Background: Recently, a number of studies using intra-articular application of tranexamic acid (IA-TXA), with different dosage and techniques, successfully reduced postoperative blood loss in total knee replacement (TKR). However, best of our knowledge, the very low dose of IA-TXA with drain clamping technique in conventional TKR has not been yet studied. This study aimed to evaluate the effectiveness and dose-response effect of two low-dose IA-TXA regimens in conventional TKR on blood loss and blood transfusion reduction.

Methods: Between 2010 and 2011, a triple-blinded randomized controlled study was conducted in 135 patients undergoing conventional TKR. The patients were allocated into three groups according to intra-articular solution received: Control group (physiologic saline), TXA-250 group (TXA 250 mg), and TXA-500 group (TXA 500 mg). The solution was injected after wound closure followed by drain clamping for 2 hours. Blood loss and transfusion were recorded. Duplex ultrasound was performed. Functional outcome and complication were followed for one year.

Results: There were forty-five patients per groups. The mean total hemoglobin loss was 2.9 g/dL in control group compared with 2.2 g/dL in both TXA groups (p > 0.001). Ten patients (22%, control), six patients (13%, TXA-250) and none (TXA-500) required transfusion (p = 0.005). Thromboembolic events were detected in 7 patients (4 controls, 1 TXA-250, and 2 TXA-500). Functional outcome was non-significant difference between groups.

Conclusions: Combined low-dose IA-TXA, as 500 mg, with 2-hour clamp drain is effective for reducing postoperative blood loss and transfusion in conventional TKR without significant difference in postoperative knee function or complication.