Interactive Evaluation of Interfacial Damages on Loosening Behavior of Acetabular Cup Loosening Using AE and IR Method

Abstract

We aim at revealing the damage behavior of HAp sprayed coating on the surface of acetabular cup subjected to cyclic loading using AE (Acoustic Emission) method and IR (Infrared thermography) methods. Fatigue test was conducted in SBF(simulated body fluid), and the displacement of acetabular cup embedded in simulated bone was measured by two cantilever pairs. Acoustic emissions from delamination or wear of HAp coating were also measured by AE method, and the temperature change due to friction and wear near the top was measured by IR method. The analysed result could estimate the process in which delamination occurs in the initial stage of test and then friction and wear occur. The rotation displacement of acetabular cup could be associated with cracking or delamination of the HAp sprayed coating, friction and wear at the interfaces between simulated bone and acetabular cup. The subsidence displacement of acetabular cup can be caused by collapse of the simulated bone accompanied by an increase in AE energy as well as an increase in dissipated energy. Combined analyses using AE method and IR method clarified that the inelastic damages in simulated bone at the top of acetabular cups could lead the acceleration of both normal and rotational displacement of the acetabular cup whereas interface damages also attributed to exaggerate the displacement by deteriorated fixation.