Metal-on-metal CoCrMo McKee-Farrar total hip arthroplasty: characteristics from a long-term follow-up study

A total of 38 cemented metal-on-metal CoCrMo McKee-Farrar total hip arthroplasties (THAs) were clinically and radiographically evaluated over a long-term follow-up. No osteolysis and no granuloma were found more than 20 years after the operation. The main radiological findings were bone erosion and migration of the acetabular component, seen in 17 hips (44.7%). The direction of the migration correlated with the setting position of the acetabular component at operation. At revision surgery, metallosis was observed in unstable THA, and no metallosis was observed in stable THA. Using a micrometer, no wear of the sockets was found. Therefore, the loosening was thought to be due to the equatorial bearing rather than to metallosis. The mean survival of the THA to data was 14.6 years in those patients 60 years old or younger at operation and was significantly less (11.9 years) in those 61 years old or older at operation (P < 0.03). The mean survival time was 13.8 years.