MEASUREMENT AND ANALYSIS ON ELONGATION,DEFORMATION AND TENSILE CHARACTERISTIC OF THE CRUCIATELIGAMENT IN THE KNEE

本研究的目的是实验测量和理论分析前交叉韧带的形状和应力分布的变化，当其附着位置在三维移动与膝关节屈曲。为了确定前交叉韧带整个区域的应力分布，我们进行了实验，测量了假韧带（一种特殊的橡胶板，具有极大的拉伸：600%_<max>）在附着点三维移动时整个表面的形状和应变分布的变化。开发了一种精密的仪器（膝关节运动模拟器），并将其连接到假韧带上。这两个附件都可以在几个方向上移动，并可以在几个轴上旋转，从而产生六度运动来模拟膝盖运动。用立体摄影测量法测量了272个标记点在韧带上的三维位置，计算了每个元素的拉格朗日张量分量。其次，采用有限元法对非压缩超弹性材料进行应力分析，验证了伪韧带（橡胶材料）的上述实验结果。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。采用Newton-Raphson方法求解与伪韧带有限元表示相关的非线性方程。实验结果与理论结果吻合较好。特别注意纵向应变随膝关节屈曲角的分布，得到以下结果：在前交叉韧带的前部，靠近胫骨附着点的区域在60的屈曲下明显拉伸，沿纤维方向几乎整个区域在90的屈曲下拉伸。胫骨附着点附近的区域在屈曲120°时明显拉伸。在后侧，靠近股骨附着体的区域有明显的应变，但靠近胫骨附着体的区域没有。在本研究中，应变分布发生了变化，甚至沿纤维方向，在骨附着体附近的区域观察到较大的应变梯度，得到了具有临床意义的结果。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.To determine stress distribution over the entire region in the ACL,experiments were carried out to measure the change in shape and strain distribution over the entire surface of a pseudo ligament (a special rubber plate with an extremely large stretch : 600%_<max>) when the attachment sites were moved in threedimensions. An elaborate instrument (knee motion simulator) was developed, to which the pseudo ligament was attached. Both of the attachments could be moved in several directions and could be rotated on several axs, resulting in six-degrees of motion to simulate knee motion. The three-dimensional positions of 272 markers on the ligament were measured by the Stereo-Photogramtric Method to compute the components of the Lagrangian st … More rain tensor for each element.Next, the stress analysis were carried out using the finite element method for a noncompressive hyper-elastic material to verify the above-mentioned experimental results for a pseudo ligament (rubber material). The non-linear stiffness relation between the node force and the node displacement for a special triangular element, was introduced. 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 of flexion. The region near the tibial bone attachment stretched 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. ln 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