Catastrophic wear in total hip arthroplasty. Complete wear-through of a metal-backed acetabular component: case report.

A unique case of catastrophic wear of a total hip arthroplasty is presented. This brief report demonstrates the presentation of catastrophic wear of a modular acetabular component with protrusion of the femoral head through a modular metal-backed titanium cup. During the revision surgery, the polyethylene was found to have disengaged from the cup, and the cup was pistoning on the femoral neck. Significant metallosis and bone loss was found. The presence of severe metallosis mimicked bone on the preoperative radiograph and obscured the severity of the osteolysis seen on imaging.