Examination of alumina ceramic components from total hip arthroplasties.

Materials analysis has been conducted on retrieved Mittelmeier-Autophor ceramic components from total hip arthroplasties, correlating articulating surface wear morphology with clinical reasons for failure. Plastically deformed, agglomerated wear debris (30-60 microns) has been identified on femoral head articulation wear surfaces, displaying exaggerated wear, especially during the initiation stage. Such surfaces were associated with clinical failures involving displacement of the acetabular cup and perforation of the cortex by the femoral stem. It is thought that this wear debris may play an important role in the promotion of the 'avalanche' wear mechanism, as it is adherent and thus difficult to remove from the wear interface.