Mortality after hip or knee arthroplasty for osteoarthritis in Chile: A survival analysis

Abstract

Background The purpose of this study is to determine if patients with osteoarthritis that undergo hip or knee arthroplasty jeopardize their life expectancy in Chile. Methods A survival analysis study was designed and approved by our institutional ethics review board. Patients were included if they underwent surgery for hip or knee oste-oarthritis and were 50 years or older at the time of surgery. Patients were excluded if arthroplasty was performed for fracture, hemophilia arthropathy, or tumor. A multiparametric Weibull regression was estimated, and the hazard ratio was re-ported. For internal validity, a bootstrap of 200 repetitions was performed. Results A total of 4 094 arthroplasties were included. The Kaplan-Meier curve estimates a higher survival than the general population up to 12 years, after which the median survival is less than the general population. The bootstrap multiparametric Weibull regression estimated a hazard ratio of 1.53 (95% confidence interval: 1.27 to 1.84) for women, 1.09 (1.08 to 1.10) for every year older, and 1.29 (1.07 to 1.53) for hip arthroplasty patients. Conclusion Mortality after hip and knee arthroplasty in Chile follows a bimodal behavior similar to reports from the United States and Europe. At first, mortality is lower than the general population but worsens after 12 to 15 years of surgery.