This meta-analysis identified 18 randomized prospective published studies which had a total of 27,807 patients (44,684 knees). From these studies, 16,419 simultaneous bilateral total knee replacements, 10,930 unilateral total knee replacements, and 458 staged bilateral total knee replacements (that had a minimum of 3 months between operations) were identified. Results from the analysis indicated that simultaneous bilateral total knee replacement had a higher risk of pulmonary and cardiac complications as well as mortality compared to the staged bilateral or unilateral total knee replacement procedures.