Dissociation of a metal-backed polyethylene acetabular component. A case report.

A case of early failure of a total hip arthroplasty presenting as a dislocation is discussed. After failed attempts at closed reduction, an open procedure revealed that the polyethylene insert of the acetabulum had separated from its metal backing. The increasing use of metal-backed acetabular components in total hip arthroplasty produces another mechanical interface that may fail: the metal-polyethylene interface. surgeons should consider this possibility in dislocations of total hip prostheses that cannot be reduced by closed means.