ISAKOS Congress 2021

2021 ISAKOS Biennial Congress ePoster

 

Biomechanical Evaluation Of An Over-The-Top Femoral Fixation Technique For Anterior Cruciate Ligament Reconstruction

Heath Patrick Gould, M.D., Baltimore, Maryland UNITED STATES
Timothy Neary, M.D., Fredericksburg, Virginia UNITED STATES
Richard Y. Hinton, MD, MPH, PT, Baltimore , MD UNITED STATES

MedStar Orthopaedic Institute (Union Memorial Hospital), Baltimore, Maryland, UNITED STATES

FDA Status Cleared

Summary

ACL reconstruction using an over-the-top femoral fixation technique demonstrated no significant difference in anterior tibial displacement compared to conventional single-bundle reconstruction, suggesting that a single-stage reconstruction using an over-the-top technique may be a biomechanically viable alternative to two-stage revision in the setting of ACL graft failure with tunnel osteolysis.

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Abstract

Introduction

Revision anterior cruciate ligament (ACL) reconstruction may be complicated by graft tunnel osteolysis, often requiring a two-stage procedure with initial bone grafting followed by definitive ligamentous reconstruction at a later date. This cadaveric study aimed to compare the biomechanical properties of an over-the-top (OTT) femoral fixation technique that does not require bone tunnels to the conventional single-bundle technique for ACL reconstruction. We hypothesized that the OTT technique would be biomechanically non-inferior to the conventional technique.

Methods

Eight matched pairs of cadaveric knees were used. Specimens in each pair were randomized to undergo either a conventional single-bundle ACL reconstruction with femoral and tibial bone tunnels or an OTT technique with extra-physeal fixation on the femoral side. An ACL rupture was simulated by transecting the ligament arthroscopically. All reconstructions were performed using a quadruple-strand hamstring autograft. Specimens were mounted onto a custom biomechanical testing jig, which held the femur in place and applied a 134N anterior force to the tibia with the knee flexed to 30 degrees. Displacement of the tibia relative to the femur was recorded and compared between groups using paired t tests.

Results

No significant difference in mean anterior tibial displacement was observed between the intact and reconstructed states for the control (6.19 vs. 7.13mm; p=0.41) or experimental (6.25 vs. 6.03mm; p=0.71) reconstruction techniques. Similarly, there was no significant difference in mean displacement observed between the reconstructed experimental specimens and reconstructed controls (6.03 vs. 7.13mm; p=0.28).

Conclusions

ACL reconstruction using an OTT femoral fixation technique demonstrated no significant difference in anterior tibial displacement compared to conventional single-bundle reconstruction. These data suggest that a single-stage reconstruction using OTT femoral fixation may be a biomechanically viable alternative to avoid a two-stage revision procedure in the setting of ACL graft failure with femoral tunnel osteolysis.

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