MEASUREMENT AND ANALYSIS ON THREE-DIMENSIONAL DEFORMATION AND STRESS DISTRIBUTION CHARACTERISTIC OF THE CRUCIATE LIGAMENT IN THE KNEE

本研究的目的是通过实验测量和理论分析ACL的附着点在膝关节屈曲的三维空间中移动时，ACL整个表面的形状和应力分布的变化。股骨和胫骨髁由透明环氧树脂制成，韧带（ACL）由硅橡胶制成。模拟膝关节的实际运动，直接观察模型韧带的变形和应变。此外，利用人筋膜和兔中侧副韧带，完全解决了胶片与活体组织的粘附问题和胶片显示活体组织变形的能力。然后，还进行了光弹性方法在体内测量实际韧带上的应变的应用，并且确定了ACL中整个区域上的应力分布。 ...更多信息 用非压缩超弹性材料的有限元方法进行应力分析，以验证上述纤维增强超弹性复合材料的实验结果。介绍了一种特殊三角形单元的节点力与节点位移之间的非线性刚度关系。用Newton-Raphson方法求解了伪韧带的非线性有限元方程组，测量结果与理论计算结果吻合较好。特别注意纵向应变的分布作为膝关节屈曲角度的函数，并获得以下结果：在ACL前侧，胫骨附件附近的区域在60 ° C屈曲时显著拉伸，并且几乎整个区域沿着纤维方向在90 ° C屈曲时拉伸。在120 °屈曲时，胫骨附件附近区域明显拉伸。在后侧，股骨附着点附近区域的应变明显，但胫骨附着点附近的应变不明显。在这项研究中，获得了具有临床意义的结果，因为应变分布变化，甚至沿着纤维方向变化，并且在骨附着附近的区域观察到大的应变梯度。少

The objectives of this study are to experimentally measure and to theoretically analyze the change in shape and stress distribution over the entire surface of the ACL when its attachment sites are moved in the threedimensions associated with knee flexion.A study was done using a unique model of a knee joint. The femoral and tibial condyles were modeled from transparent epoxy resin, and the ligament (ACL) was formed from silicone rubber. The model was manipulated in a way that simulated actual knee motion, and the deformation and strain the model ligament underwent were observed directly. Furthermore, the problems of film adhesion to living tissue and the film's ability to display deformation of living tissue were fully resolved using human fascia and rabbits' medio-collateral ligaments. Then the application of the photoelastic method to measuring strains on an actual ligament in vivo was also carried out and stress distribution over the entire region in the ACL was determined.Next, the … More stress analysis were carried out using the finite element method for a non compressive hyper-elastic material to verify the above-mentioned experimental results for a fiber-reinforced hyper-elastic composite. The nonlinear stiffness relation between the node force and the node displacement for a special triangular element, was introcuced. The Newton-Raphson method was used to solve the nonlinear equations associated with finite element representations of the pseudo ligament.Both the measurement and theoretical results were in good agreement. Special attention was paid for the distribution of longitudinal strain as a function of the knee flexion angle and the following results were obtained ; On the anterior side of the ACL,the region near the tibial bone attachment stretched noticeably at 60ﾟ of flexion, and almost the entire region along the fiber direction stretched at 90ﾟC of flexion. The region near the tibial bone attachment streched noticeably at 120ﾟ of flexion. On the posterior side, the strain in the region near the femoral bone attachment was noticeable but not near the tibial bone attachment. In this study, clinically significant results are obtained as strain distribution varied, even along the fiber direction, and large strain gradients were observed in the regions near the bone attachments. Less