OUTCOME OF FEMORAL COMPONENTS IN CHARNLEYS TOTAL HIP-ARTHROPLASTY AFTER A MINIMUM OF 20-YEAR FOLLOW-UP

Purpose of the study We evaluated the results of 309 femoral component s of total hip arthroplasties performed using Charnley prosthesis and cement, by one surgeon, between January 1972 and December 1975. Materi al and methods Observations and measurements were based on standard pe lvic X-rays. Survivorship curves were calculated to evaluate femoral c omponent failures at twenty years of follow-up. We compared the effect of different parameters on the femoral implant loosening. Result At 2 0 years of follow-up, 82 hips were included in the study, 227 were exp elled: 109 by death, 52 by revision and 66 by loss for follow-up. Prob ability for death, at 20 years follow-up, was 40.7 per cent, probabili ty for revision was 33.9 per cent, for femoral loosening was 16 per ce nt. The rate of aseptic femoral loosening was higher for men, with hig h activity and varus position of the femoral stem. Statistical analysi s showed correlation between calcar resorption and femoral loosening, between polyethylene wear and calcar resorption. No directly significa nt correlation was established between polyethylene wear and femoral l oosening. Discussion and conclusion This study confirms relations betw een polyethylene wear, calcar resorption and femoral loosening and und erlines the influence of mechanical factors on femoral loosening. Femo ral stem positioning is very important for femoral loosening. Varus po sition is clearly unfavourable. According to ours results, the best po sition is with a slight valgus.