Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawahara-Cho, Sakyo-Ku, Kyoto, 606-8507, Japan.
Sci Rep. 2023 Apr 19;13(1):6356. doi: 10.1038/s41598-023-33183-2.
Poor clinical outcomes are reported in excessive flexion of the femoral component in total knee arthroplasty (TKA), but their mechanisms have not yet been elucidated. This study aimed to investigate the biomechanical effect of flexion of the femoral component. Cruciate-substituting (CS) and posterior-stabilised (PS) TKA were reproduced in a computer simulation. The femoral component was then flexed from 0° to 10° with anterior reference, keeping the implant size and the extension gap. Knee kinematics, joint contact, and ligament forces were evaluated in deep-knee-bend activity. When the femoral component was flexed 10° in CS TKA, paradoxical anterior translation of the medial compartment was observed at mid-flexion. The PS implant was best stabilised with a 4° flexion model in mid-flexion range. The medial compartment contact force and the medial collateral ligament (MCL) force increased with the flexion of the implant. There were no remarkable changes in the patellofemoral contact force or quadriceps in either implant. In conclusions, excessive flexion of the femoral component yielded abnormal kinematics and contact/ligament forces. Avoiding excessive flexion and maintaining mild flexion of the femoral component would provide better kinematics and biomechanical effects in CS and PS TKA.
在全膝关节置换术 (TKA) 中，股骨组件过度弯曲会导致临床效果不佳，但这些机制尚未阐明。本研究旨在研究股骨组件弯曲的生物力学效应。在计算机模拟中再现了交叉韧带替代 (CS) 和后稳定 (PS) TKA。然后，在前参考的情况下，将股骨组件从前伸位弯曲 0°至 10°，保持植入物的大小和伸直间隙。在深屈膝活动中评估了膝关节运动学、关节接触和韧带力。在 CS TKA 中，当股骨组件弯曲 10°时，在中屈时观察到内侧间室的反常前向平移。在中屈范围内，4°弯曲模型可使 PS 植入物得到最佳稳定。随着植入物的弯曲，内侧间室接触力和内侧副韧带 (MCL) 力增加。在两种植入物中，髌股接触力或股四头肌都没有明显变化。总之，股骨组件过度弯曲会导致异常的运动学和接触/韧带力。避免股骨组件过度弯曲并保持其轻度弯曲将为 CS 和 PS TKA 提供更好的运动学和生物力学效果。
