ObjectiveTo evaluate the effectiveness and safety of tranexamic acid (TXA) combined with intraoperative controlled hypotension (ICH) for reducing perioperative blood loss in primary total hip arthroplasty (THA).MethodsThe clinical data of 832 patients with initial THA due to osteonecrosis of femoral head between January 2017 and July 2020 were retrospectively analyzed. All patients received TXA treatment, and 439 patients (hypotension group) received ICH treatment with an intraoperative mean arterial pressure (MAP) below 80 mm Hg (1 mm Hg=0.133 kPa) while 393 patients (normotension group) received standard general anesthesia with no special invention on blood pressure. There was no significant difference in age, gender, body mass index, American Society of Anesthesiologists (ASA) classification, basic arterial pressure, hip range of motion, internal diseases, preoperative hemoglobin (HB) and hematocrit (HCT), coagulation function, surgical approach, and TXA dosage between the two groups (P>0.05). The perioperative blood loss and blood transfusion, anesthesia and operation time, hospitalization stay, postoperative range of motion, and complications were recorded and compared between the two groups. The patients were further divided into MAP<70 mm Hg group (group A), MAP 70-80 mm Hg group (group B), and normotension group (group C). The perioperative blood loss and postoperative complications were further analyzed to screen the best range of blood pressure.ResultsThe intraoperative MAP, total blood loss, dominant blood loss, recessive blood loss, blood transfusion rate and blood transfusion volume, anesthesia time, operation time, and hospitalizarion stay in the hypotension group were significantly lower than those in the normotension group (P<0.05). The postoperative hip flexion range of motion in the hypotension group was significantly better than that of the normotension group (Z=2.743, P=0.006), but there was no significant difference in the abduction range of motion between the two groups (Z=0.338, P=0.735). In terms of postoperative complications, the incidence of postoperative hypotension in the hypotension group was significantly higher than that in the normotension group (χ2=6.096, P=0.014), and there was no significant difference in the incidence of other complications (P>0.05). There was no stroke, pulmonary embolism, or deep vein thrombosis in the two groups, and no patients died during hospitalization. Subgroup analysis showed that there was no significant difference in total blood loss, dominant blood loss, and recessive blood loss in groups A and B during the perioperative period (P>0.05), which were significantly lower than those in group C (P<0.05). There was no significant difference in blood transfusion rate, blood transfusion volume, and incidence of acute myocardial injury between 3 groups (P>0.05); the incidence of acute kidney injury in group A was significantly higher than that in group B, and the incidence of postoperative hypotension in group A was significantly higher than that in groups B and C (P<0.05), but no significant difference was found between groups B and C (P>0.05).ConclusionThe combination of TXA and ICH has a synergistic effect. Controlling the intraoperative MAP at 70-80 mm Hg can effectively reduce the perioperative blood loss during the initial THA, and it is not accompanied by postoperative complications.