Background: Approximately one-third of patients undergoing total knee replacement require one to three units of blood postoperatively. Tranexamic acid (TXA) is a synthetic antifibrinolytic agent that has been successfully used intravenously to stop bleeding after total knee replacement. A topical application is easy to administer, provides a maximum concentration of tranexamic acid at the bleeding site, and is associated with little or no systemic absorption of the tranexamic acid.
Methods: A double-blind, randomized controlled trial of 157 patients undergoing unilateral primary cemented total knee replacement investigated the effect of topical (intra-articular) application of tranexamic acid on blood loss. The primary outcome was the blood transfusion rate. Secondary outcomes included the drain blood loss, hemoglobin concentration drop, generic quality of life (EuroQol), Oxford Knee Score, length of stay, a cost analysis, and complications as per the protocol definitions.
Results: Tranexamic acid reduced the absolute risk of blood transfusion by 15.4% (95% confidence interval [CI], 7.5% to 25.4%; p = 0.001), from 16.7% to 1.3%, and reduced blood loss by 168 mL (95% CI, 80 to 256 mL; p = 0.0003), the length of stay by 1.2 days (95% CI, 0.05 to 2.43 days; p = 0.041), and the cost per episode by £333 (95% CI, £37 to £630; p = 0.028). (In 2008, £1 = 1.6 U.S. dollars.) Oxford Knee Scores and EuroQol EQ-5D scores were similar at three months.
Conclusions: Topically applied tranexamic acid was effective in reducing the need for blood transfusion following total knee replacement without important additional adverse effects.
Level of evidence: Therapeutic level I. See Instructions for Authors for a complete description of levels of evidence.