RESUMO
BACKGROUND: Topical intra-articular tranexamic acid (IA-TXA) has been proven to be safe and effective in reducing postoperative blood loss after primary total knee arthroplasty (TKA). The objective of this study was to investigate the efficacy of high dose (3 g) compared with low dose (500 mg) of IA-TXA in postoperative blood loss after primary TKA. METHODS: A double-blind randomized controlled trial was conducted in 80 patients who had undergone primary TKA. The patients were divided into two groups according to intra-articular TXA doses: high-dose group (3 g IA-TXA) and low-dose group (500 mg IA-TXA). The drug was injected into the joint capsule after fascial closure without suction drainage. The primary outcomes were maximum hemoglobin drop (g/dL) and calculated total blood loss (mL). Postoperative blood transfusions, thromboembolic events and functional outcomes were also recorded. RESULTS: The mean maximum hemoglobin drop was 1.3 g/dL lower in 3 g IA-TXA group compared to the 500 mg IA-TXA group [1.7 vs 3.0 g/dL, 95% confidence interval (CI) 0.9-1.7 g/dL, P < 0.001]. The 3 g IA-TXA group had 370 mL less calculated total blood loss compared to the 500 mg IA-TXA group (551 vs 921 mL, 95% CI 252-489 mL, P < 0.001). One patient in the 500 mg IA-TXA group required transfusion, while no patient in the 3 g IA-TXA group received transfusion (P = 0.31). Any thromboembolic event was not found, and functional outcome was similar between the two groups. CONCLUSIONS: Application of high-dose, 3 g topical IA-TXA was 43% more effective in reducing postoperative blood loss compared with low dose of 500 mg in primary TKA. Optimal doses in between the above two doses may be a worthwhile further investigation.