Metallosis following full thickness wear in total hip arthroplasty

Extreme wear through the metal-backed acetabular cup following total hip arthroplasty is rare, as symptoms such as pain and disability will usually manifest earlier. We present the second reported case of extreme wear in a 78-year-old male patient, who presented 20 years following an uncemented total hip replacement with a 3-year history of hip pain, clicking on ambulation and worsening mobility. Radiographs demonstrated that the femoral head had migrated superolaterally through the polyethylene liner and the acetabular cup, and was articulating with the superior wall of the acetabulum causing bony destruction. Metallic fragments were also evident. A review of the current literature on metallosis suggests that should there be any clinical suspicion, blood metal ion levels are monitored and an MARS-MRI scan performed if indicated. If metallosis is detected, then revision surgery can be attempted at an earlier date, where the procedure is not as technically difficult.