SEVERE OSTEOLYSIS AFTER 3RD-BODY WEAR DUE TO HYDROXYAPATITE PARTICLESFROM ACETABULAR CUP COATING

One concern about the fixation of HA-coated implants is the possible d isintegration of the surface, with the migration of HA granules into t he joint space, producing third-body wear, We report a study of six re visions of HA-coated polyethylene RM cups at 9 to 14 years after succe ssful primary arthroplasty. In all six hips, we found HA granules embe dded in the articulating surface of the polyethylene, with abrasive we ar of the cup and the metal femoral head, The cup had loosened in four hips and three showed severe osteolysis of the proximal femur, Third- body wear due to HA particles from implant coating may produce severe clinical problems with few early warning signs, Further clinical, radi ological and histological observations are needed to determine the pos sible incidence of this late complication in the various types of coat ing of a variety of substrates.