Ideal intraarticular application dose of tranexamic acid in primary total knee arthroplasty: a prospective, randomized and controlled study

Background: Combined use of tranexamic acid (TXA) via intravenous (IV) and intraarticular (IA) routes is more effective in reducing blood loss than any single route in primary total knee arthroplasty (TKA), but the optimal dose of topical administration remains controversial. The aim of this study was to evaluate the efficacy and safety of different combined administration strategies and to determine an ideal IA application dose of TXA. Methods: A total of 180 patients who underwent primary TKA were randomized to four groups (groups A/B/C/D) with the same single IV dose of 1 g TXA preoperatively and four different IA doses after wound closure: group A (0 g), group B (1 g), group C (2 g), and group D (4 g). The primary outcome measures included wound blood drainage, hemoglobin (Hb) concentration, and blood transfusion. The secondary outcome measures included wound complications, deep vein thrombosis (DVT) and symptomatic pulmonary embolism (PE). Results: A total of 165 patients finished at least 3 months of follow-up visits. The amount of 48-hour blood drainage and calculated total blood loss in four groups decreased with the increased dose of TXA injected via IA route, and no difference was observed between groups C and D (P=0.6237 and P=0.9923, respectively). Hb was significantly higher in groups C and D than in groups A and B at postoperative day 1, 3 and 7, respectively (P<0.0001). Hb in group A was significantly lower than that in groups C and D at 1 month after surgery, whereas no intergroup difference was found in other groups. No intergroup difference was observed regarding DVT, PE or wound complications. Conclusions: The topical injection of 2 g TXA may have reached the "ceiling effect" of local use. A preoperative IV dose of 1 g TXA combined with an IA dose of 2 g TXA could be an optimal combination regimen.