Wan Chao, Hao Zhixiu, Wen Shizhu
1 Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing, China.
2 State Key Laboratory of Tribology, Tsinghua University, Beijing, China.
Proc Inst Mech Eng H. 2016 Sep;230(9):867-875. doi: 10.1177/0954411916656662. Epub 2016 Aug 3.
The medial collateral ligament (MCL) is one of the main ligaments that provide knee joint with major restraints against valgus, internal, and external torque loads. The MCL injury most frequently occurs near its femoral attachment but can be healed spontaneously. Hence, the usual clinical treatment for MCL injury is conservative therapy with early controlled rehabilitation motion. However, the effect of the variations in the healing conditions of the MCL portion (i.e. near the femoral insertion) is still unclear. In this study, finite element tibiofemoral joint models with three different MCL healing conditions were analyzed under six kinds of joint loads, such as 10 and 20 N·m valgus tibial torques, 5 and 10 N·m internal tibial torques, and 5 and 10 N·m external tibial torques. The three healing conditions corresponded to the early, medium, and final (i.e. healthy) stages of the healing period, respectively. It was found that different MCL healing conditions greatly affected the main joint kinematics under valgus tibial torques, but neither the reaction force nor stress results of the MCL. The peak strain values in the MCL healing portion changed greatly under all the six loads. Moreover, all the joint kinematics, strain results, and reaction force of the MCL at the medium stage were similar to those in the healthy joint, that is, at the final healing stage. These imply that the partially healed MCL might be enough for providing the restraints for knee joints and would not lead to some high strains occurring in the MCL.
内侧副韧带（MCL）是为膝关节提供主要外翻、内翻和外旋扭矩负荷限制的主要韧带之一。MCL损伤最常发生在其股骨附着处附近，但可自发愈合。因此，MCL损伤的常规临床治疗是早期进行可控康复运动的保守治疗。然而，MCL部分（即靠近股骨附着处）愈合情况变化的影响仍不清楚。在本研究中，分析了具有三种不同MCL愈合情况的有限元胫股关节模型在六种关节负荷下的情况，如10和20 N·m的胫骨外翻扭矩、5和10 N·m的胫骨内翻扭矩以及5和10 N·m的胫骨外旋扭矩。这三种愈合情况分别对应愈合期的早期、中期和最终（即健康）阶段。研究发现，不同的MCL愈合情况在胫骨外翻扭矩下对主要关节运动学有很大影响，但对MCL的反作用力和应力结果没有影响。在所有六种负荷下，MCL愈合部分的峰值应变值变化很大。此外，中期的所有关节运动学、应变结果和MCL的反作用力与健康关节（即最终愈合阶段）相似。这意味着部分愈合的MCL可能足以对膝关节提供限制，并且不会导致MCL中出现一些高应变。
