Total Joint Arthroplasty and the Risk of Myocardial Infarction A General Population, Propensity Score-Matched Cohort Study

Objective. To replicate recent findings indicating that total knee arthroplasty (TKA) or total hip arthroplasty (THA) surgery will substantially reduce the risk of serious cardiovascular events among patients with osteoarthritis. Methods. A time-stratified, propensity score-matched cohort study was conducted to assess the incidence of myocardial infarction (MI) in a UK general population. The study population included individuals ages >= 50 years who had a UK National Health Service READ code diagnosis of knee osteoarthritis (to evaluate TKA) or hip osteoarthritis (to evaluate THA) between January 2000 and December 2012. Results. Among the patients who underwent TKA and their matched non-TKA control subjects (each n=13,849), 306 patients and 286 control subjects developed MI during the followup. During the first postoperative month, the risk of MI was substantially increased among the TKA group compared with the non-TKA group (hazard ratio [HR] 8.75, 95% confidence interval [95% CI] 3.11-24.62), and then gradually declined during the subsequent followup. The HR for the risk of MI over the entire followup was 0.98 (95% CI 0.82-1.18). The corresponding HRs for the risk of MI in those who had undergone THA compared with the non-THA group (each n=6,063) were 4.33 (95% CI 1.24-15.21) in the first postoperative month and 0.87 (95% CI 0.66-1.15) overall. In analyses using venous thromboembolism as a positive control outcome, both the first month and overall HRs for the risk of venous thromboembolism were substantially increased in both the TKA and THA groups. Conclusion. These findings provide the first general population-based evidence to indicate that TKA and THA among osteoarthritis patients are associated with a substantially increased risk of MI during the immediate postoperative period. However, the overall long-term impact of these surgeries was null, unlike the risk of venous thromboembolism, which remained elevated years after patients had undergone the procedure.