Fractures of ceramic bearings: history and present status.

During a period of 25 years (1977 to 2001), 13 fractures of an alumina component were recorded retrospectively. During the same period, approximately 5500 alumina components were implanted (3300 with all-alumina bearings and 1200 with alumina-on-polyethylene). These events occurred in seven women and six men, with a mean age of 59 years and a mean weight of 71 kg. There were eight fractures of the femoral head and five fractures of the socket component. Three fractures clearly were related to trauma (two fractures of the socket and one fracture of the head) and two were related to an abnormal design (one 22-mm head and one extra-long neck). Five fractures occurred without any rational explanation, but two fractures that occurred in the early phase could have been caused by a weaker alumina material. Finally three recent fractures of the liner were related to a change in the design of the material. This has been corrected and no additional fractures were observed. Although this dramatic event is of concern, it is infrequent and easy to solve by a limited revision procedure if done emergently. This rare complication should be balanced with the other complications of THR, including mechanical failures and osteolysis, often described with metal-on-polyethylene prostheses.