BACKGROUND Patients with high-grade preoperative side-to-side differences in anterior laxity as assessed via the Lachman test after unilateral anterior cruciate ligament (ACL) rupture are at heightened risk of early ACL graft failure. Biomechanical factors that predict preoperative side-to-side differences in anterior laxity are poorly understood. PURPOSE To assess, in a cadaveric model, whether the increase in anterior laxity caused by sectioning the ACL (a surrogate for preoperative side-to-side differences in anterior laxity) during a simulated Lachman test is associated with two biomechanical factors: (1) the tibial translation at which the secondary anterior stabilizers, including the remaining ligaments and the menisci, begin to carry force, or engage, relative to that of the ACL or (2) the forces carried by the ACL and secondary stabilizers at the peak applied anterior load. STUDY DESIGN Controlled laboratory study. METHODS Seventeen fresh-frozen human cadaveric knees underwent Lachman tests simulated through a robotic manipulator with the ACL intact and sectioned. The net forces carried by the ACL and secondary soft tissue stabilizers (the medial meniscus and all remaining ligaments, measured as a whole) were characterized as a function of anterior tibial translation. The engagement points of the ACL (with the ACL intact) and each secondary stabilizer (with the ACL sectioned) were defined as the anterior translation at which they began to carry force, or engaged, during a simulated Lachman test. Then, the relative engagement point of each secondary stabilizer was defined as the difference between the engagement point of each secondary stabilizer and that of the ACL. Linear regressions were performed to test each association (P < .05). RESULTS The increase in anterior laxity caused by ACL sectioning was associated with increased relative engagement points of both the secondary ligaments (β = 0.87; P < .001; R2 = 0.75) and the medial meniscus (β = 0.66; P < .001; R2 = 0.58). Smaller changes in anterior laxity were also associated with increased in situ medial meniscal force at the peak applied load when the ACL was intact (β = -0.06; P < .001; R2 = 0.53). CONCLUSION The secondary ligaments and the medial meniscus require greater anterior tibial translation to engage (ie, begin to carry force) relative to the ACL in knees with greater changes in anterior laxity after ACL sectioning. Moreover, with the ACL intact, the medial meniscus carries more force in knees with smaller changes in anterior laxity after ACL sectioning. CLINICAL RELEVANCE Relative tissue engagement is a new biomechanical measure to characterize in situ function of the ligaments and menisci. This measure may aid in developing more personalized surgical approaches to reduce high rates of ACL graft revision in patients with high-grade laxity.

中文翻译：

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相对于前交叉韧带的次级韧带和半月板约束的参与预测了前膝关节松弛。

背景技术单侧前交叉韧带（ACL）破裂后通过Lachman测试评估的术前松弛程度高的患者，其早期ACL移植失败的风险较高。预测术前前后松弛差异的生物力学因素知之甚少。目的在尸体模型中评估在模拟的Lachman测试过程中切片ACL引起的前松弛的增加是否与两个生物力学因素相关：（1）胫骨平移，包括剩余的韧带和半月板在内的次要前稳定器开始施加力或接合，相对于ACL的力或（2）ACL和辅助稳定器在峰值处施加的前向力所承受的力。研究设计受控的实验室研究。方法通过一个完整的ACL机器人机械手对17个新鲜冷冻的人体尸体膝盖进行Lachman测试，并进行切片。ACL和次要软组织稳定器（内侧半月板和所有剩余韧带，整体测量）所承受的净力被表征为胫骨前平移的函数。ACL（完整的ACL）和每个辅助稳定器（ACL切开）的接合点被定义为在模拟的Lachman测试期间，它们开始承受力或接合的前平移。然后，每个辅助稳定器的相对啮合点定义为每个辅助稳定器与ACL的啮合点之差。进行线性回归以检验每个关联（P <.05）。结果ACL切片导致前松弛的增加与次级韧带（β= 0.87; P <.001; R2 = 0.75）和内侧半月板（β= 0.66; P <.001; R2 = 0.58）。当ACL完好无损时（β= -0.06； P <.001； R2 = 0.53），前松弛的较小变化也与峰值施加负荷下的原位内侧半月板力的增加有关。结论次级韧带和内侧半月板需要更大的胫骨前移才能参与（即，相对于膝关节ACL，ACL切片后前松弛度的变化更大。此外，在ACL完整的情况下，ACL切片后，内侧半月板在膝关节中承受的力更大，前松弛度的变化较小。临床相关性相对组织接合是一种新的生物力学措施，可表征韧带和半月板的原位功能。这项措施可能有助于开发更个性化的手术方法，以减少高等级松弛患者的高ACL移植物翻修率。临床相关性相对组织接合是一种新的生物力学措施，可表征韧带和半月板的原位功能。这项措施可能有助于开发更个性化的手术方法，以减少高等级松弛患者的高ACL移植物翻修率。临床相关性相对组织接合是一种新的生物力学措施，可表征韧带和半月板的原位功能。这项措施可能有助于开发更个性化的手术方法，以减少高等级松弛患者的高ACL移植物翻修率。