UCSF

Instability is the most common indication for revision total hip arthroplasty in the United States. Elevated-rim acetabular liners were introduced to minimize the risk of posterior instability. We describe a patient with multiple total hip arthroplasty dislocations secondary to component subsidence leading to instability. As the patient initially refused revision of his femoral component, he was treated with an elevated-rim acetabular liner. When this too dislocated, the hip could not be reduced concentrically. During operative exposure for a stem revision, the lipped aspect of the liner was found to have folded into the acetabulum thus preventing concentric reduction of the head. We conclude that invagination of the elevated lip of a polyethylene liner should be considered when concentric reduction of a dislocated hip proves difficult.