American Journal of Sports Medicine

Kilger R, Stehle J, Fisk J, Thomas M, Miura K, Woo SL-Y


Background: While anatomic double bundle ACL reconstruction can successfully restore normal knee biomechanics for knees with typical varus-valgus alignment, the efficacy of the same reconstruction methods for knees following a valgus high tibial osteotomy (HTO) are unclear.

Hypothesis: Anatomic double bundle ACL reconstruction for valgus knees following a HTO cannot restore normal knee kinematics and can result in abnormally high in situ forces in the ACL graft.

Study Design: Controlled laboratory study

Methods: Ten cadaveric knees were subjected to valgus HTO followed by an anatomic double bundle ACL reconstruction. The valgus knees were tested using a robotic/universal force-moment sensor testing system prior to and following the anatomic ACL reconstruction. The knee kinematics in response to anterior tibial loads and combined rotatory loads, as well as the corresponding in situ forces of the ACL bundles and grafts, were compared between the ACL intact and ACL reconstructed valgus knees.

Results: Following ACL reconstruction, the anterior tibial translation and internal tibial rotation for the valgus knee decreased approximately 2 mm and 2 degrees, respectively, at low flexion angles compared to that of the ACL intact knee (p<0.05). The in situ forces in the posterolateral (PL) graft became 56% to 200% higher than those in the PL bundle of the intact ACL (p<0.05).

Conclusion: Performing an anatomic double bundle ACL reconstruction on knees following valgus HTO may over-constrain the knee and result in high forces in the PL graft that could predispose it to failure.

Clinical Relevance: Modifications of ACL reconstruction procedures to reduce PL graft force may be needed for valgus knees following a HTO.