Summary

Survival after hip and knee arthroplasty has a bimodal pattern compared to the general population. First, lower mortality compared to the general population is expected, but approximately after 12 to 15 years, patients have increased mortality. The survival rate after arthroplasty in this cohort of Chilean patients is similar to internationals reports.

Abstract

Background

The purpose of this study is to determine if patients with osteoarthritis that undergo hip (HA) or knee (KA) arthroplasty jeopardize their expectancy of life 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 osteoarthritis and have 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, the hazard ratio was reported. For internal validity, a bootstrap of 200 repetitions was performed

Results. A total of 4094 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, a hazard ratio of 1.09 (95% confidence interval: 1.08 to 1.10) for every year older, and a hazard ratio of 1.29 (95% confidence interval:1.07 to 1.53) for HA patients.

Conclusion

Mortality after hip and knee arthroplasty in Chile follows a bimodal behavior similar to series from the United States and Europe. At first, mortality is lower than the general population, but becomes worse than the general population beyond 12 to 15 years after surgery.