Predeposited Autologous Blood Transfusion in Single-Anesthetic Bilateral Total Knee Arthroplasty with Modern Blood Conservation Strategy

This study was performed to examine the hypothesis that the rate of allogeneic blood transfusion in patients who did not predeposit an autologous blood transfusion before single-anesthetic bilateral total knee arthroplasty (TKA) would be noninferior to that in patients who did predeposit blood. METHODS: We assessed the number of allogeneic transfusions required in 338 patients undergoing single-anesthetic bilateral TKA with a preoperative hemoglobin level of ≥11.0 g/dL. All TKAs were performed by a single surgeon according to the same operative and postoperative protocol. All patients received a combination of intravenous and intra-articular tranexamic acid. Neither a pneumonic tourniquet nor a drain was used. The difference in the risk of allogeneic transfusion between patients without and with autologous blood predeposit was compared with a noninferiority margin of 10 percentage points. RESULTS: Allogeneic transfusion was required in 1 (0.5%) of 194 patients who predeposited autologous blood and 3 (2.1%) of 144 patients who did not predeposit blood. The difference in risk was −1.6 percentage points (95% confidence interval, −4.1 to 1.0 percentage points); the confidence interval did not include the noninferiority margin and included zero. CONCLUSIONS: In single-anesthetic bilateral TKA, allogeneic transfusion requirements in patients who did not predeposit autologous blood were noninferior to those in patients who predeposited blood. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.