Use of Topical (Intra-articular) Tranexamic Acid to Minimise Blood Loss and Transfusion in Total Knee Replacement Surgery

Introduction Total knee replacement (TKR) is a common orthopaedic procedure, with 20-70% of patients needing 1-3 units of blood, although allogeneic transfusion is not risk free. Tranexamic acid (TXA) is a synthetic antifibrinolytic agent used intravenously to stop bleeding in TKR and other surgical procedures. Objectives To determine whether intra-articular TXA is effective, safe and cost-effective in reducing blood loss and subsequent blood transfusion after TKR. Design This thesis describes three research projects to address the objectives: 1.A systematic review and meta-analysis of the use of intravenous (IV) TXA in TKR. 2.A randomised controlled trial of the topical (intra-articular) use TXA in TKR. 3.A biomechanical study of the effect of local TXA on TKR materials. Outcome measures The primary aim of intra-articular TXA was to reduce the blood transfusion rate. Secondary outcomes included reduced blood loss, length of stay, compli-cations and cost and improved functional outcome measures. To explore whether TXA degrades TKR materials, tensile properties, wear rate and surface topographic profile were biomechanically tested. Results The systematic review found that IV TXA reduced blood loss and transfusion significantly but there was significant heterogeneity between trials. A first trial of topical (intra-articular) TXA in TKR found TXA to be effective and safe in reducing blood loss and transfusion. Thirteen patients (16.7%) were transfused in the placebo group versus 1 (1.3%) patient in the TXA group (2; P=0.001). Blood loss was reduced from 465 ml in the placebo group to 297 ml in the TXA group (t-test; P=0.00025). TXA use resulted in a net cost saving of £333 per patient (P=0.044). There was no adverse effect of TXA on the biomechanical properties of the joint materials. Conclusion Topically Applied TXA in TKR is effective, safe and cost-effective in reducing blood loss and transfusion in TKR, and avoiding the potential complications of intravenous administration.