Finite element analysis of effect of bone degradation on loosening behavior of acetabular cup subjected to cyclic loading considering interfacial damage

Abstract

This study aims to evaluate loosening risk of acetabular cup induced by different fixation condition of acetabular cup. Increased demands for artificial hip joints require their higher reliability and longer durability. Among the factors affecting service lives, interfacial damage phenomenon has a high impact on loosening of the acetabular cup. However, monitoring these damages using experimental methods is challenging. Thus, a 3 dimensional model of acetabular cup structure was developed. Next, interfacial crack growth between cup and bone was modeled in various cup inclination angles to simulate effects of deviations in cup fixation on loosening behavior of the acetabular cup. The interfacial delamination mechanism changed with increase inclination angle in which 600 case showed highest lost contact area. Consequently, strain of bone in remained bonding region accumulated in accordance with lost contact widening which clearly imply high risk of wear damage at high inclination angle. Inelastic bone properties show much higher relative motion in comparison with elastic bone. Thus, the relative rotation between cup and bone was exaggerated outside of dislocation safezone and eventually out of dislocation limit due to interaction effect between high angle and loading amplitude which reveal serious dislocation risk by only mechanical condition