Inadequate methodology renders results on the use of tranexamic acid inconclusive

With great interest we read the recent article from Iwai et al. entitled "Repeat-dose intravenous tranexamic acid further decreases blood loss in total knee arthroplasty" [1]. The authors report on the use of tranexamic acid to reduce the rate of peri-operative blood transfusions in patients undergoing total knee arthroplasty (TKA). We agree fully with the authors that the development of strategies to reduce blood loss and the rate of peri-operative transfusions is imperative in modern TKA surgery. However, we have some concerns related to the published work.