While studies have demonstrated that mortality after total hip (THA) and total knee (TKA) arthroplasty is better than the general population, the causes of death are not well established. We evaluated cause-specific mortality after THA and TKA.
The study included population-based cohorts of patients who underwent THA (N = 2019) and TKA (N = 2259) between 1969 and 2008. Causes of death were classified using the International Classification of Diseases 9th and 10th editions. Cause-specific standardized mortality ratios (SMR) and 95% confidence intervals (CI) were calculated by comparing observed and expected mortality. Expected mortality was derived from mortality rates in the United States white population of similar calendar year, age, and sex characteristics.
All-cause mortality was lower than expected following both THA and TKA. However, there was excess mortality due to mental diseases such as dementia following both THA (SMR 1.40, 95% CI 1.08, 1.80) and TKA (SMR 1.49, 95% CI 1.19, 1.85). There was also excess mortality from inflammatory musculoskeletal diseases in THA (SMR 3.50, 95% CI 2.11, 5.46) and TKA (SMR 4.85, 95% CI 3.29, 6.88). When the cohorts were restricted to patients with osteoarthritis as the surgical indication, the excess risk of death from mental diseases still persisted in THA (SMR 1.36, 95% CI 1.02, 1.78) and TKA (SMR 1.52, 95% CI 1.20, 1.91).
THA and TKA patients experience a higher risk of death from mental and inflammatory musculoskeletal diseases. These findings warrant further research to identify drivers of mortality and prevention strategies in arthroplasty patients.