Reduction of Blood Loss by Intra-articular Injection of Tranexamic Acid Combined with Knee and Hip Flexion at 45° During Primary Total Knee Arthroplasty: A Randomized Controlled Trial

Objective To explore the hemostatic effect of intra-articular administration of tranexamic acid (TXA) combined with knee flexion in total knee arthroplasty (TKA). Methods This randomized controlled trial was conducted at the Third Affiliated Hospital of Southern Medical University (Guangzhou, China) from January 2017 to February 2018. The patients were randomized 1:1 to the TXA group (TXA 500 mg into the joint after closure, knee, and hip flexed at 45 degrees for 4 h) or the control group (physiological saline, with limb fully extended). The primary endpoint was postoperative hemoglobin reduction. The postoperative levels of hemoglobin were measured at four time points: 6 h after operation, and on the first, second, and third postoperative days. Calculated blood loss (CBL) at 3 days, transfusion rate, range of motion (ROM), VAS pain score, and knee circumference increment were the secondary endpoints. Ninety-four (47/group) patients were analyzed. Results Postoperatively, there were statistically significant differences between the TXA and control groups in CBL (791 +/- 212 mLvs1175 +/- 273 mL,P< 0.05). Hemoglobin reduction was significantly lower in the TXA group (2.0 +/- 0.9 g/dLvs4.5 +/- 0.7 g/dL,P< 0.05). Based on the transfusion criteria, 3 out of 47 (6.4%) patients in the TXA group and 13 out of 47 (27.6%) patients in the control group received blood transfusions (P= 0.006). ROM (90.8 degrees +/- 6.2 degrees vs87.6 degrees +/- 6.4 degrees,P= 0.004), VAS pain score (4.1 +/- 1.1vs4.8 +/- 1.3,P= 0.004), and KCI (2.4 +/- 0.9 cmvs3.2 +/- 1.0 cm,P= 0.01) were better in the TXA group compared with thecontrols. There was no deep venous thrombosis (DVT), wound infection or other adverse events in either group. In the control group, 2 patients had a fever after blood transfusion. Conclusion Intra-articular injection of TXA combined with knee and hip flexion at 45 degrees can effectively attenuate CBL and hemoglobin reduction during primary TKA, without an additional adverse event.