BACKGROUND: This study aimed to assess whether the efficacy of tranexamic acid (TXA) would be altered when rivaroxaban or enoxaparin was used for thromboprophylaxis in primary total knee replacement (TKR). It was hypothesized that the hemostatic effect of TXA would be better with the use of enoxaparin.

MATERIAL AND METHODS: A randomized clinical trial was conducted on 194 patients undergoing primary TKR for osteoarthritis. An intravenous dose of 15 mg/kg (TXA) and 1 g topical TXA were used. Patients randomly received enoxaparin or rivaroxaban prophylaxis when the drainage was less than 30 ml/h 6–8 h postoperatively. The primary endpoint was hidden blood loss (HBL). Indexes of total blood loss drainage, hemoglobin drop, transfusion, range of motion (ROM), HSS score, VAS pain score, knee swelling, length of hospital stay (LOHS), incidence of venous thromboembolism, major/minor bleeding, and wound complications were also compared between the groups.

RESULTS: More than 80% of patients initiated anticoagulation within 6 h postoperatively. No statistically significance difference was detected in terms of HBL (679.0±205.6 vs. 770.5±206.1, p=.062) or other bleeding index, ROM, or LOHS. The motion VAS pain score and knee swelling (16.7% vs. 6.1%, p=.021) were significantly lower, and HSS score at discharge was higher in the enoxaparin group. The rivaroxaban group had less asymptomatic deep venous (4.1% vs. 0%, p=.121) and muscular venous thrombosis (2.1% vs. 9.2%, p=.033); more ecchymosis (13.5% vs. 10.2%, p=.472), and wound complications (13.5% vs. 6.1%, p=.082). No episodes of transfusion, pulmonary embolism, or major bleeding occurred in either group.

CONCLUSIONS: More attention should be paid to the increased risk of wound complications and knee swelling associated with rivaroxaban, although the hidden blood loss was similar in both groups.

Keywords: Anticoagulants, Antifibrinolytic Agents, Arthroplasty, Replacement, Knee