Bilateral total knee replacement: staging and pulmonary embolism. J Bone Joint Surg Am

Background: When a bilateral total knee replacement is indicated, it is not clear whether it is preferable to operate on both knees during the same hospitalization (simultaneously) or to stage the procedures in two separate hospital stays. A greater risk of pulmonary embolism after simultaneous total knee replacement has been reported by some authors, but little national data are available. Methods: We reviewed the records of 122,385 United States Medicare enrollees who had had a total knee replace-ment in 2000. We noted whether they had had a unilateral procedure or two procedures and, if they had had two pro-cedures, whether both had been done during the same hospitalization or whether the operations had been performed during two separate hospital stays. Age, sex, race, residence, Medicaid eligibility (a proxy for low income), and the Charlson comorbidity score were documented for each patient as were the total numbers of total knee replacements performed in the year 2000 by the hospital and the surgeon. The probability of a symptomatic pulmonary embolism de-veloping in the first three months after surgery was calculated for the simultaneous, staged, and unilateral procedures. Results: Simultaneous procedures were much more likely to be performed in high-volume hospitals and by high-volume surgeons than were staged procedures. Men had proportionately more simultaneous procedures than did women. Hospitals in the northeastern United States were the most likely to perform simultaneous procedures. A pul-monary embolism developed in the first three months in 0.81 % of the patients who had had a single procedure com