CHAOS OF THE STRESS FIELD AT THE FIXATION SITE OF A JOINT PROSTHESIS

Abstract

It is widely accepted that a wide contact area between bone and artificial materials is necessary in the fixation of hip joint prostheses. It is also considered important that the load should be applied to the proximal femur. However, these two concepts are contradictory in that the contact point cannot be determined in a wide contact area. Therefore, in this study, we revised the available concepts to improve the method of fixation of joint prostheses using finite-element-method (FEM) analysis of the equivalent mathematical models. The first model was designed based on the intramedullary cruciate fixation stem. In this model, the total contact area was limited to the small area of legs-on-plane. Another model was designed based on the fit-and-fill-type stem, and in this model, the total contact area of the plane-on-plane was equal to the total surface area of the stem. In the plane-on-plane model, there was an unstable vibrating pattern in stress distribution, and we considered that deterministic cha