Strength and reliability of alumina ceramic femoral heads: Review of design, testing, and retrieval analysis

Ceramic components are used increasingly in total hip arthroplasty (THA). Compared with metallic components, ceramic femoral heads for THA have the potential advantage of lower wear rates in articulations with acetabular liners. However, the use of ceramic components is also associated with unique risks, including sudden fracture and intolerable bearing noise or squeaking. This review paper summarizes the published literature regarding alumina ceramic femoral heads and tries to identify areas where uncertainties remain. We will discuss the following topics: (1) the fracture mechanics of ceramic materials; (2) design-related stresses acting on the femoral head, especially at the interface between the stem trunnion and the head; (3) gradual loss of strength in service by fatigue or slow crack growth and simulation using a proof test; and (4) information that can be gathered from examination of fractured explants.