Survivorship of hip prosthesis in primary arthrosis: influence of bilaterality and interoperative time in 45,000 hip prostheses from the Finnish endoprosthesis register.

We studied the influence of bilaterality and interoperative time on survivorship of the hip prosthesis. The material consisted of 45,000 (3,153 bilateral) total hip arthroplasties and 38,000 patients operated on for primary osteoarthrosis, using data from the Finnish Endoprosthesis Register between 1980 and 1999. Cox regression analysis showed that male sex, young age, uncemented prosthesis and time of surgery (first 10-year period) were significant risk factors for aseptic loosening.