Background: Knee joint stability is enhanced by ligamentus structures such as anterior cruciate (ACL), posterior cruciate (PCL), medial collateral (MCL) and lateral collateral ligaments (LCL). Rupture of ACL is the most common knee injuries, especially in sport related activities. The aim of this study is to evaluate the stress developed in knee joint structures in various degrees of knee flexion in ACL ruptured compared to normal condition. Method: CT scan images of knee joint were used to create 3d model of knee joint by use of Mimics software. Abaqus software was used to evaluate the stress developed in knee joint in normal and in ACL reconstructed conditions in various degrees of knee flexion. Results: The stress developed in ACL and other knee joint structures increased significantly by increase in knee joint flexion. The stress of knee joint structures (especially in ACL) in ACL reconstructed condition was more than that of normal condition. Conclusion: It is recommended to immobilize the knee joint in extension up to 15∘ of knee flexion in those with ACL injuries. The stress of ACL increased due to an increase in tibia translation associated with knee flexion.

中文翻译：

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膝关节屈曲不同程度前交叉韧带应力的测定，正常和重建韧带的比较

背景：膝关节稳定性通过韧带结构增强，例如前交叉韧带 (ACL)、后交叉韧带 (PCL)、内侧副韧带 (MCL) 和外侧副韧带 (LCL)。ACL 断裂是最常见的膝关节损伤，尤其是在与运动相关的活动中。本研究的目的是评估与正常情况相比，ACL 断裂时膝关节结构在不同程度的膝关节屈曲中产生的应力。 方法：膝关节CT扫描图像通过Mimics软件创建膝关节3D模型。Abaqus 软件用于评估正常膝关节和不同程度膝关节屈曲下 ACL 重建条件下产生的应力。 结果：ACL 和其他膝关节结构中产生的应力随着膝关节屈曲的增加而显着增加。ACL重建状态下膝关节结构（尤其是ACL）的应力大于正常状态。 结论：建议在伸展时固定膝关节至15∘ACL 损伤患者的膝关节屈曲情况。由于与膝关节屈曲相关的胫骨平移增加，ACL 的压力增加。