The issue of contact strength occuring in polyethylene flat inserts of total knee endoprostheses

The paper presents the numerical analysis of stress and strain occurring in the most wearable parts of knee joint endoprostheses. In the knee joint that would be the pair: sled - flat insert. The complexity of the processes taking place both in natural and artificial joints makes it necessary to conduct the analysis on the 3D model and base it on already existing mathematical models. Finite elements method makes it possible to calculate the stress in particular elements of the tested model. The interaction between the two parts of endoprosthesis takes place on a comparatively small contact surface. The material on that surface is under a spatial state of stress and its stress distribution is very complex and can be designated only as resilience theory. High stress caused by pressure between the two parts is called contact stress.