r = -0.0769, P = 0.6706. Only three times did the reconstructed ACL appear normal on MR, whereas 48.5% of the reconstructions were graded type I (normal) on US. Clinical Consequences: Ultrasound and MRT should not be considered rival but rather complementary methods: ultrasound is a good method for documenting changes within the knee joint on an outpatient basis, while the indications for MR in the postoperative course are any occurrences of pain, instability or reinjury.

Schickendantz, M. S. and G. G. Weiker (1993). "The predictive value of radiographs in the evaluation of unilateral and bilateral anterior cruciate ligament injuries [see comments]." American Journal of Sports Medicine 21(1):110-3, 1993 Jan-Feb 21(1): 110-3.

A review of 250 cases of surgical reconstruction of the anterior cruciate ligament identified 24 patients with bilateral complete tears of the anterior cruciate ligament. Twenty of these patients had previous reconstruction of one anterior cruciate ligament before rupture of the opposite ligament. Twelve injuries occurred during the same activity that was responsible for the initial opposite injury. The average time between surgical reconstruction and rupture of the opposite ligament was 29.3 months (range, 3 to 103). No significant demographic differences existed between patients with unilateral or bilateral ruptures of the anterior cruciate ligament. Standardized measurements of intercondylar notch height and width and medial and lateral femoral condyle height and width were performed on routine notchview height and width were performed on routine notchview radiographs of 31 knees of patients with bilateral injuries, 30 with unilateral injury, and 30 with no anterior cruciate ligament injury. Statistical analysis revealed no significant differences between the three groups when comparing absolute measures or any of eight mathematical ratios calculated from these measurements. We concluded that measurements of the intercondylar notch made from radiographs may not be reliable predictors of injury to the anterior cruciate ligament. We found no significant clinical or demographic differences between patients with unilateral or bilateral complete ruptures of the anterior cruciate ligament.

Schmidt, M., D. Moschinski, et al. (1993). "[Rehabilitation of fresh, surgically managed anteromedial knee instabilities]." Unfallchirurgie 19(4):221-6, 1993 Aug 19(4): 221-6.

In between 1983 and 1988, 33 patients suffering from an acute antero-medial instability of the knee were operated on for the anterior cruciate ligament. The reconstruction of the ligament was performed by transcondylar fixation. 25 of these patients took part in a retrospective examination. The postoperative treatment had been carried out according to various concepts of rehabilitation. Our investigations were supposed to measure the restoration of the muscular efficiency of the knee-extensor and -flexor by isokinetic training arrangements. The results revealed that by the operation a sufficient stabilization of the knee had not been achieved. 18 of 25 patients once more showed an antero-medial instability of the knee. Twelve of these 25 patients had an extended anterior instability. Only in seven cases the muscular system was completely restored with average isokinetic muscle efficiency. The high rate of postoperative knee-instability proves the persistent sports-incapacity. We must draw the conclusion that the after-treatment of ligamentous injuries about the knee must focus on the muscular rehabilitation.

Schweitzer, M. E., D. G. Mitchell, et al. (1993). "The patellar tendon: thickening, internal signal buckling, and other MR variants." Skeletal Radiology 22(6):411-6, 1993 Aug 22(6): 411-6.

We studied the range of appearance of asymptomatic patellar tendons and evaluated the effect of age, weight, joint effusions, and anterior cruciate ligament (ACL) tears on this tendon. One hundred and seventy-three patellar tendons in asymptomatic patients were studied at 1.5 tesla. Sagittal short and long TE images were evaluated in regard to tendon thickness, ratio of thickness of patellar to quadriceps tendons, frequency, location, and severity of intratendon signal, and frequency and severity of tendon buckling. Results were correlated with patient age, sex, weight, the presence of ACL tears, and relative volumes of joint fluid. The mean thickness of the patellar tendon was 0.52 cm. The patellar to quadriceps tendon ratio was 0.72. The patellar tendon frequently (74%) had focal areas of signal apparently within it. This signal was usually subtle, V-shaped (95%), and seen posteriorly in the proximal end of the tendon (82%). Intratendon signal was also seen commonly in the inferior aspect of the tendon (32%). This signal intensity did not increase with greater T2-weighting (99%). Buckling of the patellar tendon was a frequent asymptomatic variant (71%) but was also associated with joint effusions (p < 0.01) and ACL tears (p = 0.01). Buckling, intratendon signal, and tendon thickness increased with weight and age. Variation of the magnetic resonance appearance of the patellar tendon is frequent. Many of these changes appear to represent subclinical degeneration. Buckling of this tendon also may occur secondary to joint effusions or ACL tears.

Segesser, B., P. Michel, et al. (1993). "[Rehabilitation after cruciate ligament repair with the middle third of the patellar ligament in the athlete]." Sportverletzung Sportschaden 7(1):18-21, 1993 Mar 7(1): 18-21.

Rehabilitation of athletes following surgical reconstruction of complex instabilities of the knee joint focuses on four goals: 1. the restoration of ligament stability, 2. the restoration of muscular stabilisation ability, 3. the restoration of coordinative muscular function in sport specific kinesiology, 4. the retention and improvement of the general state of fitness. These aims can only be reached by a close cooperation between physician, physiotherapist, trainer, and coach. In order not to put the rehabilitation process at risk, everybody involved has to have knowledge about functional anatomy, surgical technique, and biology of the transplant as well as knowledge about the long duration thereof that cannot substantially be shortened by knee ortheses. No athlete should compete until he has demonstrated sufficient fitness, strength, and coordination for his sport under laboratory conditions.

Seiler, H. and H. R. Frank (1993). "[Suture of the anterior cruciate ligament--what is the real value of this method?]." Unfallchirurg 96(9):443-50, 1993 Sep 96(9): 443-50.

After suture of the anterior cruciate ligament without anatomical augmentation, used as a routine method, 88 patients were followed up after a minimum of 2 years using the Lysholm score and the activity scale. Residual laxity was checked clinically and with the KT-1000. For comparison, 20 patients with chronic symptomatic anterolateral instability were followed up who had been operated on using the Eriksson technique during the same time period. Postoperative treatment was a limited functional approach. The peripheral ligament structures were treated following the Hughston and Muller principles. In two-thirds of the knees lateral tenodesis was added. The results of the suture method were disappointing and inferior to the results obtained by the Eriksson technique (trend). The Lysholm score was 77 and 82, respectively. The activity scale was 4.4 (recreational sports) for both groups. The Lachmann sign (KT-1000) in side-to-side comparison (89 N) showed a residual laxity of 1.9 mm and 0.8 mm (average), respectively. In no series was tractopexy of demonstrable advantage. The final conclusion must be that the suture method (with iliotibial tract tenodesis) is not superior to guided conservative treatment. Despite an unfavorable situation preoperatively, the (abandoned) technique of ligament substitution is superior to the suture method (trend). In isokinetic testing dominant knees fare better. In good results, a high hamstrings-quadriceps ratio is typical. The reasons for this are not well-trained hamstrings, but the relative insufficiency of the quadriceps mechanism.

Sekiya, J. K. G., G.J.; Wojtys,E.M. "Autodigestion of a hamstring anterior cruciate ligament autograft following thermal shrinkage. A case report and sentinel of concern." J.Bone Joint Surg.Am. 82A(10): 1454-1457.

Seo, J. G., D. Y. Cho, et al. (1993). "Reconstruction of the anterior cruciate ligament with Achilles tendon autograft." Orthopedics 16(6):719-24, 1993 Jun 16(6): 719-24.

The increasingly serious complications of artificial ligaments and allografts have brought them into disrepute. Recently, autografts have drawn more attention. A new type of autograft, the Achilles tendon autograft, has been developed and applied to anterior cruciate ligament reconstructions. This report describes the advantages of the Achilles tendon autograft used and presents the results of a prospective study of 21 patients with minimum 2 year follow up. Of the 21 cases, 16 patients (75%) had a rating of excellent; 2 (10%) good, 2 (10%) fair, and 1 (5%) poor. Preoperative knee scores of 56.7 were improved to 89.5 postoperatively. The authors removed less than half of the Achilles tendon with the calcaneal bone incorporated. Through magnetic resonance imaging we confirmed that the remaining Achilles tendon of the donor site regained its volume and strength within a year without significant complication. Achilles tendon autograft offers the advantages of length, elastic strain modulus, reproducibility in technique, and consistency of the result without significant complications.

Sernert, N. K., J.; Kohler,K.; Stener,S.; Larsson,J.; Eriksson,B.I.Karlsson,J. (1999). "Analysis of subjective, objective and functional examination tests after anterior cruciate ligament reconstruction. A follow-up of 527 patients." Knee.Surg.Sports Traumatol.Arthrosc. 73160-165.

This study included 527 patients (178 female and 349 male) with unilateral anterior cruciate ligament (ACL) rupture who underwent arthroscopic ACL reconstruction using bone-patellar tendon-bone autograft and interference screw fixation. The follow-up examination was performed by independent observers at a median of 38 (21-68) months after the index operation. At the follow-up, the Lysholm score was 86 (14-100) points, the Lysholm instability subscore was 22 (0-25) points and the Lysholm pain subscore was 19 (0-25) points. The Tegner activity level was 6 (1-10). The one-leg-hop test was 91 (0-167)% of the non- injured knee. The difference in the anterior side-to-side laxity as measured with the KT-1000 arthrometer at 89 Newton (N) was 1.5 (-5-13) mm and the total KT-1000 side-to-side difference at 89 N was 2 (-7-11) mm. Using the International Knee Documentation Committee (IKDC) evaluation system, 177 (33.6%) patients were classified as normal (group A), 211 (40%) as nearly normal (group B), 109 (20.7%) as abnormal (group C) and 30 (5.7%) as severely abnormal (group D). The highest correlation coefficients were recorded between the IKDC evaluation system and the Lysholm score (p = 0.66), the patients' subjective evaluation (p = 0.53), the Tegner activity level (p = 0.34), all the laxity tests (p > or = 0.34) and the one-leg-hop test (p = 0.28). The resumption of sporting activities and work as evaluated by the Tegner activity level correlated with the patients' subjective evaluation (p = 0.34) but did not correlate with the laxity tests, i.e., the manual Lachman test (p = -0.06) and the total and anterior KT- 1000 tests (p = -0.06). Furthermore, none of the laxity tests correlated with the functional tests or the patients' subjective evaluation. We conclude that the IKDC evaluation system is a reliable and useful tool for evaluating the post-operative outcome after an ACL reconstruction

Sgaglione, N. A., W. Del Pizzo, et al. (1993). "Arthroscopically assisted anterior cruciate ligament reconstruction with the pes anserine tendons. Comparison of results in acute and chronic ligament deficiency." American Journal of Sports Medicine 21(2):249-56, 1993 Mar-Apr 21(2): 249-56.

Fifty anterior cruciate ligament-deficient knees treated consecutively with arthroscopically assisted reconstruction using a pes anserine tendon autograft were retrospectively studied. The mean followup was 36.7 months (range, 26 to 58). All patients had reconstruction with a double-stranded graft. The mean injury to surgery interval was 9.6 days in 22 patients (acute group) and 22.5 months in 28 patients (chronic group). Objective outcome, which was noted to be more optimal in the acute group, was better than subjective outcome in either group. Examination revealed 95% of patients treated acutely and 82% of those treated later to have 1+ or less Lachman test result (P < 0.036) and 96% of the acute group and 82% of the chronic group to have an absent pivot shift (P < 0.036). Eighty-eight percent of acutely treated patients had a KT-1000 result of < or = 3 mm, as compared to 61% of chronically treated patients (P < 0.001). Loss of range of motion was significantly greater in the acute group (P < 0.018). Using a strict overall rating system, patients reconstructed earlier were noted to have a better outcome compared to those after delayed reconstruction (P < 0.021). Cumulative meniscal injury appears to be the most significant contributing factor.

Sgaglione, N. A., R. F. Warren, et al. (1990). "Primary repair with semitendinosus tendon augmentation of acute anterior cruciate ligament injuries." Am J Sports Med 18(1): 64-73.

A retrospective review of 72 acute ACL injuries in 70 athletically active patients (50 recreational and 20 competitive athletes) treated with primary repair and semitendinosus tendon augmentation was conducted (mean follow-up time, 38.5 months). All patients had open primary multiple loop depth-varying suture repair and semitendinosus tendon augmentation at a mean injury to surgery interval of 9.1 days. Fifty-one cases (70.8%) were supplemented with an extraarticular procedure consisting in all cases of an iliotibial band lateral sling reinforcement. All patients underwent 6 weeks of postoperative immobilization followed by a graduated rehabilitation regimen lasting a mean 7.2 months. In 22 of the ACL tears, no other associated injury could be defined at arthrotomy, while in 27, significant medial collateral ligament injuries were noted. Lateral meniscal injuries (24) were more commonly noted than medial meniscal injuries (19). Good to excellent subjective results were reported in 82%, while 77.1% returned to preinjury sport level and participation without limitation. One patient developed "giving way" symptoms and overall, only four patients did not return to sports participation. Objective examination revealed 93.1% to have a 1+ or less Lachman test and 86.1% to have a negative pivot shift. Of 60 knees tested, 93.3% had KT-1000 side-to-side difference values (measured at 25 degrees +/- 5 degrees of flexion with an 89 N load) of less than or equal to 3 mm of anterior displacement. A 100 point Hospital for Special Surgery ligament rating score was used with 25 points assigned to subjective, 45 points to objective, and 30 points to functional assessment. The mean score at followup was 93.1. Analysis of results in patients with or without an extraarticular reinforcement revealed no difference in objective outcome. The incidence of patellofemoral pain was 27.8%. Thirty knees had some degree of loss of range of motion. Loss of terminal flexion was noted in 29, while 5 had loss of terminal extension. No correlation could be found between patellofemoral pain and diminished range of motion. Generalized ligamentous laxity was found in 37.1% of the patients; this was not associated with a poor result. This study suggests that primary repair with semitendinosus tendon augmentation of acute ACL injuries with a graduated rehabilitation regimen provides good subjective, and excellent functional and objective, results in active patients that were followed for more than 3 years.

Sgaglione NA, D. P. W., Fox JM, et al (1992). "Arthroscopic-assisted anterior cruciate ligament reconstruction with the semitendinosus tendon: Comparison of results with and without braided polypropylene augmentation." Arthroscopy 8: 65-77.

Shaffer, B., W. Gow, et al. (1993). "Graft-tunnel mismatch in endoscopic anterior cruciate ligament reconstruction: a new technique of intraarticular measurement and modified graft harvesting." Arthroscopy 9(6):633-46, 1993 9(6): 633-46.

The purpose of this study was to determine the incidence of bitunnel interference fixation and accurate femoral insertion site targeting using a modified technique of endoscopic anterior cruciate ligament (ACL) reconstruction. Thirty-four consecutive central-third bone-patellar tendon-bone autograft modified endoscopic ACL reconstructions were prospectively studied. A new technique was used intraoperatively to directly measure (a) intraarticular (graft) distance (IAD) and (b) patellar tendon graft length, thereby allowing calculation of optimal tibial tunnel length for each case. Accuracy of guide pin placement through this tibial tunnel into the proposed femoral insertion site was assessed, as was the ability to achieve interference fixation in both tunnels (minimum of 20 mm bone interference fixation within the tibial tunnel). A new technique for patellar tendon-bone harvesting and proximal graft fixation to address graft mismatch is described. The average IAD from tibial origin to femoral ACL insertion measured 26.3 +/- 3.0 mm (range 21-33). The average patellar tendon length (LP) was 48.4 +/- 6.0 mm (range 40-63). The average calculated tibial tunnel length (TT) necessary to achieve bitunnel fixation (TT > or = LP + 20 - IAD) was 42.1 +/- 5.3 mm (range 36-57). Establishment of the calculated tibial tunnel length was achieved in 25 cases (74%) (no graft-tunnel mismatch). Graft-tunnel mismatch, in which the tibial tunnel could not be established to the length calculated necessary to accommodate a minimum of 20 mm of bone graft, occurred in nine cases (26%). Graft-tunnel mismatch occurred more frequently in patients whose patellar lengths were > or = 50 mm (p < 0.005), but was not found to correlate specifically to IAD. Recession of the graft up into the femoral tunnel allowed accommodation of the mismatched graft (bitunnel interference screw fixation) in these nine cases, averaging 22.0 +/- 2.98 mm (range 16-29 mm) of available distal bone block fixation. Tibial tunnel fixation of > or = 20 mm was achieved in 30 patients (88%), 18 mm in two, 17 mm in one, and 16 mm in one. Measurement error resulted in inadequate distal graft accommodation in four patients in whom error averaged 3 mm. Targeting of the femoral insertion site guide pin was achieved without requiring any knee manipulation for all cases. Patellar tendon graft protrusion through the tibial tunnel and potentially suboptimal graft fixation poses a frequent problem during endoscopic ACL reconstruction.(ABSTRACT TRUNCATED AT 400 WORDS)

Shaffer, B. S. and J. E. Tibone (1993). "Patellar tendon length change after anterior cruciate ligament reconstruction using the midthird patellar tendon." American Journal of Sports Medicine 21(3):449-54, 1993 May-Jun 21(3): 449-54.

The purpose of this study was to determine if use of the midthird patellar tendon autograft contributes to or causes patellar tendon shortening or patella baja in anterior cruciate ligament reconstruction. Thirty-six patients undergoing arthroscopically assisted midthird patellar tendon autograft anterior cruciate ligament reconstruction were studied prospectively. Intraoperative patellar tendon length changes were measured. Half of the patients had the tendon defect closed and half had it left open (closing peritenon only). Radiographic tendon length changes and patella baja were assessed using Insall-Salvati and Blackburne-Peel ratios measured on 45 degrees lateral knee radiographs using an adjustable polypropylene jig. Bilateral films were obtained preoperatively and at 2 weeks, 3 months, and 6 months postoperatively. No patients demonstrated evidence of patellar tendon shortening greater than the 5.5% measurement error. Tendon defect closure resulted in negligible tendon shortening intraoperatively, averaging 2.28% (1.11 mm). Of the 18 patients whose defects were closed, 5 showed no shortening. The remaining 13 patients had measurable tendon shortening less than 4% (2 mm). No patients developed patella baja.

Shelbourne, K. D. and G. E. Johnson (1993). "Locked bucket-handle meniscal tears in knees with chronic anterior cruciate ligament deficiency." American Journal of Sports Medicine 21(6):779-82; discussion 782, 1993 Nov-Dec 21(6): 779-82; discussion 782.

Because we noticed patients had difficulty regaining full range of motion after surgery for a locked bucket-handle meniscal tear with simultaneous reconstruction for a chronic anterior cruciate ligament tear, we adopted a two-stage procedure for this group of patients. We evaluated the results of a two-stage procedure in the knees of 16 athletes (Group 1) and compared their outcome with the outcome of 16 matched athletes who had been treated with simultaneous repair or removal of the displaced bucket-handle meniscal tear and autogenous patellar tendon anterior cruciate ligament reconstruction (Group 2). Four patients in Group 2 required a second procedure or casting to regain full extension. No patient in Group 1 required a second procedure. One meniscal retear was detected in Group 1. The two-stage procedure also appears to have a number of theoretical advantages: 1) more aggressive use of repair rather than removal of a displaced torn meniscus, 2) prevention of problems in regaining range of motion, 3) allows a second look to judge the success of meniscal repair, and 4) allows time for the patient to prepare for anterior cruciate ligament reconstruction physically, mentally, academically, and socially.

Shelbourne, K. D., A. C. Rettig, et al. (1993). "Miniarthrotomy versus arthroscopic-assisted anterior cruciate ligament reconstruction with autogenous patellar tendon graft." Arthroscopy 9(1):72-5, 1993 9(1): 72-5.

The purpose of this study was to determine whether two groups of patients showed any early (6 months postoperative) clinical differences when treated by arthroscopic-assisted or miniarthrotomy anterior cruciate ligament (ACL) reconstruction. Fifty-two consecutive arthroscopic-assisted ACL reconstructions (Group I) were matched with 52 miniarthrotomy ACL reconstructions (Group II). An autogenous midthird patellar tendon was used in all reconstruction procedures. Group I patients were operated on by one surgeon (A.C.R.) and all Group II patients by another (K.D.S.). Both groups were similar with regard to age, sex, injury, chronicity, and previous knee surgical procedures. All patients were treated according to the same postoperative rehabilitative protocol (emphasizing early motion, immediate full passive extension, early functional activity) and evaluated on follow-up by the same personnel and protocol. Data collection included injury and surgery dates; total surgery and tourniquet times; length of hospital stay; drain output; inpatient pain medications used; follow-up range of motion at 1.5, 2.5, and 6 weeks postoperative; KT-1000 arthrometer measurements at 10, 16, and 26 weeks; and isokinetic measurements at 10 and 16 weeks postoperative. Results indicated that follow-up range of motion and KT-1000 measurements showed no statistical difference between groups. Isokinetic average scores for quadriceps strength at 180 degrees/s showed no differences at 10 and 16 weeks. The study suggested that ACL reconstruction with midthird patellar tendon performed by skilled surgeons using either open or arthroscopic-assisted techniques combined with an aggressive postoperative rehabilitation protocol will yield similar acceptable early clinical results.

Shelbourne, K. D. and J. H. Wilckens (1993). "Intraarticular anterior cruciate ligament reconstruction in the symptomatic arthritic knee." American Journal of Sports Medicine 21(5):685-8; discussion 688-9, 1993 Sep-Oct 21(5): 685-8; discussion 688-9.

We reviewed a consecutive series of young symptomatic patients with chronic anterior cruciate ligament-deficient knees to determine if an autogenous patellar tendon graft reconstruction decreased their symptoms and increased the stability of the knee. All patients had radiographic evidence of posttraumatic arthritis. Thirty-three patients met our criteria for inclusion in the study. Time from injury to reconstruction of the anterior cruciate ligament averaged 105 months. All patients underwent an accelerated rehabilitation program designed to help them regain full range of motion as soon as possible. Preoperative and postoperative range of motion, strength, stability, and subjective evaluations were compared. Followup averaged 44.8 months. Follow-up range of motion was not significantly different from preoperative measurements (P = 0.51). Postoperative stability, as measured by KT-1000 arthrometer maximum manual test, averaged 2.7 mm versus 8.4 mm preoperatively (P < 0.001). Isokinetic testing revealed no difference in the quadriceps strength after reconstruction (P = 0.99). Patients' subjective scores on a modified Noyes questionnaire improved for pain, stability, and activity level, with a total improvement from 55 to 81 points. Although the procedure and rehabilitation were successful in providing stability and decreasing pain, patients were still encouraged to limit high-impact athletic and occupational activity.

Shelbourne, K. D. a. N., Paul (1990). "Accelerated rehabilitation after anterior cruciate ligament reconstruction." Am. J. Sports Med 18: 292-299.

Shelbourne, K. D. D., TJ, Klootwyk (1999). "Correlation of the intercondylar notch width of the femur to the width of the anterior and posterior cruciate ligaments." Knee.Surg.Sports Traumatol.Arthrosc. 7: 209-214.

Shelbourne, K. D. G., T. (2000). "Results of anterior cruciate ligament reconstruction based on meniscus and articular cartilage status at the time of surgery. Five- to fifteen- year evaluations." Am.J.Sports Med. 28(4): 446-452.

We sought to determine how the status of the meniscus and articular cartilage observed at the time of anterior cruciate ligament reconstruction affects results at 5 to 15 years after surgery. Objective follow-up was obtained on 482 patients at a mean of 7.6 years after surgery. Subjective follow-up was obtained on 928 patients at a mean of 8.6 years after surgery. Patients with both menisci present had significantly better KT-1,000 arthrometer scores than did patients with any part of the medial or both menisci removed. Stepwise regression analyses determined that a partial or total medial or lateral meniscectomy and damaged articular cartilage significantly lowered the final subjective total score. Patients with both menisci present and normal articular cartilage had a mean subjective total score of 94, and 97% had normal or near normal radiographic ratings on a weightbearing 45 degrees posteroanterior radiographs. The overall International Knee Documentation Committee rating was normal or nearly normal for 204 of 235 patients (87%) with both menisci present, 52 of 74 patients (70%) with partial or total lateral meniscectomies, 71 of 113 patients (63%) with partial or total medial meniscectomies, and 36 of 60 patients (60%) with both menisci removed. We concluded that the long-term subjective and objective results of a successful anterior cruciate ligament reconstruction are affected by the status of the menisci and articular surface

Shelbourne, K. D. J. G. (1993). "Patient Selection for Anterior Cruciate Ligament Reconstruction." Operative Techniques in Sports Medicine 1(7): 16-21.

Shelbourne, K. D. M. P. D. (1996). "Anterior Cruciate Ligament Reconstruction in Athletes with an Ossicle with Osgoode-Schlatters Disease." Arthroscopy 12(5): 556-560.

Shelbourne, K. D. P., D.V. (1996). "Management of combined injuries of the anterior cruciate and medial collateral ligaments." Instr.Course Lect. 45: 275-280.

Shelbourne, K. D. P., D.V.; McCarroll,J.R. (1996). "Management of anterior cruciate ligament injuries in skeletally immature adolescents." Knee.Surg.Sports Traumatol.Arthrosc. 4(2): 68-74.

Anterior cruciate ligament (ACL) injuries in skeletally immature adolescents are being diagnosed and reported with increasing frequency. Nonoperative management of mid-substance ACL injuries in adolescent athletes frequently results in a high incidence of giving-way episodes, recurrent meniscal tears, and early onset of osteoarthritis. An intraarticular ACL reconstruction (using the central 10-mm patellar tendon graft) in young athletes approaching skeletal maturity provides predictable excellent knee stability, and the athletes are able to return to competitive sports with a decreased risk of recurrent meniscal and/or chondral injury. Guidelines for the management of ACL injuries in skeletally immature adolescents are presented

Shelbourne, K. D. P., D.V. (1996). "Prevention of complications after autogenous bone-patellar tendon-bone ACL reconstruction." Instr.Course Lect. 45: 253-262.

Shelbourne, K. D. P. D. (1992). "Anterior Cruciate ligament-medial collateral ligament injury: Non-operative management of medial collateral ligament tears with anterior cruciate ligament reconstruction." Am J of Sports Med 20(3): 283-286.

Shelbourne, K. D. P. V. (1995). "Timing of Surgery in Anterior Cruciate Injured Knees." Knee.Surg.Sports Traumatol.Arthrosc. 3: 148-156.

Shelbourne, K. D. S., K.C. (1997). "Anterior cruciate ligament (ACL)-deficient knee with degenerative arthrosis: treatment with an isolated autogenous patellar tendon ACL reconstruction." Knee.Surg.Sports Traumatol.Arthrosc. 5(3): 150-156.

We evaluated 58 patients (mean age 30.4 years) who had undergone an isolated anterior cruciate ligament (ACL) reconstruction for chronic instability (mean time from injury to surgery, 8.2 +/- 5.2 years) and showed radiographic evidence of degenerative arthrosis. Objective evaluation at a mean of 4.1 years postoperatively included KT-1000 arthrometer stability, range of motion, and quadriceps muscle strength testing. Subjective analysis at a mean of 5.5 years postoperatively included rating of pain, stability, activity level, and a total score both preoperative and postoperative. Patients were divided into two groups: group 1 (n = 28) with a follow-up < or = 5 years (mean 3.3 years); group 2 (n = 30) with a follow-up > 5 years (mean 7.2 years). Results were analyzed by length of follow-up and by the grade and compartment of arthrosis. All patients enjoyed a full range of motion preoperatively and postoperatively. The mean KT-1000 arthrometer manual maximum difference improved from a mean of 8.2 mm preoperatively to 2.4 mm postoperatively. All subjective scores showed statistically significant improvement over the preoperative values. Patients with medial compartment arthrosis reported a better subjective total score (mean 87) than patients with lateral compartment (mean 73) or bicompartmental (mean 79) arthrosis, but there was not a statistically significant difference. There was no correlation between pain, stability, or total scores and time after surgery. Patients in groups 1 and 2 had equal objective stability and similar subjective scores, but group 2 reported a lower activity level. An isolated ACL reconstruction can provide long-term stability and symptomatic pain relief in patients with chronic instability and arthrosis. The procedure has low morbidity and does not compromise future tibial osteotomy or total knee replacement

Shelbourne, K. D. T., R.V. (1997). "Preventing anterior knee pain after anterior cruciate ligament reconstruction." Am.J.Sports Med. 25(1): 41-47.

We studied a group of 602 patients who had anterior cruciate ligament reconstructions between 1987 and 1992. An autogenous patellar tendon graft was used, regardless of preexisting patellofemoral pain or chondromalacia. The surgeon and rehabilitation protocol were the same for all patients, with emphasis on obtaining full knee hyperextension postoperatively. All patients were evaluated by a questionnaire designed to determine the incidence and severity of anterior knee pain as it relates to sporting or daily living activities, prolonged sitting, stair climbing, and kneeling. Range of motion for the study group was recorded during physical examination. We compared the findings with those from a control group of 122 patients who had no previous knee injury. The study group reported a mean score of 89.5 +/- 12.5, compared with 90.2 +/- 12.3 in the control group. Both the operative and control groups reported little or no symptoms during sporting activities (94% and 92%, respectively). No differences were noted with respect to the other activities surveyed. These results demonstrate that anterior knee pain after anterior cruciate ligament reconstruction is not an inherent complication associated with patellar tendon harvesting. We suggest that the increased incidence of anterior knee pain with an autogenous patellar tendon graft can be prevented by obtaining full knee hyperextension postoperatively. This goal can be achieved through preoperative rehabilitation and a postoperative protocol emphasizing early restoration of full knee hyperextension

Shelbourne, K. D. U., S.E. (2000). "Primary anterior cruciate ligament reconstruction using the contralateral autogenous patellar tendon." Am.J.Sports Med. 28(5): 651-658.

We studied patients who underwent primary anterior cruciate ligament reconstruction using either the contralateral (N = 434) or ipsilateral (N = 228) autogenous patellar tendon graft to determine the difference between groups for the return of range of motion, quadriceps muscle strength, and return to sports. The contralateral group had statistically significantly more flexion than the ipsilateral group at 1 week and 2 weeks postoperatively. The contralateral group had statistically significantly greater quadriceps muscle strength in the reconstructed knee at 1, 2, and 4 months postoperatively and in the donor knee at 1 and 2 months postoperatively. Mean KT-1000 arthrometer results were 1.9 +/- 1.3 mm for the contralateral group and 2.2 +/- 1.1 mm for the ipsilateral group. The mean time to return to sports at full capability in a competitive subgroup was 4.1 months for contralateral patients and 5.5 months for ipsilateral patients. Overall, 49% of patients in the contralateral group and 12% of patients in the ipsilateral group returned to their preinjury levels of activity by 4 months postoperatively. Our results indicate that the contralateral patellar tendon can be used to restore range of motion and strength sooner than an ipsilateral patellar tendon graft. Patients can also have a faster return to full capability in sports without compromising ultimate stability

Shelbourne, K. D. W., H.J.;McCarroll,J.R.;Reittig,A.C. and Hirschmann,L.D. (1990). "Anterior cruciate ligament injury: evaluation of intraarticular reconstruction of acute tears without repair. Two to seven year followup of 155 athletes." Am. J. Sports Med 18: 484-489.

Shelbourne, K. D. W., J.H.; Mollabashy,Alla; and DeCarlo, Mark (1991). "Arthrofibrosis in acute anterior cruciate ligament reconstruction. The effectof timing of reconstruction and rehabilitation." Am. J. Sports Med 19: 332- 336.

Shelton, W. R., G. R. Barrett, et al. (1997). "Early season anterior cruciate ligament tears. A treatment dilemma." Am J Sports Med 25(5): 656-8.

An anterior cruciate ligament tear before or early in an athlete's season presents a treatment dilemma: surgically repair the ligament and end the season, or use rehabilitative exercises and bracing to quickly return the athlete to play. We conducted a prospective study of 43 athletes (44 acute tears) over 44 months to determine criteria for early return to play and if an early return is safe. All patients had an acute injury in a previously normal knee, a positive Lachman test, and KT-1000 arthrometry indicating ligament abnormalities. Magnetic resonance imaging of each injured knee showed an interior cruciate ligament tear but no meniscal tear. Thirty patients (31 tears) returned to play with rehabilitation and a brace at an average of 5.7 weeks after injury: Only 12 patients returned to their sports without recurrent buckling of their injured knees; 18 patients (19 knees) had recurrent buckling during play. Thirteen patients could not return to play. Patients were observed until they 1) had ligament reconstruction (29 patients, 29 tears), 2) gave up their sports because of instability but did not elect surgery (3 patients), or 3) returned to play in a brace and declined surgery (11 patients, 12 tears). All who elected reconstruction experienced recurrent knee buckling. We found 23 meniscal tears (17 knees) in the 29 patients undergoing reconstruction.

Sherman, M. F., L. Lieber, et al. (1991). "The long-term followup of primary anterior cruciate ligament repair. Defining a rationale for augmentation." Am J Sports Med 19(3): 243-55.

Fifty primary ACL repairs using the Marshall multiple suture technique were analyzed. The average age at surgery was 23 years (range, 15 to 56), with 76% under the age of 30. The average followup was 61.3 months (range, 48 to 86). The average time from injury to surgery was 7 days (range, 1 to 18). Eighty percent of the injuries were sports-related with football and skiing predominating. Thirty-eight percent were "isolated" ACL tears, and 62% had associated injuries. There was a 46% incidence of meniscal tear with 59% of the meniscal tears being repaired. The postoperative evaluation included a multifactorial analysis correlating 43 variables including subjective, objective, radiographic, and KT-1000 data. The Hospital for Special Surgery Knee Diagnostic Score, a clinical objective score based on the postoperative Lachman and pivot shift examination, a KT-1000 arthrometer data score, and an overall combined assessment score were determined. The results showed 59% excellent, 18% good, 14% fair, and 8% poor. The Lachman test was diagnostic in all cases. The quality of ACL tissue at repair was rated excellent or good in 62% of the cases. Four patterns of ACL tears were distinguished by the location of the tear. Football injury, younger age, increased peroperative pivot shift, midsubstance Type IV tear, and return of full motion correlated with poor postoperative results. Increasing age, tight jointedness, Type I tears, and a 5 degrees flexion contracture correlated with good postoperative results.

Shino, K., S. Nakagawa, et al. (1993). "Deterioration of patellofemoral articular surfaces after anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(2):206-11, 1993 Mar-Apr 21(2): 206-11.

One hundred eighty-seven patients who had undergone intraarticular anterior cruciate ligament reconstruction using either a fresh-frozen allogeneic tendon or central third autogenous pateller tendon 3 to 89 months previously were arthroscopically evaluated. The focus was on secondary changes of the patellofemoral joint at the time of second-look arthroscopy. Overall, 93 knees deteriorated, 74 knees remained unchanged, and 14 improved. The deteriorative changes were predominantly located around the central ridge of the patellae, although all but two knees remained free from anterior knee pain. Statistical multivariate analysis showed surgical approach by conventional medial parapatellar incision and use of the central one-third of the autogenous patellar tendon graft as possible risk factors for the deterioration, although chi-square analysis failed to demonstrate statistical significance for the latter.

Shino, K., K. Nakata, et al. (1993). "Quantitative evaluation after arthroscopic anterior cruciate ligament reconstruction. Allograft versus autograft." American Journal of Sports Medicine 21(4):609-16, 1993 Jul-Aug 21(4): 609-16.

We measured the anteroposterior ligamentous laxity and thigh muscle power in 92 subjects who were rated as successes after they had undergone arthroscopic anterior cruciate ligament reconstruction for unilateral anterior cruciate ligament insufficiency 18 to 36 months previously. The subjects were divided into 2 groups according to the type of graft: fresh-frozen allogenic tendon (N = 47) or central one third of the ipsilateral patellar tendon (N = 45). Instrumented drawer tests in the Lachman position were performed to measure anterior tibial displacement at 200 N (anterior laxity). Thigh muscle power was isokinetically measured with a Cybex II dynamometer. Significantly more anterior laxity was found in the reconstructed knees than in the contralateral normal knees regardless of graft material (paired t-test, P < 0.01), except for the male allograft patients. Although the mean anterior laxity difference between sides for the allograft patients was less than that for the autogenous ones, analysis of variance failed to demonstrate a statistically significant difference between the 2 groups if the comparison was strictly made within the same sex. Thigh muscle tests revealed that extension torque in the reconstructed knees was significantly less than that in the contralateral knees and analysis of variance showed that knee extension torque at 60 deg/sec for the allograft patients was significantly better than that of the autograft ones (P < 0.05). We concluded that the allograft procedure is advantageous over the patellar tendon autograft in terms of better restoration of anterior stability.

Shino, K. I., M.;Horibe,S.;Hamada,M.; and Ono,K. (1990). "Reconstruction of the anterior cruciate ligament using allogeneic tendon: long-term followup." Am. J. Sports Med., 18: 457-465.

Shires, P. K. (1993). "Intracapsular repairs for cranial cruciate ligament ruptures." Veterinary Clinics of North America - Small Animal Practice 23(4):761-76, 1993 Jul 23(4): 761-76.

Two intracapsular techniques and their modifications are described that can be regarded as the most accepted procedures in general use today. The difficulty in rationalizing a choice between intra- and extracapsular techniques is discussed with some principles being suggested to help the surgeon choose a technique.

Shoemaker, S. C., D. Adams, et al. (1993). "Quadriceps/anterior cruciate graft interaction. An in vitro study of joint kinematics and anterior cruciate ligament graft tension." Clinical Orthopaedics & Related Research (294):379-90, 1993 Sep(294): 379-90.

The Oxford Rig, a device that simulates active knee extension during stance, was used to study the effects of quadriceps force on AP tibial displacement and axial tibial rotation in vitro. Human anatomic specimen knees were tested with the anterior cruciate ligament (ACL) intact, sectioned, and reconstructed. Patellar tendon grafts used in the ACL-reconstructed state were attached distally to a load cell, allowing direct measurement of graft tension. Both ACL status and quadriceps force had significant effects on anterior tibial displacement, limits of AP displacement, axial tibial rotation, and graft tension, as shown by analysis of variance. Anterior cruciate ligament sectioning led to anterior tibial displacement in the absence of quadriceps force, whereas ACL reconstruction led to posterior tibial displacement. In the ACL-intact, quadriceps-stabilized state, anterior displacement of the tibia was observed between 95 degrees flexion and full extension, with a maximum displacement (3.5 +/- 0.2 mm) between 30 degrees and 45 degrees flexion. After ACL sectioning, anterior tibial displacement resulting from quadriceps force was accentuated relative to the intact state by as much as 4.5 mm +/- 0.9 mm at 20 degrees and 25 degrees flexion. Anterior tibial displacement in the ACL-intact and reconstructed specimens was similar when quadriceps force was present. In the quadriceps-stabilized state, graft tension increased between 5 degrees and 80 degrees flexion. The maximum increase in graft tension due to quadriceps force was at 35 degrees flexion.

Sidles, J. A. L., R.V.;Garbini,J.L.; Downey,D.J.; and Matsen,F.A.,III (1988). "Ligament length relationships in the moving knee." J. Orthop. Res(6): 593-610.

Silvaggio, V. J., F. H. Fu, et al. (1993). "The induction of IL-1 by freeze-dried ethylene oxide-treated bone-patellar tendon-bone allograft wear particles: an in vitro study." Arthroscopy 9(1):82-6, 1993 9(1): 82-6.

There have been recent reports of adverse clinical results with freeze-dried ethylene oxide-treated bone-patellar tendon-bone (FD-ETO-BPTB) allografts used in anterior cruciate ligament (ACL) reconstruction. Ethylene oxide and its residues were implicated as the cause of many of the failures. Wear particles generated from both freeze-dried ethylene oxide-treated and deep frozen bone-patellar tendon-bone (DF-BPTB) allografts were placed in culture with lapine synoviocytes. The resulting synovial-conditioned media were then assayed for interleukin-1 (IL-1) content. IL-1 is a potent mediator of tissue inflammation. FD-ETO-BPTB wear particles generated statistically significant levels of IL-1 when compared with both a negative control and DF-BPTB wear particles.

Sim, E. (1993). "[Choice of femoral reinsertion sites after rupture of the anterior cruciate ligament--a roentgenologic evaluation model]." Aktuelle Traumatologie 23(7):330-1, 1993 Nov 23(7): 330-1.

The position of transcondylar small caliber drill tunnels after reattaching of femoral avulsions of the anterior cruciate ligament usually escapes objective verification by conventional roentgenography. A model of investigation and the results of cadaver studies are presented: Stored CT data are used for 3D-reconstruction of the distal end of the femur. In such manner the sites of perforation of the K wires can be determined unequivocally and distinctly.

Simonian, P. T. H., S.D.; Cooley,V.J.; Escabedo,E.M.; Deneka,D.A.; Larson,R.V. (1997). "Assessment of morbidity of semitendinosus and gracilis tendon harvest for ACL reconstruction." Am.J.Knee.Surg. 10(2): 54-59.

This study evaluates the morbidity of harvest of both the semitendinosus and gracilis tendons for anterior cruciate ligament reconstruction on nine patients at a minimum of 3 year follow-up. Specifically, the effect on knee function, knee extension and flexion strength, the size of the individual posterior thigh muscles, and the extent of retraction of the semitendinosus and gracilis tendons were evaluated. At final follow-up, each patient was evaluated using the following functional scales: International Knee Documentation Committee (IKDC), Hospital for Special Surgery (HSS), Lysholm, and Tegner. Each patient also had a dynamometer evaluation and a comprehensive magnetic resonance imaging study of both the operated and nonoperated knees. The average functional evaluation scores were: HSS-47.9, Lysholm-88, and Tegner-0.27. The average percent quadriceps and hamstring strength of the operated compared with the nonoperated extremities were 93.7% and 95.3%, respectively; neither decrease was significant. Magnetic resonance imaging evaluation of the cross-sectional areas of the biceps femoris, semimembranosus, and sartorius muscles of both thighs at the same level above the joint were not significantly different. The distal- most insertion of the semitendinosus and gracilis tendons after harvest were always more proximal than the nonoperated side; the average difference was 26.7 mm (range: 11 to 32 mm) for the semitendinosus (unable to calculate in three patients) and 47.1 mm (range: 17 to 72 mm) for the gracilis. We conclude that tendon harvest of the semitendinosus and gracilis muscles does not significantly compromise function and strength despite a more proximal insertion of the retracted tendons. In addition, the majority of cases demonstrated some but never complete regrowth or scar formation of these tendon remnants

Simonian, P. T. M., M.H.; Larson,R.V. "Anterior cruciate ligament injuries in the skeletally immature patient." Am.J.Orthop. 28(11): 624-628.

Injuries of the anterior cruciate ligament (ACL) in children are more frequent than once thought. Special factors must be taken into consideration when treating ACL injuries in the skeletally immature patient. Risks of surgery must be weighed against potential damage to the knee caused by repeated injury. The authors prefer the use of both tibial and femoral centrally placed drill holes, hamstring tendon autografts, fixation distant from the physis, and avoidance of dissection near the physis. This technique will minimize damage to the physis and should not hinder normal growth

Small, N. C. (1993). "Complications in arthroscopic surgery of the knee and shoulder." Orthopedics 16(9):985-8, 1993 Sep 16(9): 985-8.

Arthroscopy is a valuable technique used by the majority of orthopedic surgeons in practice. Complications in arthroscopy have been compiled on a formal basis since 1983. Several studies on complications are reviewed and summarized. A recent prospective study on complications is reviewed in detail. The most frequent type of complication encountered in arthroscopic surgery is hemarthrosis. The procedure with the highest complication rate is the lateral retinacular release. Technical considerations are discussed which would be useful in lessening the incidence of complications in arthroscopy.

Smith, B. A., G. A. Livesay, et al. (1993). "Biology and biomechanics of the anterior cruciate ligament." Clinics in Sports Medicine 12(4):637-70, 1993 Oct 12(4): 637-70.

With detailed information concerning the role of the anterior cruciate ligament in the overall kinematic response of the knee during external loading, current clinical management of the orthopedic injuries to this joint may be improved upon and refined. Among the largest challenges to be met will be elucidation of the effects of various levels and types of muscular stabilization concurrent with a precise determination of the roles of passive knee restraints.

Snyder-Mackler, L., S. A. Binder-Macleod, et al. (1993). "Fatigability of human quadriceps femoris muscle following anterior cruciate ligament reconstruction." Medicine & Science in Sports & Exercise 25(7):783-9, 1993 Jul 25(7): 783-9.

The responses of quadriceps femoris muscles to an electrically elicited fatigue test were recorded from both lower extremities of 18 patients who had recently undergone unilateral, anterior cruciate ligament reconstruction. The fatigue test consisted of 40 pps, 13-pulse electrical trains that were repeated once per second for 3 min. The intensity of stimulation was set for each extremity to produce 20% of the maximum voluntary isometric contraction of the uninvolved muscle. The uninvolved quadriceps femoris muscle showed a significantly greater rate of decline in force over the first minute than the involved muscle (0.803%.s-1 for uninvolved muscle vs 0.620%.s-1 for involved muscle). Similarly, the average forces produced over the last minute were significantly lower for the uninvolved than the involved quadriceps femoris muscle (uninvolved = 42.6%, involved = 50.4% of their original forces). These surprising results showed that the involved quadriceps femoris muscles were more endurant than the uninvolved muscles. It is suggested that the increases in endurance of the involved muscle may have been due, in part, to greater recruitment of Type I fibers with electrical stimulation or selective Type II fiber atrophy in the involved muscle.

Solheim, E. and T. Strand (1993). "Postoperative pain after anterior cruciate ligament reconstruction using a transligamentous approach." American Journal of Sports Medicine 21(4):507-9, 1993 Jul-Aug 21(4): 507-9.

Anterior cruciate ligament reconstruction by free patellar tendon graft was performed using 2 different surgical approaches to the intercondylar notch in 67 consecutive patients with chronic anterior cruciate ligament insufficiency. In the first 30 patients (Group A), the traditional medial parapatellar arthrotomy with lateral luxation of the patella was done, whereas in the last 37 patients (Group B) a transpatellar tendon approach was used. Postoperative pain was managed by analgesics and, in patients who had epidural anesthesia, by administration of bupivacaine in indwelling catheters. Generally, the analgesics and bupivacaine were given immediately on request to establish comfort at rest and to permit range of motion exercises without severe pain. Compared with those in Group A, the patients of Group B had a significantly longer period from the first dose of analgesic or bupivacaine to the second, and the total number of doses of analgesic or bupivacaine was significantly lower. In the subgroup of patients with epidural anesthesia (21 in Group A and 32 in Group B), the Group B patients required significantly less analgesics, as doses equivalent to 10 mg of morphine, compared with that of Group A

Solomonow, M. B., R.;Zhou,B.H.;Shoji,H.;Bose,W.;Beck,C.; and DAmbrosia,R. (1987). "The synergistic action of the anterior cruciate ligament and thigh muscles in maintaining joint stability." Am.J.Sports Med 15: 207-213.

Sommer, C. F., N.F.; Muller,W. (2000). "Improperly placed anterior cruciate ligament grafts: correlation between radiological parameters and clinical results." Knee.Surg.Sports Traumatol.Arthrosc. 8(4): 207-213.

Despite increasing knowledge on knee biomechanics and refined operative techniques, an increasing number of patients are being seen with failed anterior cruciate ligament (ACL) reconstruction. Failure of the reconstruction and further damage to the knee are correlated with improper placement of the graft, which interferes with graft biology and biomechanical demands. Between 1994 and 1995, 63 patients with improperly placed ACL grafts were referred to our institution because of persistent knee instability and pain. A method for analysis of the femoral drill hole on radiography was developed. Before reoperation the radiograph was evaluated by our method, noting the clinical aspects according to the recommendations of the International Knee Documentation Committee (IKDC). The femoral placement of the ACL graft could easily be defined on the lateral and anteroposterior tunnel radiography. The most common error was a femoral placement anterior to the anatomical insertion of the ACL. A significant correlation (P < 0.05) was found between femoral placement of the graft in the sagittal plane and clinical results: the IKDC score declined with increasing distance of the graft from the most isometric bundle of the ACL in the anteroposterior direction

Sommerlath, K. and J. Gillquist (1993). "The effects of an artificial meniscus substitute in a knee joint with a resected anterior cruciate ligament. An experimental study in rabbits." Clinical Orthopaedics & Related Research (289):276-84, 1993 Apr(289): 276-84.

A Dacron meniscus prosthesis was substituted for the medial meniscus in an anterior cruciate ligament (ACL) resected rabbit knee. At three months, the joints were evaluated biomechanically, with gross and histologic inspection. In a paired comparison with the contralateral knee, differences between ACL resection with intact, incised, or resected medial menisci were evaluated. Knees with intact menisci and ligaments served as controls. Because of cartilage destruction, soft-tissue hypertrophy, and increased anterior laxity, joint stiffness was less than normal in all ACL-resected knees. Ingrowth and stable fixation, especially of the posterior horns of the prostheses and the incised menisci, were rare. Almost all normal menisci had ruptured in the same area. Anterior cruciate ligament resection led to severe osteoarthrosis in both compartments, regardless of initial meniscal treatment. Knees with prostheses had the same incidence and severity of osteoarthrosis as knees with meniscus resection. Anterior cruciate ligament resection alone induced excessive osteoarthrosis and synovitis and diminished the effects of different meniscal treatments three months earlier.

Souryal, T. O. and T. R. Freeman (1993). "Intercondylar notch size and anterior cruciate ligament injuries in athletes. A prospective study [published erratum appears in Am J Sports Med 1993 Sep-Oct;21(5):723]." American Journal of Sports Medicine 21(4):535-9, 1993 Jul-Aug 21(4): 535-9.

Published reports agree that there is a strong association between intercondylar notch stenosis and anterior cruciate ligament injuries. In a previously published retrospective study on bilateral anterior cruciate ligament injuries and associated intercondylar notch stenosis, we formulated the notch width index to measure and compare intercondylar notch width. The purpose of this prospective study was to establish a normal range for the notch width index and to correlate intercondylar notch size and anterior cruciate ligament injuries. We gathered data on 902 high school athletes, including range of motion, thigh girth, ligament stability and intercondylar notch width using the notch width index. The population was then followed prospectively and anterior cruciate ligament injuries were recorded and correlated with notch width index in a blind manner. Two-year results showed that the overall anterior cruciate ligament injury rate was 3%. The normal intercondylar notch ratio was 0.231 +/- 0.044. Intercondylar notch width index for men was larger than that for women. Athletes sustaining noncontact anterior cruciate ligament tears have statistically significant intercondylar notch stenosis (notch width index, 0.189). Ten of 14 athletes with noncontact anterior cruciate ligament injuries had a notch width index that was at least 1 SD below the mean. Athletes with contact anterior cruciate ligament injuries had a mean of 0.233. We conclude that athletes with a stenotic intercondylar notch are at significantly greater risk for sustaining noncontact anterior cruciate ligament injury.

Spicer, D. D. B., S.E.; Unwin,A.J.; Allum,R.L. (2000). "Anterior knee symptoms after four-strand hamstring tendon anterior cruciate ligament reconstruction." Knee.Surg.Sports Traumatol.Arthrosc. 8(5): 286-289.

Proponents of hamstring anterior cruciate ligament (ACL) reconstruction suggest that anterior knee symptoms (AKS) may be less than following the use of bone-patella-bone autograft. Our aim was to assess the incidence of AKS in a cohort of patients who had undergone hamstring reconstructions. Forty-four of 50 consecutive patients who had undergone arthroscopically assisted four-strand gracilis/semitendinosus hamstring ACL reconstructions were reviewed at a minimum follow-up of 24 months. The frequency and severity of anterior knee pain experienced during activities of daily living, sports, prolonged sitting, stair- climbing and kneeling was recorded by means of the Shelboume and Trumper anterior knee pain questionnaire. The location of both pain and any perceived sensory change was recorded using patient-drawn diagrams. Although mild or moderate symptoms occurred in a proportion of patients, only 2% experienced significant symptoms that caused limitation with daily activity, 7% with strenuous work or sport, 12% with kneeling, 5% with stairs and none with prolonged sitting. The pain was not specifically related to the incision for tendon harvest and drilling of the tibial tunnel. Areas of sensory change over the front of the knee were identifiable in 50% of patients, and of these, 86% demonstrated sensory change in the distribution of the infragenicular branch of the saphenous nerve. Although rarely a cause of limitation of activity, AKS can be a problem after hamstring ACL reconstruction and patients should be counselled accordingly

Spindler, K. P., J. A. Bergfeld, et al. (1993). "Intraoperative complications of ACL surgery: avoidance and management." Orthopedics 16(4):425-30, 1993 Apr 16(4): 425-30.

Spindler, K. P., J. P. Schils, et al. (1993). "Prospective study of osseous, articular, and meniscal lesions in recent anterior cruciate ligament tears by magnetic resonance imaging and arthroscopy." American Journal of Sports Medicine 21(4):551-7, 1993 Jul-Aug 21(4): 551-7.

Fifty-four patients with anterior cruciate ligament tears that were arthroscopically reconstructed within 3 months of initial injury were prospectively evaluated. Patients with grade 3 medial collateral ligament, lateral collateral ligament, or posterior cruciate ligament tears were excluded. Eighty percent of our patients had a bone bruise present on the magnetic resonance image, with 68% in the lateral femoral condyle. Two of the latter findings--an abnormal articular cartilage signal (P = 0.02) and a thin and impacted subchondral bone (P = 0.03)--had a significant relationship with injury to the overlying articular cartilage. Meniscal tears were found in 56% of the lateral menisci and 37% of the medial menisci. A significant association was present between bone bruising on the lateral femoral condyle and the lateral tibial plateau (P = 0.02). Results of our study support the concept that the common mechanism of injury to the anterior cruciate ligament involves severe anterior subluxation with impaction of the posterior tibia on the anterior femur. Determination of the significance of bone bruising, articular cartilage injury, or meniscal tears will require a long-term followup that includes evaluation for arthritis, stability, and function. These 54 patients represent the first cohort evaluated in this ongoing prospective clinical study.

Stahelin, A. C., N. P. Sudkamp, et al. (2001). "Anatomic double-bundle posterior cruciate ligament reconstruction using hamstring tendons." Arthroscopy 17(1): 88-97.

Recent biomechanical studies have shown that an anatomic double-bundle posterior cruciate ligament (PCL) reconstruction is superior in restoring normal knee laxity compared with the conventional single- bundle isometric reconstruction. We describe a modification of an endoscopic PCL reconstruction technique using a double-bundle Y-shaped hamstring tendon graft. A double- or triple-bundle semitendinosus- gracilis tendon graft is used and directly fixed with soft threaded biodegradable interference screws. In the medial femoral condyle, 2 femoral tunnels are created inside-out through a low anterolateral arthroscopic portal. First, in 80 degrees of flexion, the double- stranded gracilis graft is fixed with an interference screw inside the lower femoral socket, representing the insertion site of the posteromedial bundle. In full extension the combined semitendinosus- gracilis graft is pretensioned and fixed inside the posterior aspect of the single tibial tunnel. The double- or triple-stranded semitendinosus tendon is inserted in the higher femoral tunnel, presenting the insertion site of the anterolateral bundle. Finally, pretension is applied to the semitendinosus bundle in 70 degrees of flexion and a third screw is inserted. Using this technique, the stronger semitendinosus part of the double-bundle graft, which mimics the anterolateral bundle of the PCL, is fixed in flexion, whereas the smaller gracilis tendon part (posteromedial bundle) is fixed in full extension. Thus, a fully arthroscopic anatomic PCL reconstruction technique is available that may better restore normal knee kinematics as compared to the single-stranded isometric reconstruction.

Stahelin, A. C. and A. Weiler (1997). "All-inside anterior cruciate ligament reconstruction using semitendinosus tendon and soft threaded biodegradable interference screw fixation." Arthroscopy 13(6): 773-9.

A modification of anterior cruciate ligament (ACL) reconstruction using a minimally invasive and endoscopic all-inside technique is presented. Both the femoral and tibial socket are approached through the joint so that there is no open tibial tunnel, which otherwise often causes significant pain and discomfort during early rehabilitation. The autologous semitendinosus tendon is harvested with a bone plug attached to its tibial insertion. The triple-stranded semitendinosus tendon is looped around the adjacent bone plug and fixed at the original tibial attachment site of the ACL using a soft threaded biodegradable poly- (D,L-lactide) interference screw. The screw is inserted endoscopically in an inside-out direction. In the femoral socket the graft is fixed without a bone plug directly to the tunnel wall using the biodegradable screw. The free part of the graft is thus not longer than the intra- articular distance, which may increase stiffness of the construct.

Stahelin, A. C., A. Weiler, et al. (1997). "Clinical degradation and biocompatibility of different bioabsorbable interference screws: a report of six cases." Arthroscopy 13(2): 238-44.

The clinical biocompatibility and degradation of bioabsorbable interference screws of different polymer composition is described in this report for six patients who underwent repeat arthroscopy after anterior cruciate ligament (ACL) reconstruction. Bioabsorbable interference screws were used for bone plug fixation of bone--patellar tendon--bone (BPTB) autografts. Poly (L-lactide) (PLLA) interference screws were used in one case, poly (D,L-lactide-co-glycolide) (PDLLA-co- PGA) in two cases and poly (D,L-lactide) (PDLLA) in three cases. The patients either underwent removal of the femoral screw or had a biopsy taken from the screw site during re-arthroscopy. Large fragments of the PLLA screw were still present 20 months postoperatively. In one case, the PDLLA-co-PGA screw was extruded spontaneously from the tibial bone tunnel 3 weeks after the operation. In the second PDLLA-co-PGA screw case, there was no evidence left of the screw material on biopsy 12 months after implantation. The PDLLA screw in one patient was removed 6 weeks after implantation without any signs of degradation. No traces of the PDLLA screws were found in the two other patients, 10 or 14 months postoperatively. There were no clinical signs of foreign-body reactions in all cases.

Stallenberg, B., P. A. Gevenois, et al. (1993). "Fracture of the posterior aspect of the lateral tibial plateau: radiographic sign of anterior cruciate ligament tear." Radiology 187(3):821-5, 1993 Jun 187(3): 821-5.

Plain radiographs obtained in 25 patients with acute anterior cruciate ligament (ACL) tears detected with magnetic resonance imaging were retrospectively evaluated to identify associated bone lesions. Fracture of the posterior part of the lateral tibial plateau (LTP) was seen in 11 patients, impacted fracture of the lateral femoral condyle (LFC) in two, lateral tibial rim fracture (Segond fracture) in three, and avulsion fracture of the tibial attachment of the ACL in two. The latter three fractures have been associated with an ACL tear. Conversely, fractures of the posterior part of the LTP have not been associated with ACL tear and are recognizable on plain radiographs. Impaction of the LFC on the LTP and avulsion of the posterior tibial capsular junction may account for the association of the fracture of the LTP with the acute ACL tear. This type of fracture represents the most frequent indirect sign of ACL tear seen on plain radiographs.

Stanish, W. D. and A. Lai (1993). "New concepts of rehabilitation following anterior cruciate reconstruction." Clinics in Sports Medicine 12(1):25-58, 1993 Jan 12(1): 25-58.

Can a knee joint with a torn ACL of 2 years' duration ever be able to return to high performance? Very unlikely indeed. Some realistic expectations follow: 1. The knee joint can never be normal after an ACL reconstruction. 2. Surgery must take place as early after the injury as possible, before secondary joint degeneration takes place. 3. The surgery must employ a tissue that best matches the normal ACL in strength and structure. 4. The surgery must involve as little trauma as possible while restoring knee joint mechanics. 5. Stress, although guarded, must be faced by the knee joint as soon as possible after surgery. 6. Progressive weight bearing starts immediately, combined with quadriceps isometrics. ROM of the knee joint, particularly full extension, is conserved and protected. 7. Progressive active ROM without formal resistance continues for 4 weeks. 8. Progressive formal resistance exercises continue for at least 1 year. 9. Sport-specific tasks commence at 16 weeks, depending on the requirement of the sport and the response of the individual athlete. 10. Recovery will plateau at several stages, with the final plateau at approximately 18 months. Knee instability is an exciting but perplexing problem. Although we have advanced profoundly from the era of Jones, Smiley, and others, we still face many of the same challenges as our predecessors. New technology should not fool us. We are still addressing a major structural failure within the knee joint. Our attempts have been non-surgical and surgical, with repair, reconstruction, and replacement. However, fundamental to all of these hopes has been the reconditioning of the extremity after ACL surgery. Can we do better than our forefathers like Licht and others? No one is certain. This article offers an approach, in some areas our approach, but should not be perceived as a cookbook. Individual responses by our patients, athletes, dictate whether any protocol is too hasty or tardy. It is fundamental that we listen to our patients objectively and analyze the knee as it returns from the surgical aggression. The ultimate success of the rehabilitation process will be based on the marriage of science and realistic expectations.

Stanitski, C. L. (1994). "Surgical reconstruction for symptomatic ACL insufficiency in skeletally immature athletes." Am J Sports Med 22(3): 433.

Stanitski, C. L., J. C. Harvell, et al. (1993). "Observations on acute knee hemarthrosis in children and adolescents." Journal of Pediatric Orthopedics 13(4):506-10, 1993 Jul-Aug 13(4): 506-10.

Diagnostic knee arthroscopic findings in 70 children aged 7-18 years with acute traumatic knee hemarthroses showed a high incidence of intraarticular lesions. Forty-seven percent of preadolescents (aged 7-12 years) had meniscal tears, and 47% had anterior cruciate ligament (ACL) tears. Forty-five percent of adolescents (aged 13-18 years) had meniscal tears and 65% had ACL tears. Osteochondral fractures accounted for 7% of the lesions. Meniscal and ACL pathology is common in children, especially adolescents. Because arthroscopy provided accurate diagnosis, specific treatment could be instituted.

Staubli, H. U. S., L.; Brunner,P.; Rincon,L.; Nolte,L.P. (1999). "Mechanical tensile properties of the quadriceps tendon and patellar ligament in young adults." Am.J.Sports Med. 27(1): 27-34.

We analyzed mechanical tensile properties of 16 10-mm wide, full- thickness central parts of quadriceps tendons and patellar ligaments from paired knees of eight male donors (mean age, 24.9 years). Uniaxial tensile testing was performed in a servohydraulic materials testing machine at an extension rate of 1 mm/sec. Sixteen specimens were tested unconditioned and 16 specimens were tested after cyclic preconditioning (200 cycles between 50 N and 800 N at 0.5 Hz). Mean cross-sectional areas measured 64.6 +/- 8.4 mm2 for seven unconditioned and 61.9 +/- 9.0 mm2 for eight preconditioned quadriceps tendons and were significantly larger than those values of seven unconditioned and seven preconditioned patellar ligaments (36.8 +/- 5.7 mm2 and 34.5 +/- 4.4 mm2, respectively). Mean ultimate tensile stress values of unconditioned patellar ligaments were significantly larger than those values of unconditioned quadriceps tendons: 53.4 +/- 7.2 N/mm2 and 33.6 +/- 8.1 N/mm2, respectively. Strain at failure was 14.4% +/- 3.3% for preconditioned patellar ligaments and 11.2% +/- 2.2% for preconditioned quadriceps tendons (P = 0.0428). Preconditioned patellar ligaments exhibited significantly higher elastic modulus than preconditioned quadriceps tendons. Based on mechanical tensile properties analyses, the quadriceps tendon-bone construct may represent a versatile alternative graft in primary and revision anterior and posterior cruciate ligament reconstruction

Steadman, J. R. and W. G. Rodkey (1993). "Role of primary anterior cruciate ligament repair with or without augmentation." Clinics in Sports Medicine 12(4):685-95, 1993 Oct 12(4): 685-95.

Primary ACL repair with or without extra-articular augmentation can be functionally and statically successful based on our experience in high-performance athletes. Proper surgical technique, appropriate rehabilitation, and excellent quality of the tissue being repaired are required to achieve these results. Several notable improvements in diagnostic imaging, physical examination, surgical technique, and rehabilitation protocol have led to excellent results. The notchplasty, multiple loop suture technique, and improved meniscal repair are key factors. Moreover, we believe that one of the prime enhancements is to provide the highly stable extra-articular lateral capsular ligament reconstruction described previously. Laboratory findings have shown that this procedure provides excellent support against anterior subluxation immediately after surgery. It appears that release of the iliotibial band tissue proximally prevents stretching and failure of this extra-articular procedure. Rehabilitation unquestionably is a critical factor in the success of this surgical procedure. Immediate motion and appropriate biomechanical stresses on the repaired ligament have proved compatible with good functional and objective results. Even though intra-articular reconstruction of the torn ACL continues to be considered the gold standard, we remain convinced that primary repair of the ACL with appropriate extra-articular augmentation should not be ruled out in many cases. This procedure clearly is a viable, successful, and acceptable alternative to intra-articular reconstruction in selected cases.

Steenlage E, B. J., Johnson D, Caborn DM, (1999). Interference screw fixation strength of a quadrupled hamstring tendon is directly correlated to bone mineral density measured by dual photon absorptimetry. AOSSM.

Steiner ME, H. A., Brown CH, Hayes WC (1994). "Anterior Cruciate Ligament Graft Fixation, Comparison of Hamstring and Patellar Tendon Grafts." Am J of Sports Med 22: 240-247.

Stewart, N. J., L. Engebretsen, et al. (1993). "Maintenance of set force in anterior cruciate ligament grafts." Journal of Orthopaedic Research 11(1):149-53, 1993 Jan 11(1): 149-53.

This study was undertaken to determine how accurately total graft force and load-sharing between graft segments could be set and maintained during augmented anterior cruciate ligament (ACL) reconstruction in the goat knee. Special procedures were developed to reduce the effect of tissue creep and to overcome difficulties in the setting of graft force. Five knees from goat cadavers were reconstructed using a bone-tendon-bone graft (PT) and a synthetic augmentation device (LAD). Prescribed levels of total graft force and load-sharing between the autograft and LAD were set under a standardized external joint load. Immediately after fixation, the set force declined an average of 9 and 3% in the LAD and PT, respectively. After three subsequent exercise sequences, the set forces fell from their initial level by an average of 25% for the LAD and 28% for the PT. An analysis of variance did not show the loss of force with exercise to be statistically significant. We conclude from this in vitro study that our method can be used to set forces in an ACL reconstruction with reasonable maintenance of load-sharing but that losses of approximately 30% of total graft force after exercise of the reconstructed joint are to be expected.

Straub, T. and R. E. Hunter (1988). "Acute anterior cruciate ligament repair." Clin Orthop 227: 238-50.

Sixty-six consecutive patients with acute repair of a complete isolated anterior cruciate ligament (ACL) injury were retrospectively reviewed to evaluate the effectiveness of the authors' surgical technique. All patients noted either a pop, acute swelling, or had acute disability after injury with 58% experiencing all three signs and symptoms. Preoperative testing without anesthesia revealed 95% of patients to have either a positive modified Losee or Lachman test. Postoperative results were obtained by questionnaire in 41 of 42 patients (98%) with a minimum two-year follow-up period. Physical examination was completed in 32 (76%) and arthrometer testing in 30 (71%) patients. Subjective results were good or better in 91%. No patients had buckling or meniscal loss postoperatively. Patellofemoral pain, however, was significant in 15% and severe in 2%. Postoperative functional results were good or better in 78% with all patients participating in sports, 76% in "at risk" sports. A Performance Quotient (P.Q.) was developed to more accurately correlate preinjury and postoperative function. The average P.Q. was 0.87. Objective results were good or better in 100%. Stability was within normal limits by clinical observation in 88%, and by arthrometer testing in 87%. ACL repair is recommended in the young patient who is active in "at risk" sports and who is unwilling to modify activities and willing to undergo a one-year rehabilitation period.

Strobel, M. J., R. J. Castillo, et al. (2001). "Reflex extension loss after anterior cruciate ligament reconstruction due to femoral "high noon" graft placement." Arthroscopy 17(4): 408-11.

We describe a rare case of a painful reflex extension loss due to femoral malplacement of an anterior cruciate ligament (ACL) graft in a female high-level athlete. The graft was placed on the femoral site in the "high noon" position combined with a slight medial tibial tunnel placement. The resulting anterior-posterior cruciate ligament impingement near extension caused a persistent functional extension deficit of 20 degrees. Under anesthesia, the extension loss diminished, and thus it was hypothesized that the ACL-PCL impingement during extension activates a proprioceptive reflex leading to a functional extension loss while the patient is awake. After sacrifice of the graft and subsequent replacement of the ACL, full range of motion was achieved within 2 months. After a 3-year postinjury history of 3 arthroscopies and 2 ACL reconstructions, the athlete reached her preinjury activity level again. This rare cause of a reflex extension loss due to femoral high noon graft placement has not been described previously and should be included as a differential diagnosis when evaluating patients with an extension deficit after ACL reconstruction.

Swenson, T. M. and F. H. Fu (1993). "Anterior cruciate ligament reconstruction: long-term results using autograft tissue." Clinics in Sports Medicine 12(4):709-22, 1993 Oct 12(4): 709-22.

Injuries involving the anterior cruciate ligament are quite common. Numerous surgical procedures have been proposed for the management of the symptomatic ACL-deficient knee. The most popular treatment modality is currently intra-articular reconstruction with the use of autogenous graft tissue. The focus of this article is to review the long-term results of autograft ACL reconstruction.

Taenzer, A. H. C., C.; Curry,C.S. (2000). "Gender affects report of pain and function after arthroscopic anterior cruciate ligament reconstruction." Anesthesiology 93(3): 670-675.

BACKGROUND: Gender-related differences in pain have been clearly shown in experimental settings. Clinical studies of such differences have produced conflicting findings. No studies have shown a significant difference in pain experience associated with differences in functional outcomes. Arthroscopic anterior cruciate ligament reconstruction (AACLR) produces pain of moderate intensity and provides a useful setting for examining gender-related differences in pain and function. METHODS: This study was a retrospective review of prospectively gathered data collected for a continuous quality improvement program and involved all patients who underwent AACLR at a single outpatient facility since June 1992. Anesthetic, surgical, and perioperative management techniques were standardized. Using a questionnaire, all patients were routinely asked to record pain scores, narcotic consumption, and whether they were able to perform a standardized straight leg-raising maneuver on each of the first 5 postoperative days. RESULTS: A total of 736 patients were enrolled for surgery, 58% of whom completed the entire 5-day questionnaire. Women reported higher pain scores at rest as well as with activity on postoperative day 1 compared with men (P < 0.005). In addition, fewer women were able to perform the straight leg-raising maneuver on postoperative day 1 (P = 0.002) and postoperative day 2 (P = 0.004). There was no difference in the amount of narcotics consumed at any time during the study period. CONCLUSIONS: Women seem to experience greater intensity of pain after AACLR that is associated with a decrease in an intermediate measure of functional outcome. These differences may result from differences in either response to analgesics or neuroprocessing

Takai, S., S. L. Woo, et al. (1993). "Determination of the in situ loads on the human anterior cruciate ligament." Journal of Orthopaedic Research 11(5):686-95, 1993 Sep 11(5): 686-95.

A noncontact, kinematic method was used to determine the lengths and in situ loads borne by portions of the human anterior cruciate ligament (ACL) by the combination of kinematic data from the intact knee and load-length curves of the isolated ACL. Specimens from knees of cadavers of young people were tested in passive flexion and extension as well as with 100 N of anterior tibial drawer at 0, 30, 45, and 90 degrees of flexion. The results showed that the in situ load on the whole ACL (as much as 129 N) can exceed the magnitude of the applied anterior tibial drawer. The load distribution within the ligament changes with flexion of the knee. The anterior and posterior portions share the anterior drawer force equally toward full extension. However, at flexion > 45 degrees, the anterior portion supports 90-95% of the load. This information is important for the determination of the function of the entire ACL and of its subportions in response to external loading of the intact knee. In particular, the preferential loading found for one of the portions of the ACL demonstrates that successful operative reconstruction of this ligament may not be achieved simply by reproduction of its gross anatomy; consideration of the role of the ligament in the overall kinematics of the knee is necessary.

Tanaka, N. (1993). "[Early revascularization of the reconstructed anterior cruciate ligament using a patellar tendon autograft]." Nippon Seikeigeka Gakkai Zasshi - Journal of the Japanese Orthopaedic Association 67(10):953-62, 1993 Oct 67(10): 953-62.

Early revascularization of the reconstructed anterior cruciate ligament (ACL) using a patellar tendon autograft was investigated microangiographically and electron microscopically. In sixteen skeletally mature mongrel dogs, the ACL of the right knee was completely excised and tunnels through the tibia and femur were created at the insertion sites using a 3 mm Steinmann pin. The central portion of the patellar tendon (3 mm wide) was pulled through the holes and secured with sutures and buttons. The leg was immobilized with a plaster cast at 90 degrees of knee flexion until sacrifice. Eight dogs divided into four groups (two dogs each) were examined microangiographically at 1, 2, 3 and 4 weeks after the operation. Other eight dogs divided into four groups (two dogs each) were examined with an electron microscope at 3, 5, 7 and 14 days after the operation. The microangiographic study showed capillary buds invaded the graft from the bone tunnels and ran along the graft-bone interface at one week. Newly-formed capillaries were observed near the fat pad, but only at the surface of the graft. At two and three weeks, vascular sprouts anastomosed with each other, forming a network which extended internally into the graft. Although vascularity was present throughout the graft at four weeks, there was little in the midsubstance. The transmission electron microscopy (TEM) demonstrated that mesenchymal cells (undifferentiated fibroblasts) were in the process of migration to the graft in the area of the bone tunnels at five days. At seven days, these cells formed new vascular lumina and differentiated endothelial cells. At fourteen days, the newly-formed vessels had developed basement membrane. Some of mesenchymal cells appeared to differentiate into fibroblast. These results suggest that bone marrow plays an important role in revascularization and remodelling of the reconstructed graft.

Ternes, J. P., R. B. Blasier, et al. (1993). "Fracture of the femur after anterior cruciate ligament reconstruction with a GORE-TEX prosthetic graft. A case report." American Journal of Sports Medicine 21(1):147-9, 1993 Jan-Feb 21(1): 147-9.

Terry, G. C., L. A. Norwood, et al. (1993). "How iliotibial tract injuries of the knee combine with acute anterior cruciate ligament tears to influence abnormal anterior tibial displacement." American Journal of Sports Medicine 21(1):55-60, 1993 Jan-Feb 21(1): 55-60.

A knowledge of the patterns of injury to the components of the iliotibial tract allows a clearer interpretation of motion limits testing in patients with abnormal anterior tibial translation of the knee (anterior cruciate ligament-deficient knees). Eighty-two consecutive patients with acute knee injuries were classified as anteromedial-anterolateral rotatory instability (anterior cruciate ligament-deficient) based on the abnormal motion demonstrated by clinical examination tests for instability. At surgery, injuries to the intraarticular and extraarticular anatomic structures were identified and correlated to the abnormal grades of motion demonstrated by the knee motion limits examination. Tears of the anterior cruciate ligament occurred in 80 (98%) of the knees. However, the grade of abnormal motion demonstrated by the Lachman and pivot shift tests was quite variable. This variation did not correlate statistically with anterior cruciate ligament tears. Injuries to the anatomic components of the iliotibial tract were confirmed in 76 (93%) of the knees. These injuries correlated highly with variations in grades of abnormal motion detected by the following tests: lateral joint line opening at 30 degrees (r2 = 0.05); Lachman test (r2 = 0.08); pivot shift (r2 = 0.16); and anterior translation at 90 degrees of flexion (r2 = 0.34). Thus, injuries to the components of the iliotibial tract are thought to contribute to the variation in grades of abnormal motion observed in this complex subgroup of anterior tibial translation instabilities.

Tetzlaff, J. E. D., J.A.; Abate,J.; Parker,R.D. (1999). "Preoperative intra-articular morphine and bupivacaine for pain control after outpatient arthroscopic anterior cruciate ligament reconstruction." Reg Anesth.Pain Med. 24(3): 220-224.

BACKGROUND AND OBJECTIVES: The purpose of this study was to determine whether intra-articular injection of bupivacaine, morphine, or a combination prior to surgery provided pain control after arthroscopic anterior cruciate ligament (ACL) reconstruction. METHODS: These data were collected as a two-stage prospective, randomized, blinded observer study. All patients received a standard general anesthetic, which included an intra-articular injection 20 minutes prior to incision. In phase I, three solutions were assigned randomly in a 60-mL volume. Group 1 was saline, group 2 was 0.25% bupivacaine, and group 3 was 0.25% bupivacaine with 1 mg morphine sulfate (MS). Phase II was identical to phase I in technique and had four groups. Group 1 was 0.25% bupivacaine, group 2 was 1 mg MS in saline, group 3 was 0.25% bupivacaine with 1 mg MS, and group 4 was 0.25% bupivacaine with 3 mg MS. All groups in phases I and II contained 1:200,000 epinephrine, freshly added. Pain scores were evaluated at 0, 30, 60, 90, 120, and 240 minutes postoperative using a visual analog scale. For pain scores of 5 or greater, 50 microg fentanyl was administered at 5-minute intervals until pain was controlled. After transition from phase I to phase II of the postanesthesia care unit (PACU), hydrocodone/acetaminophen tablets were used. RESULTS: Thirty patients were entered into phase I of the study. Both treatment groups (2 and 3) had significant (P < .05) pain reduction on arrival to the PACU. Group 3 had significantly (P < .05) reduced need for fentanyl during the PACU stay. Forty-nine patients entered phase II of the study. In phase II, group 3 had the lowest pain scores on arrival to the PACU. At 120 and 240 minutes, pain scores were lower in groups 3 and 4. Fentanyl and hydrocodone uses were significantly lower during the PACU stay in groups 3 and 4. CONCLUSIONS: Presurgical injection of a solution of 0.25 % bupivacaine, morphine, and epinephrine provided pain control and decreased opioid use in the PACU. Increasing the morphine dose did not improve the clinical result

Thietje, R. F., M.; Nurnberg,H.J. (2000). "Spontaneous fracture of the tibia after replacement of the anterior cruciate ligament with absorbable interference screws. A case report and review of the literature]." Unfallchirurg 103(7): 594-596.

We report a granulomatous inflammatory reaction after administration of absorbable interference-fit screws for fixation of patellar-tendon- autograft in anterior-cruciate-ligament reconstruction, leading to spontaneous fracture of the tibia. Radiological evaluation demonstrated osteolytic lesions at the interference-fit screw insertion-site. Histological findings included a sterile inflammatory reaction and giant-cell formation

Thompson, W. O. and F. H. Fu (1993). "The meniscus in the cruciate-deficient knee." Clinics in Sports Medicine 12(4):771-96, 1993 Oct 12(4): 771-96.

Evidence clearly implicates meniscectomy as a primary factor in the premature development of OA of the knee joint. Although data demonstrate the ability of the menisci to transmit load, they do not contribute to the primary stability of the knee. In the absence of the ACL, the menisci have been shown to enhance the knee's stability in the AP, varus-valgus, and internal-external directions in vitro. Clinically, the argument that the menisci are important secondary stabilizers is less clear. The restraining capacity of the menisci to AP translation is much smaller than the forces the knee is subjected to in vivo during activities of daily living. Additionally, these forces can increase as much as threefold during strenuous athletics. It becomes apparent, on review of the literature, that the menisci clearly are not designed to participate as a significant restraining mechanism for the ACL-deficient knee. The incidence of acute meniscal tear is 52% and increases to 83% in the long run. It is important to realize that although the menisci contribute in part to the stability of the ACL-deficient knee, such a role places them at risk for injury. When meniscal lesions are noted in the ACL-deficient knee, it is important to bear in mind the patient's goals, including his or her willingness to have an ACL reconstructive procedure and desire to return to sports. Also, the tear's configuration and location dictate its the ability to heal. One final area of interest relates to the fate of an ACL reconstruction in the meniscus-deficient knee. Although the meniscus is not a participant in primary stability, the subtle alteration in knee joint kinematics may create unfavorable conditions for the ACL graft. It is possible that the menisci may provide some protection to an ACL-reconstructed knee by restoring normal knee joint kinematics. Such a situation may explain why some ACL reconstructions in the meniscectomized knee fail over time. Prosthetic meniscal substitution or allograft meniscal transplantation are techniques on the horizon and may prove useful in the future when the remaining meniscus cannot be repaired.

Tibone, J. E. and T. J. Antich (1993). "Electromyographic analysis of the anterior cruciate ligament-deficient knee." Clinical Orthopaedics & Related Research (288):35-9, 1993 Mar(288): 35-9.

The protective relationship of the human anterior cruciate ligament (ACL) by active contraction of the hamstring musculature has been known and understood by sports orthopedists and physical therapists for many years. Rehabilitation programs for patients with torn ACLs as well as those treated with ligament reconstruction have always stressed hamstring strengthening. Research in this area during the past decade has begun to define the proprioceptive mechanism that governs this relationship as well as the actual recording of dynamic muscle firing patterns in pre- and postoperative subjects. Laboratory studies suggest that altered hamstring activity may help these subjects compensate for a knee that is lax because of ACL damage.

Tifford, C. D. S., L.; Luke,T.; Plancher,K.D. (2000). "The relationship of the infrapatellar branches of the saphenous nerve to arthroscopy portals and incisions for anterior cruciate ligament surgery. An anatomic study." Am.J.Sports Med. 28(4): 562-567.

The purposes of this study were 1) to carefully define the anatomic distribution of the infrapatellar branches of the saphenous nerve, 2) to provide the surgeon with reliable parameters for where the nerve is most commonly encountered, and 3) to provide specific surgical recommendations to minimize the risk of nerve injury. To accomplish these goals, we dissected 20 cadaveric, fresh-frozen, matched-pair knees. Calipers were used to measure the distance from the nerve to three clinically relevant and easily reproducible landmarks: the inferior pole of the patella, the medial border of the patella at its midpoint, and a point 2 cm medial to the patellar ligament at the level of the joint line. Distances were recorded with the knees in extension and in 90 degrees of flexion to examine the effect of dynamic knee motion on nerve position. We consistently found two main trunks of the nerve that traverse the knee primarily in a medial to lateral but somewhat proximal to distal direction. Because of this, we recommend that incisions for arthroscopy portals be made in a horizontal fashion to decrease the likelihood of nerve injury. Measured from both the inferior pole of the patella and the medial border of the patella, the nerve moved distally with knee flexion. We therefore recommend that incisions across the anterior aspect of the knee be made with the knee in flexion. In 8 of our 20 specimens, the nerve was actually found at the landmark located 2 cm medial to the patellar ligament. This is an extremely high-risk area and should be avoided if possible

Timoney, J. M., W. S. Inman, et al. (1993). "Return of normal gait patterns after anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(6):887-9, 1993 Nov-Dec 21(6): 887-9.

Individuals with anterior cruciate ligament deficiency typically do not have quadriceps activity during stance. This aberrant pattern has been termed "quadriceps avoidance" gait. We performed gait analysis during walking on 10 normal controls and 10 subjects 8 to 12 months after they had anterior cruciate ligament reconstruction using autogenous middle third of the patellar tendon. All patients had good subjective and objective results at the time of analysis. Differences in gait between subjects and controls persisted up to 12 months after surgery. Specifically, subjects with anterior cruciate ligament reconstructions demonstrated significant reductions in midstance knee flexion moments (P < 0.01) and tibially directed loading rates (P < 0.05) when compared with controls. However, the subjects had a net external flexion moment throughout most of the stance phase of gait, implying that quadriceps activity was present. After anterior cruciate ligament reconstruction, there is a tendency toward gait normalization, and a quadriceps avoidance mechanism is no longer present.

Tosch, U., P. Hertel, et al. (1993). "[Gadolinium-DTPA enhanced MRT in the evaluation of the healing of autologous patellar ligament transplants for anterior cruciate ligament reconstruction]." Radiologe 33(1):40-5, 1993 Jan 33(1): 40-5.

Eighteen patients with autologous patellar tendon transplant for reconstruction of the anterior cruciate ligament were examined postoperatively. The time between operation and MR study was up to 3 weeks in ten patients, between 3 and 35 weeks in three patients and more than 35 weeks in five patients. In all patients, Gd-DTPA enhancement on the surface of the ligamentous transplant was visualized. This enhancement was between 1 and 10 mm thick. In all patients, complete stability of the knee joint was achieved, postoperatively. In 15 patients flexion and extension were normal at the postoperative investigation. Three patients had a limitation of knee movement. In these MR studies, significant hyperplasia of the synovial membrane of the entire joint was diagnosed, explaining the persisting problems. Gd-DTPA-enhanced MR of the knee joint allows non-invasive documentation of remodelling following a patellar ligament transplant and possible complications.

Tung, G. A., L. M. Davis, et al. (1993). "Tears of the anterior cruciate ligament: primary and secondary signs at MR imaging [see comments]." Radiology 188(3):661-7, 1993 Sep 188(3): 661-7.

To investigate primary and secondary signs of anterior cruciate ligament (ACL) tear at magnetic resonance (MR) imaging, the authors retrospectively reviewed 103 MR imaging examinations obtained in 99 patients, the original interpretations of these examinations, clinical records, and arthroscopy reports. Fifty cases of arthroscopy-documented complete ACL tear were included. The primary signs of ACL tear (ie, abnormal ACL morphologic features or signal intensity) had respective sensitivity and specificity values of 96% (48 of 50 examinations) and 94% (50 of 53) on sagittal images and 92% (46 of 50) and 83% (43 of 52) on coronal images. As a secondary sign of ACL tear, bone bruise involving the lateral compartment of the knee was found in 40% (20 of 50) of cases of ACL tear and in 4% (2 of 53) of cases of normal ACL. The mean curvature of the posterior cruciate ligament was increased (0.40 vs 0.27; P < .0001) in cases of ACL tear. An abnormal appearance of the ACL on sagittal images remains the single most sensitive and specific sign of ACL tear.

Tyler, T. F. M., M.P.; Gleim,G.W.; Nicholas,S.J. (1999). "The effect of immediate weightbearing after anterior cruciate ligament reconstruction." Clin.Orthop.(357): 141-148.

Immediate weightbearing has been advocated after anterior cruciate ligament reconstruction and is thought to enhance the return of quadriceps muscle activity and knee extension range of motion without jeopardizing graft integrity. This study examined the effect of immediate weightbearing after anterior cruciate ligament reconstruction on the return of vastus medialis oblique electromyography activity, knee extension range of motion, knee stability, physical examination, Lysholm score, and anterior knee pain. Forty-nine patients (24 men and 25 women) undergoing endoscopic central third patella tendon autograft reconstruction were randomized prospectively into two groups. Group 1 patients underwent immediate weightbearing as tolerated. Group 2 patients were kept nonweightbearing for 2 weeks. All measurements were taken before surgery, 2 weeks after surgery, and between 6 and 14 months (average, 7.3 months) followup. There was no effect of weightbearing on knee extension range of motion or vastus medialis oblique function at followup. In addition, knee stability was not compromised after surgery. Seven of 20 (35%) nonweightbearing patients and only two of 25 (8%) immediate weightbearing patients reported anterior knee pain at followup. Overall, immediate weightbearing did not compromise knee joint stability and resulted in a better outcome with a decreased incidence of anterior knee pain

Uhorchak, J. M., P. M. d. White, et al. (1993). "Type III-A tibial fracture associated with simultaneous anterior cruciate ligament avulsion from the femoral origin." American Journal of Sports Medicine 21(5):758-61, 1993 Sep-Oct 21(5): 758-61.

Vahasarja, V., P. Kinnuen, et al. (1993). "Arthroscopy of the acute traumatic knee in children. Prospective study of 138 cases." Acta Orthopaedica Scandinavica 64(5):580-2, 1993 Oct 64(5): 580-2.

We performed diagnostic arthroscopy for acute knee trauma in 138 children and adolescents aged 13 (1-15) years. The compatibility between the clinical examination and the arthroscopic findings was 59 percent. Ligament injuries were found in 32 cases, 14 of which had rupture of the anterior cruciate ligament. The compatibility in the case of ligament injuries was 31 percent. 48 patients had dislocation of the patella, and a displaced osteochondral fragment was seen in 19, 14 of which were radiographically silent. In 37 cases of distortion of the knee a correct diagnosis would have been missed unless arthroscopy had been performed. Arthroscopy is therefore indicated in children with severe distortion of the knee, hemarthrosis and with dislocation of the patella.

Vahey, T. N., J. E. Hunt, et al. (1993). "Anterior translocation of the tibia at MR imaging: a secondary sign of anterior cruciate ligament tear." Radiology 187(3):817-9, 1993 Jun 187(3): 817-9.

The authors evaluated measurement of the degree of anterior subluxation ("translocation") of the tibia in regard to the femur as a predictor of anterior cruciate ligament (ACL) tear. Eighty-nine magnetic resonance (MR) imaging studies of patients with either an arthroscopically confirmed intact (n = 29), acutely torn (n = 27), or chronically torn (n = 33) ACL were retrospectively reviewed. The degree of translocation was measured on hard-copy images by using two methods. Buckling of the posterior cruciate ligament (PCL) was also evaluated. Anterior tibial translocation, when measured at the midsagittal plane of the lateral femoral condyle with regard to a plane parallel to the cephalocaudal axis of the image, was a relatively specific indicator of ACL disruption. Subluxation of 5 mm or more had 58% sensitivity, 93% specificity, and 69% accuracy for an ACL tear. All knees with subluxation of 7 mm or more had torn ACLs. Buckling of the PCL was less sensitive and less accurate than anterior translocation as an indicator of ACL disruption.

Vailas, J. C. and M. Pink (1993). "Biomechanical effects of functional knee bracing. Practical implications." Sports Medicine 15(3):210-8, 1993 Mar 15(3): 210-8.

Bracing of the anterior cruciate-deficient knee remains controversial. Close review of published data has revealed enough common observations about braces that strong suggestive information can be utilised for clinical purposes until more concrete data are provided. Brace function can vary with design. The primary differences noted are between the shell-type and strap-type braces. Shell braces tend to provide more stability to the knee than do the strap braces. Proper hinge placement, rather than type, affects pistoning and overall performance of the brace. Custom braces provide a better fit than off-the-shelf devices, but they can feel more restrictive, especially the shell braces. Static bench-testing data have shown that these braces provide little stability against anterior tibial translation at forces comparable to athletic play. Yet kinematic and force plate data suggest that they may produce some mechanical constraining effect to the entire lower extremity instead of just the knee joint. The literature still supports the philosophy that functional bracing should be considered as part of a comprehensive rehabilitation programme for an anterior cruciate-deficient athlete with significant functional deficits.

Vangsness, C. T., Jr., J. DeCampos, et al. (1993). "Meniscal injury associated with femoral shaft fractures. An arthroscopic evaluation of incidence." Journal of Bone & Joint Surgery - British Volume 75(2):207-9, 1993 Mar 75(2): 207-9.

We studied 47 patients with closed, displaced, diaphyseal fractures of the femur caused by blunt trauma, to determine the incidence of associated knee injuries, particularly of the meniscus. After femoral nailing, all patients had an examination under anaesthesia and an arthroscopy. There were 12 medial meniscal injuries (5 tears) and 13 injuries of the lateral meniscus (8 tears). Ten of the 13 tears were in the posterior third of the meniscus, and two patients had tears of both menisci. Synovitis was common at the meniscal attachments. Complex and radial tears were more common than peripheral or bucket-handle tears. Examination under anaesthesia revealed ligamentous laxity in 23 patients (49%), but meniscal injuries had a similar incidence in knees with and without ligament injury. Femoral shaft fractures are often associated with injuries to the ipsilateral knee, and a high index of suspicion is necessary to identify these lesions.

Vargas, J. H., 3rd and D. G. Ross (1989). "Corticosteroids and anterior cruciate ligament repair." Am J Sports Med 17(4): 532-4.

A two group (N = 62) historical comparative design was used to study patients undergoing ACL repair. This retrospective study examined the effect of corticosteroids on analgesic use during hospitalization, the length of hospitalization, and the 1st day of ambulation. Thirty-one ACL repair patients receiving a standard protocol of intravenous intraoperative and oral postoperative corticosteroids (experimental group) were compared to 31 similarly aged ACL repair patients who received similar surgical repair and medical therapy but no steroids (control group). Patients with chronic disease or current steroid use were not included in the study. Even though the experimental group had a higher incidence of coincidental injuries of the knee (meniscal and/or collateral ligament injuries), the group used 50% less analgesics while hospitalized (means = 14.19 doses) than the control group (means = 21.29). Similarly, the experimental group had a length of stay 59% less long (means = 3.61 days versus means = 5.74 days) and ambulated 38% more quickly (means = 1.93 days versus means = 2.67 days) than the control group. No differences were noted between groups in incidence of postoperative infection or problems with wound healing after a 1 year followup.

Veselko, M. R., A.; Tonin,M. (2000). "Cyclops syndrome occurring after partial rupture of the anterior cruciate ligament not treated by surgical reconstruction." Arthroscopy 16(3): 328-331.

Cyclops syndrome is one of the specific causes of loss of extension of the knee following anterior cruciate ligament (ACL) reconstruction. The syndrome is manifested by progressive loss of extension associated with pain and audible clunk at terminal extension caused by a pedunculated nodule of fibrovascular proliferative tissue usually arising from the graft. The entity has been described recently and has been reported exclusively as a complication of ACL reconstructions. We report the case of a patient with symptoms and arthroscopic and histological findings compatible with cyclops syndrome that developed after a partial ACL rupture that was not treated by surgical reconstruction. A different etiology and classical histological and immunohistological microscopic analysis of the nodule presented in this report may further clarify the pathogenesis of the cyclops syndrome

Viola, R. V., R. (1999). "Intra-articular ACL reconstruction in the over-40-year-old patient." Knee.Surg.Sports Traumatol.Arthrosc. 7(1): 25-28.

We compared two groups of patients who had undergone anterior cruciate ligament (ACL) reconstruction. The groups were similar in regard to sex distribution, index injury, absence of meniscal or chondral lesions, surgical technique, and postoperative rehabilitation programs, but different in age. In the study group the mean age was 42.6 years, while in the control group the mean age was 20 years. The clinical results were assessed at a mean of 29 months after surgery using the Lysholm score, International Knee Documentation Committee form, Tegner activity level, and the KT-1000 arthrometer test. No significant differences were reported. Standard X-ray studies showed no variation between the two groups in the postoperative period. Intra-articular ACL reconstruction using a bone-patellar tendon-bone graft can be recommended in selected patients over 40 years of age as an alternative to conservative treatment

Viola, R. V., R. (1999). "Three cases of patella fracture in 1,320 anterior cruciate ligament reconstructions with bone-patellar tendon-bone autograft." Arthroscopy 15(1): 93-97.

Between September 1992 and December 1996 we reviewed three transverse displaced fractures of the patella occuring in 1,320 ACL reconstructions using bone-patellar tendon-bone autograft. All the patients suffered local injury to the donor knee between 8 and 12 weeks postoperatively. Immediate rigid fixation using single or double anterior tension band allowed early mobilization and full weight bearing. Between 6 and 9 months after fracture, the screws and the wire were removed and the grafts tested. Results of the pivot shift and Lachman test under anesthesia were negative and arthroscopic visualisation showed the graft to be intact. Postoperative assessment included the Lysholm and Tegner scales, the International Knee Documentation Committee Evaluation form (IKDC), KT-1000 arthrometer, and isokinetic dynamometer strength testing. No significant differences in the final outcome were noted between reconstructions complicated by patellar fracture and normal ACL reconstructions

Viola, R. W. S., W.I.; Newfield,D.; Steadman,J.R.; Torry,M.R. (2000). "Internal and external tibial rotation strength after anterior cruciate ligament reconstruction using ipsilateral semitendinosus and gracilis tendon autografts." Am.J.Sports Med. 28(4): 552-555.

The internal and external tibial rotation torques of subjects who had undergone anterior cruciate ligament reconstruction using semitendinosus and gracilis tendon grafts were measured to determine whether harvest of the tendons results in weakness of tibial internal and external rotation. Cybex NORM dynamometer examinations were performed to measure internal and external tibial torque at angular velocities of 60, 120, and 180 deg/sec in 23 subjects. The sex-specific average torque data of the reconstructed limbs were compared with those of the contralateral limbs. Relative internal and external torque scores were calculated for each subject by subtracting the peak torque of the reconstructed knee from that of the contralateral knee. These relative scores were averaged and compared with the null hypothesis that each score should be statistically similar to zero. Subjects were evaluated at an average of 51 +/- 40 months postoperatively. The mean relative internal torque scores of the reconstructed limbs showed a statistically significant decrease from those of the contralateral limbs at all angular velocities. The mean relative external torque scores of the reconstructed limbs were statistically similar to those of the contralateral limbs at all angular velocities. Subjects who had undergone ligament reconstruction using semitendinosus and gracilis tendons demonstrated internal tibial rotation weakness in their reconstructed knees compared with their contralateral knees at all angular velocities tested. These results suggest that semitendinosus and gracilis tendon harvest causes weakness of internal tibial rotation

Vosberg, W., K. Weise, et al. (1993). "[Value of the radiologic Lachman test in evaluating long-term results of operations on the anterior cruciate ligament]." Aktuelle Traumatologie 23 Suppl 1:62-5, 1993 Jul 23(Suppl 1): 62-5.

A retrospective study including a 5-years follow-up of 114 patients, that had been operated because of a lesion of the anterior cruciate ligament, used the parameters of the IKDC-score, in 110 cases a radiological Lachman-test was performed simultaneously. A comparison of patient's subjective estimate, of clinical testings, using the pivot shift-test and measurement of anterior instability with the KT-1000 knee arthrometer, and of radiological Lachman-test shows correlations between the 3 first parameters with mostly good results, but poor results in radiological Lachman-test. Mistakes in using the KT-1000 arthrometer may be a reason for this, or a much higher sensitivity of the radiological method, which seems to make it problematic analyzing the radiological measures within the same limits as the arthrometric measures especially in view of demanded scaling scores.

Vukadinovic, S., L. Somer, et al. (1993). "[Morphologic characteristics and static resistance of transplanted patellar ligaments after replacement of the cruciate ligaments in the knee--an experimental study in a dog]." Medicinski Pregled 46(11-12):406-12, 1993 46(11-12): 406-12.

An experimental study on transplantation validity of patella's ligament, when transplanting front crossed ligament, was performed on 106 knees in 53 grown-up dogs. The investigation had three stages. Three months after the transplantation of the front crossed ligament with the medial third part of the patella's ligament animals were sacrificed and in one group the static resistance and the resistance to elongation, by using special tweezers (Alfred Amsler Co., Schafhausen, Switzerland), was investigated. The results showed that the patella's ligament is very suitable for transplantation because its resistance and strength were almost identical with the same parameters of intact front crossed ligament. Revascularization of the new ligament using Spaltenholz's technique was done in the second group, and three months after the operation, complete revascularization of transplants took place. The synovial membrane which covers the new ligament represents the main source of fresh blood vessels on one side, while similar process takes place along the bone tunnels where the new ligament was fixed. The new ligament histologic analysis carried out in the third group of experimental animals showed that after three months the transplant acquires the structure which is very similar to the front crossed ligament. The obtained results of the investigation show that the patella's ligament is a very good biologic material for transplantation of the crossed ligament.

Wallenbock, E. (1993). "[Rupture of the patellar ligament--a late complication after removal of a bone-tendon-bone transplant as cruciate ligament replacement]." Langenbecks Archiv fur Chirurgie 378(6):339-40, 1993 378(6): 339-40.

Ruptures of the patellar ligament have been observed in surgery for complete substitution of the knee joint and with application of the operation method according to Roux and Goldwilde; ruptures of this ligament after removal of a graft cruciate ligament substitution have been described very rarely. Since 1990 we have been practicing the method of autologous substitution of the cruciate ligament by using material from the median part of the patellar ligament. In one patient treated by this method who had displayed no complications during 10 months after the operation a new adequate trauma resulted in rupture of the patellar ligament at its tibial insertion. As far as we can assess on the basis of available technical literature, such injury might be due to problems of paraligamentary blood supply, partial or complete resection of the infrapatellar fatty tissue additionally contributing to lasting vascular damage.

Walton, M. (1999). "Absorbable and metal interference screws: comparison of graft security during healing." Arthroscopy 15(8): 818-826.

Anterior cruciate ligament replacement was performed on 71 sheep to compare graft security using a titanium or an absorbable polyglyconate interference screw (Acufex, Mansfield, MA) to hold the bone-patellar tendon-bone autograft. Early self mobilization was followed later by retrieval of most specimens up to 12 weeks. No grafts failed in vivo or migrated within the bone tunnel. Failure strengths of femur-graft-tibia preparations held by absorbable screws were lower initially but at no time were they statistically different to those held by metal screws. By 4 weeks, fibrous union between the graft tendon and tunnel wall led to no difference in failure strength if the screw was present or removed before measurement. Histologically, ossific incorporation of the graft bone was not evident until 6 weeks. A mild tissue reaction occurred around the absorbable screw. In the 2 12-month specimens, the polyglyconate had been largely replaced by fibrous tissue. Overall, the absorbable screw performed to a level comparable to the metal screw

Warden, W. H. F., R.; Teresi,L.M.; Jackson,D.W. (1999). "Magnetic resonance imaging of bioabsorbale polylactic acid interference screws during the first 2 years after anterior cruciate ligament reconstruction." Arthroscopy 15(5): 474-480.

Bioabsorbable screws composed of poly(L-lactic acid) (PLA) were used for graft fixation and studied prospectively with serial magnetic resonance imaging (MRI) scans at 8, 16, and 24 months after autogenous patellar tendon anterior cruciate ligament (ACL) reconstruction in 10 patients. Conventional spin echo, proton density, and T2-weighted double echo sequences were obtained, as well as T2-weighted fat- saturated fast spin echo sequences. All but one of the screws (19 of 20) were evident in all serial scans. These showed minimal decrease in size over time. The one screw that had completely disappeared 8 months after reconstruction had cracked during insertion. None of the reconstructed ACL grafts showed clinical instability, persistent effusions, or detectable adverse reactions to the screws. Two patients developed abnormal signal in the tibial tunnel: one developed fluid anterior to the graft, and the other developed increased signal within the graft. The abnormal signal resolved with time in both patients. Other than the preceding changes, no abnormalities were detected on conventional sequences. Fat-saturated fast spin echo sequences showed a variable amount of increased signal around the tunnels, suggesting edema or fibrovascular marrow changes. The changes noted near the tunnels on the fat-suppressed scans most probably represent a general reaction to surgical insult rather than a reaction to the bioabsorbable screws, as similar changes were noted at the patellar harvest site

Warren, R. F. (1983). "Primary repair of the anterior cruciate ligament." Clin Orthop(172): 65-70.

The anterior cruciate ligament (ACL) is the primary restraint preventing anterior tibial translation on the femur. Its absence is highly correlated with the presence of a pivot shift sign and clinical instability. Primary ACL repair, at times with augmentation, is advocated in those patients most apt to develop symptomatic instability. Follow-up studies demonstrate that it is possible to prevent the development of symptomatic giving way as well as the meniscal degeneration frequent in active patients with chronic ACL insufficiency.

Wascher, D. C., K. L. Markolf, et al. (1993). "Direct in vitro measurement of forces in the cruciate ligaments. Part I: The effect of multiplane loading in the intact knee." Journal of Bone & Joint Surgery - American Volume 75(3):377-86, 1993 Mar 75(3): 377-86.

Specially designed load-transducers that measured the resultant forces exerted by the posterior and anterior cruciate ligaments on their respective femoral and tibial insertions were applied to eighteen fresh-frozen cadaveric knees for a series of controlled loading experiments. The mean force in the posterior cruciate ligament at 5 degrees of forced hyperextension of the knee was 23 per cent of the mean force in the anterior cruciate ligament. When the knee was hyperflexed by application of 10.0 newton-meters of bending moment to the tibia, the mean force in the posterior cruciate ligament was 55 per cent of that in the anterior cruciate ligament. Quadriceps tendon pull increased the force in the posterior cruciate ligament in twelve of the fourteen specimens to which it had been applied, at 80 and 90 degrees of flexion only. The force generated in the posterior cruciate ligament by applied internal tibial torque was greatest when the knee was in 90 degrees of flexion; the force in the anterior cruciate ligament was greatest when the knee was fully extended. External tibial torque generated force in the posterior cruciate ligament in only eight specimens, and only at 80 and 90 degrees of flexion. The levels of force that were generated in the posterior cruciate ligament by applied varus and valgus bending moment were greatest at 90 degrees of flexion of the knee; the levels of force in the anterior cruciate ligament were greatest with the knee in full extension. With the knee flexed 90 degrees and the tibia in neutral rotation, fifty newtons of applied posterior tibial force increased the mean force in the posterior cruciate ligament by 58.4 newtons; at full extension, no increase in the force in the ligament was recorded, indicating that tensed capsular structures were absorbing the applied load. When the tibia was internally or externally rotated by applied tibial torque, the increases in the force in the ligament from applied posterior tibial force were sharply diminished.

Wasilewski, S. A., D. J. Covall, et al. (1993). "Effect of surgical timing on recovery and associated injuries after anterior cruciate ligament reconstruction." American Journal of Sports Medicine 21(3):338-42, 1993 May-Jun 21(3): 338-42.

This study was undertaken to determine the optimal time after injury for arthroscopically assisted anterior cruciate ligament reconstruction using a double semitendinosus graft. We analyzed 87 patients. Time from injury to surgery was established as acute, subacute, or chronic; the three groups were matched. Meniscal damage and treatment were categorized. Chondral lesions were graded, postoperative parameters of motion, strength recovery, and stability were tabulated at 3, 6, 12, and 18 months. Complications were compared. Six percent of the patients with chronic knee injuries had two normal menisci at surgery, compared with 29% of the acute and subacute groups. Reparable tears were found in 37.8% of the knees. Chondral lesions were found in the tibiofemoral joint in 17% of acute, 7% of subacute, and 44% of the chronic knees. Postoperative motion recovery was significantly less at all time intervals for the acute group. Quadriceps strength recovery was slower in the acute knees. Stability was similar in all groups. Arthrofibrosis was found in 22% of acute, 0 subacute, and 12.5% of the chronic knees. Patellofemoral pain was noted in 17% of the acute, 0 of the subacute, and 9.3% of the chronic knees. This study showed that surgery done within 6 months of injury does not jeopardize the knee. Recovery after acute anterior cruciate ligament reconstruction is significantly slower than after subacute or chronic reconstruction.

Weaver, J. K., R. S. Derkash, et al. (1985). "Primary knee ligament repair--revisited." Clin Orthop(199): 185-91.

There were 4710 knee sprains resulting from skiing in the four Aspen ski areas between 1976 and 1979. Twenty percent of the patients (942) had complete tears. Of these, 302 elected to remain in Aspen for treatment. All were treated by primary ligament repair without augmentation. These cases were evaluated an average of 42 months after injury. Patients with isolated tears of the medial collateral ligament were found to be doing well; virtually all of them had returned to preinjury activity levels. Thirty-six percent of the isolated anterior cruciate repairs were rated failures, and 43% of the combination ACL-MCL injuries had failed because of anterior cruciate deficiency. Twenty-nine percent of the ACL and ACL-MCL injuries had meniscal tears. Cases that included meniscectomy had a failure rate twice as great as those in which the meniscus was preserved. The results following repair of anterior cruciate tears were not acceptable, and augmentation was indicated. Primary repair of medial collateral ligament tears produced excellent results. Meniscal tears were frequent in association with ligament disruption. Ligament repairs were less satisfactory when meniscectomy was performed at the time of the repair.

Weber, K. S., A.; Wentzensen,A. (2000). "Patellar tendon rupture after anterior cruciate ligament reconstruction with autologous patellar tendon-bone transplant. A case report]." Weber,K.; Schmidgen,A.; Wentzensen,A. 103(12): 1124-1127.

Patellar ligament ruptures due to a complication after usage of bone- tendon autograft for an anterior cruciate ligament reconstruction happens seldom. During surgeries to restore continuity a fascia-lata- strip may be wrapped in and fixated to secure the primary tendon suture. This may be done in addition to the usually employed patella- tibial wiring cerclage. Whether a matrix for the scarred healing tendon will be created in addition to the construction of a support for the primary tendon seam without a foreign body reaction has to be left to further histological clarifications that cannot be implemented in the present casuistry

Weiler, A., H. J. Helling, et al. (1996). "Foreign-body reaction and the course of osteolysis after polyglycolide implants for fracture fixation: experimental study in sheep." J Bone Joint Surg Br 78(3): 369-76.

Foreign-body reaction to polyglycolide (PGA) implants has been described in man. Many animal experiments have verified the mechanical properties of fixation devices made from PGA, but a significant foreign- body reaction has not been described. We studied the effect of PGA rods in 12 sheep with standardised osteochondral fractures of the medial femoral condyle fixed with uncoloured, self-reinforced PGA rods (Biofix). Radiographs were taken at intervals ranging from two weeks to two years, and the sheep were killed at intervals ranging from six to 24 months. All knees were examined histologically. Eleven of the 12 fractures healed radiologically and histologically. Moderate to severe osteolysis was seen at four to six weeks with maximum changes at 12 weeks in ten animals. Six knees showed fistula-like connections between the implant site and the joint space. Three developed synovitis, one with inflammatory changes involving the whole cartilage and one with destruction of the medial condyle. Although in our study osteochondral fractures fixed with PGA rods healed reliably, there were frequent, significant foreign-body reactions. Caution is needed when considering the use of PGA fixation devices in vulnerable regions such as the knee.

Weiler, A., R. F. Hoffmann, et al. (2000). "The influence of screw geometry on hamstring tendon interference fit fixation." Am J Sports Med 28(3): 356-9.

We used a standardized model of calf tibial bone to investigate the influence of screw diameter and length on interference fit fixation of a three-stranded semitendinosus tendon graft for anterior cruciate ligament reconstruction. Biodegradable poly-(L-lactide) interference screws with a diameter of 7, 8, and 9 mm and a length of 23 and 28 mm were used. We examined results in three groups of 10 specimens each: group 1, screw diameter equaled graft diameter and screw length was 23 mm; group 2, screw diameter equaled graft diameter plus 1 mm and screw length was 23 mm; group 3, screw diameter equaled graft diameter and screw length was 28 mm. The mean pull-out forces in groups 1, 2, and 3 were 367.2+/-78 N, 479.1+/-111.1 N, and 537.4+/-139.1 N, respectively. The force data from groups 2 and 3 were significantly higher than those from group 1. These results indicate that screw geometry has a significant influence on hamstring tendon interference fit fixation. Increasing screw length improves fixation strength more than oversizing the screw diameter. This is important, especially for increasing tibial fixation strength because the tibial graft fixation site has been considered to be the weak link of such a reconstruction.

Weiler, A., R. F. Hoffmann, et al. (1998). "Hamstring tendon fixation using interference screws: a biomechanical study in calf tibial bone." Arthroscopy 14(1): 29-37.

It has recently been shown that graft fixation close to the ACL insertion site is optimal in order to increase anterior knee stability. Hamstring tendon fixation using interference screws offers this possibility and a round threaded titanium interference screw has been previously developed. The use of a round threaded biodegradable interference screw may be equivalent. In addition, to increase initial fixation strength, graft harvest with a distally attached bone plug may be advantageous, but biomechanical data do not exist. This study compares the initial pullout force, stiffness of fixation, and failure modes of three strand semitendinosus grafts in 36 proximal calf tibiae using either biodegradable poly-(D,L-lactide) (Sysorb; Sulzer Orthopaedics Ltd, Munsingen, Switzerland) or round threaded titanium (RCI; Smith & Nephew DonJoy, Carlsbad, CA) interference screws, harvested either without (biodegradable: group I, titanium III) or with (biodegradable: group II, titanium: group IV) attached tibial bone plugs. Maximum pullout force in group I (507 +/- 93 N) was significantly higher than in group III (419 +/- 77 N). Pullout force of bone plug fixation was significantly higher than that of direct tendon fixation (717 +/- 90 N in group II and 602 +/- 117 N in group IV). Pullout force of biodegradable fixation was significantly higher in both settings. These results indicate that initial pullout force of hamstring-tendon graft interference screw fixation can be increased by using a biodegradable interference screw. In addition, initial pullout force of hamstring-tendon graft fixation with an interference screw can be greatly increased by harvesting the graft with its distally attached tibial bone plug.

Weiler, A., R. F. Hoffmann, et al. (2000). "Biodegradable implants in sports medicine: the biological base." Arthroscopy 16(3): 305-21.

Biodegradable implants are increasingly used in the field of operative sports medicine. Today, a tremendous variety of implants such as interference screws, staples, sutures, tacks, suture anchors, and devices for meniscal repair are available. These implants consist of different biodegradable polymers that have substantially different raw material characteristics such as in vivo degradation, host-tissue response, and osseous replacement. Because these devices have become the standard implant for several operative procedures, it is essential to understand their biological base. The purpose of this report is to provide a comprehensive insight into biodegradable implant biology for a better understanding of the advantages and risks associated with using these implants in the field of operative sports medicine. In particular, in vivo degradation, biocompatibility, and the osseous replacement of the implants are discussed. A standardized classification system to document and treat possible adverse tissue reactions is given, with special regard to extra-articular and intra- articular soft-tissue response and to osteolytic lesions.

Weiler, A., R. F. Hoffmann, et al. (1999). "[Replacement of the anterior cruciate ligament. Biomechanical studies for patellar and semitendinosus tendon fixation with a poly(D,L- lactide) interference screw]." Unfallchirurg 102(2): 115-23.

Anterior cruciate ligament (ACL) reconstruction using autologous hamstring tendons are being performed more frequently and satisfactory results have been reported. Advantages such as low donor site morbidity and ease of harvest as well as disadvantages like low initial construct stiffness have been described. Recently, it has been demonstrated that graft fixation close to the original ACL insertion sites increases anterior knee stability and graft isometry. Hamstring tendon fixation techniques using interference screws offer this possibility. To reduce the risk of graft laceration, a round threaded titanium interference screw (RCI) was developed. To improve initial fixation strength, fixation techniques for hamstring tendons with separate or attached tibial bone plugs were introduced. However, data on fixation strength do not yet exist. With respect to the proposed advantages of biodegradable implants, like undistorted magnetic resonance imaging, uncompromised revision surgery and a decreased potential of graft laceration during screw insertion, we performed pullout tests of round threaded biodegradable and round threaded titanium interference screw fixation of semitendinosus (ST) grafts with and without distally attached tibial bone plugs. Data were compared with bone-tendon-bone (BTB) graft fixation using biodegradable and conventional titanium interference screws. We used 56 proximal calf tibiae to compare maximum pullout force, screw insertion torque, and stiffness of fixation for biodegradable direct ST tendon and bone plug fixation (group I: without bone plug, group II: with bone plug) versus titanium interference screw fixation (group III: without bone plug, group IV: with bone plug). A round threaded biodegradable poly-(D, L-lactide) (Sysorb) and a round threaded titanium interference screw (RCI) were used. As a control calf bone-tendon-bone (BTB) grafts fixed with either poly-(D, L-lactide) (group V) or conventional titanium (group VI) interference screws were used. ST tendons were harvested either with or without their distally attached tibial bone plugs from human cadavers and were folded to a three-stranded graft. Specimen were loaded in a material testing machine with the applied load parallel to the long axis of the bone tunnel. Maximum pullout force of ST bone plug (group III: 717 N +/- 90, group IV: 602 N +/- 117) fixation was significantly higher than that of direct tendon (group I: 507 N +/- 93, group III: 419 N +/- 77) fixation. Maximum pullout force of biodegradable screw ST fixation was higher than that of titanium screw fixation in both settings. There was no significant difference in pullout force between biodegradable (713 N +/- 210) and titanium (822 N +/- 130) BTB graft fixation or between ST fixation with bone plug and biodegradable screw with BTB fixation. Pullout force of hamstring tendon interference screw fixation can be improved by using a biodegradable implant. In addition, initial pullout force can be greatly improved by harvesting the hamstring tendon graft with its distally attached tibial bone plug. This may be important, especially in improving tibial graft fixation. This study encourages further research in tendon-bone healing with direct interference screw fixation to confirm the potential of this advanced method.

Weiler, A., M. Richter, et al. (2001). "The EndoPearl device increases fixation strength and eliminates construct slippage of hamstring tendon grafts with interference screw fixation." Arthroscopy 17(4): 353-9.

PURPOSE: The EndoPearl (Linvatec, Largo, FL), a biodegradable device to augment the femoral interference screw fixation of hamstring tendon grafts has been developed. The first objective of this study was to compare the initial fixation strength of quadrupled hamstring tendons and biodegradable interference screw fixation with and without the application of the EndoPearl device. The second objective was to determine the influence of the EndoPearl device on the fatigue behavior under incremental cyclic loading conditions in a simulation of critical fixation conditions. TYPE OF STUDY: Biomechanical study. METHODS: Fresh human hamstring tendons were harvested and grafts were fixed with biodegradable poly-L-lactide interference screws. Twenty proximal calf tibias were used to compare the initial fixation strength of the study and the control group. In the study group, the EndoPearl device was secured to the graft using two No. 5 Ethibond sutures (Ethicon, Somerville, NJ). Specimens were loaded until failure in a materials testing machine. For cyclic testing, human hamstring tendons and 20 distal porcine femurs were used. Critical graft fixation conditions were simulated by increasing tunnel diameter 2 mm over the graft diameter. Grafts were loaded progressively in increments of 100 N until failure; 100 cycles were applied per load increment. RESULTS: Graft fixation with the additional EndoPearl device had a significantly higher maximum load to failure (658.9 +/- 118.1 N v 385.9 +/- 185.6 N, P =.003) and stiffness (41.7 +/- 11 N/mm v 25.7 +/- 8.5 N/mm). Graft fixation with the EndoPearl device sustained a significant higher total number of cycles (388.5 +/- 125.6) compared with the control group (152.8 +/- 144.9, P =.002). CONCLUSIONS: We demonstrated that the augmentation of a hamstring tendon graft with the EndoPearl device increases interference screw fixation strength significantly. Under dynamic loading conditions, specimens of the study group sustained substantially higher loads and a larger number of cycles, which indicates a greater resistance to graft slippage. The application of the EndoPearl device may also allow for a secure soft-tissue graft fixation with interference screws in cases of critical fixation conditions.

Weiler, A., S. U. Scheffler, et al. (2000). "[Current aspects of anchoring hamstring tendon transplants in cruciate ligament surgery]." Chirurg 71(9): 1034-44.

The use of hamstring tendon grafts in cruciate ligament surgery has recently raised strong interest. Hamstring tendons are superior to the mid third patellar tendon graft by virtue of lower harvest site morbidity combined with high tensile strength. Osseous graft incorporation relies on a proper tendon-to-bone healing, which relies on specific biomechanical and biological boundary conditions. Several different fixation devices have recently been introduced, with special emphasis on high initial fixation strength and moving the level of fixation closer to the joint line, the so-called aperture fixation. The goal of the present review is to focus on the advantages and disadvantages of different fixation principles for hamstring tendon grafts in order to give a comprehensive insight into current developments, such as interference fit fixation, cross-pin fixation, and the concept of hybrid fixation.

Weiler, A., H. J. Windhagen, et al. (1998). "Biodegradable interference screw fixation exhibits pull-out force and stiffness similar to titanium screws." Am J Sports Med 26(1): 119-26.

Recently, increased interest in biodegradable interference screws for bone-tendon-bone graft fixation has led to numerous screws becoming available. The implants are made from different polymers and have different designs, which might influence their mechanical properties. Several studies have reported a wide range of mechanical results for these screws using different biomechanical models. The aim of the present study is to compare reliable biomechanical data for six different biodegradable interference screws, consisting of five different polymers, with a conventional titanium screw in a standardized model. Seventy proximal calf tibias were used to determine maximal pull-out force, stiffness of fixation, and insertion torque for interference screw fixation of bone-tendon-bone grafts. Additionally, maximal torque at failure was determined. Data were analyzed with respect to aspects of screw design, such as drive and thread shape. Five of the six biodegradable screws provided initial pull-out force and stiffness of fixation comparable with that of a conventional titanium screw. Torque at failure can be greatly increased by adapting the drive design to the mechanical properties of the polymeric raw material. A correlation between pull-out force and thread height indicates that fixation rigidity depends on screw design, even in a biodegradable implant.

Wening, V. J., A. Loeck, et al. (1993). "[Changes in the femoral nerve and medial articular nerve after medial arthrotomy and replacement of the anterior cruciate ligament]." Unfallchirurgie 19(2):65-73, 1993 Apr 19(2): 65-73.

The effect of combined medial arthrotomy (Payr's approach) and replacement of the anterior cruciate ligament upon the femoral nerve and the medial articular nerve has been studied. Resection and prosthetic replacement of the anterior cruciate ligament was performed on the right hindlimb of twelve Merino sheep. Three unoperated animals served as controls. Eight to 48 weeks after the operation, myelinated axons of the femoral nerve and the medial articular nerve were examined using morphological and morphometric methods. Compared with the un-operated control side, only discrete morphological alterations were detectable, such as an increase in non-circular axons. In contrast, considerable morphometric changes were observed: A decrease in large axons and an increase in small axons were found in the femoral nerve of the operated side resulting in a significant reduction in axon diameter (p < or = 0.05). This decrease in axon diameter was associated with a significant increase in the number of axons. Both changes persisted throughout the period examined (48 weeks). Similar changes, i.e. increase in small axons, decrease in large axons and reduction in mean axon diameter were also observed in the medial articular nerve. The results show that medial arthrotomy with prosthetic replacement of the anterior cruciate ligament results in irreversible changes of the femoral nerve and the medial articular nerve. These findings indicate that the medial articular nerve is injured during medial arthrotomy. Mechanisms are discussed which may explain the alterations observed in the femoral nerve a long distance (30 to 35 cm) away from the operation site.

Werlich, T., H. Brand, et al. (1993). "[The knee arthrometer KT-1000: value of instrumental measurement in diagnosis of complex anterior knee instability]." Aktuelle Traumatologie 23(1):43-9, 1993 Feb 23(1): 43-9.

Clinical examination is the most accurate means of determining cruciate ligament integrity in the initial evaluation. In the case of a rupture of the anterior cruciate ligament the Lachman test has a high diagnostic accuracy, especially if the end point is absent. The Knee Arthrometer KT-1000 is a useful tool, as it is easy and fast to handle by an experienced examiner. Supplementary to noninvasive diagnostical methods it improves the confidence in clinical diagnosis. However, the importance of instrumental measurement should not be overrated even though reproducible results can be obtained. To compare the results of different studies the design has to be very similar. Although the examination conditions in this study were very homogeneous, a systematic mistake was produced. The average value of tibial displacement was significantly higher for the left knee. Data, obtained retrospectively in clinical practice, should not be used to scientifically document the results of therapeutic procedures.

White, D. M. (1993). "Comparison of closed and open kinetic chain exercise in the anterior cruciate ligament-deficient knee [letter; comment]." American Journal of Sports Medicine 21(4):633; discussion 633-4, 1993 Jul-Aug 21(4): 633; discussion 633-4.

Wiger, P. B., S.; Kartus,J.; Eriksson,B.I.; Karlsson,J. (1999). "A comparison of results after arthroscopic anterior cruciate ligament reconstruction in female and male competitive athletes. A two- to five- year follow-up of 429 patients." Scand.J.Med.Sci.Sports 9(5): 290-295.

The aim of this study was to compare the results after arthroscopic anterior cruciate ligament reconstruction in female and male competitive athletes who had a pre-injury Tegner activity level of > or =7 and a non-injured contralateral anterior cruciate ligament. One hundred and thirty-three female and 296 male patients were followed at 38 (21-68) months after the index operation. All the patients were operated on by experienced knee surgeons using patellar tendon autografts and interference screw fixation. At the index operation the median age of the female patients was 23 (1645) years and the median age of the male patients was 26 (16-47) years. The reconstruction was performed a median of 10 (0-141) and 10 (0-203) months after the injury in women and men respectively. The patients were re-examined by independent observers. At the follow-up, the median Lysholm score was 89 (38-100) points in the female group and 90 (22-100) points in the male group (P=0.015). The IKDC evaluation system, subjective anterior knee pain, subjective evaluation of the results, the knee-walking test and the KT-1000 tests revealed no differences between the groups. The mean (+/-2 SD) pre-injury Tegner activity level was 8.1 (+/-1.9) (median 8 (7-10)) in the female group and 8.4 (+/-1.8) (median 9 (7- 10)) in the male group (P=0.003). At the follow-up, the Tegner activity level was 6.2 (+/-3.8) in the female group and 6.8 (+/-3.6) in the male group (P=0.012). At the follow-up, the Tegner activity level had decreased by 1.9 (+/-3.8) for the women and 1.6 (+/-3.3) for the men, as compared with the pre-injury level (n.s.). The difference between the performed and the desired activity level at the follow-up was 1.1 (+/-3.2) in the female group and 0.9 (+/-3.0) in the male group (n.s.). In the female group 53/133 (40%) and in the male group 115/296 (39%) returned to the pre-injury activity level (n.s.). The median one-leg- hop quotient was 93 (0-116)% in the female group and 96 (0-130)% in the male group (P=0.006). Concomitant meniscal injuries prior to the index operation, at the index operation or during the follow-up period were found in 64/133 (48%) women and in 185/ 296 (62%) men (P<0.01). The main conclusion was that the overall results in female and male athletes were comparable two to five years after the anterior cruciate ligament reconstruction. However, concomitant meniscal injuries were more common in male than females athletes after anterior cruciate ligament injuries

Wilk, K. E. and J. R. Andrews (1993). "The effects of pad placement and angular velocity on tibial displacement during isokinetic exercise." Journal of Orthopaedic & Sports Physical Therapy 17(1):24-30, 1993 Jan 17(1): 24-30.

The purpose of this study was to compare the effects of proximal single resistance pad placement (PSPP) and distal single pad placement (DSPP) on tibial displacement during isokinetic exercise on anterior cruciate ligament (ACL)-deficient knees. This study is important to the clinician because it documents tibial displacement during open chain isokinetic knee extension exercise at various isokinetic speeds. In addition, this study documents the range of motion where the greatest amount of anterior tibial displacement occurs. The anterior displacement of the tibia was recorded by a computerized knee laxity testing device during isokinetic exercise. Data were collected from 12 ACL-deficient knees. Each subject was tested on an OSI Knee Signature System for quantifiable tibial displacement during a Lachman's test, anterior drawer test, and active vs. passive knee extension. Following this, each subject was tested on a Biodex isokinetic dynamometer at isokinetic velocities of 60, 180, and 300 degrees/sec with the computerized knee laxity testing device in place. Pad placement consisted of distal single pad placement, which is 1 inch proximal to the medial malleolus, and proximal single pad placement, which is 3 inches proximal to the DSPP location. The testing procedure was standardized, and peak torque was monitored to ensure consistent maximal effort throughout the study. The results indicated that PSPP resulted in less anterior tibial displacement at all three test speeds. The peak anterior tibial displacement occurred in a range from 30 to 15 degrees of knee flexion at both pad placements and all three test speeds.(ABSTRACT TRUNCATED AT 250 WORDS)

Wilk, K. E., J. R. Andrews, et al. (1993). "Quadriceps muscular strength after removal of the central third patellar tendon for contralateral anterior cruciate ligament reconstruction surgery: a case study." Journal of Orthopaedic & Sports Physical Therapy 18(6):692-7, 1993 Dec 18(6): 692-7.

Surgical reconstruction of the anterior cruciate ligament (ACL) using a patellar tendon autograft is a common orthopaedic procedure. Complications such as arthrofibrosis, patellar fracture, significant donor site pain, and quadriceps muscle weakness can occur from this procedure. Previous studies have not documented the effects of isolated graft procurement without concomitant ligamentous reconstruction on the donor extremity. This case study documents the clinical outcome results of an individual who underwent a central one-third graft harvest from his contralateral uninjured knee for an ACL graft of his injured ACL-deficient knee. The results indicate that at 4 months following graft procurement, the knee extensors were equal to the preoperative isokinetic test results of that leg. In addition, the patient exhibited full range of motion and no patellofemoral complaints of dysfunction. At 12 months postsurgery, the graft donor leg was 5-9% stronger than the preoperative test results. The results of this case study suggest that isolated harvesting of a 10-mm central patellar tendon free graft may not result in significant quadriceps muscle weakness or contribute to donor site pain.

Wilk, R. M. and J. C. Richmond (1993). "Dacron ligament reconstruction for chronic anterior cruciate ligament insufficiency." American Journal of Sports Medicine 21(3):374-9; discussion 379-80, 1993 May-Jun 21(3): 374-9; discussion 379-80.

We report the 5-year follow-up results of a prospective, multicenter study evaluating the use of a Dacron prosthetic ligament in reconstruction of anterior cruciate-deficient knees. The study group consisted of 84 patients, followed for at least 5 years. The patients were divided into 2 groups: 50 patients with isolated anterior cruciate ligament laxity (Group 1) and 34 patients with a failed previous anterior cruciate ligament surgery or combined laxities (Group 2). Two surgical techniques were employed: reconstruction through drill holes in the tibia and femur (30 patients) and reconstruction using the over-the-top position with the Dacron ligament wrapped in a strip of iliotibial band (54 patients). The overall failure rate was 35.7% at 5 years. The failure rate at 2 years was 20%, illustrating a significant deterioration of results between the two follow-up intervals. Evaluation of subjective criteria using the Lysholm score showed an improvement from preoperative status at the 2-year followup; however, there was a slight decline when 5-year results were evaluated. Tegner activity levels increased from a mean of 2.9 +/- 2.1 at the preoperative visit, to a mean of 4.9 +/- 2.0 at the 2-year followup and a mean of 5.0 +/- 2.0 at the 5-year visit. These results show that the Dacron ligament prosthesis achieves the short-term goal of restoring stability and improving function and may be sufficient to provide long-term stability for the anterior cruciate-deficient knee.

Williams, R. J., 3rd, C. T. Laurencin, et al. (1997). "Septic arthritis after arthroscopic anterior cruciate ligament reconstruction. Diagnosis and management." Am J Sports Med 25(2): 261-7.

We performed a retrospective study of knee joint infections after arthroscopic anterior cruciate ligament reconstruction at our institution. Two thousand five hundred anterior cruciate ligament reconstructions were performed between 1988 and 1993. Seven (0.3%) patients experienced postoperative deep infections of the knee. All anterior cruciate ligament reconstructions were performed using arthroscopically assisted techniques. Six (86%) of these patients had concomitant open procedures performed, including meniscal repair, posterolateral corner reconstruction, and medial collateral ligament reconstruction. Four patients had acute (< 2 weeks), two patients had subacute (2 weeks to 2 months), and one patient had late (> 2 months) infections. All patients had positive cultures from knee joint aspirates with the organisms Staphylococcus aureus, Staphylococcus epidermidis, Peptostreptococcus, or a combination thereof. All patients underwent immediate arthroscopic irrigation and debridement. All infections were intraarticular; six patients also had extraarticular sites of infection. Four patients underwent repeat irrigation and debridement at approximately 1 week. The anterior cruciate ligament graft was removed from four patients. All patients were treated with intravenous antibiotics for 4 to 6 weeks, protected weightbearing, and physical therapy. At a mean followup of 29 months, mean knee extension was 0 degree, and mean knee flexion was 122 degrees (range, 70 degrees to 135 degrees). Six (86%) patients had minimal to no pain in their operative knee, and they were satisfied with their functional results.

Williams, R. J. W., T.L.; Warren,R.F. (2000). "Management of unicompartmental arthritis in the anterior cruciate ligament-deficient knee." Am.J.Sports Med. 28(5): 749-760.

There exists a group of patients who are difficult to manage because they have both anterior knee instability secondary to anterior cruciate ligament deficiency and unilateral degenerative joint disease. A large majority of these patients report a history of previous meniscal injury or meniscectomy after knee trauma at a relatively young age. Active patients who report symptomatic knee instability or pain associated with athletics or activities of daily living after conservative treatment may be indicated for surgery. Current endoscopic methods of anterior cruciate ligament reconstruction result in low patient morbidity, the elimination of anterior knee instability, and a timely return of function. Osteotomies about the knee joint are an effective means of treating unicompartmental knee arthrosis. Long-term studies have demonstrated that knee osteotomy is a good surgical option for patients with unicompartmental arthritis who are considered too young for total knee arthroplasty. We describe a comprehensive treatment approach to the patient with anterior cruciate ligament deficiency and isolated medial or lateral osteoarthritis. An assessment of pain symptoms, instability symptoms, and lower extremity alignment is used to formulate a treatment plan

Wilson WJ, L. F., Scranton PE (1990). "Combined Reconstruction of the Anterior Cruciate Ligament in Competitive Athletes." Journal of Bone and Joint Surgery 72A(5): 742-748.

Wirth, C. J. and D. Kohn (1993). "[Revision surgery after failed anterior cruciate ligament repair]." Orthopade 22(6):399-404, 1993 Nov 22(6): 399-404.

Not every reconstruction of the anterior cruciate ligament is successful. Possible reasons for failure are renewed severe trauma, inadequate fixation of the transplant, an isometric mistake, weak transplant material, an anterior cruciate ligament reconstruction performed in isolation in a complex unstable knee, or prosthetic ligaments. Revision surgery is indicated when patients complain about the recurrence of knee instability. Preoperative diagnostic procedures must include X-rays with the knee in defined positions in order to determine drill hole courses and visualize any signs of arthrosis and the patellar position. Revision surgery is hampered by disadvantageously placed drill holes, exhaustion of the supply of transplant material, secondary instabilities, gonarthrosis or a possible arthrofibrosis. During rehabilitation a variable knee position is imperative, because of the different procedures that might need to be implemented.

Woo, S. L.-Y. H., J.M.; Adams,D.J.;Lyon,R.M. and Takai,Shinro (1991). "Tensile properties of the human femur-anterior cruciate ligament-tibia complex. The effects of specimen age and orientation." Am.J. Sports Med 19: 217-225.

Woods, G. A. I., P.A.; and Prevot,T.J. (1991). "The Gore-tex anterior cruciate ligament prosthesis. Two versus three year results." Am. J. Sports Med 19: 48-55.

Woods, G. W. (1993). "Sports medicine: anterior cruciate ligament injuries." Seminars in Perioperative Nursing 2(2):70-4, 1993 Apr 2(2): 70-4.

Newer techniques in anterior cruciate ligament surgery and accelerated rehabilitation has significantly altered the recovery process as well as the degree of functional recovery and the long-term prognosis. In most cases full recovery can be expected within 6 to 12 months following injury. Although great emphasis is placed on rapid progress in physical therapy and rehabilitation, it is also important to provide the necessary emotional support during this period of disability and altered functional state.

Woods, G. W. S., R.F.,Jr.; and Tullos,H.S. (1979). "Lateral capsular sign: x-ray clue to a significant knee instability." Am. J. Sports Med 7: 27-33.

Wroble, R. R., E. S. Grood, et al. (1993). "The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee." American Journal of Sports Medicine 21(2):257-62; discussion 263, 1993 Mar-Apr 21(2): 257-62; discussion 263.

We measured the increases in tibiofemoral motion when lateral structures were sectioned in anterior cruciate ligament-deficient knees of 20 unembalmed cadaveric whole lower limbs. Motion was measured with a six degrees-of-freedom electrogoniometer. The lateral structures investigated were the iliotibial band and mid-lateral capsule, lateral collateral ligament, and popliteus tendon and the posterolateral capsule. Cutting the anterolateral structures increased anterior translation and internal rotation, particularly in flexion. Increases in motions were highly variable, reflecting the variation in function in the lateral collateral ligament and posterolateral structures. Cutting the lateral collateral ligament produced small changes in anterior translation and external rotation and larger increases in adduction. Cutting the posterolateral structures produced small increases in external rotation. Large increases in external rotation were found only if the lateral collateral ligament was also sectioned. The posterolateral structures act in concert with the lateral collateral ligament in restraining internal and external rotation. External rotation was affected at all flexion angles; internal rotation was affected mainly in extension. Our results can be used in the diagnosis of complex knee ligament injuries. Findings of increased anterior translation in both flexion and extension and increased internal rotation at 90 degrees of flexion are consistent with combined injury to the anterior cruciate ligament and the anterolateral structures. The anterior cruciate ligament-deficient knee with significant posterolateral compromise (posterolateral structures/lateral collateral ligament) would exhibit larger anterior translation in extension than in flexion, increased adduction, and increased external rotation in both flexion and extension.

Wu, C. L. B., R.D.; Chen,J.M.; Lee,D.H.; Rouse,L.M. (2000). "Postoperative analgesic requirements in patients undergoing arthroscopic anterior cruciate ligament reconstruction." Am.J.Orthop. 29(12): 974-978.

Anterior cruciate ligament (ACL) procedures are associated with significant postoperative pain and have traditionally been done on a short-stay hospitalization basis because of concerns for adequate postoperative analgesia. A retrospective chart review was performed to determine postoperative intravenous patient-controlled analgesia (PCA) morphine requirements for 80 patients who had undergone arthroscopically assisted ACL reconstruction under general anesthesia by means of a patellar tendon autograft by 1 of 2 surgeons. The mean +/- SD PCA morphine used after surgery was 20.4+/-20.0 mg. There was a wide interpatient difference in postoperative opioid consumption: the amount of PCA morphine used ranged from 0 mg to 124 mg. A comparison between the surgeons revealed that 1 surgeon had significantly longer intraoperative surgical, tourniquet, and anesthesia times; however, there was no difference in the length of recovery room stay, amount of postoperative PCA morphine used, or time to hospital discharge. Predicting which patients may benefit from short-stay hospitalization after arthroscopic ACL reconstruction may be difficult because of considerable interpatient differences in postoperative analgesic requirements

Yack, H. J. (1993). "Further evidence against a direct automatic neuromotor link between the ACL and hamstrings [letter; comment]." Medicine & Science in Sports & Exercise 25(3):407-8, 1993 Mar 25(3): 407-8.

Yack, H. J., C. E. Collins, et al. (1993). "Comparison of closed and open kinetic chain exercise in the anterior cruciate ligament-deficient knee [see comments]." American Journal of Sports Medicine 21(1):49-54, 1993 Jan-Feb 21(1): 49-54.

The purpose of this study was to quantify the amount of anterior tibial displacement occurring in anterior cruciate ligament-deficient knees during two types of rehabilitation exercises: 1) resisted knee extension, an open kinetic chain exercise; and 2) the parallel squat, a closed kinetic chain exercise. An electrogoniometer system was applied to the anterior cruciate ligament-deficient knee of 11 volunteers and to the uninvolved normal knee in 9 of these volunteers. Anterior tibial displacement and the knee flexion angle were measured during each exercise using matched quadriceps loads and during the Lachman test. The anterior cruciate ligament-deficient knee had significantly greater anterior tibial displacement during extension from 64 degrees to 10 degrees in the knee extension exercise as compared to the parallel squat exercise. In addition, the amount of displacement during the Lachman test was significantly less than in the knee extension exercise, but significantly more than in the parallel squat exercise. No significant differences were found between measurements in the normal knee. We concluded that the stress to the anterior cruciate ligament, as indicated by anterior tibial displacement, is minimized by using the parallel squat, a closed kinetic chain exercise, when compared to the relative anterior tibial displacement during knee extension exercise.

Yamato, M., T. Yamagishi, et al. (1993). "[MR imaging of bone bruise associated with ACL tear]." Nippon Igaku Hoshasen Gakkai Zasshi - Nippon Acta Radiologica 53(1):23-7, 1993 Jan 25 53(1): 23-7.

The authors reviewed 56 MR studies of the knee performed for suspected cruciate ligament tear at the Tokyo Metropolitan Hiroo Hospital from April 1990 to March 1991. There were 10 patients with abnormal signal in the subcortical bone marrow. Eight of these patients had concomitant anterior cruciate ligament (ACL) tear with no evidence of fracture on plain radiographs of the knee. The abnormal signals were all seen in the lateral compartment, almost invariably in the middle third of the lateral femoral condyle and posterolateral aspect of the tibial plateau, and were of low intensity on T1-weighted and proton density images and of high intensity on T2-weighted images. It was speculated that these abnormalities resulted from impaction of the lateral femoral condyle into the posterior lip of the tibial plateau due to rotary subluxation of the tibia. One patient had a follow-up study three months later, which revealed complete resolution of bone bruise. It was concluded that bone bruise associated with ACL tear is seen specific locations, which may be a useful secondary sign of acute ACL tear.

Yasuda, K., A. R. Erickson, et al. (1993). "Dynamic elongation behavior in the medial collateral and anterior cruciate ligaments during lateral impact loading." Journal of Orthopaedic Research 11(2):190-8, 1993 Mar 11(2): 190-8.

The objectives of this experimental study were to determine (a) how quickly the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) elongate when a lateral impact force is imparted to the knee and if a person can react rapidly enough to provide protective muscle forces in the case of such an impact, (b) if the MCL and the ACL elongate simultaneously during a lateral impact, and (c) if resection of the ACL affects elongation of the MCL during a lateral impact. Eight whole-leg cadaver specimens were used. Each leg was mounted vertically in a testing-frame with the knee in 0 and 30 degrees of flexion. A submaximal impact was delivered from the lateral side by a pendulum instrumented with a force transducer. Elongation of the midsubstance of the MCL and the ACL was measured with Hall-effect displacement transducers. The ACL was resected and the entire test sequence was repeated. Following a lateral impact, elongation of the MCL and ACL reached peak values by 70 ms. This study indicated that contraction of the leg musculature would not protect the MCL and ACL from injury when a lateral impact load is applied to the knee. The MCL and the ACL never elongated simultaneously during a lateral impact. After lateral impact loading, the time required to reach maximum elongation (peak delay) averaged 52 ms in the anterior MCL fibers and 61 ms in the ACL when the knee was in 0 degrees of flexion. At 30 degrees of flexion, the peak delay averaged 38 ms in the anterior MCL fibers and 22 ms in the ACL.(ABSTRACT TRUNCATED AT 250 WORDS)

Yasuda, K. and T. Sasaki (1987). "Exercise after anterior cruciate ligament reconstruction. The force exerted on the tibia by the separate isometric contractions of the quadriceps or the hamstrings." Clin Orthop(220): 275-83.

The anterior or posterior drawer force exerted on the tibia by the separate isometric contractions of the quadriceps or hamstrings at various angles of knee flexion was examined in 20 healthy males. A two-dimensional model was analyzed using roentgenographic films. In separate isometric contractions of the quadriceps, the mean value of the anterior drawer force was equivalent to 14% of the tension of the quadriceps at 5 degrees knee flexion. The value decreased with the increase in the angle of knee flexion. The mean angle at which the anterior drawer force became zero was 45.3 degrees +/- 12.5 degrees. When the angle was increased further, the posterior drawer force gradually increased. In separate isometric contractions of the hamstrings, the posterior drawer force was exerted at all angles of flexion. Thus, during the early stage of rehabilitation after the anterior cruciate ligament injury, the quadriceps exercise by isometric muscle contraction should be performed with the knee flexion at more than 70 degrees (mean +/- 1.96). Exercise of the hamstrings by isometric muscle contractions can be carried out regardless of flexion angle.

Yasuda K, T. J., Ohkoshi y, Tanabe Y, Kaneda K (1995). "Graft site morbidity with autogenous semitendinosus and gracilus tendons." Am J Sports Med 23: 706-713.

To distinguish between morbidity caused by harvesting semitendinosus and gracilis tendons and morbidity associated with anterior cruciate ligament reconstruction surgery, we performed a prospective randomized study using 65 patients who underwent anterior cruciate ligament reconstruction using these tendons. The patients underwent either contralateral (N = 34) or ipsilateral (N = 31) graft harvest. For the nonoperated knees in the ipsilateral harvest group, isometric and isokinetic strength of the quadriceps and hamstring muscles increased to approximately 120% of the preoperative value at 12 months after surgery. Compared with these knees, the tendon harvest did not affect quadriceps muscle strength at all. However, harvest did decrease hamstring muscles strength for 9 months after surgery. The graft harvest in the knees with anterior cruciate ligament reconstruction also did not significantly affect quadriceps muscle strength, but it did significantly decrease hamstring muscles strength only at 1 month. Activity-related soreness at the donor site was rarely restricting and resolved by 3 months. This study demonstrated that the semitendinosus and gracilis tendon graft is a reasonable choice to minimize the donor site morbidity in ligament reconstruction using autografts

Yoshiya, S. A., J.T.;Manley,M.T.; and Bauer,T.W. (1987). "Graft tension in anterior cruciate ligament reconstruction." Am.J. Sports Med 15: 464-470.

Yu, W. D. P., V.; Hatch,J.D.; Liu,S.H.; Finerman,G.A. (2001). "Combined effects of estrogen and progesterone on the anterior cruciate ligament." Clin.Orthop(383): 268-281.

Yunes, M., J. C. Richmond, et al. (2001). "Patellar versus hamstring tendons in anterior cruciate ligament reconstruction: A meta-analysis." Arthroscopy 17(3): 248-257.

PURPOSE: To compare the outcome of ACL reconstuction using patellar tendon (PAT) to that when using hamstring tendons. Type of Study: Meta- analysis of controlled trials of patellar tendon versus hamstring tendons for ACL reconstruction. METHODS: Meta-analysis is a systematic method for statistical analyses that allows compilation of combined data from various independent studies. This allows one to assess the potential benefits of various treatments when conclusions based on individual studies are difficult to assess. We conducted a meta- analyses (M-A) using controlled trials (CTs) to determine if there are differences between the 2 methods. Although both surgical techniques have potential for good results, we hypothesized that there are differences in outcomes between these techniques. We included CTs that used standard evaluation techniques with a minimum 2-year follow-up. Outcomes evaluated included: return to preinjury level of activity, KT testing, Lachman scores, pivot shift scores, range of motion (ROM) loss in flexion and extension, complications, and failures. Relative risks for each outcome were calculated for each study and pooled across studies using a fixed effects method. RESULTS: Four studies fulfilled our inclusion criteria. Relative risks with 95% confidence intervals and P values were obtained for each of the outcomes listed above. The results show significant differences between PAT and semitendinosus and gracilis tendon (ST&G) reconstructions. PAT patients have a greater chance of attaining a statically stable knee (as measured by KT) and nearly a 20% greater chance of returning to preinjury activity levels. CONCLUSIONS: Although both techniques, as performed in the late 1980s and early 1990s, yielded good results, PAT reconstuction led to higher postoperative activity levels and greater static stability than hamstring reconstruction. This is statistically significant based on this meta-analysis.

Zacherl, J. (1993). "[Replacement of the anterior cruciate ligament with an artificial Leeds-Keio ligament]." Wiener Klinische Wochenschrift 105(5):147-51, 1993 105(5): 147-51.

Zaricznyj, B. (1987). "Reconstruction of the anterior cruciate ligament of the knee using a double tendon graft." Clin Orthop 220: 162-175.

Zarins, B., and Rowe,C.R. (1986). "Combined anterior cruciate-ligament reconstruction using semitendinosus tendon and iliotibial tract." J. Bone and Joint Surg 68A: 160-177.

Zatterstrom, R. F., T.; Lindstrand,A.; Moritz,U. (2000). "Rehabilitation following acute anterior cruciate ligament injuries--a 12-month follow-up of a randomized clinical trial." Scand.J.Med.Sci.Sports 10(3): 156-163.

The efficacy of two non-operative rehabilitation programs was studied in a consecutive randomized controlled clinical trial of 100 patients after 12 months subsequent to an acute anterior cruciate ligament (ACL) injury. Follow up of randomization to two training models was evaluated after 3 and 12 months: A self-monitored training program (SM) of traditional mobility and muscle strength training of the injured leg was compared to a supervised (SV) training model exercising postural function in closed kinetic-chains. Nearly 50% of the patients in the SM group required supervision after 6 weeks. An intention-to-treat analysis was performed and showed significantly better values in most of the results of the supervised group at 3 and 12 months. An alternative analysis of subgroups showed a significant difference between transferred male patients and original SV male patients at 3 months but not at 12 months, indicating the importance of initial guiding after an ACL injury. No such difference was observed in the female patients

Zhang, J. S. (1993). "[Acute repair and reconstruction of the anterior cruciate ligament]." Chung-Hua Wai Ko Tsa Chih [Chinese Journal of Surgery] 31(5):303-7, 1993 May 31(5): 303-7.

28 patients with anterior cruciate ligament (ACL) injury were reported in this article. Of them, 7 were isolated ACL injury, 21 were complicated with other ligaments injury or tear of meniscus: 5 were posterior cruciate ligament (PCL) injury, 8 were medial collateral ligament (MCL) injury, 1 was LCL injury and 1 was tear of lateral meniscus, 6 were MCL injury and tear of medial meniscus. Among these 28 cases with ACL, 23 patients were repaired and were followed-up for an average of 26 months. The result revealed that excellent and good result was 87%. In 5 cases of acute reconstruction, 4 were excellent and 1 was good. In addition, points of diagnosis, operation indication and operative methods are discussed.

Zijl, J. A. K., A.E.; Willems,W.J. (2000). "Comparison of tibial tunnel enlargement after anterior cruciate ligament reconstruction using patellar tendon autograft or allograft." Am.J.Sports Med. 28(4): 547-551.

This retrospective study was designed to compare tibial tunnel enlargement in patients with autograft or allograft anterior cruciate ligament reconstructions. The changes were related to position of the tibial tunnel and clinical outcome. Twenty-six patients with autograft reconstructions and 41 with allograft reconstructions were studied at a mean follow-up of 59 months (range, 41 to 84) after surgery. The average tunnel enlargement on the anteroposterior view was 2.2 mm (SD, 2.5) for autografts and 2.8 mm (SD, 2.1) for allografts. On the lateral view, the tunnel enlargement was 2.6 mm (SD, 2.4) and 3.4 mm (SD, 2.6) for autografts and allografts, respectively. No significant differences were found between the autograft and allograft groups. A trend was found in the correlation between the position of the tibial tunnel and the tunnel enlargement: more anteriorly placed tunnels had more enlargement. The changes in tunnel diameter did not relate to knee functional score or laxity. There was a significant correlation between malposition of the tibial tunnel and poor clinical scores. A significant negative correlation was found between postoperative follow- up time and tunnel enlargement in both groups. We conclude that placement of the tibial tunnel is a determining factor in tibial tunnel enlargement and clinical knee scores after anterior cruciate ligament replacement with an autograft or allograft. Tunnel enlargement tends to be less at a longer postoperative follow-up

Zysk, S. P. K., A.; Baur,A.; Veihelmann,A.; Refior,H.J. (2000). "Tripled semitendinosus anterior cruciate ligament reconstruction with Endobutton fixation: a 2-3-year follow-up study of 35 patients." Acta Orthop.Scand. 71(4): 381-386.

We evaluated the clinical outcome of tripled semitendinosus tendon ACL reconstruction with femoral Endobutton (Acufex, Smith&Nephew, Andover, MA) and tibial Suture Washer (Acufex, Smith&Nephew, Andover, MA) (n 29) or post screw fixation (n 6) in 35 patients on an average of 28 (20-37) months after surgery. On the basis of IKDC criteria, 22 patients showed a normal or nearly normal knee function and 25 patients had a KT 1000 maximal manual side-to-side difference of < or =5 mm at follow-up. Subjectively, 28 patients graded their knee function as normal or nearly normal. The average Lysholm score was 88 points, average OAK score 90 points and average modified HSS score 93 points. 19 patients reached their preinjury level of activity at follow-up. The postoperative Lachman test was < or =1+ in 24 patients and 24 patients also showed an absent pivot shift. Significant bone tunnel enlargement occurred in 26 patients on the femoral side and in 23 patients on the tibial side. We found no correlation between bone tunnel enlargement and clinical outcome. The clinical outcome of tripled semitendinosus tendon ACL reconstruction with Endobutton fixation on the femoral side was not entirely satisfactory. The procedure was associated with a high incidence of bone tunnel enlargement in this series