ACL Study Group 2004

Forte Village Resort, Santa Margherita di Pula, Sardegna, Italy

Abstracts and PowerPoint Presentations- 2004

Instructions: Click on the title for the abstract and click on Download PDF for the PowerPoint Presentations
Sun May 30, 2004 AM

Treatment trends with Anterior Cruciate Ligament, Posterior Cruciate Ligament, Medial Collateral Ligament, and Cartilage Problems. John Campbell, MD. Bozeman Montana. Download PDF file

Longterm-Results of ACL-Reconstructions Dr. Med. Dieter Gmur Bern Switzerland Download PDF file

Septic Arthritis Following Arthroscopic Anterior Cruciate Ligament Reconstruction: A Retrospective Case-Control Study of Risk Factors and Outcomes. Walter Lowe MD. California Download PDF file

Functional Outcome of ACL Revision with 4 years Follow-up. Tom Patt MD. The Netherlands Download PDF file

Effectiveness of Bio-Transfix in ACL Reconstruction: a prospective study with three year follow-up. A. Schiavone Panni MD Rome Italy. Download PDF file

The Effect of Age on the Histologic Response to ACL Injury. Martha Murray, MD, Minder S. Kocher, MD Boston Mass. Download PDF file

ACL Reconstruction in Children and Skeletally Immature Adolescents. Burt Jacobsen MD Aarhaus, Denmark. Download PDF file

ACL Reconstruction in the Immature Skeleton, Andrew Unwin, B Sc FRCS Berkshire UK Download PDF file

ACL Replacement in Sheep with Open Epiphysis: An Evaluation of Risk Factors. Dr. Seil Download PDF file

Timing of Biologic Fixation and Knee Stability After ACL Reconstruction with Hamstring Tendons. Mitsuo Ochi MD Hiroshima Japan Download PDF file

Indications for Ancillary Surgery in ACL Deficient Knee. Philippe Neyret MD Lyon France, Download PDF file

Comparison of Femoral and Tibial Fixation in ACL Reconstruction. Don Johnson Ottawa Canada. Download PDF file

Reproduction of Anatomic ACL Reconstruction in the Sagital Plane: A comparison of Two Endoscopic Techniques. David Chao MD, San Diego California. Download PDF file

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials Peter Burkart, MD. Innusbruk Austria. Download PDF file

Sunday May 30, 2004 PM

Endoscopic Reconstruction of the Anterior Cruciate Ligament Using the Quadriceps Tendon Graft and Rigid Fixation: A Randomized Prospective Study with 2 years follow-up. Pietro Randelli MD Milan Itlay. Download PDF file

A Novel ACL Reconstruction with Bone-Patellar-Tendon-Bone Graft: A Biomechanical Analysis - Konsei Shino MD Osaka Japan. Download PDF file

Tissue Engineering of Xenografts for ACL Reconstruction. Kevin Stone MD, San Francisco CA. Download PDF file

Do Femoral Tunnel Positions Affect the Function of the ACL Reconstructed Knee? Volker Musahi MD Pittsburgh PA. Download PDF file

Double Bundle Reconstruction of the ACL Using Hamstring Tendons Versus One Bundle Reconstruction: A Biomechanical Cadaveric Study. Guy Bellier MD Paris France.. Download PDF file

The Double Graft ACL Reconstruction: Can it restore normal mechanics? Denny Lie MD London England. Download PDF file

Posterolateral Corner Injuries - Symposium

Russ Warren - Download PDF file

Hans Staubli - Download PDF file

Don Shelbourne -Download PDF file

Hans Passler -Download PDF file

Monday May 31, 2004 AM

Patellofemoral Symposium

The Detection, Prevention, and Control of Arthrosis Following ACL Reconstruction Scott Dye MD, San Francisco. Download PDF file

Monday May 31, 2004 PM

Neuromuscular Factors for Injury During Tasks Impicated in Non-contact ACL Injuries. T. Sell MD Pittsburgh PA. Download PDF file

Proposed Mechanism for Anterior Cruciate Ligament Injury K Don Shelbourne MD Indianapolis IN. Download PDF file

Is Phase of Menstrual Cycle Associated with ACL Injury in Alpine Skiers? Bjarne Brattbrack, MD Burlington VT. Download PDF file

A Centile Chart of Functional Recovery Following ACL Reconstruction. A Useful Incentive for Patients? Tim Spaulding, MD Warwick UK. Download PDF file

Comparison of One-Leg Hop for Distance Scores in the ACL Deficient With a Group of Healthy Controls. Paul Marks, MD, FRCS, Toronto, Canada . Download PDF file

Isokinetic Evaluation of Quadriceps, Hamstrings, and Rotational Muscle Strength of the Knee: Comparison Prospective Study of Hamstrings and BTB ACL Reconstruction. Matteo Denti Milan Italy. Download PDF file

The Influence of Core Strength on Lower Extremity Performance. M.L. Ireland MD Lexington KT. Download PDF file

Applying Conventional Measurements to Modern Modalities: MRI Determination of Tibial Tubercel Lateralization, Patellar Lateralization, Patellar Tilt, and Patella Index in Patients Presenting with Anterior Knee Pain. Ed Bartlett, MD. Download PDF file

Risk to Popliteal Vessels in Major Knee Surgery: An Anatomical Study and Survey on Vascular Surgeons. John Barlett MD Heidelberg Australia. Download PDF file

Video Informed Consent Improves Knee Arthroscopy Patient Comprehension. James Lubowitz MD Taos NM. Download PDF file

An Improved Technique for Open Wedge Osteotomy Using a Biplanar Cut and a new Internal Plate Fixator. Philippe Lobenhoffer, MD. Hanover Germany. Download PDF file

Knee Malalignment Corrected by Opening Wedge Osteotomies. Arne Ekeland, Baerum Norway. Download PDF file

Tuesday June , 2004 AM

Prospective Clinical and MRI Analysis Of Stored Osteochondral Allografts for the Treatment of Knee Cartilage Defects. Riley Williams New York NY. Download PDF file

Soft Tissue Healing in Biglycan Knockout Mice. Narimasa Nakamura, Japan. Download PDF file

Recellularization and Remodeling of Allografts Used to Replace the Anterior Cruciate Ligament. Variables that have an Influence on these Process. Vicent Sanchis-Alfonso MD PhD, Valencia Spain . Download PDF file

Transplantation of Culture Born Myofibroblasts into the Medial Collateral and Anterior Cruciate Ligaments. J Menetrey, MD, Geneva Switzerland. Download PDF file

The Effect of Short-term Mechanical Stimulation on Fibroblasts Cultured on Synthetic Scaffolds. David McAllister MD Los Angles, CA. Download PDF file

ACL Graft Rupture after Anatomic Reconstruction and Rehabilitation. A Problem of Lack of Reinnervation. Roland Biedert MD Magglingen, Switzerland. Download PDF file

Double Bundle ACL Reconstruction. Paulo Aglietti, MD, Florence Italy. Download PDF file

Clinical Outcome After Anatomical Reconstruction of the Anteromedial and Posterolateral Bundles of the Anterior Cruciate Ligament. Kazunori Yasuda, MD, PhD, Sapporo, Japan. Download PDF file

The Outcome of Anterior Cruciate Ligament Reconstruction Using Quadrupled Semitendinosus Tendon: One-bundle Versus Two-bundle Methods. Taseski Muneta MD Tokoyo Japan. Download PDF file

Two-bundle ACL Reconstruction. Guy Bellier MD, Paris France. Download PDF file

Outcome of ACL Revision Reconstruction. KP Benedetto, MD Feldrich, Austria. Download PDF file

Allograft versus Autograft Patellar tendon for ACL Reconstruction. A 2-year follow-up. Herman Mayr. Munich, Germany. Download PDF file

Reconstruction of the Posterolateral Corner. A New Surgical Procedure. BW Jakobsen, Aarhus Denmark. Download PDF file

Round Table Discussion - Partial Tears of the ACL in the Young Athlete. K Donald Shelbourne. Download PDF file

For Consideration: Can we expect a normal knee after ACL reconstruction? K Donald Shelbourne. Download PDF file

Thursday June 2, 2004 AM

Why Do We Create a Round Tunnel for a Rectanglar Tendon? Development of a New Technique for ACL Reconstruction Using a Patellar Tendon. Christian Fink MD. Innsbruk Austria. Download PDF file

Tunnel Widening After Hamstring ACL is Dependent on the Type of Fixation Used. A Prospective Randomized Study. Peter Fanoe, Randers Denmark. Download PDF file

How to Reduce the Tibial Widening in ACL Reconstruction. Tricks and Techniques. V Calvisi MD L'Aguila Italy. Download PDF file

The Cross Sectional Area of the Quadruple Hamstring Graft Correlates with the Size of the Donor. AK Aune MD Oslo Norway. Download PDF file

Biomechanical Properties of Tibial Hamstring Graft Fixation Techniques for Circumferential Graft Ingrowth. Experimental Roentgen-Stercometric Analysis (RSA) Study. Dieter Kohn MD Homburg Germany. Download PDF file

Relationships Between Objective Assessment of Ligament Stability and Subjective Assessment of Symptoms and Function After ACL Reconstruction. Minder S. Kocher. MD Boston Massachusetts. Download PDF file

Reducing Invasiveness and Improving Accuracy with Computer Assisted Surgery (CAS) in ACL Reconstruction. Christian Hoser, MD, Innusbruk Austria. Download PDF file

Work in Progress: MRI Virtual Arthroscopy of the Knee. Charles Ho. Palo Alta, CA. Download PDF file.

Three Years Experience with Computer Navigation-Assisted Positioning of Drilling Tunnels in Anterior Cruciate Ligament Replacement. Jurgen Eichhorn, MD. Staubing Germany. Download PDF file

The Influence of Menisectomy or Meniscus Suture on the Stability of the Knee in Computer Assisted Anterior Cruciate Ligament Reconstruction Burt Klos MD. Eindhoven, Netherlands. Download PDF file

Reduction of Post-operative Pain Following Arthroscopic ACL Reconstruction Using Low Temperature Arthroscopy Irrigation Fluid. Jon Borrill Melbourne Australia. Download PDF file

Integrity of Reconstruction of the Anterior Cruciate Ligament: A Roentgen Sterophotogrammetric Analysis. Rhiodan Thomas MD London England. Download PDF file

Arthroscopic Treatment of Avulsion Fracture of Anterior Cruciate Ligaments. Matjaz Veselko MD. Download PDF file

Thursday June 2, 2004 PM

Effect of Lateral Femoral Tunnel Placement on Knee Stability and Graft Fixation. Yuji Yanamoto MD, PhD Pittsburg PA. Download PDF file

The Effect of Tibial Slope on Anterior Tibial Translation in the ACL Deficient Knee. Mark Clatworthy, MD. Auckland NZ. Download PDF file

Posterior Tibial Slope Angle and its Association with Anterior Cruciate Ligament Teas in Male and Female Patients. Mark Sherman. MD, Staten Island, New York. Download PDF file

Primary Repair of the ACL: Do we need to go there again? John Feagin MD. Download PDF file

Alternatives for the Active Individual with Symptomatic Arthritis of the Knee. What would you do? John Bergfeld. Download PDF file

Intra-articular Analgesia Using Meperidine/local Anesthesia Combination in Arthroscopic Knee Procedures. John Vander Schilden MD. Little Rock Arkansas USA. Download PDF file

Salvage Treatment of Massive Non-structural Osteochondral Lesions of the Knee. The Use of Allograft MegaOATS versus Mosiacplasty. Albert Pearsall IV, MD. New York NY. Download PDF file

Articular Cartilage Defects in Children and Adolescents: Treatment with Osteochondral Implantation. Jon Browne MD Kansas City MO. Download PDF file

A Prospective Outcome Analysis of Patients Treated with Microfracture Abrasion for Chondral Lesions of the Knee. A Preliminary Review. Russelll Warren MD, New York NY. . Download PDF file

Chondral and Meniscal Injuries Associated with Chronic Anterior Ligament Deficient Knee. Arturo Almazan MD, Mexico City DF. Download PDF file

Normal Versus Transplanted Meniscii: Evaluation of Extrusion Using MRI and US. A Preliminary Report. Rene Verdonk MD, Gent Belgium. Download PDF file

Meniscus Refixation Using the Fast-Fix meniscus Repair Device: A Preliminary Results. Dimitrios Mastrokalos MD Heldelburg Germany. Download PDF file

Wound Repair in the Meniscus. New Insights. Cahir McDevitt Clevland OH. Download PDF file

Friday June 3, 2004 AM

What Can We Learn From In-Vitro Bioamechanical Studies of the ACL? Guiliano Ceruli MD. Perugia Itlay. Download PDF file

Tibio-Femoral Kinematics in Normal Knees and Knees Following ACL Reconstruction. A Pilot Study of Weight Bearing Knees Using Dynamic MRI. Andy Williams, London England. Download PDF file

Finite Element Modeling and Simulation of Knee Motion. Dereck Bickerstaff, MD. Download PDF file

Non-invasive In-vitro Evaluation of the Pivot Shift Using an Electormagnetic Device for the ACL Deficient and Reconstructed Knees. Ryosuke Kuroda, Kobe, Japan. Download PDF file

A Pilot Study Presenting New Methodology to Quantify in Vivo Tissue Loads by in-vitro Robotic Reproduction. Cy Frank MD Calgary Alberta, Canada. Download PDF file

The Remains of ACL Graft Tension After Cyclic Loading. Markus Arnold MD, Nijmigen Neterlands. Download PDF file

Anterior Knee Pain After ACL Reconstruction Arising in the Popliteal Aspect of the Knee. Vicente Sanchis-Alfonso MD Valencia, Spain. Download PDF file

The Effectiveness of Reconstruction of the Anterior Cruciate Ligament Using the New Knot/Pressfit Technique: a Cadaveric Study. R. Kilger, Pittsburgh PA. Download PDF file

The Tibialis Tendon as a Valuable Anterior Cruciate Ligament Allograft Substitute: In-vitro Properties. Rene Verdonk MD, Ghent Belgium. Download PDF file

Hamstring ACL Reconstruction: Is it necessary to sacrifice the gracilis: Alberto Gobbi. Milano, Italy. Download PDF file

Angle Osteochondral Grafts - Effects on Articular Contact Pressure. Jason Koh. Chicago IL. Download PDF file

Best Practice for Anterior Cruciate Ligament Reconstruction. Do we need standards? Who should set them? Robin Alum MD FRCS Buckinghamstire, UK. Download PDF file

Longterm-Results of ACL-Reconstructions

Dieter Gmür, MD, FMH für orthopädische Chirurgie

OKB (Orthopädische Klinik Bern am Salemspital)

Office: Bundesgasse 16, CH 3011 Bern/Switzerland

Private: Burgackerweg 23, CH 3047 Bremgarten/Switzerland

e-mail: dg.sen@bluewin.ch

What happened to patients who have been operated on their ACL-deficient knee 30 years ago (1974) with an intraarticular ACL-reconstruction with either the transplantation of the medial or lateral meniscus or those who have been operated on their ACL-deficient knee with reconstruction of the ACL with a BPTB graft according the method of Bill Clancy 20 years ago (1983).

During our ACL Study Group meeting 1986 in Zermatt, I reported about 52 cases of intraarticular ACL-reconstructions, substituting the torn ACL by either the medial or lateral meniscus of the same knee. At that time, they have been operated more than 10 years ago by my predecessor. I could show, that it was a big difference between the view of the patient and the objective view of the examiner:

subjective objective

very good / good 33 13

fair / poor 19 39

At that time we put to discussion

1. how the then tested knee joints work after another 10 or 20 years

and whether

2. ACL-reconstructions with more modern methods like BPTB effectively lead to better longterm results.

Therefore I tried to contact all the 52 patients who have been involved in the above mentioned study. Of the 52 patients having undergone the operation 30 years ago I could control 45 personally and 3 by questionaire only. Not astonishing that the 10-years results from 1986 changed in the meantime.

subjective objective

very good / good 12 18

fair / poor 33 27

At the same time I contacted the 57 patients whom I operated on with the original Clancy method between march 1983 and march 1984. At that time we used the BPTB graft leaving attached to the Hoffa fat pad, believing this would improve the vascularization of the graft. Of the 57 patients whom I operated 20 years ago I was able to control 50 personally and 4 by questionaire. In these patients the overall results have mainly been compromised by patellofemoral problems. These problems existed from the beginning and are – in my opinion – depending on the technical procedure of the operation at that time.

Summary

Ø I had the opportunity to control 48 patients, operated by my predecessor, 30 years after stabilization of a significant rotatory instability of their knee joint with either the medial or lateral meniscus of the involved knee.

Ø As I expected, most of these patients developped significant degenerative changes within about 10 years, but they have been bothered by arthrosis only more than 20 years after the operation.

Ø Between 25 and 30 years after the operation more than 30 % needed TKA.

Ø At the same time I controlled 54 of my patients 20 years after reconstruction of the ACL with BPTB in the method of Bill Clancy (leaving the ligament attached to the Hoffa fat pad to improve vascularisation of the graft).

Ø These patients suffered mainly of patellofemoral problems. Those problems could be significantly reduced, but not quite eliminated, by improving the technical procedure: free graft.

Ø Of course, the stability of the knees operated with BPTB is much better than with menisci. But it is very astonishing, that patients have been quite happy with the nowadays abandoned technique.

Conclusion

Ø 20 – 30 years after stabilizing of a rotatory instability of the knee, overall results in patients and in doctors view are often more depending on concomitant factors at the operation as age of the patient, varus-valgus axis, quality of cartilage and menisci, than on the technical procedure of the operation.

Ø Stability does influence the speed of degenerative changes but is not the most important factor.

Ø After more than 20 years there are mainly degenerative (postmeniscectomy) changes, which lead to further operations. This is true for both groups and has nothing to do with the technical procedure of the ACL substitution.

THE EFFECT OF AGE ON THE HISTOLOGIC INJURY RESPONSE TO ACL INJURY

Martha M. Murray, MD, Lyle J. Micheli, MD, David Zurakowski, PhD and Mininder Kocher, MD

From The Division of Sports Medicine, Department of Orthopaedic Surgery, Children’s Hospital of Boston, Boston, MA.

ABSTRACT

Background: New biologically-based techniques are being developed for treatment of the ruptured ACL. The success of these treatments is dependent on the response to injury by the cells in the ligament. This study was designed to determine whether skeletally immature patients had a different response to injury than older patients, and thus might have a different response to biologically-based treatments.

Hypothesis: Younger patients have a different proliferative and vascular response to injury than older patients.

Methods: Ruptured ACLs were obtained from 48 patients undergoing ACL reconstruction. Seven of the patients were skeletally immature at the time of surgery (immature). This group of seven was compared with two groups: an adolescent group (skeletally mature but younger than 20 years), and adult (older than 20 years). All ligaments had ruptured in the proximal 1/3. The ligaments were removed en bloc, and longitudinal sections analyzed for cell density and vascularity as previously described (Murray et al, JBJS, 2000). The statistical significance was determined using an unpaired Student t-test for cell density, vessel density and nuclear aspect ratio; Mann-Whitney U-test for % SMA positive cells.

Results: The ACLs from immature knees had significantly higher cell density and vascularity from those of the adult knees. These differences were most apparent in the first two months after injury. Although the ACLs in the immature group also had a higher cell density than the adolescents, the difference was not found to be statistically significant between these two groups.

Conclusions: The histologic response to injury is different in skeletally immature patients. The more vigorous proliferative and vascular response may bode well for enhanced repair techniques in this patient population, as these techniques are dependent on an intrinsic cellular response within the ACL.

INDICATIONS FOR ANCILLARY SURGERY IN ACL DEFICIENT KNEE

Philippe Neyret, Tarik Aït Si Selmi, Geraldo Schück de Freitas

INTRODUCTION

To better understand the place of the extraarticular tenodesis combined to an ACL graft we did a prospective randomised study.

MATERIAL AND METHOD

It ‘s a prospective series of chronic ACL deficient knees without previous surgery. We included two groups statistically comparable: 60 isolated ACL graft and 60 ACL graft combined with an extra articular plasty pre and post operative subjective and objective IKDC evaluation were used. Comparative AP + Lateral Monopodal Stance and Stress XRays were obtained preoperatively.

The two groups were preoperatively comparable in terms of : Sexe ratio, Age, Weight, Type/Sport level, Delay injury – op, Meniscal status, Subjective IKDC (75.3% // 72.6%), Swelling, Mobility, Crepitus, X-Rays.

107 patients (89.2%) 51 KJ, versus 56 KJT were available at follow. 92% were reviewed with pre & post-op Stress X-Rays.

The follow-up was 16.5 ± months in the KJ group versus 18.5 months in the KJT group.

RESULTS

93.5% were very satisfied or satisfied in the KJ group versus, 96.3% in the KJT group

Subjective IKDC score was improved in both groups: But the gain was higher in the KJT group (+ 21) versus (+ 13) in the KJ group (p > 0.05)
ROM was better in the KJ group
Objective measurements, using stress X-Rays showed that there is a tendency to better control the Anterior Tibial Translation of the medial side in the KJT group (4.6 mm pre-op, 2.3 mm at F.U. than in the KJ group 4.5 mm pre-op, 3.2mm at F.U.) The control of the differential ATT of the lateral compartment is also better in the KJT group (4.6 mm) than in the KJ group (2mm). Globally the ligament testing was more favourable in the KJT group (A + B = 91%) than in the KJ group (A + B = 82.3%)
The final evaluation was also influenced by the ligament testing.

DISCUSSION

Draganish demonstrated that isolated extra-articular tenodesis can control some amount of laxity at 30° flexion. However after isolated extra-articular tenodesis without ACL reconstruction, clinical failures are frequent: the anterior tibial translation is not controlled and at long term F.U. the arthrosis is frequent. Frank Noyes underlined the benefits to add an extraarticular tenodesis when an allograft is performed. Failure rate decreased from 16% to 3% and the control of anterior laxity was better.

At the contrary several authors (O’Brien, Holmes, Buss) in different retrospective studies found no superiority to add an extra articular tenodesis.

Very recently during the French Society, Hulet from Caen in a retrospective study did not find statistical difference between two groups with and without extraarticular tenodesis but the factor ß was unknown and the number of patients in the two groups was not large enough.

F Cladiere (Lerat-Moyen) compared in a prospective randomised study two groups with and without extraarticular tenodesis and recommended a lateral complementary procedure when there is a preoperative differential anterior tibial translation measured on the lateral compartment, called “TACE” of more than 8 mm.

CONCLUSIONS

The place of extraarticular tenodesis is still discussed. This series encourages us to evaluate this comparison is larger groups and longer Follow-up.

Timing of Biological Fixation and Knee Stability after ACL Reconstruction of with Hamstring Tendons

Mitsuo Ochi, Yuji Uchio, Nobuo Adachi　　(Hiroshima, Japan)

The Hypothesis The success of anterior cruciate ligament (ACL)

reconstruction is considered to be affected by several factors such as

surgical skill, graft selection, and the postoperative rehabilitation

program. Timing of the graft incorporation within the bone tunnels is

considered to be one of the important factors but it has been unclear when a

hamstring tendon graft becomes biologically fixed in the bone tunnel after

ACL reconstruction. The purpose of this study was to prospectively examine

changes over time in the biomechanical properties of the knee and their

representation on MRI during the 2-year period after ACL reconstruction and

to analyze the factors predicting a poor outcome.

Methods: Sixty-four patients were evaluated by serial biomechanical testing, magnetic resonance imaging, and second-look arthroscopy 2 years after surgery. Biologic fixation of the graft was confirmed radiographically by injecting a contrast medium into the femoral bone tunnel.

Results: Forty-two stable knees with graft fixation maintained a high stiffness (120% of normal) and showed low signal intensity in an early postoperative magnetic resonance image (12±8 months). Fourteen stable knees without graft fixation had gradually increased anterior displacement with nearly normal stiffness and high signal intensity. Five unstable knees with graft fixation retained low stiffness (70%) and showed late low signal intensity at 20±9 months. Three unstable knees without biologic fixation had rapidly increased anterior displacement, with half the stiffness of a normal knee.

Conclusion: Postoperative low stiffness and high signal intensity might indicate late biologic graft fixation, predicting a possibility of postoperative anterior knee instability.

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials

Burkart P*, Tecklenburg K⁺, Hoser C⁺, Fink C⁺*St. Anna Hospital, Luzern CH

⁺University Hospital for Traumatology, Innsbruck A

Introduction: During recent years metal interference screws for graft fixation in ACL reconstruction. have been continuously replaced by resorbable screw materials. Resorbable screw materials are found to be biologically safe and provide reliable graft fixation. However, degradation rates are highly variable and bony replacement of these screws has not been sufficiently documented. Therefore new screw materials (composites of polylactid and HA) which should enhance bone formation have been investigated and compared to an allograft interference screw.

Materials and methods: Three groups of patients have been prospectively evaluated. In all patients ACL reconstruction has been performed using patellar tendon autograft and distal fixation was either (A) Biloc screw (Atlantec) , (B) Bio RCI - HA (Smith&Nephew) or an (C) allograft interference screw (Regeneration).

IKDC and subjective IKDC were used preoperative and for follow up. CT scans have been performed post op and at 3, 12 months (24 months) and MRI‘s at 3 months (and 24months).

Each group consisted of 19 patients (A: mean age 32,3 ± 10,9 (20-52) , B: 32,2 ± 10,6 (18-55) and C: 31,1 ± 6,6 (21-42) . There was no significant (p>0.05) difference in age, sex and time of follow up.

Results: (2 year follow up will be completed February 2004 and presented)

One breakage of an interference screw during insertion was encountered intraoperatively in groups A and B. At one year follow up there were no significant differences within the groups with respect to objective and subjective clinical results. IKDC evaluation revealed group A: 13 A, 5 B, 1 C, group B: 13 A, 6 B and group C: 18 A, 1 B.

On MRI no inflammatory response could be detected in any of the patients of all groups.

CT scans documented no loss of graft fixation, no significant bony resorption, but also no signs of bone ingrowth or replacement in the two groups with composite screws (A and B). At one year the allograft screws (C) remained unchanged without signs of resorption.

Discussion: All 3 screw types proved successful in providing adequate graft fixation. Ultimately a resorbable screw has to be replaced by bone in order to facilitate revision surgery. At one year only the screw made out of bone could meet this task. If the composite material will be of any advantage has to been seen with longer follow up.

Randomized Clinical Trials of Femoral and Tibial Fixation Devices in ACL Reconstruction. Don Johnson MD, Ottawa Canada

STUDY DESIGN: Prospective randomized clinical trial comparing femoral and tibial fixation devices.

OBJECTIVES: To investigate the efficacy of femoral and tibial fixation devices in ACL reconstruction.

Question - Is BioScrew/EndoPearl equal to Endobutton for femoral fixation in ACL hamstring reconstruction as measured by KT-1000 and IKDC outcome measurements?

Question –Is ExtraLok BioScrew equal to Intrafix for tibial fixation in hamstring ACL reconstruction as measured by KT-1000 and IKDC outcome measurements?

BACKGROUND: ACL rupture may cause severe problems with recurrent giving way of the knee. In reconstruction of the anterior cruciate ligament, a hamstring or patellar tendon autograft is used to replace the ruptured ligament and is securely fixed to bone tunnels in both the femur and tibia that correspond to the position of the original ligament. Fixation of the graft to the femur is now most commonly performed by interference fit screws or Endobutton. Fixation in the femur has been with interference fit screws, and recently by the use of the Intrafix device. BioScrews are an effective means of fixation but do demonstrate late laxity in a previous 2 year study done at our institution (27% 3-5mm SSD). The recent introduction of continuous loop Endobutton and the Intrafix has improved graft fixation with few reported complications, but it is unknown if they are superior to BioScrew fixation.

METHODS: The patients were randomly assigned to femoral fixation with either Endobutton or Bioscrew/Endopearl. The mean age was 29.1 years with a follow up of 2 year. Similarly patients were randomized to either a BioScrew (ExtrLok) or the Intrafix tibial device.

RESULTS: There was no significant SSD (side to side difference) in laxity (Endobutton group= 2mm, Bioscrew=2.3mm) at 2 year. Both groups also had a similar percentage falling within the 3-5mm laxity range. Subjective IKDC scores were also similar in both groups. The SSD was similar for the tibial fixation devices at 1 year.

CONCLUSION: Fixation of the ACL on the femoral side appears have similar results whether using BioScrew/Endopearl or Endobutton. There are still 30-40% of patients with 3-5mm SSD however, this did not affect the subjective outcome of the patient. Fixation of the graft with either the ExtrLok screw or the Intrafix device provided good stability at 1 year, with a reduction of the 3-5 mm SSD.

Reproduction of Anatomic ACL Sagittal Angle:

A Comparison of Two Endoscopic Reconstrucion Techniques

David J. Chao, MD – San Diego, CA, USA

Purpose: Current orthopedic techniques involving ligament reconstruction generally attempt to restore native anatomic structure and form. One method of assessing whether or not an ACL reconstruction accurately reproduces the native ligament’s anatomic orientation involves measuring its sagittal angle. The purpose of this study was to compare the established Magnetic Resonance Imaging (MRI) angle of the anatomic Anterior Cruciate Ligament (ACL) to two endoscopic ACL techniques to determine if one method more accurately reproduced the anatomic sagittal angle of the native ACL.

Methods: The sagittal orientation of a reconstructed ACL graft using two endoscopic reconstructive techniques was compared to the native uninjured ACL using two established magnetic resonance imaging (MRI) techniques. The two endoscopic methods, performed by a single surgeon, differed only in the technique used to drill the femoral tunnel. In the first method of reconstruction the femoral tunnel was drilled through the tibial tunnel (transtibial) and in the second method the femoral tunnel was drilled through the medial portal with the knee in maximal flexion. There were a total of thirty patients giving fifteen subjects each reconstructed group. Two separate evaluators recorded two established methods of sagittal angle measurement using MRI scans. These values were then compared to the same measurements obtained from MR images of normal, uninjured ACLs.

Results: There was a statistically significant difference when the mean value of the sagittal ACL angles of the transtibial grafts (74.7) were compared to the anatomic ACLs (56.9) (p<0.001). There was also a statistically significant difference between the mean value of the sagittal angles of the transtibial ACL grafts and the medial portal ACL grafts (57.5) (p<0.001). No statistical significance was noted when comparing the sagittal angles of the medial portal ACL grafts to the anatomic ACLs (p<0.8).

Conclusions: Endoscopic anterior cruciate ligament (ACL) reconstruction has become the standard of care. When employing this technique, the femoral tunnel can be drilled through the tibial tunnel or via the medial portal with knee in hyperflexion. Based on MRI measurements, the authors conclude that the medial portal technique for drilling the femoral tunnel reproduces a more anatomic ACL reconstruction by producing a more normal sagittal orientation.

References:

Gentili A, Seeger LL, Yao L. Anterior cruciate ligament tear: Indirect signs at MR imaging. Radiology 1994;193:835-840.

Murao H, Morishita S, Nakajima M. Magnetic resonance imaging of anterior cruciate ligament tears: Diagnostic value of ACL-tibial plateau angle. J Orthop Sci 1998;3:10-17.

Arnold M, Kooloos J, van Kampen A. Single-incision technique misses the anatomical femoral anterior cruciate ligament insertion: a cadaver study. Knee Surg Sports Traumatol Arthrosc 2001 Jul;9(4):194-9.

ACL RECONSTRUCTION IN THE IMMATURE SKELETON

Andrew Unwin BSc FRCS (Orth)

Consultant Orthopaedic Surgeon, The Windsor Knee Clinic, Windsor, Berkshire, UK

The ACL-deficient knee in the immature skeleton is a difficult management problem. Left untreated the orthopaedic literature suggests a poor outcome, with loss of sporting potential, regular episodes of instability, recurrent arthroscopic surgery for meniscal tears and osteoarthritic change within the knee at a young age.

Our group is of the view that reconstruction of the ACL is appropriate and largely necessary in the presence of symptomatic instability in the immature skeleton, a view which is not uniformly held in the orthopaedic community.

We have performed 48 ACL reconstructions in the immature skeleton, 8 under the age of 11 years, 12 at ages 11-14 and 28 in the 15-16 year age group.

The decision to proceed to reconstruction is symptomatic instability in the presence of ACL rupture, either as a single ligament deficiency or in combination with other ligament deficiencies. Meniscal repair and articular cartilage surgery is undertaken at the same episode of surgery. Most of our series underwent a preliminary examination under anaesthetic and arthroscopy to assess the degree of laxity and assess intra-articular pathology prior to reconstruction.

All reconstructions were performed using ipsilateral medial hamstrings as the graft. Tunnel diameters were on average 7mm to minimise disruption of the growth plate. The quality of hamstring grafts is good in this immature age group, and the grafts are relatively larger than in the adult population. A variety of fixation methods have been used although all have minimised disruption of the tibial and femoral growth plates. Latterly the preferred method of fixation is a bioabsorbable cross-pin proximally with interference screw fixation and a low profile staple distally.

All of our cases have been retrospectively reviewed and 23 are on prospective review. We have not had any cases of evidence of growth plate damage and no deformity or significant leg length discrepancy has occurred. There have been no ruptures of any of the reconstructed grafts. All except one retrospective and prospective cases reviewed have scored A or B on the IKDC scoring system. One case has scored D but on analysis this was due to factors other than ACL deficiency, and largely reflected meniscal and chondral pathology within the knee; this case had waited 47 months from the time of injury to reconstruction. There is a trend in our results for better outcome with more prompt reconstruction. Even in the case which scored D, no child or parent regretted the decision to have undergone reconstruction.

Although the results of ACL reconstruction in the immature skeleton offer an improved outcome over conservative treatment, the results of reconstruction in this age group are not as successful as in the adult population.

We conclude that ACL reconstruction in the immature skeleton is indicated in those children who have symptomatic instability. The results are better than conservative treatment alone although not as good as in the adult population. We have experienced no cases of catastrophic complication such as growth plate-derived deformity or leg length discrepancy. With respect to the pre-pubescent child with symptomatic instability, we do not believe there is a case for waiting until puberty to reconstruct.

ACL replacement in sheep with open physes: an evaluation of risk factors. Dr Seil

Objective

An in vivo sheep model was used to evaluate the risk of different transphyseal ACL reconstruction techniques for growth disturbances. The following potential risk factors were analyzed: (1) the peripheral localization of the femoral tunnel and its relation to the perichondral structures of the growth plate, (2) transphyseal bony bridge formation with respect to different graft diameters and (3) transphyseal graft fixation using a biodegradable interference screw on the tibial side.

Methods

Unilateral ACL reconstruction using an autologous Achilles tendon graft and rigid button fixation was performed in 24 4-months-old Merino sheep. The tunnel diameter was 5 mm in all groups. In group I (N=6) the transphyseal tunnels were left empty. In groups II, III and IV (N=6 in all groups) ACL reconstruction was performed using either a double-stranded graft with a diameter of 5 mm (groups II and IV) or a single stranded graft with a diameter of 3 mm. In group IV a supplemental transphyseal fixation using a biodegradable interference screw fixation ( 5 mm) was used on the tibial side. The grafts were all tensioned with 40 N.

Six months after the procedure, the animals were euthanized. Longitudinal growth was evaluated using X-rays of the operated and nonoperated legs. MRI was used to quantify the physeal injury. Physeal abnormalities and transphyseal bony bridges were analyzed histologically.

Results

Longitudinal growth was 1.6 (+/- 0.7) cm on the tibial side and 2.5 (+/- 0.7) cm on the femoral side. This corresponded to a longitudinal growth of 9.5 % of the initial length of the tibia and 13.4% of the femur, which was comparable to the expected remaining growth of a 10 year old child.

17/18 knees with ACL replacement (groups II-IV) were stable. Macroscopic analysis revealed one graft failure (group III). Quantification of the physeal injury revealed a lesion of 1.7 (+/- 1.8) % of the surface of the femoral physis and 1.7 (+/- 0.1) % of the tibial physis.

In 3 animals of group I (empty tunnels) a significant shortening of the lateral femoral condyle of 7.8 mm in average could be noted (p= 0.02). This corresponded to a valgus deformity of 12.8° (12-14°) and a flexion deformity of the lateral femoral condyle of 8.6° (5-15°). Histology showed a strong bony bridge formation over the physis and an injury to the perichondral structures. In the 3 remaining sheep of group I with an intact perichondral groove, no growth changes could be noted. In groups II-IV (tunnels filled with tendon grafts) the presence of a transphyseal bony bridge did not depend on the graft diameter. These bony bridges were smaller in comparison to those of group I and did not result in growth disturbances, even if the perichondral groove was injured (p<0.05).

Transphyseal fixation of the graft with a biodegradable interference screw (group IV) resulted in a dip deformity of the physis (p<0.01), but not in a shortening of the affected tibia.

Conclusions

Transphyseal ACL replacement in sheep did not cause any clinically relevant growth disturbances. Filling the tunnels with tendon grafts did not always prevent a transphyseal bony bridge formation. However, these bony bridges had no influence on longitudinal growth. Performing a transphyseal fixation of the graft on the tibial side by using a biodegradable interference screw resulted in a deformity of the physis, but did not affect longitudinal growth. Leaving the tunnels empty resulted in major growth deformities on the femoral side if the perichondral structures were injured. These structures, which might be injured either in a transphyseal or in an over-the-top technique for ACL replacement, represent a zone at risk for growth deformities.

TWO-BUNDLE ACL RECONSTRUCTION USING HAMSTRING TENDONS :

1 YEAR FOLLOW-UP RESULTS OF A PROSPECTIVE STUDY

G.Bellier*,P.Djian*,P.Christel

*Cabinet Goethe 3,rue Goethe 75116 PARIS FRANCE

email : bellier@genou.net

The hypothesis

Current techniques do not completely reproduce the anatomy and function of the ACL.They address only the anteromedial bundle,and do not fully reproduce ACL function throughout the range of motion.Current grafts control the anteroposterior stability of the knee in extension.To control the rotatory instability,several authors have suggested reconstructing also the posterolateral bundle.Anatomic two-bundle reconstruction restores knee kinematics more closely to normal than does single-bundle reconstruction.

Method

This nonrandomized prospective study is conducted on 148 patients operated on from January 2002 to July 2003,for an isolated ACL tear.Of them,46 patients (28 male,18 female) were available for 1-year follow-up.

Both antero-medial (AM) and postero-lateral (PL) bundles are arthroscopically reconstructed using hamstring tendons,with two femoral sockets and two tibial tunnels.The femoral fixation is achieved with Endobutton^® CL, and after cycling the tibial fixation is performed with BioRCI screws under a 50 N tension. The AM bundle is fixed at 20°-30° of flexion while the PL is fixed close to full extension. In addition both bundles are stapled on the tibia.All patients underwent the same postoperative rehabilitation protocol : passive range of motion exercises are immediately begun on CPM,50% partial weightbearing with a knee immobilizer for 1 month (1).

Results

According to the IKDC Knee Ligament Evaluation Form (global score), the pre-operative global scores were : 1(2.2%) normal,19(41.3%) nearly normal,20(43.5%) abnormal,6(13%) severely abnormal,the mean score was 60.3+/-2.4 [58-95].At 1 year follow-up, 15 patients (32.7%) are graded as normal ,22(47.8%) as nearly normal,6 (13%) as abnormal, 3(6.5%) as severely abnormal,the mean score is 79.5+/-1.6 [30-100].The improvement is statistically significant (p=0.003).The diminution of the anterior laxity measured with the KT 1000 is also statistically significant (p=0.001).

There are only 1 deficit in extension (B) and 5 deficits in flexion (3B,2C).The pivot-shift is absent in 37 patients (80%),scored as B (glide) in 8 patients and C (gross)only in 1 patient.

6 complications occurred : 3 stiffness in flexion which required an arthroscopic lysis of adhesions at 4 month post-op,2 post-op hemarthrosis treated by drainage,1 deep infection treated by lavage and antibiotics.

Discussion

The procedure is validated by a biomechanical study on cadaveric knees (5),and by clinical results (2,3,4). The persistence of the pivot-shift in 20% of cases doesn’t blame the principle of the procedure but probably the graft.The mean diameter of the posterolateral bundle (double stranded gracilis) is only 6mm. The rotational laxity has not been measured in our study.This will be done in a further work using the “Flock of Birds”,technique developped by A.Amis.

References

Bellier G, Christel P, Colombet Ph, Djian P, Franceschi JP, Sbihi A.

Double Stranded Hamstring Graft For Anterior Cruciate Ligament Reconstruction. Accepted for publication in Arthroscopy

M.Hamada,K.Shino et al.

Single versus bi-socket ACL reconstruction using autogenous multiple-stranded hamstring tendons.A prospective study. Arthroscopy,17,2001,801-807.

T.Muneta et al. Two-bundle reconstruction of the ACL using semite,dinosus tendon with endobuttons : operative technique and preliminary results. Arthroscopy,15,1999,618-624

JP.Franceschi,A.Sbihi,P.Champsaur Arthroscopic reconstruction of the ACL using anteromedial and posterolateral bundles.

Rev Chir Orthop 88,2002,691-697.

A.Sbihi, JP.Franceschi, P.Christel, G.Bellier*, P.Djian, P.Colombet.: Double bundle reconstruction of the ACL using hamstring tendons versus one bundle reconstruction : a biomechanical cadaveric study. Accepted for publication in Rev Chir Orthop.
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The Double Graft ACL Reconstruction. Can it restore normal kinematics?

DTT Lie,, AA Amis

Biomechanics Section, Imperial College, London.

Introduction: The pivot shift instability is not always completely abolished after ACL reconstruction. Despite objective restoration of the anterior laxity to intact levels, a residual tibial internal rotation of about 5° may persist (a ‘mini-pivot’). We hypothesised that the double graft (DG) technique would be better able to resist tibial rotation, and thus would be able to abolish this persistent rotation. This experiment was designed to validate whether the DG technique was superior to a typical reconstruction with a single graft (SG), in restoring laxity and kinematics.

Material & Methods: 8 cadaver knees were studied; intact, after cutting the ACL and after reconstruction with single and double grafts. Antero-posterior laxity was tested under ±150N, and rotational laxity under 5Nm internal-external torque in an Instron machine. The Flock-of-birds electromagnetic tracking device was used to measure tibio-femoral motion, during the pivot shift and unloaded flexion-extension. Bovine flexor tendons were used to simulate hamstring grafts. In the SG technique, the graft was positioned from the centre of the tibial footprint to a point determined by a 5mm-offset femoral drill guide at the 10:30 or 1:30 position. This position was close to the AM bundle. Laxity-matched pretensions were applied at 90° flexion. In the DG technique the graft was left in-situ to act as the AM bundle, the PL bundle was positioned posterior to the AM bundle on the tibia, and on the femur, about 10mm distal and 5mm posterior to the AM bundle (i.e. 10mm shallower and 5mm lower in a 90^o notch view). Laxity-matched pretension was applied at 20° flexion.

Results: Anterior laxity was restored by the SG and DG techniques at 60 and 90° flexion. At 20° flexion the DG technique reduced laxity (6.5mm) more (p=0.005) than the SG (7.4mm), compared to the intact (6.7mm). Tibial rotation was significantly reduced (p=0.002) at the above flexion angles, with the DG (range 28-38°) compared to the SG and normal rotation (32-40°). The pivot shift was recreated by applying 54N ilio-tibial band load, 2.9Nm valgus and 1.8Nm internal rotatory torques. Anterior subluxation was reduced by both techniques. The internal rotation during the pivot shift (17.4°) was persistent after the SG technique (8.5°) compared to normal (4.8°). This rotation was abolished or overcorrected by the DG technique (1.3°), significantly different from intact (p=0.02) and SG (p=0.0005). During flexion, tibiae after both SG and DG reconstruction were subluxed posteriorly and rotated internally.

Conclusion: The SG technique was adequate if anterior laxity was the only objective test, though residual rotation was present. The DG technique was better able to restore rotational laxity and abolish the pivot shift. This technique appears to be biomechanically superior in vitro.

Is phase of menstrual cycle associated with ACL injury in alpine skiers?

B Beynnon, R Johnson, M Sargent, A Frodsham, S Braun, B Brattback

Department of Orthopaedics and Rehabilitation

McClure Musculoskeletal Research Center

University of Vermont, Burlington, Vermont

Background and Significance

The incidence of anterior cruciate ligament (ACL) injury among female athletes has been shown to be 2 to 8 times greater than that of male athletes.^1,2,3,4,5,6 Several intrinsic and extrinsic factors for these injuries have been identified.⁷ Three studies have investigated the association between phase of menstrual cycle and ACL injury risk.^6,8,9 Two of these studies^8,9confirmed actual hormone levels and phase of the cycle at the time of injury. Wojtys et al.⁹ found a higher than expected number of non-contact ACL injuries during the ovulatory phase of the menstrual cycle based on urine samples. Slauterbeck⁸ found an increased risk of incurring ACL injury during the follicular phase of the menstrual cycle based on saliva analysis of hormone levels. Myklebust⁶ found a greater risk of ACL injury during the late luteal and menstrual phases based on self-reported menstrual history. While these studies suggest an increased risk of sustaining an ACL injury during certain phases of the menstrual cycle, there are limitations that have not been addressed in this type of investigation. First, none of these studies compared the risk of injury with respect to phase of the menstrual cycle to that of a matched control group that accurately represents the population at risk for ACL injury. Additionally, urinalysis is an indirect technique for the measurement of hormone levels as compared to either saliva or serum-based approaches, and may not be reliable because it is dependent on hydration status. Likewise, self-report has not been shown to be a reliable method of determining phase of menstrual cycle and only one study followed the subjects to verify the onset of next menses,⁹ a detail which is important for accurately determining the phase of cycle during which the subject was injured. Epidemiological evidence has yet to clearly elucidate the relationship of hormonal factors to ACL injury risk. The purpose of this study was to determine, based on serum hormone levels, if the phase of menstrual cycle has an effect on the risk of ACL injury.

Specific Aims and Hypothesis

The specific aims of this case-control study were to identify female athletes with ACL disruptions, obtain serum estrogen and progesterone levels, and then correlate these values with the menstrual cycle to determine if incidence of ACL injury is affected by phase of menstrual cycle. These subjects were compared with matched, uninjured control subjects. Our primary hypothesis was as follows: menstrual cycle phase, as documented by serum concentrations of estradiol and progesterone, can be used to identify female athletes at increased risk of anterior cruciate ligament trauma.

Methods

This case-control study was performed at the Sugarbush Clinic (in affiliation with The University of Vermont) during the 2001-2003 ski seasons. Subjects were excluded for the following: history of Grade II or Grade III knee ligament sprain, history of previous surgical procedure involving the knee, history of metabolic disease such as diabetes, presence of a degenerative joint disease such as Juvenile Rheumatoid Arthritis, use of oral contraception, recent or current pregnancy. Female alpine skiers with ACL injuries and uninjured female controls were enrolled. Immediately following injury on the mountain, subjects were transported to the Sugarbush Clinic where the diagnosis of a knee ligament injury was made by an orthopaedic surgeon or sports medicine physician. Determination of an ACL injury was made using the most sensitive clinical testing method, Lachman’s Test, by the treating physician. ACL injuries were then confirmed by arthroscopy or MRI through the use of a questionnaire and follow-up contact via telephone. At the time of the initial diagnosis on the day of injury, serum levels of estradiol and progesterone were measured. Control subjects also provided serum for the analysis of estradiol and progesterone levels. The blood samples were transported to the laboratory for chemiluminescence immunoassay analysis by the investigators. Injured and control subjects completed a questionnaire regarding menstrual history, use of medication, and injury history.

Determination of menstrual cycle phase was made based on serum concentrations of estradiol and progesterone. In the normal menstrual cycle, low estradiol (<100 pg/ml) and low progesterone (<2.0 ng/ml) define follicular phase. High estradiol (>100 pg/ml) and low progesterone (<2.0 ng/ml) define ovulatory phase. Moderately high estradiol (>100 and < 300 pg/ml) and high progesterone (>2.0 ng/ml) define luteal phase.

The Pearson Chi-Square test was used to compare the proportion of subjects in each phase of the menstrual cycle (follicular, ovulatory, and luteal) between those who suffered ACL injuries and uninjured controls.

Results

All Injured subjects were alpine skiers. Thirty-seven females with grade III ACL sprains and 41 controls participated. Ninety percent of subjects had the injury confirmed by arthroscopy or MRI. Injured subjects ranged from 15 to 50 years of age (mean ± SD, 37.41 ± 9.22 years) and control subjects ranged from 14 to 50 years of age (33.68 ± 9.17 years).

Serum analysis of the injured subjects demonstrated that there were 14 (38% of those injured) subjects in the follicular phase, 12 (32%) in the ovulatory phase and 11 (30%) in the luteal phase. Serum analysis of the control subjects demonstrated that there were 13 (32% of those uninjured) subjects in the follicular phase, 10 (24%) in the ovulatory phase, and 18 (44%) in the luteal phase.

There was no significant differences found between injured and uninjured groups with regard to the proportion of subjects in the follicular, ovulatory, or luteal phases of menstrual cycle (x²=1.70, p=0.43).

Discussion

Previous research has implicated phase of menstrual cycle as a risk factor for ACL injury ^6,8,9; however, we were unable to demonstrate that phase of menstrual cycle is associated with risk of ACL injury in alpine skiers. One explanation for our inability to demonstrate an effect of phase on risk of ACL injury may be explained, at least in part, on the sample size. A power analysis revealed that ninety injured and control subject would be needed to demonstrate a twenty percent increase in the proportion of skiers injured during the follicular phase in comparison to controls. Alternatively, we only studied one risk factor and it may be that other extrinsic (eg skis, binding, boots, conditions etc.) and intrinsic (eg neuromuscular, biomechanical, anatomic etc.) factors act in combination to increase the risk of ACL injury amongst females.

References

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

2. Gwinn DE, Wilkens JH, McDevitt ER, Ross G, Kao T-C: The relative incidence of anterior cruciate ligament injury in men and women at the United States Naval Academy. Am J Sports Med 28(1):98-102, 2000

3. Ireland ML: Anterior cruciate ligament injury in female athletes: Epidemiology. J Athl Train 34(2):150-154, 1999

4. Lindenfeld TN, Schmitt DJ, Hendy MP, Mangine RE, Noyes FR: Incidence of injury in indoor soccer. Am J Sports Med 22:364-371, 1994

5. Messina DF, Farney WC, DeLee JC: The incidence of injury in Texas high school basketball. A prospective study among male and female athletes. Am J Sports Med 27(3):294-299, 1999

6. Myklebust G, Maehlum S, Holm I, Bahr R: A prospective cohort study of anterior cruciate ligament injuries in elite Norwegian team handball. Scan J Med Sci Sports 8:149-153, 1998

7. Murphy DF, Connolly DAJ, Beynnon BD: Risk factors for lower extremity injuries: A review of the literature. Br J Sports Med 37:13-29, 2003

8. Slauterbeck JR, Fuzie SF, Smith MP, Clark RJ, XU KT, Starch DW, Hardy DM: The Menstrual Cycle, Sex Hormones, and Anterior Cruciate Ligament Injury. J Athl Train 37(3):275-280, 2002

9. Wojtys EM, Huston LJ, Boynton MD, Spindler KP, Lindenfeld TN: The effect of the menstrual cycle on anterior cruciate ligament injuries in women as determined by hormone levels. Am J Sports Med 30(2):182-88, 2002

Neuromechanical Factors for Injury During Tasks Implicated in Noncontact ACL Injuries

Sell TC, Ferris CM, Abt JP, Tsai Y, Myers JB, Lephart SM, Fu FH

Neuromuscular Research Laboratory

Department of Orthopaedic Surgery

University of Pittsburgh

OBJECTIVE: Researchers performing qualitative analyses of noncontact anterior cruciate ligament injuries have implicated jumping and landing tasks that have a change in direction with a deceleration component as a possible mechanism of injury. To date, biomechanical research has focused primarily on cutting tasks and straight landing tasks. In addition, these assessments are typically performed during controlled, planned jumps. The purpose of this study was to examine jumping and landing tasks that incorporate both directional change and deceleration components like the mechanisms implicated in noncontact ACL injuries. This examination also included tasks with a reactive component that was designed to better simulate game conditions.

METHODS: Thirty-five healthy, varsity basketball players (18 males [age: 16.4±1.5 yrs], 17 females [age 15.9±1.1 yrs]) underwent a neuromechanical analysis of the right knee during two-legged stop-jump tasks in three different directions (left, vertical, and right) under two different conditions (planned and reactive). For the reactive jumps, the subjects had to react to a visual cue (from a computer screen) regarding jump direction after the initiation of the task. Ground reaction forces, joint kinematics, and EMG activity were assessed during the task. In addition, an inverse dynamics procedure was used to calculate joint resultant moments and anterior tibia shear force.

RESULTS: All data were analyzed with three-way ANOVA for jump direction, condition (planed vs. reactive), and sex. Also, a stepwise multiple linear regression procedure (p<0.05) was performed to determine what neuromechanical factors predicted anterior tibia shear force at the point of maximum deceleration (peak posterior ground reaction force). Significant differences were observed (p<0.05) among the jump directions such that jumping away from the tested knee (right) resulted in increased anterior tibia shear force, flexion moment, valgus moment, vertical ground reaction forces, deceleration forces, and a decreased flexion angle at initial contact. During the reactive jumps, subjects demonstrated significantly (p<0.05) greater anterior tibia shear force at takeoff, greater flexion moment, greater deceleration forces, and less knee flexion at initial contact. Females demonstrated significantly greater anterior tibia shear force, less knee flexion, less deceleration forces, greater hamstrings activity, and co-contraction of the quadriceps and hamstrings compared to males. For the regression analysis, an equation based on flexion angle, valgus angle, flexion moment, hamstrings activity, and posterior ground reaction force was able to significantly predict anterior tibia force at the time of maximum deceleration (R²=0.7584).

CONCLUSION: Both jump direction and type of task (planned vs. reactive) significantly influenced the neuromechanical characteristics of the knee during the jumps indicating that future research should target reactive athletic tasks that include a change in direction. There was also a difference between sexes in dynamic knee stabilization strategies as evidenced by the greater anterior tibia shear force. This may possibly indicate that females are at a greater risk for noncontact ACL injuries during jumping and landing tasks that include a deceleration component and a change in direction.

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials

Peter Burkart , Tecklenburg K⁺, Hoser C⁺, Fink C⁺

*St. Anna Hospital, Luzern CH

⁺University Hospital for Traumatology, Innsbruck A

Materials and methods: Three groups of patients have been prospectively evaluated. In all patients ACL reconstruction has been performed using patellar tendon autograft and distal fixation was either (A) Biloc screw (Atlantec) , (B) Bio RCI - HA (Smith&Nephew) or an (C) allograft interference screw (Regeneration).

IKDC and subjective IKDC were used preoperative and for follow up. CT scans have been performed post op and at 3, 12 months (24 months) and MRI‘s at 3 months (and 24months).

Results: (2 year follow up will be completed February 2004 and presented)

One breakage of an interference screw during insertion was encountered intraoperatively in groups A and B. At one year follow up there were no significant differences within the groups with respect to objective and subjective clinical results. IKDC evaluation revealed group A: 13 A, 5 B, 1 C, group B: 13 A, 6 B and group C: 18 A, 1 B. On MRI no inflammatory response could be detected in any of the patients of all groups. CT scans documented no loss of graft fixation, no significant bony resorption, but also no signs of bone ingrowth or replacement in the two groups with composite screws (A and B). At one year the allograft screws (C) remained unchanged without signs of resorption.

Endoscopic Reconstruction of the Anterior Cruciate Ligament Using the Quadriceps Tendon Graft and Rigid Fixation

A Randomized Prospective Study with 2 Years Follow-up

Pietro Randelli MD, Massimo Berruto MD, Eugenio Uderzo MD, Simonetta Odella MD, and Matteo Denti MD

From the San Donato Polyclinic Institute, San Donato Milanese, Milan, Italy (P.R.) and the Gaetano Pini Orthopaedic Institute, Milan, Italy (M.B., E.U., S.O.) and the Galeazzi Orthopaedic Institute, Milan, Italy (M.D.)

Address Corrispondence: Pietro Randelli M.D. , Via Quintiliano 5, 20138 Milano, Italy. Email: pietro.randelli@tin.it Tel +39-02-58.01.80.09 , Fax +39-02-700.352.42

Introduction

No agreement has been achieved yet about the best grafting procedure for the reconstruction of the Anterior Cruciate Ligament (ACL). The ideal graft should be easy to obtain and should cause the lowest possible damage to the donor site(1). The graft should also reproduce as much as possible the insertional anatomy of the ACL, thus allowing an immediate and rigid fixation which should lead to a progressive ligamentization. Moreover, the graft should have the same mechanical and structural characteristics as an healthy ACL.

As to the works of Cooper, Muellner and Noyes (2, 3, 4), the biomechanical characteristics of the middle third of the patellar tendon are more than satisfactory, with a Strength of 2900 +/- 260 N thru 3899 +/- 298 N and a Stiffness of 454 +/- 57 N/mm thru 685 +/- 86 N/mm. Nevertheless it also has some non negligible disadvantages, such as pain in the sampling location (31% to 79%), anterior patellar pain (3% to 47%), the risk of patellar fracture (0.35% to 2.3%) and finally, in the 6% of the cases, patellar tendinitis might arise (1).

The use of quadruple semitendinosus and gracilis tendon became very popular, especially during the last five years. The biomechanical characteristics of this type of graft are, as well, more than satisfactory for the substitution of the ACL, as it has a Strength of 2830 +/- 538 N thru 4590 +/- 674 N, and a Stiffness of 455 +/- 97 N/mm thru 861 +/- 186 N/mm, according to the authors (5 - 6). Yet, this type of graft could produce various disadvantages, such as pain in the sampling location (6% of cases), reduction of about 10% of the lever function of the hamstring group (gracilis, sartorius and semitendinosus), and risk of injuries at the saphenous nerve (7). An expansion of the tibial reaming can also occur, due to the windshield wiper effect.

There are still many doubts about the reliability of the various ways of fixation of this type of grafting, both at femoral and at a tibial level, and also about the kind and quality of bone-tendon integration, at reaming level (8 - 9). Besides, the sampling of the knee flexor muscles can interfere with the proprioceptive reflex arc which protects the ACL (10 - 11), causing a loss in the limb control, concerning the lower extremities. Post-mortem grafts (fresh frozen grafts) also are a good choice for the reconstruction of the ACL, thanks to the absence of morbidity in the donor location, to the inexhaustible source, to the possibility of a more rapid rehabilitation. Unfortunately there also are some disadvantages, such as the risk of transmission of infectious disease , the high costs and a slow ligamentization (12 - 14). Besides, in Europe the use of this type of graft is very difficult, due to a lacking regulation.

Several authors as Blauth (15), Staubli (16), Harris (12), Fulkerson (17) and Pederzini (18), published their works about the use of the graft from the quadriceps tendon as a good substitute of the patellar tendon: in fact it has a breaking load of 2376 +/- 152 N and a stiffness of 313 +/- 50 N/mm. Also, it has a cross section of 64.6 mm², so it is much wider than the patellar tendon and its sampling shows less morbidity in the donor location (1). Other remarkable characteristics of the quadriceps tendon are its length, 6.1 +/- 1 cm, its width, 2.7 cm (range 2.1 - 3.7) and its thickness, which is on average 1.8 times thicker than the patellar tendon (12). The graft from the quadriceps tendon allows a better fixation than the gracilis and semitendinosus, due to a bony section at one of the two ends of the tendon.

Theoretical Premises

A rigid and bioabsorbable system of fixation (Rigid-Fix, Mitek, Ethicon, Westwood, Massachusetts, U.S.A.), already used for the proximal fixation both of the semitendinosus and of the patellar tendon, recently became available on the market. This suggested us to develop a new potentially highly reliable surgical technique of fixation for the graft from the quadriceps tendon.

The femoral fixation with double bioabsorbable pin, in fact, combines both the reliability characteristics of the classical transcondylar fixation and the possibility to obtain a growth of the fibres by inserting the nails through the fibres of the graft, with a following enlargement of the tendon-bone contact area at reaming level.

The quadriceps tendon is similar to the loop of the duplicated semitendinous, due to its structural characteristics and to its section area. The passage of the nails through its fibres can, therefore, cause their growth, thus increasing the contact area and making the fixation of the tendinous section of the graft at the femoral level more reliable.

Aim of the study

Aim of this study is to compare the reliability of an original new technique of ACL reconstruction with QTG to reconstruction with other grafts (BPTB /HAMS) and other fixation options.

Materials and Methods

In the period may 2000- may 2001 we treated 75 consecutive male with ACL deficient Knee with 5 different ACL reconstruction procedures for a Prospective Randomized study.

The patients were included in 5 groups. In the group A we treated 15 male, age 16-36 (mean 22.2), using the BPTB graft fixed with interference screws at both side. In the group B we treated 17 male, age 16-40 (mean 20.5), using the BPTB graft fixed with interference screw at the tibial side and a transcondilar metallic screw on the femur. In the group C we treated 15 male, age 17-39 (mean 24.5), using the BPTB graft fixed with Rigid-fix on the femur and interference screw at the tibial side. In the group D we treated 15 male, age 16-42 (mean 23.4), using the HAMS graft fixed with the Rigid-fix at the femur and with a Washer Lock at the tibial side. In the group E we treated 13 male, age 20-41 (mean 23.5), using the quadriceps tendon graft fixed using the Rigid-fix at the femur (soft end) and with an interference screw at the tibial side (bone end). The patients were evaluated using different criteria: Subjective (IKDC / new IKDC, pain, swelling, donor site morbidity), Objective (Lachman, Pivot-Shift, KT1000), Functional (One leg hop / Tegner), Overall(IKDC). An MRI was performed on every patient of the group E at 1 and 2 years after surgery. The results were statistically evaluated using the Student T-Test.

Original Surgical Technique for the Acl Reconstruction using the Quadriceps Tendon Graft and the Rigid-Fixation

The initial phase includes the standard procedure that the authors used for the reconstruction of the ACL, regardless of the graft type chosen. At first, an articular balance is performed by arthroscopic diagnosis, and then, if necessary, the possible combined injuries of the meniscus or of the cartilage are treated. The plasty of the groove should then be performed very carefully, in order to find the proximal isometric site of insertion, as Rosemberg described (19).

After that, a 7 or 8 cm long median longitudinal sovrapatellar surgical inlet is created. A transverse epirotulian inlet (20) is also possible, but, although preferable from an aesthetical point of view, it could cause necrotic cutaneous sufferings, so it is not advisable. Some authors also described the possibility of performing the arthroscopy and the sampling simultaneously, with two teams (17).

Once the cutaneous and subcutaneous tissues are cut, the quadriceps tendon should be exposed. As the quadriceps tendon is slightly curved, and bends, at a proximal level, on one side (12), be careful that its middle section is perfectly evident up to its proximal ending. At the patellar level, the corresponding proximal bone plug, 9 - 10 mm wide and about 20 mm long, can then be obtained. It is important that the swinging saw does not go deeper than 7 mm. Starting from the bone plug, the dissection of the tendon of the vastus intermedious is carried out up to a maximum depth of 6 - 7 mm (the total thickness of this tendon is 8 mm); the aim is not to open the sovrapatellar pouch, to avoid a loss of distension in the following arthroscopic phase. It is also possible to extract the whole tendon, with a minimum length of 7 cm . The tendon defect is then sutured carefully.

It is better to postpone the suture of the cutaneous and subcutaneous tissues at the end of the operation, because in case of loss of articular distension, the possible lack of tendon approach is easy to locate.

While the surgeon continues the arthroscopy, the assistant performs the preparation for the graft. This is very important for the success of the operation. The end of the tendon should be prepared for a length of 27 thru 30 mm and should be armed with bioabsorbable 0 thread; the aim is to make the tendon end regular and even for the whole length of the reaming. Another non bioabsorbable thread (Dexon 2 - Ethicon, Westwood, Massachusetts, U.S.A.) should subsequently be passed through and anchored, to pull the graft through the femoral tunnel, without causing any laceration.

A tibial tunnel (8 thru 10 mm diameter, depending on the patellar plug dimensions) with emergency at the isometric point of the tibial plateau and a femoral tunnel (7 thru 10 mm diameter, depending on the cross section of the quadriceps tendon, by 30 mm length), in isometric position too, are then reamed.

The Rigid - Fix tool assembly (Mitek, Ethicon, Westwood, Massachusetts, U.S.A.) for soft tissues can now be inserted. This tool assembly is composed by an U - shaped compass, which is to be inserted in the femoral tunnel with one of its proximal endings. The opposite ending stays on one side of the femur and must be set to let the two reaming pointers well above the lateral articular spacing. The reaming cannulae are inserted and the two tunnels for the fitting of the Pins are drilled (use the 3.2 mm diameter pins designed by the company for gracilis and semitendinosus tendons) (see Fig. 1).

Fig. 1: the Rigid - Fix compass system

(Mitek, Ethicon, Westwood, Massachusetts, U.S.A.)

At this time, a measurement of the tunnels length is carried out by inserting a Kirschner thread up to its end, and depending on the tunnels dimension, the final preparation of the quadriceps tendon can be performed.

An eyed thread is inserted into the tunnels and pulled over the anterolateral femoral cortics, as described in the Half - Tunnel technique (19). The eyed thread is connected to the bioabsorbable traction thread of the free end of the quadriceps tendon, to pull it and to insert it into the joint. The fibres of the graft must preferably be perpendicular to the pins; in fact the pins must cut across the two quadriceps bundles to produce its expansion. Once the graft packs the femoral tunnel, the 2 bioabsorbable pins of the Rigid-Fix system can be inserted (see Fig 2). Subsequently the graft is pulled in distal direction and a cyclic load, with repeated flexo-extensions of the knee, is applied. Make sure, by arthroscopy, that there is no loosening of the femoral fixation, and then perform the distal fixation with an interference or bioabsorbable screw.

This last fixation should be done with the extended knee, maximum 15° bending, and a manual traction of the graft. 30 articular flexo-extensions are usually performed before the distal fixation of the graft, to avoid a secondary extension, as Brown and Skylar suggested (21).

Finally, the tightness of the graft is checked out with the tests of Lachman and Pivot-shift (22) and, after inserting a double drainage, the cutaneous and subcutaneous tissues and of the arthroscopy inlets are sutured.

Fig. 2: illustration after proximal fixation with Rigid - Fix (Mitek, Ethicon, Westwood, Massachusetts, U.S.A.) and distal interference metal screw.

Rehabilitation Protocol

The post-operative rehabilitation is similar to that of the grafts with hamstrings or patellar tendon, which consists of a controlled partial load for 15 - 20 days without knee orthosis, a fast articular recovery, running after three months and contact sports at normalization of the recovery parameters (muscular strength, agility and proprioceptive control) (23).

Results

The mean follow-up is 2.7 years (24-34 months). No patient had complications nor revision surgeries. The Subjective IKDC score is illustrated in tab. 1

Tab.1

The subjective evaluation for pain included in the ranking A the 84% of the patients of the group E, 79% of the patients with BPTB harvested and the 80% of the group D. In the evaluation of the swelling were classified A the 92% of the patients in group E, 93% of the group D and 86% of the BPTB groups. In the evaluation of the giving way were classified A the 100% of the patients in group E, 100% of the group D and 95% of the BPTB groups. The Donor site morbidity was extremely low in the group E (8% of the patients scored B-C), if compared with group D (14%) and the BPTB groups (15%). The Lachman test was negative in 84% of the patients in group E, 80% of group D and 77% of the BPTB groups. The Pivot-shift test was negative in 86% of the patients in group E, 80% of group D and 82% of the BPTB groups. The KT-1000 evaluation was 0-2.5 mm for 84% of the patients in group E, 80% of group D and 80% of the BPTB groups. In the Tegner Evaluation we had 73% of the patients having the same sport at the same preinjury level in the group E, 64% in the group A, 77% in the group B, 67% in the group C, 73% in the group D. The Overall IKDC evaluation score is reported in tab. 2.

Tab.2

The 1 and 2 years MRI evaluation of the group E, showed 13 cases of pins still in place, 1 case of femoral tunnel enlargement, and 1 case of tibial tunnel enlargement.

Discussion about the Quadriceps Tendon Graft and Its Fixation

Stated that the graft from the quadriceps tendon has biomechanical characteristics similar to those of the patellar tendon and can therefore be considered as an alternative for the reconstruction of the ACL, we still have to settle the problem of the fixation.

There are only two studies with a 2 year follow-up, about the use of this kind of graft. The first one, done by Fulkerson (24), relates quite the same results as the central third of the patellar tendon, considered as the Gold Standard, but it shows a method of fixation which is different to the one we described in this study, that concerns both of the two endings. The bony end of the graft is inserted at the femoral level, and fixed with an interference screw, while at the distal level a new system (Compression Anchor) is used, together with the interference screw. This system showed a high tightness level in the laboratory tests: slippage of 0.2 mm under a load of 150 N for 5000 cycles (25).

There still are many doubts on that technique, which is less successful then the one we described, because, as Kousa and Jarvinen showed (8), at the femoral level the Rigid-Fix system is more successful then the interference screws. Besides, on the distal side, we have the bone plug, instead of the soft tissues. We can therefore use the interference screw avoiding the risk of insufficient fixation, which happens, for example, if we use bioabsorbable interference screws with the gracilis or the semitendinosus (9).

The other work, a 2 year follow-up study too, by Shelton (20), relates quite the same results as those of the control group, which was treated with patellar tendon. In this study the proximal method of fixation on the bone plug, with interference screw, was used as well, whereas on the distal side the tendon was divided into two tails, and the bioabsorbable interference screw was inserted between those two parts.

We still have doubts about the efficacy of the tibial fixation, which is peculiar of the pro-ACL soft tissues grafts. Brand (10), in his study on cadavers, showed that the tightness of the interference screws on the quadriceps tendon free ending, when fixed to the tibia, is 59 % less then the interference fixation bone plug - tibia; therefore he proved the insufficiency of the soft tissues fixation at the tibial level.

Besides, those two techniques do not avoid the risk of secondary effects such as the windshield wiper, due to the unsatisfactory tibial fixation of the soft tissues.

Our technique, on the other hand, using a system which proved reliable for the fixation of the soft parts at the femoral level, avoids the problem of the tibial fixation, making it similar to the patellar tendon fixation

Conclusion

Results of ACL reconstruction with QTG are better subjectively and in terms of donor site morbidity if compared with those obtained with BPTB & HAMS grafts. Objectively the stability obtained with QTG is similar to BPTB fixed with “gold standard” fixation methods and better when compared to BPTB and HAMS fixed with the same method.

The fixation of the soft end of the QTG in the femoral tunnel by absorbable cross-pins seems to be reliable in terms of stability over time.

The fixation of the bone block in the tibial tunnel by interference screw reduces the incidence of tunnel widening observed in the ACL reconstruction with HAMS.

With this procedure QTG should represent a possible valid alternative to BPTB but in particular to HAMS for ACL reconstruction.

The authors recommend the use of the quadriceps tendon, with the surgical technique explained, both in the primary ACL reconstruction, and in the revision.

The use of the quadriceps tendon pro-ACL in the primary reconstruction, as a standard, is advisable in case of pre-operative pain in the anterior area, or when the patient does a working or sporting activity in a genuflected position.

REFERENCES

1. Brown C.H.. Hamstring Autograft. ACL graft selection in 2001. Instructional Course, 68^th AAOS. San Francisco. 1/3/2001

2. Cooper D.E., Deng X.H., Burstein A.L., Warren R.F. The strength of the central third patellar tendon graft. A biomechanical Study. Am J Sport Med, 1993; 21; 818-824.

3. Muellner T., Rihsner R., Mrkonjic W., Kaltenbrunner W. Et al. Twisting of patellar tendon grafts does not reduce their mechanical properties. J. Biomechanics 1998, 31: 311-315.

4. Noyes F.R., Butler D.L., Grood E.S., et al. Biomechanical analysis of human ligament grafts used in knee ligament repairs and reconstructions. J Bone Joint Surg 1984, 66-A: 344-352.

5. Hamner D.L., Brown C.H., Steiner M.E., Hecker A.T., et al. Hamstring tendon graft for reconstruction of the anterior cruciate ligament: Biomechanical evaluation of the use of multiple strands and tensioning technique. J Bone Joint Surg 1999, 81-A: 549-577.

6. Hecker A.T., Brown C.H., Deffner K.T., et al. Tensile properties of young multiple stranded hamstring tendon grafts. Book of abstracts and outline speciality day American Orthopaedic Society for Sports Medicine, California, page 8, 1997.

7. Bertram C., Porsch M., Hackenbroch M.H., Terhaag D. Saphenous Neuralgia After Arthroscopically Assisted Anterior Cruciate Ligament Reconstruction With a Semitendinosus and Gracilis Tendon Graft. Arthroscopy, 16: 763-766, 2000.

8. Kousa P., Jarvinen T., Vihavainen M., Kannus P., Jarvinen M. Biomechanical evaluation of five different fixation devices for Anterior Cruciate Ligament Hamstring grafts- Femoral site. Presented at the AOSSM 2001 Specialty Day 3/3/2001, San Francisco. U.S.A.

9. Kousa P., Jarvinen T., Vihavainen M., Kannus P., Jarvinen M. Biomechanical evaluation of five different fixation devices for Anterior Cruciate Ligament Hamstring grafts- Tibial site. Presented at the AOSSM 2001 Specialty Day 3/3/2001, San Francisco. U.S.A.

10. Brand J., Hamilton D., Selby J., Pienkowski D., Caborn D.N.M., Johnson D.L. Biomechanical comparison of quadriceps tendon fixation with patellar tendon bone plug interference fixation in cruciate ligament reconstruction. Arthroscopy 16: 805-812, 2000

11. Tsuda E., Okamura Y., Otsuka H., Komatsu T., Tokuya S. Direct evidence of the Anterior Cruciate Ligament-Hamstring Reflex Arc in Humans. Am J Sport Med 2001; 29; 83-87.

12. Harris L.N., Smith D.A.B., Lamoreaux L., Purnel M. Central Quadriceps Tendon for Anterior Cruciate Ligament Reconstruction. Morphometric and Biomechanical Evaluation. Am J Sport Med 1997; 25; 23-28.

13. Falconiero R.P., DiStefano V.J. Comparison of revascularization and ligamentization of autograft and allograft tissue for anterior cruciate ligament reconstruction in humans. Orthop Trans 1994, 18: 1096.

14. Jackson D.W., Grood E.S., Goldstein J.D., et al. A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat models. Am J Sport Med 1993; 21; 176-185.

15. Blauth W. 2-strip substitution-plasty of the anterior cruciate ligament with quadriceps tendon. Unfallheilkunde 87: 45-51, 1984

16. Staubli HU: Arthroscopically assisted ACL reconstruction using autologous quadriceps tendon, in Jacob RP, Staubli HU (eds): The knee and cruciate ligaments: Anatomy, Biomechanics, Clinical Aspects, Reconstruction, Complications, Rehabilitation. New York, Springer Verlag, 1992, pp 443-451.

17. Fulkerson J.P. Central Quadriceps Free Tendon Reconstruction of the ACL. ACL graft selection in 2001. Instructional Course, 68^th AAOS. San Francisco. 1/3/2001

18. Pederzini L., Adriani E., Botticella C., Tosi M. Technical note: double tibial tunnel using quadriceps tendon in anterior cruciate ligament reconstruction. Arthroscopy 16: 9-9, 2000

19. Rosenberg TD. Endoscopic technique for anterior cruciate ligament reconstruction with PRO-TAC tibial guide. Norwood, Mass: Acufex microsurgery Technical Bulletin, 1991.

20. Shelton W.R. Quadriceps Tendon Graft for ACL Reconstruction. AANA 2001 Specialty Day 3/3/2001, San Francisco. U.S.A.

21. Brown C.H., Skylar J.H. Quadrupled hamstring tendons and Endobutton femoral fixation. Tech Orthop 13(3): 281-298, 1998.

22. Insall J.N. Chirurgia del Ginocchio. Verduci ed. 1994, pag. 68-69.

23. Shelbourne KD, Nitz P: Accelerated rehabilitation after anterior cruciate ligament reconstruction. Am J Sports Med 1990; 18: 292-299.

24. Fulkerson J.P., Langeland. An alternative cruciate reconstruction graft: the central quadriceps tendon. Arthroscopy 11: 252-254, 1995

25. Nagarkatti D.G., McKeon B.P., Donahue B.S., Fulkerson J.P. Mechanical evaluation of a soft tissue Interference screw in free tendon anterior cruciate ligament graft fixation. Am J Sport Med 2001; 29; 67-71

TISSUE ENGINEERING OF XENOGRAFTS FOR ACL RECONSTRUCTION

Authors:

Kevin R Stone MD The Stone Clinic, San Fransisco, CA, United States of America
Ann W Walgenbach RNNP The Stone Clinic, San Fransisco, CA, United States of America
Thomas J Turek CrossCart Inc., San Francisco, CA, United States of America
Damon Somers CrossCart Inc., San Francisco, CA, United States of America
Winston Wicomb PhD CrossCart Inc., San Francisco, CA, United States of America
Uri Galili PhD Rush University, Chicago, IL, United States of America

Objective: Advances in tissue engineering, xenograft immunology and bioprosthetic tissue pathophysiology have contributed to our development of an immunochemically modified porcine bone-patellar tendon-bone ACL reconstruction device. Treatments include: enzymatic cleavage of the primary pig to human discordant epitope with alpha-galactosidase, low-level glutaraldehyde cross-linking and validated sterilization at 1.8 mRAD. Objectives were to evaluate the long-term functional efficacy of treated porcine grafts in a primate ACL reconstruction model.

Methods: : Testing used a rhesus ACL reconstruction model with 2, 6 and 12-mo sacrifice time points and clinical, histological and biomechanical evaluations. Twenty animals were used in this evaluation, with 2-mo controls of untreated porcine graft and rhesus allograft and 12-mo rhesus allograft controls. Biomechanical assessment at 6 and 12-mo used standard methods to test both reconstructed and un-operated ACL’s.

Results: Treated porcine grafts were well tolerated and all animals presented with acceptable outcomes for range of motion and laxity. Operative limb gross observations revealed normal articular cartilage and synovium. Graft histopathology at 2-mo showed normal peripheral synovial formation and modest fibrohistiocytic cellular infiltration for treated porcine and rhesus allograft, and a contrasting resorption and granular tissue replacement of the untreated porcine graft. Histopathology at 6 and 12 mo revealed functional graft integrity characterized by remodeled and mature collagen and interspersed fibroblasts. The host bone interface exhibited mature integration and active loading of graft tendon and bone. Graft maturation from 6-mo to 12-mo included a decrease in cell density and increased remodeling of graft collagen. Biomechanical testing yielded structural and material property values with: increases in ultimate load (50%) and stiffness (65%) between 6 and 12-mo evaluations, no significant differences between treated porcine grafts and rhesus allografts at 12 months, and comparable findings to published ACL reconstruction studies.

Conclusions: Evaluations demonstrate a mechanism of host incorporation and graft remodeling similar to human autograft “ligamentization” with temporally increasing graft strength. This investigation supports the long-term efficacy of immunochemically modified porcine grafts for ACL reconstruction. Preliminary results from an FDA approved pilot trial of human ACL reconstruction using treated porcine bone patellar tendon bone devices will be presented.

Acknowledgements: Authors would like to thank Thomas Hansen and Dr. Roy Gealer from Harrington Arthritis Research Center for biomechanical testing. Authors have received funding from and have a financial interest in CrossCart, Inc. the manufacturer of the xenograft devices.

Proposed Mechanism for Anterior Cruciate Ligament Injury

K. Donald Shelbourne, MD

Background: Several mechanisms for ACL injury have been described. Recent studies have found that forceful quadriceps (DeMoret et al.) and gastrocnemius muscle (Elias et al) contractions produce anterior displacement of the tibia on the femur. Personal observation and concepts from these two studies have led me to propose a new mechanism of ACL injury.

Proposed mechanism: When playing sports, athletes generate both quadriceps and hamstring muscle contractions in anticipation of foot plant with changing directions or landing from a jump. The quadriceps muscle has to generate greater forces than the hamstring muscles in order to absorb the landing forces and to keep the knee from being flexed too quickly. Furthermore, the gastrocnemius and soleus muscles are contracted to avoid unopposed dorsiflexion of the ankle. These muscle contractions occur thousands of times during athletic practice or competition. When the timing of the foot plant is miscalculated and is a split second later than planned, the exaggerated muscle contractions cause the tibia to shift farther anterior than what would have occurred had the foot struck the ground at the correct time. With anterior translation, he tibia becomes internally rotated because the shorter and downward slope of the lateral tibial plateau. At the time of impact, the sulcus terminalis of the lateral femoral condyle comes into uncontrolled contact with the posterolateral tibial plateau. I propose that, because of the downward and shorter slope of the lateral tibial plateau, the impact of the femur on the posterior part of the tibia causes a fulcrum action or “crow bar” type effect on the tibia, pushing it further anteriorly and medially, causing the stretched ACL to rupture. Typical findings of bone bruises on the lateral aspect of the femoral condyle and the posterolateral aspect of the tibial plateau, which occur at the time of impact, can be explained by this mechanism.

Comment: This mechanism of injury might explain other observations about ACL injuries and recovery from ACL reconstruction: 1) Why ACL tears occur mostly when the knee is in 20°-30° of flexion when the ACL is in relatively lax position instead of with the knee in hyperextension when the ACL is more taut; 2) Why ACL tears occur when the foot becomes fixed on the ground instead of on slippery surfaces; 3) Why ACL tears occur almost exclusively when athletes are competing and reacting to other players in twisting, pivoting, and jumping sports, such as basketball and soccer, at a time when athletes are more likely to give their most concentrated and maximal effort. 4) Why, when athletes return to sports after ACL reconstruction, many new ACL injuries occur in the opposite normal and stronger knee that is capable of generating greater muscle force and has the native but smaller ACL instead of in the weaker ACL-reconstructed knee that has a large ACL graft. 5) Why an ACL graft tear does not occur early in the rehabilitation process when patients are beginning to return to sports but, instead, occurs when the patient has returned to near normal levels of strength, ability, and confidence.

Do Femoral Tunnel Positions Affect the Function of the ACL Reconstructed Knee?

Volker Musahl, M.D., Anton Plakseychuk, M.D., Andrew VanScyoc, B.S., Tomoyuki Sasaki, M.D., Richard E. Debski, Ph.D., Patrick J. McMahon, M.D., Freddie H. Fu, M.D., Savio L-Y. Woo, Ph.D.

Musculoskeletal Research Center, University of Pittsburgh Medical Center, Pittsburgh, PA, USA

Objective: In this study two different robotic systems were used to evaluate knee kinematics and in situ forces resulting from ACL reconstructions with two different femoral tunnel positions.

Methods: Ten fresh frozen human cadaveric knees were tested in the ACL intact and deficient states at 0, 30, and 90° of knee flexion in response to a 134 N anterior-posterior (a-p) external load. Testing was also performed at 15° and 30° of knee flexion in response to a combined 10 Nm varus-valgus (v-v) and 5 Nm internal-external (i-e) load. A robotic universal force moment sensor (UFS)/testing system was used for all testing and the resulting anterior tibial translations (ATT) were reported. An active surgical robot system was then used for positioning tunnels in two different locations in the femoral notch: 1) near the anatomic insertion site of the ACL (position 1) and 2) near the position for best graft isometry (position 2). The same quadrupled hamstring tendon graft was used for ACL reconstruction after each and the two loading conditions were again applied and the resultant ATT was reported. A two factor repeated ANOVA test was used to compare the intact ACL, anatomic, and isometric positions, significance was set at p<0.05.

Results: The ATT in response to the external a-p load for the intact ACL was 5.2±1.4 mm, 9.8±3.1 mm, and 7.2±3.9 mm for 0, 30, and 90°, respectively. Both of the femoral tunnel positions resulted in significantly higher ATT at 0° and 30° of knee flexion and, for position 1 (7.1±3.2 mm, 13.8±4.6 mm) and position 2 (9.0±2.8 mm, 16.6±3.7 mm) (p<0.05). There was also a significant difference between the two tested tunnel positions at 0 and 30° of knee flexion (p<0.05). In response to the combined load, both tunnel positions resulted in significantly higher ATT at 30° of knee flexion with respect to the intact ACL (p<0.05), but no significant differences (p>0.05) were detected between the two tested tunnel positions (for the intact (7.7±4.0 mm), position 1 (10.4±5.5 mm), and position 2 12.0±5.2 mm.

Conclusion: While neither ACL reconstruction restored normal knee kinematics, the results from this study suggest that under the loading conditions tested, a femoral tunnel near the anatomic insertion site of the ACL resulted in knee kinematics closer to that of an intact ACL than a femoral tunnel position near the position for best graft isometry.

A CENTILE CHART OF FUNCTIONAL RECOVERY FOLLOWING ACL RECONSTRUCTION. A USEFUL INCENTIVE FOR PATIENTS?

Tim Spalding MD

University Hospitals Coventry and Warwickshire NHS Trust, UK

North Hampshire Hosital NHS Trust UK

Purpose: To present a centile chart of the results of the Single Leg Hop Test (SLHT) following ACL reconstruction, in order to better advise patients of the status of their functional recovery.

Methods and Results: The SLHT has been shown to correlate with knee function following ACL reconstruction and is used to provide a guide for return to sport. 136 patients who underwent autograft primary ACL reconstruction using patella tendon or a 4-strand hamstring construct were evaluated at 6, 9, 12 and 24 months post surgery, as part of a prospective outcome study.

The SLHT result was recorded as the percentage of the distance achieved in a static hop on the post reconstruction leg against the non-operated leg. The best of three hops was recorded and patients were instructed to land in control and not to run on.
The SLHT result correlated with both the Mohtadi Quality of Life Score and the IKDC at 12 and 24 months. The graph below shows the results expressed as centile scores.

Although only half of the patients had a hop score above 85% at 6 months, nearly 90% of patients achieved a score above 85% at 1 year.

Conclusion: The Single Leg Hop Test is a simple yet useful tool in follow-up clinics. The result can be used against the above graph to determine actual versus expected function allowing for redirection of rehabilitation in underachieving patients. This data is currently the subject of a randomised controlled trial on rehabilitation using the single leg hop test as a weekly method for monitoring progress and acting as a home incentive scheme for patients in order to optimize their return to sport.

Isokinetic evaluation of quadriceps, hamstrings and rotational muscle strength of the knee. Comparative prospective study of hamstrings vs BPTB ACL reconstruction

Matteo Denti*, Marco Bandi**, Davide Tornese**, Piero Volpi*, Simone Lazzaretti**,Gianluca Melegati**,

* Orthopaedic Surgery Unit, ** Sports Rehabilitation Unit; Galeazzi Orthopaedic Institute, Milan - Italy

Rotational strength deficit is still reported in literature as a complication after anterior cruciate ligament (ACL) reconstruction employing ST-GR autograft. In this preliminary 12 months study we evaluated the deficit of rotational strength (particularly, intrarotational vs extrarotational) and the deficit of flexoestensory strength through a comparison between ST-GR (doubled) and B-PT-B newly implanted ACL.

MATERIALS AND METHODS: In this investigation we compared two groups of subjects (preliminarily 10 per group) who underwent ACL doubled semitendinosus – gracilis (dST-GR, group A) and bone-patellar tendon-bone (B-PT-B group B) reconstruction. Each 10 B-PT-B & ST-GR subjects were randomly distributed into the two groups of rehab-treatment & evaluation. From day of surgery to 7^th postoperative day an early rehabilitation program, similar in both groups by exercise and improvement criteria and different only by initial ROM values and initial operated limb load (up to 3^rd week) , was applied. All the subjects followed the same rigorous, accelerated, well controlled rehabilitation protocol which had a whole duration of 10 weeks. Each subject was evaluated as follows: pre-operative and post-operative (2^nd week – 6^th month – 12^th month) assessment of passive / active range of motion (PROM / AROM) by long arms goniometer, quadriceps / hamstring and intra / extrarotational isokinetic strength test at the 10^th postoperative week; and 6^th - 12^th postoperative month, KT 1000 arthrometric measurement at the 6^th - 12^th postoperative month. The PROM / AROM of both injured and non-injured knee was recorded according to Shelbourne’s method: A° / B° / C°. A dynamometer assessment of isokinetic quadriceps and hamstring plus IR / ER strength was made at the 10^th postoperative week. Both extension / flexion and intra / extrarotation were assessed at 60°/sec and 150°/sec angle speeds. At the 10^th postoperative week; and 6^th - 12^th postoperative month a KT 1000 arthrometric assessment of side- to- side difference in anterior laxity at 30 lbs between the operated and non-operated knee was recorded, and the highest of three readings was used for the subsequent analysis. The results were statistically evaluated using the Power Analysis, Wilcoxon paired rank test, Confidence Intervals (95%), descriptive statistics and ANOVA, Pearson’s correlation factor.

RESULTS:

Passive / Active range of motion

Preoperative values were homogeneous (p > 0,06) between the involved and uninvolved knee of each group and also between the groups. At 10^th postoperative week; follow-up were was no significant difference between the PROM of the involved knee of the groups (p > 0,06) and was a slight numerical difference in angle degrees in AROM, not significant at the Wilcoxon test (p > 0,06). Neither 6^th nor 12^th postoperative month follow-up statistical comparison follow-up articular values, shown a significant difference between group A and B (p < 0,06).

Isokinetic test

Statistical analysis of peak torques ratios shown statistical difference at 6^th month follow up between the groups (p >0,06) related to side by side flexion deficit in group A (24% instead of extension 12%) and extension deficit in group B (26% instead of flexion 13%). At 12^th month follow up, flexion deficit in group A decreases (8% instead of extension 12%, remained the same) and extension deficit in group B slightly decreases (24% instead of flexion 7%) showing a statistical significance (p>0,06) confirming the group B extension loss of peak torque.

Intrarotational deficit for group A (dST-GR) were 46% at 6^th postoperative month follow-up (instead 24% extrarotational) (p<0,06) but at 12^th postoperative month follow-up; there were a decrement (according with some Authors) up to 12%. The extrarotational deficit were confirmed at 12^th post-op month into 25% (p>0,06).

KT 1000

Statistical analysis of side-to- side mean difference of the groups, at all the follow up times sampling, shown no significant differences (p >0,06).

CONCLUSIONS: In subjects who underwent ACL dST-GR reconstruction the intrarotational deficit decreases with statistical significative weight in the evolution from 6 to 12 postoperative months, according to literature. In our study we also reported a permanence of ER deficit that will be subject of further study and evaluation to know the related causes and to improve the rehab-programs to correct it. The extension deficit shown by B-PT-B grafts was expected and the rehabilitation program due to be targeted to recovery that strength loss. In addition, the employed different grafts resulted in good stability of the knee until the end of rehab program and return to sport. The muscle strength recovery did not compromise the resistance of the grafts.

THE INFLUENCE OF CORE STRENGTH ON LOWER EXTREMITY PERFORMANCE

M.L. Ireland ¹, I.S. Davis ^2.3, J.D. Willson ²

¹ Kentucky Sports Medicine, Lexington, KY

² Joyner Sportsmedicine Institute, Mechanicsburg, PA

³ University of Delaware, Newark, DE

Introduction: Core (lumbopelvic) musculature is believed to play an important role in lower extremity injury prevention and overall athletic performance. Recent evidence suggests that gender differences may exist with respect to the strength of these muscles. The purpose of this study was to compare the strength of core, as well as knee, musculature between males and females. Further, we intended to analyze the association between the strength of these muscles, tibiofemoral valgus (TFV) angle during single leg squats, and single leg hop for distance measurements. It was hypothesized that females would exhibit weakness in core strength measures, and that core strength would be correlated to TFV in a single leg squat and performance in the single leg hop (SLH) for distance.

Methods: 9 male (mean age = 21.7 years, height = 187 cm, weight = 86.1 kg, Tegner level = 9.7) and 8 female (19.4 years, height = 175 cm, weight = 67.2 kg, Tegner = 10.0) were evaluated in this ongoing study. Isometric trunk flexion, extension, and side bridging, hip abduction and external rotation, and knee flexion and extension measurements were recorded using hand-held dynamometers and strap stabilization. Strength measurements were normalized to body weight (BW) and segment length (SL) for each subject. To determine TFV angle, markers were placed at the midpoint of the ankle mortise and TF joint as well as at the midpoint of a line connecting the ASIS to the mid-TF joint marker. Digital images were recorded in SL stance and during SL squats to 45° knee flexion. Single leg hop for distance was recorded for the dominant leg and normalized to height. One tailed independent t-tests (alpha = 0.05) were used to compare all variables by gender.

Results:

Variable Male Female p r (TFV) r (SLH)

Trunk FL torque 10.03 7.91 0.060 -0.06 0.33

Trunk EXT torque 7.14 7.16 0.494 -0.17 0.19

Sidebridge torque 40.23 23.42 0.004 -0.25 0.30

Hip ABD torque 26.74 16.87 0.000 -0.05 0.48

Hip ER torque 7.53 4.01 0.000 -0.41 0.43

Knee FL torque 17.04 10.02 0.000 -0.31 0.59

Knee EXT torque 24.67 19.10 0.016 -0.02 0.38

Peak TF Valgus 1.54 8.04 0.015

TF Valgus Excursion 0.76 4.74 0.111

Single Leg Hop 99.90 88.53 0.021

Discussion: These results add to a growing body of literature that suggests that females possess decreased muscle torque (normalized to BW and SL) in hip and knee muscle groups versus males. The greatest isometric torque differences between genders appear to be found in Hip ABD, ER and knee FL muscles. Additionally, females demonstrated significantly greater TFV and a trend (p=0.11) towards greater TFV excursion during single leg squats, and significantly shorter single leg hop for distance scores (normalized to ht). Interestingly, Hip ABD strength was not correlated with TFV. From these data, it appears that hip ER strength may most significantly influence TFV angle, while knee FL strength may be most influential to single leg hop for distance scores. These correlations may become strengthened as additional subjects are added.

Graph of knee 6, illustrating an example of tibial rotation during the pivot shift: the minimal rotation of the intact ACL was increased dramatically after cutting it. The SG technique still had persistent rotation, but rotation after DG technique was similar to the intact.

RISK TO POPLITEAL VESSELS IN MAJOR KNEE SURGERY – AN ANATOMICIAL STUDY AND SURVEY OF VASCULAR SURGEONS

Presenter: BARTLETT R.J; Roberts A: Wong J

AIM

To investigate the incidence in Australia of popliteal artery injury during knee surgery; to assess the distance from the popliteal artery to the posterior tibia in flexion and extension; and to investigate the influence of major trauma or surgery on the anatomy.

METHOD

A questionnaire was sent to Australian members of the ANZ Society of Vascular Surgeons. Duplex Ultrasound studies were obtained through the Vascular Laboratory University of Melbourne. Studies in extension and 90 degrees of flexion assessed the distance from the popliteal artery to the posterior tibia. 12 persons with normal knees were assessed bilaterally. 8 patients with a posterior cruciate ligament deficient knee were assessed bilaterally.

RESULTS

70 Vascular Surgeons responded documenting 115 popliteal artery injuries occurring during knee surgery. There were 69 lacerations, 27 thromboses, 13 AV fistula, 19 false aneurysms.

In 12 normal people (24 knees) the popliteal artery was 5.5mm (2.9 – 9.9) from the tibia in extension and 5.7mm (2.9 – 10.0) in 90 degrees of flexion. In 10 of 24 knees the artery moved closer in flexion.

In the 8 posterior cruciate ligament deficient knees, the artery was 4.7mm (2.7 – 6.9) from the tibia in extension and 3.8mm (2.6 – 4.5) at 90 degrees of flexion. In 8 PCL knees, the artery moved closer in flexion.

CONCLUSION

In normal knees the popliteal artery may move closer to the tibia in flexion – average distance is about 5.5mm. The artery is closer following trauma or surgery and specifically closer in flexion than in extension. Risks are significant with 115 popliteal artery injuries (11 amputations) reported in a survey of Vascular Surgeons. ACL graft rupture after anatomic reconstruction and rehabilitation: a problem of lack of reinnervation

Video Informed Consent Improves Knee Arthroscopy Patient Comprehension

Michael J. Rossi, MD, Wenatchee Valley Clinic, Wenatchee, WA.

James H. Lubowitz, MD, Taos Orthopaedic Institute, 1219-A Gusdorf Road, Taos, NM 87571. 505 758-0009; Fax 505 758 8736; jlubowitz@kitcarson.net.

Dan Guttmann, MD, Taos Orthopaedic Institute, Taos, NM.

Megan J. MacLennan, MS, Taos Orthopaedic Institute, Taos, NM.

Purpose: The purpose of this study is to test the hypothesis that video informed consent improves knee arthroscopy patient comprehension and satisfaction as compared to traditional verbal informed consent.

Type of Study: Prospective, randomized, case-control study.

Methods: Consecutive patients having informed consent in preparation for knee arthroscopy by a single surgeon were stratified by educational level less than or equal to 12^th grade or greater than 12^th grade, then randomized to video or traditional verbal informed consent groups. Immediately after the informed consent process, patients completed an outcome questionnaire evaluating comprehension and satisfaction.

Results: Patients in the video group demonstrated significantly higher comprehension (78.5%) than patients in the verbal group (65.4%) (p=0.00001). In the subgroup with less than or equal to 12^th grade education level, the video patients scored 73.1% comprehension and the verbal patients only 54.2% (p=0.0011). In the subgroup with greater than 12^th grade education level, the video patients scored 82.3% and the verbal patients scored 72.2% (p=0.0002).

There was no significant difference in subjective self-assessment of satisfaction between groups.

Conclusion: Video informed consent improves knee arthroscopy patient comprehension as compared to traditional verbal informed consent

COMPARISON OF ONE-LEG HOP FOR DISTANCE SCORES IN THE ACL DEFICIENT WITH A GROUP OF HEALTHY CONTROLS

SIOBHAN O'DONNELL, RPT, MSc, SCOTT THOMAS PhD, and

PAUL MARKS MD, FRCSC

From the Centre for Studies of Physical Function, Division of Orthopaedic Surgery, Orthopaedic and Arthritic Institute, University of Toronto, Toronto, Canada.

BACKGROUND:

The sensitivity of the one-leg hop for distance (OLHD) in detecting functional limitations in the ACL deficient population has not been fully evaluated to date. One specific impact on the performance of the OLHD is the distance hopped on the non-injured limb.

HYPOTHESIS:

1) Differences in the hop distance on the non-injured limb impacts the sensitivity of the Hop index in the ACL deficient population.

2) Transformation (log ₁₀) of the hop distance scores will minimize the impact of this source of error and improve the sensitivity of the hop index.

STUDY DESIGN: Cross-sectional

METHODS:

OLHD performance was evaluated in a consecutive sample of 10 ACL deficient males with an isolated ACL tear. Nine gender, age-matched controls were utilized. A modified version of Daniel et al.'s (1982) OLHD described was employed in this study.

RESULTS:

A formal sample size calculation was performed for this study to ensure the expected difference in the absolute hop distance between ACL deficient and healthy non-injured Controls would be detected with a power of 0.80 and probability of 0.05. Descriptive statistics and comparisons between groups (t-tests) and correlation analysis (Pearson's Product Moment Coefficients) were performed using SigmaStat.In the ACL deficient population, the hop index was associated with the distance hopped on the non-injured limb (r=0.66, p= 0.04) but not on the injured limb. Transformation of the hop distance scores improved the sensitivity from 50 to 70% in the detection of an abnormal hop index ( <90% hop index).

CONCLUSIONS:

The distance hopped on the non-injured limb is a critical factor in the sensitivity of the hop index in the ACL deficient population. Transforming the hop distance scores, to minimize the effect of the arithmetic differences between limbs, improves the sensitivity of the hop index.

Further research is required to investigate whether the diagnostic ability of the hop index, in the detection of functional limitations in the ACL deficient, improves upon transformation of the hop distance scores in a larger population across the spectrum of injury, with varying levels of

chronicity. This is critical prior to recommending the use of the logarithmic transformation to improve the sensitivity of the hop index in the assessment of ACL injuries within a clinical setting.

If the sensitivity of the OLHD proves to be suboptimal in a larger sample of ACL deficient individuals who report functional limitations secondary to knee instability, consideration should be given to the development of a more challenging lower limb functional test in

the assessment of ACL injuries.

Knee Malalignment Corrected by Opening Wedge Osteotomies

Arne Ekeland, Stig Heir, Sigbjørn Dimmen, Hamid Sarkandi, Martina Hansens Hospital, Bærum, Norway

Introduction: The operational technique for opening wedge osteotomies has been simplified by the use of the Puddu-plate. This study presents results after use of Puddu-plates on distal femoral and proximal tibial osteotomies.

Methods: Thirteen distal femoral and 18 proximal tibial osteotomies have been performed with opening wedge technique due to knee osteoarthritis with malalignment in the period 2000–2003. The knee osteoarthritis was mainly due to a previous meniscal extirpation. Eight patients had an additional rupture of the anterior cruciate ligament. The mean age of the patients was 50 years (36-66 years), and 15 females and 16 males were operated. The patients with femoral osteotomies had a mean preoperative tibiofemoral valgus angle of 12° (8°-20°) whereas those with tibial osteotomies had a mean tibiofemoral angel of 0° (5° varus - 3° valgus). The osteotomy was fixed with a Puddu-plate securing the planned angular correction, and the osteotomy cleft was filled by autogenous pelvic bone. The mean follow-up time was 13.5 months (6-31 months).

Results: The width of the osteotomy cleft was determined by the tooth of the implant. The mean width of the tooth was 8.5 mm (5–12.5 mm), and the mean angular correction measured on pre- and postoperative radiographs was 8.3° (5-15°). The osteotomy cleft healed after a mean of 13 weeks (7–26 weeks). One patient suffered venous thrombosis of the leg and one a postoperative wound infection. The knee injury and osteoarthritis outcome score (KOOS) increased significantly during the observation period. For pain the mean preoperative score was 53 and the score at follow-up was 79. The corresponding scores for symptoms were 58 and 73, for activity of daily life (ADL) 65 and 86, for sport and recreation 26 and 43 and for quality of life 33 and 57 (P<0.001).

Conclusion: The results after opening wedge osteotomy using the Puddu-plate seem satisfactory. The operational technique is simpler compared to previous methods, and the degree of angular correction is accurate depending on the width of the tooth of the implant which in mm corresponds relatively well with the degrees of angular correction.

AWARD PAPER

Soft tissue healing in biglycan knockout mice

Norimasa Nakamura, MD, Ken Nakata, MD, Yukiyoshi Toritsuka, MD, Shuji Horibe, MD, Hideki　Yoshikawa，MD，Konsei Shino, MD, Osaka University, Osaka, Japan

Naomitchi Fujie, PhD, Kougakuinn University, Tokyo, Japan

Richard S. Boorman, MD, Cyril. B. Frank, MD, David A. Hart, PhD, University of Calgary,

Alberta, Canada

Marian F. Young, PhD, NIDCR, NIH, USA

This proposal is aimed to define the biological role of a small leucin-rich proteoglycan, biglycan, in the healing processes of ligament/tendon healing using biglycan knockout mice. We previously identified that biglycan, among several proteoglycans contained in ligament, drastically elevates its expression following injury. We therefore hypothesize that significant over-expression of biglycan in early damaged soft tissue may be related to tissue scarring processes. And further, suppression of biglycan in early scar might prevent tissue scarring. Based on this background, we curently analyze the normal and healing ligament of biglycan knockout mice, using morphological, biomechanical, and molecular approaches. Our preliminary result shows that there is alteration in collagen fibril size and morphology in tendon tissue of biglycan KO mice. Therefore, in addition to the conventional hitological analysis, collagen profile in healing ligament and tendon tissues is currently analyzed. Further, the effect of biglycan deficiency on the expression levels of other matrix proteins is under investigation. Results of this study will provide a significance of biglycan in soft tissue repair.

RECELLULARIZATION AND REMODELING OF ALLOGRAFTS USED TO REPLACE THE ANTERIOR CRUCIATE LIGAMENT

Variables that have an influence on these processes

* Vicente Sanchis-Alfonso, MD, PhD, ** Esther Rosello-Sastre, MD, PhD

Departments of Orthopaedic Surgery * and Pathology **, Hospital Arnau de Vilanova *, and Hospital Universitario Dr. Peset **, Valencia, Spain

Objective. To evaluate the recellularization, remodeling and maturation processes of a cryopreseved tendinous allograft used to replace the anterior cruciate ligament (ACL). We use allografts because they are the best experimental model to study recellularization, given that freezing and thawing destroy tendon cells although the framework of collagen remains normal.

Material and Methods. ACL reconstruction with cryopreserved tendinous allograft was performed on 53 rabbits. In half of them the Hoffa Fat Pad (HFP) was conserved and in the other half resected. The allografts were evaluated at 1, 2, 3, 4, 6, 12, 24 and 52 weeks using conventional histology (hematoxylin-eosin and Masson’s trichrome); cytophotometric, morphometric (Cue-2 Densitometry Image Anazlyzer) and ultrastructural analyses (JEOL JEM-100B transmission electron microscope).

Results. Cellular repopulation of the previous acellular grafts begins at the periphery and progresses centrally (“creeping substitution”). The graft seems to be repopulated by cells from the peripheral synovial tissue first. These cells modulate into fibrochondrocytes (“polarized differentiation”). Cases with preserved HFP begin their proliferative activity earlier than those in which HFP was resected, the former finishing the restocking period earlier as well. During the remodeling process two simultaneous and synchronic phenomena occur: lysis of the old collagen fibers of the graft and production of newly formed collagen by active young fibroblasts. During the remodeling process, the entire ligament structure is not affected simultaneously; this would maximize graft weakness, rendering it incapable of functioning adequately. During peripheral remodeling, the central fiber bundles remain acellular and compact. After the periphery of the graft has been successfully repopulated, the process progresses until the entire ligament is completely restored. During the graft maturation process the number of cells and vessels decreases to physiological levels; the hypercellular and vascular connective covering undergoes atrophy. We have found an inverse relationship between hypervascularization-mesenchymal envelope proliferation and the histological remodeling processes. At the end of the process the tendon allograft acquires the morphology of a normal ACL (“phenomenon of ligamentization”) and provides a functional replacement (not articular degeneration) for the removed ACL. In three cases that exhibited anterior instability the graft maturation was incomplete. We have observed that when the lesser the graft tension, the poorer the cellular orientation.

Clinical implications. (1) The results of this study derived from animal experiment. It is, however, likely that the recellularization, remodeling and maturation processes in humans will take place in the same manner. (2) The grafts provide a functional replacement for the removed ACL. (3) Graft tension and isometric ligament placement are important to the formation and reorganization of the transplanted connective tissue. (4) Hoffa fat pad should be not excised with the synovial resector when performing endoscopic ACL surgery.

Prospective Clinical and MRI Analysis of Stored Osteochondral Allografts for the Treatment of Knee Cartilage Defects

Riley J. Williams III MD, David B. Cohen MD, Colin Walsh, Hollis G. Potter MD,

Background

Osteochondral allografts (OCA) can effectively treat chondral and osteochondral lesions of the knee. Historically, donor condyles have been stored up to 5 days pre-implantation. However, commercial grafts became available in 1998, and are available for clinical use up to 45 days post-retrieval. Currently, there is no information on the use of these grafts. The purpose of this study was to prospectively analyze the clinical outcomes, MRI appearance, and chondrocyte viability of stored OCAs used to treat chondral and osteochondral lesions in the knee.

Materials and Methods

A prospective cartilage registry has existed at our institution since 1999; this registry collects baseline and followup clinical outcome scores and standardized pulse sequence on all patients undergoing cartilage repair procedures. Baseline and follow-up data were available on 15 patients who underwent OCA transplantation. The ADL and SF-36 (physical and mental components) were used for clinical outcome assessment, and were obtained preoperatively, 6, 12, and 24 months following surgery. Knee imaging was typically performed at 3, 12, and 24 months postoperatively; MRIs were blindly assessment using a standardized scoring assessment. Donor graft chondrocyte viability was assessed, histologically, using paravital staining techniques. The surgical technique utilized a cylindrical osteochondral graft that was placed through a mini-arthrotomy, and secured by a press-fit.

Results

At surgery, the mean patient age was 34.9 years (20-45 yrs.); 10 males, 5 females. Mean clinical and MRI follow-up were 17 and 22 months, respectively. Indications for allograft implantation included: osteochondritis dissecans (10), focal chondral lesion (4), osteonecrosis (1). All lesions were located on the distal femur, and were Grade IV with mean size of 587 mm² (121 – 875 mm²).

The mean ADL score increased from 62.2 ± 5.4 to 66.5 ± 6.4 (p=0.578). The mean SF-36 physical component score increased from 34.3 ± 2.6 to 40.5 ± 3.3 (p=0.061). The mean SF-36 mental component score increased from 50.1 ± 4.0 to 50.8 ± 3.2 (p=0.813). MRI assessment demonstrated an isointense (normal) cartilage signal in 60% of grafts; the remaining 40% were hyperintense. Other MRI findings included: graft edema (74%), trabecular incorporation (complete-33%, partial-40%, poor-27%), subchondral edema (74%), graft-host interface junction (less than 2mm-53%, greater than 2mm-47%). Graft morphology was maintained in 14 grafts (93%); one graft collapsed. Graft storage duration ranged from 21 to 45 days. Graft chondrocyte viability was highly variable, and inversely proportional to storage time.

Conclusion

This short-term clinical outcome scores did not change significantly (p=0.578) in this study. Additionally, MRI analysis demonstrated that these grafts undergo a prolonged process of incorporation that provides additional insight into the biology of these grafts, and may ultimately have an impact on long-term clinical outcome.

The Effect of Short Term Mechanical Stimulation on Fibroblasts Cultured on Synthetic Scaffolds

David McAllister, MD Seth Gamradt, MD Billy Puk, BS Benjamin Wu, DDS, PhD

UCLA Departments of Orthopaedic Surgery and Biomedical Engineering Los Angeles, CA

Background: Previous research has demonstrated that mechanical forces can affect tissue structure and stimulate extracellular protein synthesis, especially in load bearing tissue. Therefore, mechanical stimulation is likely to be an important component of tissue engineering strategies for ligament tissue. The objective of this study was to evaluate the effect of mechanical stimulation in a bioreactor on fibroblasts cultured on poly-L-lactic acid (PLLA) scaffolds.

Methods: Ring-shape poly(L-lactic acid) (PLLA) scaffolds were fabricated by solvent casting in chloroform to achieve 95% porosity. Scaffolds were coated with fibronectin followed by seeding of 4 million mouse embryonic fibroblasts (NIH/ 3T3, ATCC, VA) per scaffold. A custom bioreactor with 2 cultivation chambers was placed in a cell culture incubator at 5% CO2 at 37oC. Scaffolds to be stretched were affixed on pegs within the chambers. Each chamber delivers cyclic, uniaxial stretching of 1% strain and 0.125 Hz. Each scaffold (N=2) was stretched for 24h. Scaffolds seeded with cells in an identical fashion were also cultured in a static environment as a control group (N=5). Scaffolds were embedded in 5% sucrose/5% gelatin solution and cryosectioned at a thickness of 10 um. H+E staining as well as rhodamine-phalloidin stain for actin was performed.

Results: Mechanical stimulation had three main effects on the scaffold cell constructs at 24 hours. First, cell density was significantly increased in the center of the stretched scaffolds (140 cells/mm2 stretch and 49 cells/mm2 – static; p < 0.05). Second, mechanical stimulation caused the fibroblasts to elongate, adhere to the scaffold, and conform to the shape of the scaffold. This was not observed in static scaffolds. Third, rhodamine-phalloidin staining for actin was significantly increased in the stretched scaffolds.

Conclusions: This study demonstrates the effects of controlled mechanical stimulation in vitro on scaffold/fibroblast constructs. Short term mechanical stimulation increased cell density at the center of the scaffolds, induced cells to elongate and adhere to the PLLA scaffolds, and induced increased actin formation. Further research will investigate mechanical stimulation of cells for ligament tissue engineering

ACL graft rupture after anatomic reconstruction and rehabilitation: a problem of lack of reinnervation

Roland M. Biedert *, Edouard Stauffer #

* Institute of Sport Sciences, Orthopaedics and Sports Traumatology, CH-2532 Magglingen, Switzerland # Institute for Pathology, University of Berne, CH-3010 Berne, Switzerland

Hypothesis: The lack of graft reinnervation may be a cause for the rerupture of a properly anatomically reconstructed ACL.

Material & Methods: During the last 6 years, we observed 5 patients (all males, average age 23.6 years) with a rerupture of the ACL graft (4 BPTB, 1 QT). The time between the initial reconstruction and the reinjury was on average 12.8 months (range 7 to 30 months). All patients were retrospectively analyzed with regard to the IKDC Score, isokinetic and sportspecific functional tests and course of rehabilitation. Radiographs and MRIs were taken to evaluate the exact position of the tunnels and the intraarticular portion of the graft. Histologic examinations (H&E, Masson’s trichrome) and immunohistochemical tests (S-100 for Schwann’s cells, Synaptophysin for motor end-plate, PGP 9.5 for nerve fibers) were performed to document neural elements in the graft.

Results: All 5 patients had an anatomic reconstruction of the graft. We found no causes for the graft failures. At the last clinical control, the overall IKDC score showed 60% A and 40% B with good results. The course and time of rehabilitation (at least 6 months) were normal. The isokinetic tests showed force differences (operated vs nonoperated) under 10%. The sportspecific tests were normal. The histologic examination revealed vital collagen structures of the graft with correct ligamentization and revascularization. But all immunohistochemical tests to document neural elements were negative.

Discussion: We could not document obvious mechanical or other causes for the graft failures, such as improper placement of the graft, roof impingement, abnormal axes of the lower extremity, loosening of graft fixation, arthrofibrosis, overconstraint, or low grade infection. The only documented pathology was the complete lack of neural elements in the grafts.

Conclusion: We believe that a rerupture of an ACL graft after proper reconstruction and rehabilitation may be due to persistent lack of reinnervation and therefore continued sensory loss.

Double bundle ACL reconstruction

P. Aglietti, F. Giron, P. Cuomo, N. Mondanelli

First Orthopaedic Clinic – University of Florence - Italy

Despite ACL reconstruction with modern techniques provides satisfactory results in the majority of the cases, the activity level is often reduced, a residual “mini-pivot shift” is present and the oasteoarthritic progression is debated. One of the possible explanation of these unsatisfactory results is that ACL reconstruction usually aims at replacing only the anteromedial bundle of the native ACL without reconstructing the posterolateral bundle which provides a great contribution to the rotatory stability of the knee joint.

In vitro cadaveric studies have demonstrated that the reconstruction of both the anteromedial bundle and the posterolateral bundle, results in a more stable knee, expecially in terms of rotatory loads. Clinical experiences with early favourable results are available.

We have been performed two bundle ACL reconstruction since 2002 and three groups of patients are prospectively evaluated and compared: a) single bundle; b) double bundle (one tibial tunnel); c) double bundle (two tibial tunnels). Free hamstring tendons grafts are employed (semitendinosus pro anteromedial bundle and gracilis pro posterolateral bundle). The anteromedial bundle tibial tunnel is drilled with the “One Step Guide” (Arthrotek) and the femoral tunnel is drilled through a transtibial approach at the 11 o’clock position. As to the posterolateral bundle, when a single tibial tunnel is performed, a second femoral tunnel from the anteromedial approach is drilled with the knee in hyperflexion. When two tibial tunnel are performed, a second tibial tunnel is performed with a prtothotype attachment to the “One Step Guide” and the femoral tunnel is drilled transtibial. Both bundles are fixed with the Endobutton Continuous Loop (Smith&Nephew) to the femur and with the Washerloc system on the tibia at 20 degrees of knee flexion.

No major complications occurred till now using this technique. Early results at the 4 months evaluation are encouraging expecially in terms of rotatoty instability restoration.

Clinical Outcome after Anatomical Reconstruction of the Anteromedial and Posterolateral Bundles of the Anterior Cruciate Ligament

Kazunori Yasuda, MD, PhD, Eiji Kondo, MD, Hiroki Ichiyama, MD,Harukazu Tohyama, MD, PhD

Department of Sports Medicine and Joint Reconstruction Surgery,

Hokkaido University School of Medicine, Sapporo, Japan

(Address correspondence to K. Yasuda <yasukaz@med.hokudai.ac.jp)

Introduction

The normal ACL consists of the anteromedial (AM) and posterolateral (PL) bundles. In conventional ACL reconstruction procedures, however, only one bundle that mimic the anteromedial bundle has been grafted. This may be one of the reasons why completely normal ACL function cannot be restored by current ACL reconstruction. To improve the results of one-bundle ACL reconstruction, two-bundle reconstruction procedures have been developed. In the two-bundle procedures reported previously, however, tunnel position for the PL bundle is not located on the anatomical attachment. Thus, an anatomical ACL reconstruction procedure has not been established yet, specifically concerning PL bundle reconstruction. Based on our anatomical studies, we developed a 2-bundle ACL reconstruction procedure in which the AM and PL bundles were anatomically reconstructed using doubled hamstring tendon autografts. I have conducted clinical outcome studies to evaluate this anatomical ACL reconstruction procedure.

The hypothesis

The postoperative anterior laxity after the anatomical reconstruction of the AM and PL bundle of the ACL may be significantly less than that after the conventional one-bundle and two-bundle reconstructions with the hamsting tendons.

Methods

A prospective comparative study was carried out with 72 consecutive patients who underwent unilateral isolated ACL reconstruction in our hospital in 2001. The first 24 out of the 72 patients underwent ACL reconstruction with the conventional one-bundle procedure using a doubled hamstring graft (Group I). The next 24 patients underwent ACL reconstruction with the conventional two-bundle procedure using doubled hamstring grafts, which was reported by Rosenberg et al (Group II). The last 24 patients underwent ACL reconstruction with the anatomical two-bundle procedure using hamstring tendon grafts (Group III). In Group III, first, 2 tunnels were drilled in the tibia through the anatomical attachment of the 2 bundles, respectively, in order to reconstruct the AM and PL bundles. The position and direction of a guide wire for each tunnel were determined using a specially developed "wire-navigator" so that the tip of the wire was aimed at the anatomical attachments of each bundle. Then, 2 femoral tunnels for the Endobutton fixation were created through the center of the anatomical attachment of each bundle, using the trans-tunnel technique. All surgeries were performed by one senior surgeon (K.Y.) who had sufficient experience of each procedure. All 72 patients were evaluated at the time of 12 months after surgery. Subjective evaluation was performed using the modified Noyes scoring preoperatively and postoperatively. Objective evaluations involved a range of knee motion, the side-to-side anterior laxity measured at 30 degrees of flexion (KT-2000 arthrometer), and quadriceps and hamstring strength (Cybex II). Statistical comparison among the three groups was made using the analysis of variance (ANOVA) with a Bonferoni/Dunn correction for multiple comparisons. Significance level was set at p<0.05.

Results

There were no significant differences in the background factors among the 3 groups. No intra-operative and postoperative complications were experienced in this study. The postoperative side-to-side anterior laxity averaged 2.8, 2.2, and 1.6 mm in Groups I, II, and III, respectively. The ANOVA demonstrated a significant difference among the three groups (p=0.006). The post-hoc test showed that there was a significant difference between Groups I and III (p=0.002). There were no significant differences in the subjective score, the ROM, and muscle torque among the 3 groups.

Conclusions

This study demonstrated that the postoperative anterior laxity after the anatomical reconstruction is significantly less than that after the conventional one-bundle reconstruction, However, there were no significant differences between the conventional one-bundle and two-bundle reconstructions. These results suggested that the anatomical reconstruction of the AM and PL bundles using hamstring tendon autografts is useful in the treatment for the ACL-deficient knee.

The outcome of anterior cruciate ligament reconstruction using quadrupled semitendinosus tendon: One-bundle vs. two-bundle methods

Takeshi Muneta, Kazuyoshi Yagishita, Ichiro Sekiya

Department of Orthopedic Surgery, Tokyo Medical and Dental University Hospital Tokyo, Japan

Background: Our clinical experience of comparative study between patellar tendon and quadrupled semitendinosus tendon anterior cruciate ligament (ACL) reconstructions left a problem how to achieve a reconstructive method with better anterior stability as more realistic therapeutic method.

Hypothesis: Two-bundle ACL reconstructions reconstruction using quadrupled semitendinosus tendon is superior to one-bundle reconstruction using a same graft.

Objective of the study: To compare the outcome of the first series of two-bundle ACL reconstruction using quadrupled semitendinosus tendon with those of one-bundle reconstruction performed consecutively from July, 1992 through September, 1996.

Methods: One-bundle group consisted of 56 patients with average follow-up period of 46.5 (24-119) months. Two-bundle group consisted of 79 patients with average follow-up period of 40.8 (24-91) months. Manual knee stability tests, anterior stability measured with the KT-1000, and knee extension and flexion strength measured by Cybex were evaluated between the two groups by side-to-side differences. Lysholm knee scale and subjective recovery scale compared with the uninjured side as 100% were also evaluated. The both procedures were performed by arthroscopically-assisted method. Semitendinosus tendon was basically fixed with pull-out method in both procedures.

Results: Lachman test was positive in 34% of patients in one-bundle and 13% in two-bundle, anterior drawer test was positive in 21% in one-bundle, 10% in two-bundle and pivot-shift test was positive in 29% in one-bundle, 22% in two-bundle. Statistically greater number of patients in one –bundle group was positive with Lachman test and ADT. Average anterior stability of 2.7±2.3mm in one-bundle group measured with the KT-1000 at manual maximum pull was statistically greater than 1.9±1.9mm in two-bundle group. Total score of Lysholm knee scale was 93 points in both one-bundle and two-bundle groups. Average subjective score of 83% in one-bundle group was not different from 86% in two-bundle group.

Conclusion: The outcome of the initial series of two-bundle ACL reconstruction was found superior to that of one-bundle reconstruction using same quadrupled semitendinosus tendon regarding anterior knee stability. The results of the study will elucidate the theoretical superiority of the two-bundle ACL reconstruction over one-bundle technique although the study was not performed in a randomized prospective fashion.

Allograft versus Autograft Patellar Tendon for ACL Reconstruction in Revision Surgery – a 2-Year Follow-up

Mayr HO, Schettle T, Muench EO, Topar C, Plitz W

· Question

Are the 2-year results using allograft patellar tendons for ACL reconstruction in revision surgery comparable to those of the autograft cases?

· Method

Between May 2000 and July 2002 we performed 24 ACL revisions with fresh frozen allograft patellar tendons. The transplants were processed with a low temperature, chemical sterilization technology using ascorbic acid, povidone jodine, saline and sterile water for irrigation. 20 of these patients took part in this retrospective study. Another group with 20 of our patients who have undergone the same surgery during this time-period, but with the use of an autograft patellar tendon, have served as a control-group. The autograft patients and allograft patients, who have undergone the surgery nearly at the same time were combined as pairs (matched pairs). In 9 cases with previous ipsilateral BPTB autografts we had to harvest from the contralateral side in the autograft group. Patients with complex instabilities or x-rays showing an arthritis > I° were excluded from this study. The results were evaluated by the IKDC 2000 grades, the Lysholm score, and the Tegner scale. The groups were compared, based on side-to-side KT 1000 difference. Results were analyzed using Wilcoxon-Mann-Whitney-U-test and T-test.

· Results

According to the IKDC in the autograft group 4 (20%) patients were rated normal (grade A), 14 (70%) nearly normal (grade B) and 2 (10%) abnormal (grade C). In the allograft group 20 (100%) patients had a nearly normal knee. In both groups the Lysholm score showed excellent and good results. (autograft: mean: 89.9, std. dev.: 4.84; range: 85-100, allograft: mean: 91.9 std. dev.: 4.95; range: 84-10). Using the Tegner acivity score, both groups reached comparable results: (allograft: mean: 5.6 (std. dev.:2.37; range: 3-10), autograft: mean: 5.0 (std. dev.:2.00; range: 3-10). Regarding these scores, a significant difference between both groups was not noticed. Comparing the side-to-side KT 1000 test, we could not see a significant difference too: Autograft: KT-1000, 30lb., side-to-side difference: mean: 0.9mm (std. dev.: 1.52; range: -2 to +3mm)

KT-1000, max., side-to-side difference: mean: 1.2 mm (std. dev.: 1.48; range: -2 to +3mm)

Allograft: KT-1000, 30lb., side-to-side difference: mean: 1.3mm (std. dev.: 2.26; range: -3 to +4mm) KT-1000, max., side-to-side difference: mean: 1.4mm (std. dev.: 2.12; range: -2 to +4mm)

· Conclusions

Allograft is a useful alternative to autograft patellar tendons for ACL reconstruction in revision surgery. Regarding the 2 year results there are no significant differences between both methods.

Using an BPTB allograft you can avoid harvesting the contralateral knee and you can fill bone defects in the tunnel.

Why do we create a round tunnel for a rectangular tendon? -

Development and evaluation of a new technique for ACL reconstruction using patellar tendon

Fink C, Tecklenburg K, Hoser C University Hospital for Traumatology, Innsbruck A

Introduction: Patellar tendon bone-tendon-bone graft has been the gold standard for ACL reconstruction over many years. However, it was found to be associated with marked harvest site morbidity especially at the patella, as well as widening of the tibial tunnel. In order to minimize these problems it was the aim of the study to develop and evaluate a new operative technique.

Materials and methods: 1. The Insertion of the patellar tendon on the patella was evaluated on 10 cadaveric human knees.
2. Instruments ( a cannulated rectangular rasp and dilators and a harvesting chisel) have been designed and manufactured.

3. The operative technique has been developed using cadaveric specimens.

Differently to common harvesting techniques only a flat, rectangular bone block resembling the thickness of the actual patellar tendon is harvested from the patella. Instead of drilling a femoral tunnel a cannulated, rectangular rasp is used which resembles the dimensions of the tendon graft. Therefore the graft can be advanced into the femur without creating a dead space. This allows for a near joint line fixation of the tibial bone block.
4. 20 patients (mean age 31,2 years) with ACL reconstruction using the described technique have been evaluated clinically (IKDC) as well as radiologically using CT scans over a period of two years.

Results: Harvesting a flat, rectangular bone block of the patella was found to be sufficient for graft fixation. No intraoperative complications have been experienced. At the two year follow up IKDC revealed 15 patients as “normal” and 5 as “nearly normal”. On CT scans no enlargement of the tibial or the femoral tunnel was found. There was complete ingrowth of all bone blocks.

Discussion: Using a cannulated, rectangular rasp resembling the dimensions of the harvested tendon and a flat bone block from the patellar provides several advantages compared to common techniques: Bone loss is reduced for the femoral tunnel compared to a common drilled tunnel, graft rotation can be controlled, harvest site morbidity on the patella is reduced and the patellar tendon -ACL length mismatch can be compensated avoiding the creation of a dead space within the tunnels.

Tunnel Widening after ACL Reconstruction is dependent on type of Fixation used. A Prospective randomised Study comparing two different fixation Methods for Hamstring Grafts.

Peter Faunoe, Denmark

Soeren Kaalund, Denmark Dept. Orth. Surg, Randers Denmark.

Purpose: To compare the incidence of tunnel widening (TW) in patients undergoing ACL reconstruction with hamstring graft using either A) transfixation implant (Transfix, Arthrex) in femur and interference screw (Arthrex) in tibial tunnel or B) endobutton in femur and bicortical screw and washer distally to the tibial tunnel.

Material and Method: 100 patients were included and randomised. 87 patients were assessed at one year follow-up. The evaluation included standardized x-rays, KT-1000, IKDC and Lysholm score. The diameter of the tunnel at one year follow-up was after correction for magnification, compared to the original reamed diameter. A more than 2mm enlargement was considered TW.

Results: In the group where transfixation in femur and interference screw in tibia was used. 7/41 had developed femoral TW and 5/41 in tibia. In the endobutton group 20/46 had TW in femur and 16/46 in tibia. (Fischers exact test p<0,05) No difference was found with respect to Lysholm, IKDC or arthrometric evaluation.

Conclusion: There was a significant reduction of TW in both femur and tibia using fixation points close to the joint compared to the system where the distance between the fixation points is long. We conclude that the position of the fixation site and the quality of the fixation device are major factors in the development of TW after ACL surgery.

How to reduce the tibial tunnel widening in ACL reconstruction:

tricks and technique.

V. Calvisi , M. Nocente, A. A. Patricola

Malattie dell’Apparato Locomotore, Università degli Studi “L’Aquila” - Italy

Hypothesis

Reconstruction of the ACL utilizing autologous tendon in an endoscopic fashion has historically had a high success rate, but the graft-tunnel mismatch can occur also in correctly reconstructed deficient knees. Widening of the tibial tunnel, due to leakage of synovial fluid into the bone tunnel around the soft tissue portion of the graft and due to motion of the graft inside the tunnel, is frequently observed. As a result of this evidence since 1997 we have developed a reconstruction technique which relies on completely filling the tibial tunnel and fixing the graft in an almost anatomic position, obtaining a significative reduction of the radiographic evidence of the tunnel enlargement. The aim of the present study was to demonstrate how suturing the residual portion of the broken-ACL, as a coverage of the articular entrance of the tibial tunnel, is effective in minimizing tibial tunnel enlargement in ACL reconstruction.

Method

We selected 20 ACL reconstructions performed from June to October 2002 in 20 patients, 15 male and 5 female (mean age: 23 yrs), with acute functional instability of the knee. In all cases we performed the suture of the distal residual portion of the ACL with 0-PDS covering the articular entrance of the tibial tunnel. In the BPTB technique the extension of the tibial bone-plug has been used. Femoral fixation was obtained by means of a BioRCI HA screw (Smith & Nephew) in the BPTB group, and Rigid-Fix device (Mitek) in the DSGT group. Tibial fixation was guaranteed by BioRCI HA screw in both groups plus staple in the hamstrings quadrupled group. The patients have been evaluated over a 1-year period clinically (IKDC activity score, KT-1000) and radiographically (confirmed by MRI). The operated knee was radiographed immediately and 6 and 12 months postoperatively. The femoral and tibial bone tunnel diameter was measured on anteroposterior and lateral images. Success criteria included restoration of functional stability and radiographic diameter of the tibial tunnel.

Results

Only 4 out of 20 patients were not available at one year follow-up. Stability of the knee was evident in all cases and no complications were observed. No lytic bone changes or tunnel widening were seen at BPTB group while a wider diameter of the tibial tunnel was observed in 2 patients (20%) of the DSGT group, even if without any clinical significance.
Conclusions

The coverage of the articular tibial tunnel entrance by a flap of the old ACL seems to help avoiding “synovial bathing effect” one of the causes of tunnel enlargement. The technique, even if requires more surgery time, proved to be safe with medium term excellent functional testing and radiographic results.

Biomechanical properties of tibial hamstring graft fixation techniques for circumferential graft ingrowth. Experimental Roentgen-Stereometric-Analysis (RSA) study.

AUTHORS: Frank Adam, Dieter Kohn

Introduction: Hamstring tendon grafts are frequently used in ACL reconstruction. A maximum of tendon-bone contact inside the tibial tunnel is recommended for stable ingrowth of the graft. Some doubt exists about the elasticity and the primary stability that can be achieved with graft fixation devices allowing for circumferential graft ingrowth. The purpose of the present study was to evaluate ultimate failure load, stiffness of fixation and graft motion within the tibial tunnel of tendon grafts fixed with Washerloc (Arthrovision), Cross-Pins (Mitek), Intrafix-System (Mitek) or Suture-Disc (Aesculap). Tests were carried out in an animal model under standardized conditions with high precision RSA.

Method: Fresh frozen porcine hind legs of 12 months old animals were used. The extensor hallucis longus tendon of the hind leg was folded to a four-stranded graft. Graft diameter was 9mm in all samples. The graft was anchored within a 9mm tibial tunnel of 40mm length. The graft was fixed with a Washerloc (WL), 2 Cross-Pins (CP) or with an Intrafix (IF). In the Suture-Disc (SD) group 8 polyester sutures (Ethibond 5USP) were knotted over a titanium button. Ten specimen were tested in each group. The tibial bone and the tendon-graft were marked with tantalum beads. A custom-made load frame was developed that allows for periodical RSA measurement while loading the graft. A preload of 100N was applied three times. The grafts were then loaded axially increasing the force in steps of 50N to load of failure. Motion between tendon graft and tibial bone was measured with RSA.

Results: Accuracy of RSA for the in vitro study was 0.05mm. Load at failure was significantly higher for IF fixation (1125±120N) compared to WL (745±196N), CP (647±113N) and SD fixation (445±37N). Stiffness of fixation was significantly higher (p<0,01) for WL (714±305N/mm), IF (653±147N/mm) and CP fixation (511±254N/mm) compared to SD (111±26N/mm). Graft motion in line with the tunnel exceeded 0.5mm in the IF group when 417±272N load was applied. Graft motion at significantly lower loads was observed for WL (246±103N), CP (196±36N), and SD (86±26N) fixation. The highest amount of elastic deformation (bungee cord effect) was observed for the SD fixation (1.32mm at 200N load compared to 0.22mm for IF and WL). Fixation failure was caused in the IF and WS group by tendon rupture. The CP fixation failed in 50% by breakage of the pins. SD fixation failed in all cases by rupture of the suture material.

Conclusions

Tendon-graft fixation with the Intrafix system in vitro was superior to WL, CP and SD fixation . The SD with linkage suture material showed a low linear stiffness and allowed for a high amount of elastic deformation. Our RSA method showed irreversible graft motion in all groups at loads that may occur during rehabilitation after ACL reconstruction.

The cross sectional area of the quadruple hamstring graft correlates with the size of the donor.

Aune, AK and Nordsletten, L. Volvat Medical Centre and Orthopaedic Centre, Ullevaal University Hospital, Oslo, Norway.

Some have questioned if the length and cross sectional area of the hamstring graft is sufficient for fixation and load distribution. Its variation with the size of the donor has not been described in the literature. This study was done to provide basic data on this issue.

Materials and methods: The following parameters were registered in 30 consecutive ACL reconstructions: Height and weight of the patient. Length of the prepared Semi T and gracilis tendons. Diameter and cross sectional area of the graft. Any correlation between graft size and donor size was evaluated using regression analysis.

Results: The parameters are presented in the table below.

	Age	Height	Weight	Gracilis	SemiT	Graft diameter	Cross sectional area
Mean	32	171 cm	71 kg	22,0 cm	25,13 cm	7,67 mm	46,46mm2
SD	11,91	10	14	2,53	2,51	0,67	7,61

All grafts had sufficient length. There was a high correlation between the cross sectional area and height (p=0,0001) and weight (p=0,0001) of the donor. The length of the tendons showed a weaker correlation with donor size.

Discussion: A quadruple Semi T/ gracilis graft seems to be long enough for secure fixation with any device. The larger the patient is, the more load is distributed through the graft at a given activity. Graft stress is reduced with increasing cross sectional area. Nature is wise. As Semi T and gracilis tendons are concerned, nature provides a product sufficient to fit the patient. When using a patellar tendon graft, the surgeon has to choose the right size. To reach the same cross sectional area as in this study, a 11-12 mm PTB graft should be harvested.

Reducing invasiveness and improving accuracy with computer assisted surgery (CAS) in ACL reconstruction

Authors: Christian Hoser, Christian Fink, Alfred Muehl, Katja Tecklenburg, Ralph Rosenberger

Department of Traumatology and Sportstraumatology, University Hospital Innsbruck

Anichstr. 35 A_6020 Innsbruck Austria

e-mail Christian.hoser@uibk.ac.at

Background: Surgeons have constantly modified and refined surgical techniques in order to minimize the invasiveness and to improve the accuracy of their procedures. Arthroscopy has played a big role in this process. Recently computer assisted surgery (CAS) has shown its potential to improve the accuracy of tunnel placement in ACL reconstruction. It was our goal to develop a percutaneous ACL reconstruction technique employing CAS.

Method: Five human cadaver knees were used. The specimens were immobilized in full extension applying a suction immobilization device (body fix ®) and computed tomography (CT) scans were performed. The CT data set was transferred to a navigation system (Stealth Station) and 3 dimensional reconstructions were done. A tibial and a femoral path were planned, each leading to the insertion site of the ACL. With the use of a special aiming device 2.4 mm guide wires were advanced into the tibia and the femur. 8 mm cannulated drills were used for overreaming the guide wires. The arthroscope was introduced into the femoral tunnel and the remnants of the ACL were resected with a shaver, which has been introduced through the tibial tunnel. A bony widening of the intercondylar notch was not performed. A pulling suture was threaded from the tibia through the joint and out through femur. The graft was then pulled into the tunnels and fixed with interference screws. A post operative CT scan was then performed to evaluate the graft and the tunnel position.

Results: 1. It was consistently possible to perform an ACL reconstruction without traditional arthroscopic visualization. Anteromedial or anterolateral portals were not used. The intercondylar region was not enlarged (no notch plasty).

2. The femoral and tibial tunnel positions were accurate with a distance of 0 to 2mm from the preplanned path.

Conclusion: Our results have shown that it is possible to reconstruct the ACL with a percutaneous technique in the cadaver model. CAS may not only improve accuracy but may also reduce the invasiveness of an ACL reconstruction technique.

WORK IN PROGRESS: MRI VIRTUAL ARTHROSCOPY OF THE KNEE

Charles P. Ho, Bernhard Geiger

MRI examinations of the knee provide exquisite detail in resolution and contrast of the internal chondral, meniscal, and synovial/capsular surfaces and recesses, as well as underlying and surrounding bone, ligaments, and tendons. Conventional 2-dimensional display of the MRI exams provide accurate evaluation of internal derangement, but the detail may not be appreciated fully by patients and users not familiar with standard MRI tomographic display and tissue contrast.

Hypothesis: With suitable display and manipulation tools, this MRI detail may be presented from intra-articular 3-dimensional perspective to demonstrate meniscal tears, chondral defects, and other intra-articular lesions as a virtual diagnostic arthroscopy.

Methods: High resolution 3-dimensional MRI data set of the knee using imaging sequences that provide optimal contrast differentiation among chondral, meniscal, and synovial surfaces and intra-articular fluid are obtained. This exam is obtained initially with preceding intra-articular injection of sterile saline in MRI saline arthrogram to distend the joint recesses, as would be done during true arthroscopy. The data set is displayed and manipulated on workstation from an intra-articular perspective. Additional tools then allow virtual arthroscopic display of standard MRI data sets obtained without preceding sterile saline injection.

Results: Surface rendering and shading tools allow demonstration of the intra-articular surfaces with high resolution and differentiation among meniscal, chondral, and synovial/capsular tissues. Fly/flythrough tool permit the user to examine from any desired angle. 3-dimensional registration tool allows the high resolution MRI data set to be matched precisely with additional short low resolution MRI sequences obtained with the knee in sequential varying positions of flexion/distension to display the intra-articular surfaces with appropriate positioning and stretching during motion or external manipulation of the knee. A push/distention tool may then be used with standard non-distended MRI data sets to push synovial surfaces away from chondral and meniscal surfaces wherever any fluid is detected to simulate distention of the joint by fluid/saline during arthroscopy/arthrography.

Conclusions: High resolution MRI exam of knee may be displayed from intra-articular perspective as an MRI virtual diagnostic arthroscopy. This technique may assist in evaluation and operative planning, as well as in patient and student education and training. With use and modification of the registration tool and development of additional tools such as to simulate intra-articular and extra-articular probing, manipulation, and muscle forces, this technique could also be helpful for musculoskeletal research such as in tissue properties and biomechanics.

Three years of experience with computer navigation-assisted positioning of drilling tunnels in anterior cruciate ligament replacement

Eichhorn Jürgen

We have been using the “Orthopilot” computerised navigation system to optimise the positioning of drilling tunnels in anterior cruciate ligament replacement for more than three years. During this time additional safety elements have been integrated into the software, so that it is now possible not only to use navigation to find the anatomically optimal insertion area on the tibia and femur, but also to project the fossa intercondylaris in extension onto the head of the tibia so that ventral and lateral impingement situations can be shown in advance, allowing adequate notchplasty to be performed. In addition to this, the direction of the tunnel is displayed in the frontal and sagittal plane to make sure that the extrapolation of Blumensaat’s line is ventral to the drilling tunnel.

To establish the accuracy of navigated tunnel positioning eight junior doctors, who must be considered beginners in terms of their arthroscopic experience, each attempted ten consecutive tunnel placements. The deviation in the ten attempts was recorded, as was the difference between the eight investigators. The results showed that the anatomical insertion site on the tibia and femur was accurately arrived at in each case with only minimal deviations. In addition, 300 postoperative x-rays of navigated anterior cruciate ligament replacements were analysed and the position of the tunnels evaluated. To provide a comparison, 300 non-navigated anterior cruciate ligament replacements were also assessed. Whereas in each of the navigated cases, with only two exceptions, it was possible to achieve the optimal tibial insertion site sagittally at 47 % (+/- 5 %) as well as the dorsal margin of the femoral cortex in the 10 or 2 o‘ clock position +/- 30 minutes, the tendency could be demonstrated in the non-navigated cruciate ligaments to site the tibial tunnel too far in a dorsal direction (mean value 50 %, +/- 3 %) and to site the femoral tunnel too high at 11 or 1 o‘ clock +/- 30 minutes. Through the use of the navigator, it was possible to change over to the anteromedial portal technique when the anatomical area on the femoral insertion was not attained. This occurred distinctly less often with the non-navigated cruciate ligaments.

The influence of a meniscectomy or meniscus suture on the stability of the knee in computer assisted anterior cruciate ligament reconstruction

Dr. T.V.S. Klos, J. Bos, Catharina Hospital Michelangelolaan 2

Eindhoven Netherlands

Introduction

It is suspected that there is a relationship between the stability after an anterior cruciate ligament (ACL) reconstruction and meniscectomy or meniscus suture. The knee is believed to be more stabile after a meniscus suture, and less stabile after a meniscectomy. The purpose of this research project was to identify whether this relationship could actually be demonstrated scientifically.

Methods

116 Patients, who underwent computer assisted anterior cruciate ligament reconstruction, were divided into 5 different groups:

1. meniscus suture or trephination of the meniscus in the medical history

2. meniscectomy in the medical history

3. during the ACL reconstruction also a meniscus suture or trephination

4. during the ACL reconstruction also a meniscectomy

5. control group: no surgery on the meniscus

There were intra-operative stress X-rays available of all these patients, both pre- and postreconstructive and of both knees, on which calculations were made with CAACLREC (= computer assisted anterior cruciate ligament reconstruction), a computer program used during the ACL reconstruction. The groups were compared to each other in flexion as well as in extension on their improvement in stability.

We used a comparison of variance (ANOVA) for the statistical analysis.

Results and conclusions

There were no statistical significant differences between the groups in flexion (p<0,7) as well as in extension (p<0,5). A possible explanation for this might be that the groups we used were small (21, 28, 13, 11 and 43 patients). Still, the knees from the first group tended to be more stabile than the knees in the controlgroup, and the knees from the second group less stabile.

Conclusion: There was no significant difference found between the different groups with or without meniscectomy or meniscus suture after an ACL reconstruction.

Integrity of Reconstruction of the Anterior Cruciate Ligament: A Roentgen Stereophotogrammetric Analysis.

Rhidian Thomas, Rashid Khan, Andrew Amis, Imperial College, London.

Background

Roentgen stereophotogrammetric analysis (RSA) is the most accurate radiographic technique for the measurement of three-dimensional micromotion in joints and has been used successfully in total joint replacement outcome studies.

Introduction

Using RSA we undertook a prospective study of 14 patients who had ACL reconstruction – seven, bone-patellar tendon-bone and seven hamstring (four stranded semitendinosus/gracilis). Our aim was to analyse and compare the two types of grafts.

Methods

Beads were inserted into the both the graft and bone (distal femur and proximal tibia). With the graft the beads were therefore placed in both the tunnels and also the intra-component of the graft. Both types of grafts had the same method of fixation with titanium ‘soft’ interference screws. Multiple beads were also inserted into the femoral condyles and proximal tibia in order to assess the relative displacement of tibia with femur. With such a method 6 degrees of freedom can be measured. X-Ray Stress testing was performed using the “Telos system” at 100N anterior displacement. Clinical outcomes were measured using the KT2000 Arthrometer, IKDC, Lysholm and Tegner scoring systems.

Results

Our early results indicate that, in addition to measuring anteroposterior laxity, we are able to calculate any slippage of the graft ends in the bony tunnels, and also any stretching of the graft itself. To the best of our knowledge, this detailed use of RSA in comparing the two commonly used autografts in ACL reconstruction has not been previously described. We hope to gain valuable “in-vivo” insight into the outcome of autograft ACL reconstructions Back to top

Immediate Mobilization after Anterograde Arthroscopic Fixation of Avulsion Fracture of the Tibial Eminence with Cannulated Screw. Five-year Results.

Matjaž Veselko, M.D., Ph. D., Dpt. Of Traumatology, Ljubljana, Slovenia

Purpose: To evaluate five-year results of arthroscopic reduction and anterograde fixation of the tibial emminence fracture with cannulated screws.

Type of study: Retrospective

Introduction: Fractures of the tibial emminence can be treated arthroscopically. Fixation of the fracture is ussually followed by temporary immobilization. According to the literature, only anterograde fixation with cannulated screws and washer is considered to be stable enough to start immediate mobilization and weight bearing.

Methods: Thirty-two patients were arthroscopically treated for Type II, III and IV fractures of the intercondylar eminence of the tibia. The fragments were reduced and fixed with a cannulated screw or cannulated screw and washer. The intermeniscal ligament was involved in a fracture in 29, and anterior part of the medial meniscus in 3 cases, requiring a temporary shift prior to reduction of the fragment. Arthrotomy was never performed for reduction nor for fixation of the fragment. All patients began continuous passive and active motion of the involved knee and were mobilized on crutches the next day after the procedure. They were allowed immediate pain-free weight-bearing. The patients were followed up for 16-69 months.

Results: Good therapeutic results were obtained at follow-up. Average value for KT 1000 was 1.1mm, flexion deficit 1.2°, extension deficit 0.6°, and Lysholm score 98.8. The average duration of treatment was 12 weeks. There was one case of aseptic synovitis and no other complications. In all but one patient the implants were removed.

Discussion: Arthroscopic fixation of the fracture of the intercondylar eminence of the tibia with a cannulated screw, or screw and washer, is a simple, safe, reproducible and effective procedure. The fixation is stable even in Type IV fractures, so that immobilization is unnecessary.

EFFECT OF LATERAL FEMORAL TUNNEL PLACEMENT ON KNEE STABILITY AND GRAFT FUNCTION

*Yamamoto, Y., *Hsu, W.H., *Van Scyoc, A.H., *Takakura, Y., *Debski, R.E., +*Woo, S.L-Y.

+*Musculoskeletal Research Center, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA,

INTRODUCTION: ACL reconstructions that more closely approximate the anatomy of the ACL are being explored by an increaseing number of orthopaedic investigators [1, 2]. A study from our research center has shown that an anatomic ACL reconstruction replacing both the anteromedial (AM) and posterolateral (PL) bundles could restore normal knee kinematics and in situ force of the ACL more closely than a single-bundle graft is placed at the 11 o’clock femoral tunnel position [3]. As published data also demonstrated that using a graft placing the femoral tunnel at a 10 o’clock position is more effective in resisting rotatory loads than that at the 11 o’clock position [4], the objective of this study was to compare whether a more lateral graft placement (10 o’clock position),could restore knee function as well as the anatomic reconstruction. The hypothesis to be tested is a more laterally placed single-bundle reconstruction could restore knee function is in response to anterior tibial and rotatory loads when the knee is near extension because the PL bundle is duplicated.

MATERIALS AND METHODS: Ten human cadaveric knee specimens (48.6 ± 5.5 yrs) were tested using a robotic/universal force-moment sensor testing system [5]. The anterior tibial translation (ATT) of the intact knee and the in situ force in the ACL were determined in response to 1) a 134 N anterior tibial load at full extension, 15°, 30°, 60° and 90° and 2) rotatory loads of 10 N-m valgus and 5 N-m internal tibial torque at 15° and 30°. Further the same loading conditions were also applied to the ACL-deficient knee and the resulting changes in ATT were recorded. For the anatomic double-bundle reconstruction, two femoral tunnels were created at the AM and PL insertion of the ACL [3]; while a single femoral tunnel was created at the PL insertion for the 10 o’clock single-bundle reconstruction. Both ACL reconstructions were performed in the same knee using the same hamstrings graft, fixation methods and single tibial tunnel. The kinematics of the ACL-reconstructed knee and in situ force in the ACL grafts were determined following the method described for the intact knee. The data obtained included the ATT of the intact, ACL-deficient, and ACL-reconstructed knees and the in situ force of the intact ACL and ACL replacement grafts. The data was analyzed using a repeated measures analysis of variance with multiple contrasts. The significance level was set at p < 0.05.

RESULTS: In response to a 134 N anterior tibial load, there was no significant difference in ATT between the two methods of reconstructions except at 60° and 90° of knee flexion. In terms of in situ forces in the graft, there also was no significant difference except at 90° of knee flexion (Table). In response to rotatory loads, the coupled ATT for the anatomic double-bundle reconstruction was 4.8 ± 2.4 mm and 6.7 ± 2.6 mm at 15º and 30º, respectively. Whereas those for the 10 o’clock single-bundle reconstruction was 4.7 ± 3.1 mm and 6.5 ± 3.0 mm at 15º and 30º, respectively. There were no significant differences in the ATT and ACL in situ forces between intact and the two reconstructions (Figure).

DISCUSSION: The data confirmed our hypothesis that there was no difference between the anatomic reconstruction and the 10 o’clock single-bundle reconstruction when the knee is near full extension. These findings were true for both of the anterior tibial and rotatory loads that were applied. The anatomic reconstruction restored kinematics and in situ force of the ACL to the level of the intact knee at all flexion angles of the knee. Similarly, the 10 o’clock single-bundle reconstruction could limit the ATT when the knee is near extension. However, it was not the same at high flexion angles of the knee because the AM bundle is not represented. Studies have shown that the AM bundle is known to carry the majority of load at high flexion angles. Because the 10 o’clock femoral tunnel position is closely approximating the PL bundle insertion and is located more laterally than the AM bundle of the ACL, it can help to stabilize knee rotation more effectively.

REFERENCES: 1). Muneta, T., et al., Arthroscopy, 1999; 2). Hamada, M., et al., Arthroscopy, 2001; 3). Yagi, M., et al., Am J Sports Med, 2002; 4). Loh, J., et al., Arthroscopy, 2003; 5). Rudy, T.W., et al., J Biomech, 1996.

ACKNOWLEDGMENT: Prof. Masahiro Kurosaka (Kobe Univ.), NIH grant AR 39683, Mitek and Smith & Nephew supplied the fixation devices

The Effect of Tibial Slope on Anterior Tibial Translation in the ACL deficient knee.

*Mark Clatworthy and Ralph Maddison Auckland Bone and Joint Surgery, Auckland, New Zealand.

Introduction. The purpose of this study was to examine the effect of tibial slope on anterior tibial translation in the ACL deficient knee measured objectively using the KT 1000 arthrometer.

Method. Eighty-eight patients (male = 60, female 28) aged between 14 and 48 years (Mean = 28.64, SD 8.54) with a diagnosis of isolated anterior cruciate ligament rupture were prospectively recruited. All participants had intact ACLs of the contralateral limb. The following information was recorded for all patients; time from injury to surgery, IKDC objective and subjective assessment and KT 1000 arthrometer readings. Tibial slope was assessed from long tibial lateral x-rays as described by Dejour and Bonnin. Finally, assessment of the menisci occurred intra-operatively.

Results. Bivariate correlations showed a significant correlation between tibial slope and KT 1000 (r= .321, p < .001). This relation was strengthened when the integrity of the menisci were controlled for (r = .354, p <. 001). When time to surgery was controlled for, correlations between tibial slope and KT 1000 were unaffected. There was also a positive correlation between medial meniscal integrity and time to surgery. No relationships between time to surgery and KT 1000 were evident.

Discussion. This study demonstrates a significant relationship between increasing tibial slope and anterior tibial translation of the ACL deficient knee.

Primary Repair of the ACL: Do we Need to Go there Again? John Feagin

Hypothesis: Basic Science Knowledge, Technical Advancements, and “Circumstances” have ruled invalid the conclusions of our “Classic”: The Isolated Tear of the ACL: 5 year Follow-up study: Am J. Sports Med. 4:95-100. 1976.I have re-read our Classic many times. I would not change a word of the text. It was a “Classic” because the time was right, the experience was there, and Lottie and Walt Curl wrote it. We said what we meant and we meant what we said. Primary repair of the ACL, in the West Point Cadet, works one-third of the time. Why then re-visit the subject? The data was not flawed, the conclusions were appropriate – was the surgery flawed? John Marshall said it was and his young scholar Mark Sherman has continued to use the Marshall technique with success. The Historical background is important; but more important is the Basic Science, the Technical Factors, and the Circumstances which form the basis of our every day judgment. I will review the below listed factors which bring new material to address and judge the hypothesis from three points:

1. How is it we were successful in one-third of the cases?

2. What role did patient selection play?

3. Could our surgical technique have been improved then or now?

Basic Science progress since our reported experience:

1.Better understanding of the Anatomy of the ACL

2.The spectrum of ACL injury (the pathophysiology) is better understood. (ie. partial tears, tear location, interstitial disruption, related meniscal injury, primary and secondary restraints, rotational laxity and the pivot shift.)

3. The importance of meniscal preservation and limb alignment

4. Activity level, and result grading by the IKDC has made patient selection more “scientific”.

5.The “healing response” is a viable theory and concept.

Technical Progress and Equipment:

1. Arthroscopy and MRI give us expanded diagnostic, prognostic, and therapeutic opportunities

2. MRI provides better preoperative injury evaluation

3.The concept of minimally invasive surgery is ever with us

4.Instrumentation has been vastly improved. Fixation devices, sutures, stents are improved. Our commercial colleagues have contributed in great measure to surgical evolution.

5.Multiple solutions have proven successful thereby increasing the breadth of our therapeutic options.

Circumstances:

1. We have educated the public – they are more sophisticated, demanding, litiginous.

2.The ACL has become epidemic in our Society

3. Bright minds have brought innovative concepts and improved skills.

4.Our organizations have had a salutory effect on our results.

Conclusion:

One size no longer fits all. We need to re-think the ACL solution collate and integrate our new found knowledge and seek solutions with less morbidity and more applicability. Re-visit Primary Repair. The ACL SG is the right place for this to originate. We are expected to be the leaders in ACL care. Our considerable resources must be focused on improved treatment and injury prevention.

Intraarticular Analgesia Using a Meperidine/Local Anesthetic Combination in Arthroscopic Knee Procedures

Brent L. Walker, M.D.; J.L. Vander Schilden, M.D.; W. Brooks Gentry, M.D.

Departments of Anesthesiology and Orthopaedic Surgery

University of Arkansas for Medical Sciences, Little Rock, Arkansas

Corresponding Author:

W. Brooks Gentry, M.D. Assistant Professor Departments of Anesthesiology, And Pharmacology and Toxicology. College of Medicine. University of Arkansas for Medical Sciences

4301 W. Markham, Slot 515

Little Rock, AR 72205

Phone: 501-696-7611

Fax: 501-603-1951

Email: gentrywilliamb@exchange.uams.edu

OBJECTIVE: This study compared the efficacy of the opioids meperidine and morphine combined with local anesthetics (LA) for intraarticular analgesia to LA alone for postoperative analgesia in eighty six knee arthroscopy patients.

DESIGN: This was a two-part study in which each patent rated his knee pain with a verbal pain score (VPS) on admission to the post-anesthesia care unit (PACU), on discharge from the PACU, and 24 hours following knee arthroscopy as part of a quality assurance survey.

INTERVENTIONS: Patients received an intraarticular injection of one of three drug combinations prior to skin incision. The drug combinations included bupivacaine and lidocaine (0.5%, 30ml with epinephrine 1:200,000) bupivacaine and lidocaine with meperidine (50mg), or bupivcacaine and lidocaine with morphine (5mg).

RESULTS: On admission to the PACU, the combination of meperidine and local anesthetics provided significantly better analgesia than did the other two regimens VPS did not differ among the groups at discharge from the PACU. VPS 24 hr postoperatively were significantly lower for both opioid/LA combinations compared to local anesthetics alone, with meperidine exceeding morphine.

CONCLUSIONS: Compared to morphine with LA, meperidine combined with LA gave significantly improved pain relief. Further data will be presented comparing intraarticular ketoralac (Toradol) with LA and meperidine as well.

Salvage Treatment of Massive Non-Structrual Osteochondral Lesions of the Knee:

The Use of Allograft MegaOATS versus Mosiacplasty

Albert W. Pearsall, IV, MD; Sudhakar G. Madanagopal, MD; Robert J. Heitman, PhD; Jay Hughey, BS. Departments of Orthopaedic Surgery and Health Sciences, University of South Alabama Medical Center, Mobile, Alabama.

Introduction: The treatment of full thickness cartilage lesions of the knee remains a challenge, with morbidity rates as high as 50% reported. Treatment options for full thickness osteochondral lesions include lavage, marrow stimulation techniques, abrasion arthroplasty, subchondral drilling, microfracture. The results of these treatments is partial filling of the defect with fibrocartilage which has a predilection for deterioration over time.The use of fresh osteochondral allografts in the treatment of full thickness articular cartilage defects of has been well documented, with success rates of 75% reported at 5 years, slightly deteriorating to 63% at 14 years. Recently, excellent chondrocyte viability of refrigerated allografts has been reported. The term “megaOATS” (OsteoArticular Transplant Surgery) is used to define large single plug allografts (>3.1cm²). Purpose: To compare the results of megaOATS allograft versus mosicplasty as salvage treatment of massive cartilage lesions of the knee.

Materials and Methods: Between 1998 and 2001, 46 patients underwent transplantation with either a megaOATS allograft or mosiacplasty for a massive articular cartilage lesion of the femur or patella. All patients failed previous attempts at conservative treatment for a minimum of 6 months. There were 30 allografts and 16 mosiacplasties. All patients underwent evaluation including range of motion, knee radiographs, WOMAC, SF-36, Knee Society Scoring (KSS) and VAS pain measurement preoperatively and at the most recent follow-up. Statistics: Pre and post scores were assessed with a single paired t-test. ANOVA was used to assess single variable correlations and logistic regression analysis was performed on multiple variables. Significance was defined at p< 0.05.

Results: Patient age averaged 47 years for both groups. Minimum follow-up was 2 years. Analyzing both groups, paired t-tests (2-tailed) showed significant improvement in all WOMAC scores (pain p= 0.009), (stiffness p=0.015), (function p= 0.0001). KSS demonstrated significant improvement (p=0.003). There was no significant improvement in range of motion (p=0.260). Pearson correlation analysis showed no significant correlation between age, sex, BMI, size of defect, graft type, number of plugs and improvement in WOMAC and KSS scores. MegaOATs and mosiacplasty were analyzed separately with initial t-tests to test equality of means and variances between groups and ensure that both groups were comparable. There was no difference in age, sex, BMI, pre-op WOMAC and KSS scores. There was a significant difference in defect size treated (mosiacplasty=6.1cm2 / MegaOATS=17.5cm2). T-tests performed between groups did not show any significant difference in improvement of WOMAC, KSS and range of motion.

Conclusion: Treatment with mosaicplasty (autograft) and megaOATS (allograft) provided significant functional improvement in patients with massive non-structural knee osteochondral lesions. No significant difference in outcome was noted between the 2 treatment groups. Age, sex, BMI, size of defect, type of graft and plug number did not have a significant effect upon outcome.

Normal vs. transplanted menisci: evaluation of extrusion using MRI and US. A preliminary report.

Verdonk R., Verdonk P., Depaepe Y., Desmyter S., De Muynck M., Almqvist F.

Department of Orthopaedic surgery and rehabilitation, University Hospital Ghent, Belgium

Aim of the study: To develop a clinically useful and reproducible method to evaluate and to compare lateral meniscal extrusion in normal and transplanted knees. We also hope to establish a correlation between extrusion and clinical outcome.

Method: Two imaging techniques were used: magnetic resonance imaging and ultrasonography. MRI images of 10 normal knee and 17 laterally transplanted knee were analysed, both medial and lateral compartments. Extrusion was defined as the distance measured from femoral condyl to the outer edge of the meniscus. These measurements were done using MRI written software.

Ultrasonographic print-outs were analysed of 10 laterally transplanted knees and 10 normal knees. Extrusion was defined in 2 way: extrusion surface was defined as the surface measured outside the knee, extrusion distance was measured as the greatest distance from a line connecting femur and tibia to the outer edge of the meniscus. Patients were evaluated in the supine position, bipodal stance and unipodal stance.

Results:A. MRI Results: The lateral transplanted meniscus is statistically (p<0,005) more extruded than the normal lateral meniscus. The anterior horn of the transplanted meniscus tends to be more extruded than the posterior horn. The normal meniscus shows no extrusion.

B. US Results: The lateral transplanted meniscus is statistically (p<0,005) more extruded than the normal lateral meniscus in all patient positions. Both surface and distance are equally good parameters to determine meniscal extrusion. There is no statistical difference between patient positions.

Discussion: The lateral meniscal implant is more extruded than the normal meniscus measured by MRI and ultrasonography. Correlation between meniscal extrusion and clinical results remains to be determined.

Angled Osteochondral Grafts-Effects on Articular Contact Pressure

Authors:

Jason Lee Koh MD, Northwestern University School of Medicine, Chicago, IL
Adam Kowalski, Northwestern University, Chicago, IL, United States of America
Eugene Lautenschlager PhD, Northwestern University School of Medicine, Chicago, IL

Objective: Small articular surface incongruities may occur after osteochondral plug grafting. We investigated the effect of angled grafts on femoral condyle articular cartilage defects on contact pressure in the knee.

Methods: An 80N load was applied with an Instron for 120s to the femoral condyles of 50 fresh swine knees covered with Fuji pressure sensitive film under 5 conditions: (1) intact surface; (2)4.5mm diameter circular defect; (3) grafted with a flush 4.5mm diameter plug; (4) grafted with a 30 degree angled 4.5mm diameter plug, with lower edge flush (tip elevated with respect to adjacent surface); (5) grafted 30 degree plug, with tip flush to adjacent surface(lower edge sunk). Angled grafts were obtained using a rotational bearing vise aligned with a 30-degree fixed angle track. The height difference at graft edges was sin(30)times 4.5mm equals 2.25mm. Film was digitally scanned and analyzed, and standard statistical tests performed.

Results: Mean peak pressures of intact (8.57kg/cm2), flush (9.81kg/cm2), and sunk angled (9.15kg/cm2) were not significantly different (p>0.5). The defect (12.00kg/cm2) and the elevated angled graft (14.50kg/cm2) were significantly (p<0.05) higher than intact.

Pressure-sensitive film following testing of sunk angled plug. Note gradual decrease in optical density (pressure) as surface of plug goes below adjacent cartilage and has less load.

Conclusions: It is often difficult to perfectly match the articular surface with an osteochondral graft. Slightly sunk grafts were still able to reduce elevated contact pressures to normal levels. However, elevated angled grafts increased contact pressure. These results suggest that it is preferable to leave an edge slightly sunk rather than elevated.

Chondral and Meniscal Injuries Associated to the Chronic Anterior Cruciate Ligament Deficient Knee.

Dr. Arturo Almazan, Dr. Michell Ruiz, Dr. Ivan Encalada, Dr. Francisco Cruz, Dr. Clemente Ibarra, Dr. Francisco Xavier Perez.

National Center for Rehabilitation. Sports Medicine and Arthroscopy Service. Mexico City, Mexico

In some developing countries it is not uncommon to reserve surgical reconstruction of the anterior cruciate ligament (ACL) just for the highly active patients, leaving a lot of patients with an ACL deficient knee that may develop degenerative changes. Until now we don’t know the true natural history of the ACL deficient knee. The chronic ACL injuries may lead to the development of associated injuries which can jeopardize the results of the ACL reconstruction and hence the performance of the patient.

Purpose: Determine the incidence of arthroscopic associated injuries in the chronic ACL deficient knee at the time of the primary reconstruction. Type of study: Prospective cohort.

Patients and methods: We designed a surgical form to record the arthroscopic findings during the primary ACL reconstruction; the surgeon immediately filled this form after the case was done. The chondral injuries were graded as described by Outerbridge, and the meniscal ones according to its morphology. The inclusion criteria for the study were any patient with a chronic ACL deficient knee who had sustained a primary arthroscopic ACL reconstruction at the National Center for Rehabilitation between the March 01 2002 and April 30 2003 and who had a fully filled surgical form. We defined chronic injuries as being more than 3 months since the initial injury and if they had had additional giving-way episodes. We performed 155 primary ACL reconstructions within that year but only 113 patients had a fully filled understandable surgical form. There were 95 males and 18 females; the average age was 30.9 years, ranging from 16 to 53 years; the average time from injury to surgery was 30.8 months, ranging from 3 to 144 months. 66 patients had a BPTB reconstruction and 47 a quadruple hamstrings reconstruction

Results: According to its location, the most frequent cartilage injuries were on the medial femoral condyle (22.12%), followed by the patella (18.58%) and the lateral femoral condyle (16.18%). According to the grade of the injury, the most frequent was a grade 2 on the patella in 12.38%, followed by a grade 3 on the medial femoral condyle in 11.50% and a grade 3 on the lateral femoral condyle in 8.84%. The medial meniscus was injured in 66.37% of the cases, the lateral one in almost half of the patients (48.67%). Of the 130 meniscal injuries we just did 14 repairs (10.76%), 11 on the medial meniscus (78.57%) and 3 on the lateral meniscus (21.43%). The partial menisectomy was the most frequent procedure done in the meniscus (68.14%).

Conclusion: Our study shows that there is a high incidence of associated injuries e.g. meniscal and chondral in the un treated chronic ACL deficient knees. This observation would support the early surgical reconstruction in the symptomatic ACL deficient knees.

Dr. Arturo Almazan

Malaga Sur 43

Col. Insurgentes Mixcoac C.P. 03920

Mexico D.F. Mexico

Tel: (525) 5 55638657

Fax: (525) 5 85009369

docalmazan@hotmail.com

A Pilot Study Presenting New Methodology To Quantify In Vivo Tissue Loads By In Vitro Robotic Reproduction

CB Frank, RA Howard, JM Rosvold, JM Tapper, LL Marchuk, JL Ronsky, NG Shrive

McCaig Centre, University of Calgary, Calgary, Alberta, Canada

Introduction: A complete understanding of normal diarthrodial joint mechanics and the mechanobiology of load bearing tissues would assist in clinical restorations of mechanical function in disrupted knee ligaments and possibly elucidate why these repaired joints often require revision surgery and may eventually develop osteoarthritis. Historically, mechanical properties of isolated joint tissues have been determined using traditional uniaxial material testing equipment. A recent advance in testing was the introduction of robotic techniques which have sought to estimate likely tissue loads and function throughout passive joint motion [1,2]. What has been missing, however, and is therefore the aim of this pilot study, is the ability to reproduce in vitro, true in-vivo load bearing kinematics with measurement of the resulting kinetics.

Methods: In-vivo kinematics of adult sheep knee joints were measured to an accuracy of 0.5mm 3-dimensionally using rigid marker systems implanted on the femur and tibia [3]. Following sacrifice, the joint was dissected, and marker positions were related to coordinate systems on the tibia and femur based on anatomical landmarks. The motion of the femur was then described relative to the tibia using 100 transformation matrices, each representing an equal, sequential time increment during one gait cycle. The same joint (n = 3) was then rigidly mounted on the end-effector of a parallel robot (PRSCo, Hampton, NH, USA, accuracy +/- 50 µm), whereby the femur was manipulated relative to the tibia, which was mounted on a universal load sensor (ATI, NC, USA), fixed to a stationary, stiff, external load frame. Referencing of the joint was performed using a coordinate measuring machine (Faro, FL., USA, accuracy +/- 0.05mm). Landmark-based coordinate systems were reconstructed, and referenced to the robot coordinate system. Custom software was then used to calculate the 100 positions of the robot end-effector corresponding to the in-vivo joint positions defining one gait cycle. The joint was then conditioned with 10 cycles at 1/20^th of the in-vivo speed, after which 10 cycles were performed with load measurement, followed by various cycles in which the normal path of motion was perturbed 0.5mm in the anterior, posterior, medial, lateral, superior, and inferior directions to measure the sensitivity of the system to kinematics perturbations. The ACL was then transected, and the cycle and load acquisition repeated. The MCL, LCL, and PCL were sequentially transected and the motion repeated in turn. The loading contributions of each of these structures were then calculated from the difference in total load measured at the sensor using the principle of superposition [4].

Results: The magnitudes and lines of action of the force in each ligament during one unique gait cycle beginning and ending at hoof strike were calculated from joint loading before and after removal of the structure and repetition of the motion.

Discussion: This pilot study demonstrates that in-vivo joint loads and subsequent joint structure loading contributions can be successfully measured through in-vitro re-creation of in-vivo kinematics. The method developed will facilitate comprehensive studies relating mechanics and biology to in vivo joint function and may help in understanding and developing clinical ligament repair and replacement technologies.

References: [1]Woo SL etal J Sci Med Sport 2(4):283-97,1999 [2]Fujie H etal Trans 25:474, 2000 [3]Tapper JE etal J Biomech Eng (Accepted, 2003) [4]Abramowitch SD Trans 28:1283, 2003.

Acknowledgments: CFI, CIHR, GEOIDE, AHFMR, TAS, CCIT, McCaig Centre, L Jacques.

Non-Invasive In-vivo Evaluation of the Pivot Shift Using an Electromagnetic Device for the ACL-Deficient and Reconstructed Knees

Ryosuke Kuroda, *Masayoshi Yagi, Seiji Kubo, Kouichi Tanaka, Kiyonori Mizuno, Hirotsugu Muratsu, Shinichi Yoshiya, Masahiro Kurosaka

Kobe University Graduate School, Department of Orthopaedic Surgery

*Shin-suma Hospital, Department of Orthopaedic Surgery

Hypothesis

The intact ACL provides not only anteroposterior (AP) stability but also rotational stability. In the previous in-vitro studies, it was reported that an anatomic two-bundle ACL reconstruction restored knee kinematics better than a single-bundle reconstruction. The pivot shift phenomenon represents the complex rotational and translational instabilities in kinematics of the motion of ACL-deficient knee. Therefore, in clinical assessment of the knees w

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials Peter Burkart, MD. Innusbruk Austria. Download PDF file

MATERIAL AND METHOD

RESULTS

DISCUSSION

CONCLUSIONS

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials

Method

Results

Discussion

Background and Significance

Specific Aims and Hypothesis

Methods

Results

Prospective evaluation of patellar tendon graft fixation using new interference screws -

A comparison of allograft and composite materials

THE INFLUENCE OF CORE STRENGTH ON LOWER EXTREMITY PERFORMANCE

M.L. Ireland 1 , I.S. Davis 2.3, J.D. Willson 2

2 Joyner Sportsmedicine Institute, Mechanicsburg, PA

3 University of Delaware, Newark, DE

Results:

Variable Male Female p r (TFV) r (SLH)

Trunk FL torque 10.03 7.91 0.060 -0.06 0.33

Hip ER torque 7.53 4.01 0.000 -0.41 0.43

Presenter: BARTLETT R.J; Roberts A: Wong J

AIM

CONCLUSION

PAUL MARKS MD, FRCSC

Knee Malalignment Corrected by Opening Wedge Osteotomies

Background

Materials and Methods

Conclusion

Why do we create a round tunnel for a rectangular tendon? -

Development and evaluation of a new technique for ACL reconstruction using patellar tendon

Materials and methods: 1. The Insertion of the patellar tendon on the patella was evaluated on 10 cadaveric human knees. 2. Instruments ( a cannulated rectangular rasp and dilators and a harvesting chisel) have been designed and manufactured.

3. The operative technique has been developed using cadaveric specimens.

How to reduce the tibial tunnel widening in ACL reconstruction:

tricks and technique.

Hypothesis

AUTHORS: Frank Adam, Dieter Kohn

Dr. T.V.S. Klos, J. Bos, Catharina Hospital Michelangelolaan 2

Methods

Results and conclusions

Background

Introduction

Methods

Results

Purpose: To evaluate five-year results of arthroscopic reduction and anterograde fixation of the tibial emminence fracture with cannulated screws.

Type of study: Retrospective

M.L. Ireland ¹, I.S. Davis ^2.3, J.D. Willson ²

² Joyner Sportsmedicine Institute, Mechanicsburg, PA

³ University of Delaware, Newark, DE

Materials and methods: 1. The Insertion of the patellar tendon on the patella was evaluated on 10 cadaveric human knees.
2. Instruments ( a cannulated rectangular rasp and dilators and a harvesting chisel) have been designed and manufactured.