抄録
This study aims at revealing the effects of wear/ delamination of HAp coating on the surfaces of acetabular cups on loosening behaviors of the acetabular cups during cyclic loading. Loosening behaviors of acetabular cups are caused by osteolysis or aseptic loosening. However, a physical mechanism of aseptic loosening has not been clarified yet. A cyclic loading system for artificial acetabular cups with stems was facilitated. Wear/ delamination behaviors of plasma-sprayed coating on the surface of the acetabular cups were indirectly observed by AE measurement. AE measurements revealed that wear/delamination of HAp coating started from the edge of acetabular cup where concentration of shear stress occurred and propagated to the center region of the cup. Loosening behaviour of the acetabular cup was promoted by cyclic loading for both positions and fixation angles. Extents of changes in positions were larger than the critical value for deteriorating good fixation between human bone with artificial joints. Consequently, loosening behaviours due to fracture of bonding between simulated bones- HAp coating- titanium substrates were successfully observed.
