Simultaneous vs Staged Bilateral Total Knee Arthroplasty Among Medicare Beneficiaries, 2000–2009

Simultaneous bilateral total knee arthroplasty (TKA) reportedly has higher postoperative complication rates than staged procedures, but little is known about recent trends and outcomes among Medicare patients. In a 5% national sample of Medicare beneficiaries older than 65 years, we identified 83,441 patients who underwent elective TKA between 2000 and 2009 and compared patients undergoing simultaneous bilateral TKA (n = 4519) to staged TKA (n = 3788). Use of simultaneous TKA did not change over time (3 in 10,000), but use of staged TKA increased three-fold from 1.4 to 4.4 in 10,000 person-years. We assessed length of stay; 5-year risk of revision; periprocedural (i.e., 90-day) risk of infection; hospitalization for venous thromboembolism (VTE) and myocardial infarction (MI); and death using Kaplan–Meier methods. Simultaneous TKA had higher 90-day risk of death (0.7% vs. 0.3%, P = 0.02), VTE (0.9% vs. 0.5%, P = 0.07), and MI (0.5% vs. 0.2%, P = 0.02). Infection and revision rates were similar between the two groups.