Osteolysis in a cementless, second generation metal-on-metal hip replacement

A 65-year-old man with osteoarthritis of the hip underwent a cementless tot al hip replacement with a modern generation, metal-on-metal bearing. Two ye ars later the patient presented with localized osteolysis at the tip of the femoral stem. At the time of revision, the stem was found to be well-fixed . Extensive analyses of the bearing surfaces and periprosthetic tissues wer e done. There was minimal bearing surface wear and only small numbers of in flammatory cells, such as macrophages, in the tissues, and it was concluded that this was not a typical case of particle-induced osteolysis. All cultu res and laboratory studies were negative for infection. This case report su pports the multifactorial nature of osteolysis, which includes the osteolyt ic potential of joint fluid access to and fluid pressures within, the effec tive joint space.