Dynamic Movement Analysis and Optimal Design for Stabilizer Type Artificial Knee Joint

为了考虑稳定器部分在动态条件下的接触情况，对日常生活中最常见的行走运动进行了三维运动测量，并采用逆向动力学和非线性优化方法对人工膝关节的运动进行了动态数值模拟。然后，通过股骨稳定器安装位置的平移，研究了人工膝关节股骨稳定器的接触条件和最佳安装位置。由此可知，在动态条件下，稳定器对膝关节的稳定有显著的作用，即膝关节角度变大时股骨后侧运动（回滚运动），接触条件下稳定器位置的轻微平移会产生较大的问题，目前的安装位置处于不发生这些问题的状态。此外，通过对膝关节运动与活体的同一性、接触点运动的平整度、膝关节接触面磨损、稳定器接触部分磨损等磨损参数的评价，也阐明了存在比目前安装位置更优的位置，由于各参数对最优位置的影响存在差异，需要从综合的角度进行优化设计。此外，考虑到人工膝关节组件在关节手术中安装误差对关节运动的影响，提出了提高安装精度和更全面的设计以吸收手术中的安装误差的必要性，从而延长人工膝关节的使用寿命。

In order to consider the contact condition of the stabilizer part under dynamic conditions, three-dimensional movement measurement for walking, which is considered to be the most general movement in daily life, was performed and the dynamic numerical simulation of the movement of artificial knee joint was performed using the reverse dynamics and the nonlinear optimization method. And then, the contact condition and the optimal installation position of a femur stabilizer of an artificial knee joint were investigated using translation of the installation position of the femur stabilizer. Consequently, it is clarified that, in dynamic conditions, the stabilizer has contributed significantly to the stabilization of knee joint, i.e., posterior movement of a femur (rollback movement) when knee angle becomes large, slight translation of the stabilizer position makes big problem on contact condition, and the present installation position is in the state where these problems do not occur. Moreover, by the evaluation with wear parameters, which are the identity of the knee joint movement with living body, smoothness of the contacting point movement, wear of the contact surface of knee joint, and wear of a stabilizer contact part, it is also clarified that the more optimal position than the present installation position is exist and that comprehensive point of view is required for the optimal design because of the difference of optimal position depending on the parameters. Furthermore, by consideration of the effect of the installation error of the artificial knee joint component at an joint operation on the joint movement, it is suggested that the necessity of installation accuracy and more comprehensive design which could absorb the installation error in the operation, for a longer life artificial knee joint.