Anatomical Double-Bundle Anterior Cruciate Ligament Reconstruction after Valgus High Tibial Osteotomy

Abstract

Background Although anatomical double-bundle anterior cruciate ligament reconstruction can successfully restore normal knee biomechanics for knees with typical varus-valgus alignment, the efficacy of the same reconstruction method for knees after a valgus high tibial osteotomy is unclear. Hypothesis Anatomical double-bundle anterior cruciate ligament reconstruction for valgus knees after a high tibial osteotomy cannot restore normal knee kinematics and can result in abnormally high in situ forces in the ligament graft. Study Design Controlled laboratory study. Methods Ten cadaveric knees were subjected to valgus high tibial osteotomy followed by an anatomical double-bundle anterior cruciate ligament reconstruction. The valgus knees were tested using a robotic/universal force-moment sensor system before and after the ligament reconstruction. The knee kinematics in response to anterior tibial load and combined rotatory loads, as well as the corresponding in situ forces of the anterior cruciate ligament bundles and grafts, were compared between the ligament-intact and ligament-reconstructed valgus knees. Results After reconstruction, the anterior tibial translation and internal tibial rotation for the valgus knee decreased approximately 2 mm and 2°, respectively, at low flexion angles compared with those of the anterior cruciate ligament–intact knee (P < .05). The in situ forces in the posterolateral graft became 56% to 200% higher than those in the posterolateral bundle of the intact anterior cruciate ligament (P < .05). Conclusion Performing an anatomical double-bundle anterior cruciate ligament reconstruction on knees after valgus high tibial osteotomy may overconstrain the knee and result in high forces in the posterolateral graft, which could predispose it to failure. Clinical Relevance Modifications of anterior cruciate ligament reconstruction procedures to reduce posterolateral graft force may be needed for valgus knees after a high tibial osteotomy.