Acta Orthopædica Belgica, Vol. 87 - 4 - 2021 The aim is to study whether a 3 day course of Tranexamic acid (TXA) is more effective in reducing blood loss following a TKR than a 1 day course. 250 patients were prospectively randomised into Group A (n=138; Perioperative and additional oral TXA for two days) and Group B (n=112; only perioperative TXA). Total Blood loss was calculated by the Haemoglobin (Hb) loss method at 4 days and compared in both groups using Mann Whitney test. The mean peri- operative blood loss in group A was 631.69 ± 264.99 ml as compared to 685.55 ± 239.033 ml in group B (p=0.0434). Use of TXA for 3 days following a TKR can be more effective in reducing blood loss. Keywords: Tranexamic acid; total knee replacement; routes; duration. INTRODUCTION True blood loss following a TKR is the sum of the visible and hidden blood loss. The visible blood loss consists of the loss measured intra-operatively and the post-operative drainage. The hidden blood loss consists of bleeding into the joint and other tissues and RBC loss due to haemolysis (1-3). Chen et al showed that the maximum blood loss can be estimated postoperatively on day 4 (4) and Newman et al showed that the hidden blood loss can exceed the visible blood loss (5).Various published articles have looked at perioperative blood loss following a TKR in different ways. These articles have been included in a recent major meta-analysis (6). Various studies have shown (7) that the increased fbrinolysis after TKR lasts for 1 day and peaks within a few hours after TKR especially when a tourniquet is used. As TXA is an antifbrinolytic agent, it is traditionally used for 1 day to counter the hyperfbrinolysis induced by surgery and tourniquet. The half-life of TXA is approximately 2 hours (8). In surgical specialities, where there is a risk of continued bleeding, TXA has been used for multiple days to reduce bleeding e.g. for 4 to 5 days in reducing menorrhagia (9) in prostate surgery for up to 7 days or till macroscopic haematuria is resolved (10) and in cases of hepatic resection for up to 3 days (11). The use of TXA to reduce blood loss in joint replacement surgeries was frst demonstrated in 1995-96 (12-14). Currently, TXA is used commonly for 1 day either as a single dose or in divided doses (6). As the total blood loss following a TKR does not manifest till 4 days and the half-life of TXA is a few hours, the question arises as to whether a Level of Evidence- III The Authors declare no conficts of interest. This research did not receive any specifc grant from funding agencies in the public, commercial, or not-for-proft sectors. Acta Orthop. Belg., 2021, 87, 697-703 Should tranexamic acid be used for 3 days after total knee replacement? A randomized study in 250 patients Nilen Shah, Vatsal Khetan, Hari Sivanadan From the Smt S R Mehta and Sir K P Cardiac Institute, Mumbai, India ORIGINAL STUDY n Nilen Shah n Vatsal Khetan n Hari Sivanadan Smt S R Mehta and Sir K P Cardiac Institute, Mumbai, India. Correspondence : Dr Vatsal Khetan, 9 Oakwood Hall Drive, Moorgate, Rotherham, South Yorkshire S603AQ. Email : drvatsalortho2015@gmail.com © 2021, Acta Orthopædica Belgica.