Multiple Boluses of Intravenous Tranexamic Acid to Reduce Hidden Blood Loss After Primary Total Knee Arthroplasty Without Tourniquet: A Randomized Clinical Trial.

BACKGROUND: The optimal dosage and timing of tranexamic acid (TXA) in total knee arthroplasty (TKA) are undetermined. The purpose of this study was to explore the effect of multiple boluses of intravenous TXA on hidden blood loss (HBL), inflammatory response, and knee function after primary TKA without tourniquet.

METHODS: A total of 151 patients were randomly divided into 3 groups to receive single bolus of 20 mg/kg IV-TXA before skin incision (group A), or another bolus of 10 mg/kg IV-TXA 3 hours later (group B), or another 2 boluses of 10 mg/kg IV-TXA 3 hours and 6 hours later (group C). TKAs without tourniquet were operated by 1 single surgeon. The primary outcomes were HBL and maximum hemoglobin drop. Other outcome measurements such as total blood loss, transfusion rate, inflammation markers (C-reactive protein, interleukin 6), visual analog scale pain score, limb swelling ratio, Hospital for Surgery Score, range of motion, length of hospital stay (LOH), and deep venous thrombosis were also compared.

RESULTS: The mean HBL and maximum Hb drop in group C (467.6 ± 305.9 and 20.9 ± 9.3) was lower than those in group A (763.0 ± 373.3, P < .001; 28.7 ± 12.2, P < .001) and group B (637.5 ± 303.5, P = .010; 25.2 ± 8.4, P = .036). However, such differences were not detected between groups A and B (P = .058 and P = .080, respectively). The mean value of total blood loss in the groups A, B, and C were 967.2 ± 380.1, 803.7 ± 321.8, and 677.6 ± 326.0 mL, respectively, with a significant intergroup difference (P < .001). The mean serum level of C-reactive protein and interleukin 6 in group C were lower than those in group A and group B on postoperative days 1 and 2. The visual analog scale pain score and swelling ratio were also lower in group C than in the other 2 groups with statistical significance on POD 1-3. Moreover, the Hospital for Surgery Score, range of motion, and LOH were better in group C. No episodes of transfusion or deep venous thrombosis had occurred.

CONCLUSION: Multiple boluses of IV-TXA can effectively reduce HBL after primary TKA without tourniquet. What is the most important is that, by adding another bolus of IV-TXA, patients can gain a smaller decline of Hb, less postoperative inflammatory response, less pain, less knee swelling, better knee function, and shorter LOH.