Background:Injuries to the deep medial collateral ligament (dMCL) and partial superficial MCL (psMCL) can cause anteromedial rotatory instability; however, the contribution of each these injuries in restraining anteromedial rotatory instability and the effect on the anterior cruciate ligament (ACL) load remain unknown.Purpose:To investigate the contributions of the different MCL structures in restraining tibiofemoral motion and to evaluate the load through the ACL after MCL injury, especially after combined dMCL/psMCL injury.Study Design:Controlled laboratory study.Methods:Sixteen fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic simulator. Tibiofemoral kinematic parameters were recorded at 0°, 30°, 60°, and 90° of knee flexion for the following measurements: 8-N·m valgus rotation, 4-N·m external tibial rotation (ER), 4-N·m internal tibial rotation, and a combined 89-N anterior tibial translation and 4-N·m ER for both anteromedial rotation (AMR) and anteromedial translation (AMT). The kinematic parameters of the 3 different MCL injuries (dMCL; dMCL/psMCL; dMCL/superficial MCL (sMCL)) were recorded and reapplied either in an ACL-deficient joint (load sharing) or before and after cutting the ACL (ACL load). The loads were calculated by applying the principle of superposition.Results:The dMCL had the largest effect on reducing the force/torque during ER, AMR, and AMT in extension and the psMCL injury at 30° to 90° of knee flexion ( P < .05). In a comparison of the load through the ACL when the MCL was intact, the ACL load increased by 46% and 127% after dMCL injury and combined dMCL/psMCL injury, respectively, at 30° of knee flexion during ER. In valgus rotation, a significant increase in ACL load was seen only at 90° of knee flexion.Conclusion:The psMCL injury made the largest contribution to the reduction of net force/torque during AMR/AMT at 30° to 90° of flexion. Concomitant dMCL/psMCL injury increased the ACL load, mainly during ER.Clinical Relevance:If a surgical procedure is being considered to treat anteromedial rotatory instability, then the procedure should focus on restoring sMCL function, as injury to this structure causes a major loss of the knee joint’s capacity to restrain AMR/AMT.

中文翻译：

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深层和浅层内侧副韧带的负荷分配、部分浅层内侧副韧带损伤的影响以及对 ACL 负荷的影响


背景：深层内侧副韧带（dMCL）和部分浅层内侧副韧带（psMCL）损伤可导致前内侧旋转不稳定；然而，这些损伤在抑制前内侧旋转不稳定方面的贡献以及对前交叉韧带（ACL）负荷的影响仍然未知。 目的：研究不同的MCL结构在抑制胫股运动中的贡献，并通过评估负荷MCL 损伤后的 ACL，特别是 dMCL/psMCL 联合损伤后。研究设计：对照实验室研究。方法：使用 6 自由度机器人模拟器对 16 个新鲜冷冻的人体膝盖进行测试。在膝关节屈曲 0°、30°、60° 和 90° 时记录胫股运动参数，进行以下测量：8-N·m 外翻旋转、4-N·m 胫骨外旋 (ER)、4-N·m m 胫骨内旋转，以及前内侧旋转 (AMR) 和前内侧平移 (AMT) 的组合 89-N 胫骨前平移和 4-N·m ER。记录 3 种不同 MCL 损伤（dMCL；dMCL/psMCL；dMCL/浅层 MCL (sMCL)）的运动学参数，并在 ACL 缺陷关节（负载分担）或切割 ACL 前后（ACL 负载）重新应用。应用叠加原理计算载荷。结果：dMCL 对伸直时 ER、AMR 和 AMT 期间的力/扭矩以及膝关节屈曲 30° 至 90° 时 psMCL 损伤的减小作用最大（ P < .05）。比较 MCL 完整时通过 ACL 的负载，ER 期间膝关节屈曲 30° 时，dMCL 损伤和 dMCL/psMCL 联合损伤后，ACL 负载分别增加了 46% 和 127%。在外翻旋转中，仅在膝关节屈曲 90° 时才观察到 ACL 负荷显着增加。结论：在屈曲30°至90°的AMR/AMT过程中，psMCL损伤对净力/扭矩的减少贡献最大。伴随的 dMCL/psMCL 损伤增加了 ACL 负荷，主要是在 ER 期间。临床相关性：如果考虑通过外科手术来治疗前内侧旋转不稳定，则手术应侧重于恢复 sMCL 功能，因为对该结构的损伤会导致 ACL 的重大损失。膝关节抑制AMR/AMT的能力。