Influence of tranexamic acid on postoperative autologous blood retransfusion in primary total hip and knee arthroplasty: a randomized controlled trial

BackgroundPostoperatively shed blood salvage is commonly used to reduce allogenic blood transfusion in patients undergoing total hip (THA) and knee arthroplasty (TKA). Autologous blood retransfusion is not devoid of risk. We hypothesized that adding tranexamic acid (TXA) to a restrictive blood transfusion protocol would reduce the need for postoperative autologous blood retransfusion in primary knee and hip arthroplasty. Study Design and MethodsNinety-eight adult patients undergoing primary THA or TKA were randomly assigned to receive an intraoperative intravenous loading dose of 1.0g of TXA followed by another 1.0-g dose 3 hours later (TXA group) or a matching volume 0.9% saline placebo (control group). A postoperatively shed autologous blood recovery system was used in all patients and the minimum reinfusion volume set at 250mL. Red blood cells were transfused if hemoglobin level was less than 8 or if 8 to 10g/dL with symptoms of anemia. ResultsThe proportion of patients receiving autologous blood reinfusion was significantly lower in the TXA group (5/49) compared to placebo (42/49) with an absolute difference of -75.5% (adjusted relative risk, 0.005), and none of the patients in the TXA group received more than 400mL retransfused. Median total external blood loss during the first 24 hours was lower in the TXA group, 320mL (range, 80-930mL), compared to 970mL (range, 100-2600mL) in the placebo group (p<0.001). There were no significant differences in homologous blood transfusions and hematologic variables between groups. Treatment differences were consistent by size and significance when the analysis was repeated separately in patients undergoing TKA or THA. ConclusionAddition of TXA to a restrictive transfusion protocol makes the use of a postoperative blood salvage system in patients undergoing primary hip and knee arthroplasty unnecessary.