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 CoCr-Mo McKee-Farrar total hip a rthroplasties (THAs) were clinically and radiographically evaluated ov er a long-term follow-up. No osteolysis and no granuloma were found mo re than 20 years after the operation. The main radiological findings w ere bone erosion and migration of the acetabular component, seen in 17 hips (44.7%). The direction of the migration correlated with the sett ing position of the acetabular component at operation. At revision sur gery, metallosis was observed in unstable THA, and no metallosis was o bserved in stable THA. Using a micrometer, no wear of the sockets was found. Therefore, the loosening was thought to be due to the equatoria l bearing rather than to metallosis. The mean survival of the THA to d ata was 14.6 years in those patients 60 years old or younger at operat ion and was significantly less (11.9 years) in these 61 years old or o lder at operation (P < 0.03). The mean survival time was 13.8 years.