The Relationship of Sporting Activity and Implant Survivorship After Hip Resurfacing

Background The effect of sports on the durability of the prosthesis after hip resurfacing has not been studied, to our knowledge. The purpose of this study was to correlate sporting activity levels calculated as Impact and Cycle Scores with the survivorship of the hip resurfacing implants. Methods Four hundred and forty-five patients were surveyed from one to five years after surgery. The mean age of the patients was 48.7 years, and 74% were men. The Impact and Cycle Score included two scores: an Impact Score and a Hip Cycle Score. All patients were also evaluated with the University of California at Los Angeles activity score. Twenty-three patients (twenty-seven hips) underwent revision surgery after they had completed the survey. Results The mean duration of follow-up at the time of survey data collection was 1.9 years (range, 1.0 to 4.9 years), and the mean follow-up period was 10.2 years (range, 6.1 to 13.7 years). The mean Impact Score was 28.1 (range, 0 to 128), and the mean Hip Cycle Score was 33 (range, 0 to 144). Positive correlations were found between the University of California Los Angeles activity score and the Impact Score (r = 0.535) or Hip Cycle Score (r = 0.497). After adjustment for femoral component size, body mass index, and femoral defect size, a 10-point increment in Impact Score corresponded to a 37% increase (hazard ratio, 1.37; 95% confidence interval, 1.18 to 1.59) in the risk of revision arthroplasty, while a 10-point increment in the Hip Cycle Score increased the risk of revision by 22% (hazard ratio, 1.22; 95% confidence interval, 1.06 to 1.41).Patients with an Impact Score of