Tranexamic acid use and risk of thrombosis in regular users of antithrombotics undergoing primary total knee arthroplasty: a prospective cohort study

Background. The effect of tranexamic acid has not been examined in patients who are regular users of antithrombotics before undergoing total knee arthroplasty. The aim of this study was to determine the impact of tranexamic acid on bleeding and the risk of transfusion and thrombosis in patients taking an antithrombotic treatment before primary unilateral total knee arthroplasty. Material and methods. A prospective observational study was conducted in a series of 385 consecutive primary total knee arthroplasties performed with and without the administration of tranexamic acid. We compared post-operative bleeding, as determined by a bleeding index, and postoperative haemoglobin and haematocrit between patients taking an antithrombotic treatment before the operation (ATT+group) and those naive or non-regular users of antithrombotics (ATT-group). Post-operatively, rivaroxaban was prescribed for deep vein thrombosis prophylaxis, unless contraindicated. Antiplatelet therapy and vitamin K antagonist anticoagulants were not resumed during the early post-operative period. Results. The prevalence of total knee arthroplasty performed in patients who are regular users of antithrombotics was 33%. Tranexamic acid was administered during 62% of the arthroplasties in the ATT+group and to 90% in the ATT-group. In both study groups, the bleeding index was significantly lower in patients who received tranexamic acid, both in the ATT+(p<0.001) and in the ATT-group (p=0.001). No patients in the ATT+group received a blood transfusion during the first post-operative week. No thrombotic complications were identified for up to 2 months in the ATT+group. Discussion. Tranexamic acid use after the induction of general anaesthesia in total knee arthroplasty represents a fast, inexpensive, and effective opportunity to reduce peri-operative blood loss in patients on chronic antithrombotic treatment undergoing total knee arthroplasty.