Contact analysis of artificial knee joint during gait (2nd report, effect of shape of contact surface on wear behavior of UHMWPE articular plate)

摘要

Ultrahigh-molecular-weight polyethylene (UHMWPE) is the material generally used for the articular plate contact surface in artificial knee joints; however, the wear of this material becomes a serious problem during extended life of the joint. Inorder to understand the wear mechanism of the plate during gait and to improve its wear life, the cyclic contact behavior of the plate was analyzed using the constitutive equation for cyclic plasticity, since the plate is subjected to cyclic contactdeformation during gait. The posterior cruciate ligament (PCL) retention-type artificial knee joint as the basic analytical model, as well as two other modified contact surface models, were analyzed to investigate the effect of the shape of the contactsurface on the wear behavior of the plate. As a result, it was clarified that the wear behavior of the plate is closely related to the shape of the contact surface. The optimal design of contact surface is considered using this analysis.