Histopathologic Evaluation in Failed Gerard Double Cup Arthroplasty

Fifteen femoral head remnants were removed at revision of an uncemented double cup arthroplasty and were investigated by histological methods. Nine showed resorption of the head, partly due to osteoporosis by stress protection, preexistent pseudocysts, or osteonecrosis. Necrosis was frequently seen in the apicocranial area, and in six cases extended into deeper areas. One failure was attributed to synovitis caused by polyethylene debris. A smooth collagenous membrane developed at both the femoral head and the acetabular interfaces. In some cases metaplasia into cartilage and osteophytes developed at the cup rim.