Abstract

Purpose

The role of the anterior cruciate ligament (ACL) in knee biomechanics in vivo and under weight-bearing is still unclear. The purpose of this study was to compare the tibiofemoral kinematics of ACL-deficient knees to healthy contralateral ones during the execution of weight-bearing activities.

Methods

Eight patients with isolated ACL injury and healthy contralateral knees were included in the study. Patients were asked to perform a single step forward and a single leg squat first with the injured knee and then with the contralateral one. Knee motion was determined using a validated model-based tracking process that matched subject-specific MRI bone models to dynamic biplane radiographic images, under the principles of Roentgen stereophotogrammetric analysis (RSA). Data processing was performed in a specific software developed in Matlab.

Results

Statistically significant differences (p < 0.05) were found for single leg squat along the frontal plane: ACL-deficient knees showed a more varus angle, especially at the highest knee flexion angles (40°–50° on average), compared to the contralateral knees. Furthermore, ACL-deficient knees showed tibial medialization along the entire task, while contralateral knees were always laterally aligned. This difference became statistically relevant (p < 0.05) for knee flexion angles included between 0° and about 30°.

Conclusion

ACL-deficient knees showed an abnormal tibial medialization and increased varus angle during single leg squat when compared to the contralateral knees. These biomechanical anomalies could cause a different force distribution on tibial plateau, explaining the higher risk of early osteoarthritis in ACL deficiency. The clinical relevance of this study is that also safe activities used in ACL rehabilitation protocols are significantly altered in ACL deficiency.

Level of evidence

III.

中文翻译：

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ACL缺乏会影响体内活动期间的中外侧胫骨对齐和膝内翻-外翻

摘要

目的

前交叉韧带（ACL）在体内和负重的膝关节生物力学中的作用仍不清楚。这项研究的目的是在进行负重活动时比较ACL缺陷型膝关节与健康的对侧膝关节的股骨运动学。

方法

该研究包括八名孤立的ACL损伤和健康的对侧膝盖患者。要求患者先向前迈出一步，然后先用受伤的膝盖进行单腿下蹲，然后再对侧进行下蹲。根据Roentgen立体摄影测量分析（RSA）的原理，使用经过验证的基于模型的跟踪过程确定膝盖的运动，该过程将特定于受试者的MRI骨骼模型与动态双平面放射线图像相匹配。数据处理是在Matlab开发的特定软件中执行的。

结果

 沿额平面发现单腿下蹲具有统计学上的显着差异（p <0.05）：与对侧相比，ACL缺陷型膝关节表现出更大的内翻角，尤其是在最大屈膝角度（平均40°–50°）膝盖 此外，ACL缺陷型膝关节在整个工作过程中均表现出胫骨中转，而对侧膝关节始终横向对齐。 对于包括在0°和大约30°之间的屈膝角度，此差异在统计学上具有相关性（p <0.05）。

结论

与对侧膝关节相比，ACL缺陷膝关节在单腿下蹲时表现出异常的胫骨中位和内翻角增大。这些生物力学异常可能导致胫骨平台上的力分布不同，这说明ACL缺乏导致早期骨关节炎的风险更高。这项研究的临床意义在于，在ACL缺乏症中，ACL康复方案中使用的安全活动也发生了显着变化。

证据水平

三，