INDUCED STRESSES AND SHELL/LINER MICROMOTIONS IN THA COMPONENTS DURING DISLOCATION. A FINITE ELEMENT STUDY

摘要

During total hip replacement (THR) many supporting structures for the retention of the femoral head within the acetabulum are removed. Previous studies have determined that this lack of supporting structures leads to separation of the femoral head within the UHMWPE liner. During the relocation phase the femoral head impacts with the liner creating high stress conditions that may contribute to premature polyethylene wear and instabilities. The proposed study focuses on the femoral head, liner and acetabular shell when subjected to intermittent loading conditions due to dislocations of the femoral head. The objective of this paper is to address the effect of dislocation and the induced stresses during impact. The parameters studied include the dislocation or gap distance, the impact force duration and the friction between all the components involved. The research highlights the build up of residual stresses and their contribution to the cup/liner and acetabular bone instability.