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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