Wear debris from total hip arthroplasty presenting as an intrapelvic mass

A granulomatous reaction to the small particles worn off from an implanted prosthesis is a common complication in arthroplasty. The chronic inflammato ry response to the wear debris from either the polyethylene or the metal co mponents is thought to be responsible for osteolysis, implant loosening, ar id filially mechanical failure. Formation of an extra-articular granulomato us tissue Mass is uncommon, however. We report a case of a huge granulomato us mass that presented as an intrapelvic tumor. The prosthesis was ail Anat omical Medullary Locking (AML) hip arthroplasty with cementless fixation. T he polyethylene insert was manufactured by ram extrusion and sterilized wit h gamma irradiation in air. Fragments of the insert were among the contents in the cystic mass together with black metallic debris. There was no loose ning of the prosthesis, and the acetabulum floor was preserved.