Biomechanical influence of deficient posterolateral corner structures on knee joint kinematics: A computational study

The posterolateral corner (PLC) structures including the popliteofibular ligament (PFL), popliteus tendon (PT) and lateral collateral ligament (LCL) are important soft tissues for posterior translational, external rotational, and varus angulation knee joint instabilities. The purpose of this study was to determine the effects of deficient PLC structures on the kinematics of the knee joint under gait and squat loading conditions. We developed subject-specific computational models with full 12-degree-of-freedom tibiofemoral and patellofemoral joints for four male subjects and one female subject. The subject-specific knee joint models were validated with computationally predicted muscle activation, electromyography data, and experimental data from previous study. According to our results, deficiency of the PFL did not significantly influence knee joint kinematics compared to an intact model under gait loading conditions. Compared with an intact model under gait and squat loading conditions, deficiency of the PT led to significant increases in external rotation and posterior translation, while LCL deficiency increased varus angulation. Deficiency of all PLC structures led to the greatest increases in external rotation, varus angulation, and posterior translation. These results suggest that the PT is an important structure for external rotation and posterior translation, while the LCL is important for varus angulation under dynamic loading conditions. (c) 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2202-2209, 2018.