Comparison of simultaneous versus staged bilateral total hip arthroplasty via the direct anterior approach: A propensity score matched analysis.

PURPOSE It remains unclear whether simultaneous bilateral total hip arthroplasty (SimBTHA) or staged bilateral total hip arthroplasty (StaBTHA) is clinically superior. No study has compared these two procedures matching surgical approach and patient background. This study aimed to clarify the differences between SimBTHA using direct anterior approach (SimBTHA-DAA) and StaBTHA using the direct anterior approach (StaBTHA-DAA). METHODS Patients who underwent THA between 2012 and 2020 were enrolled, resulting in a total of 1658 hips of 1388 patients. After propensity score matching for patient background, 204 hips of 102 patients (51 patients in each group) were examined. Clinical and radiographic outcomes, complications, intraoperative blood loss and blood transfusions (BT) were evaluated. In complications, we evaluated periprosthetic fractures, pulmonary embolism, deep venous thrombosis, surgical site infection and dislocation. RESULTS At the final follow-up, clinical and radiographic outcomes and complications were not significantly different between the groups. Intraoperative blood loss was equivalent for SimBTHA and the sum in the first- and second-stage StaBTHA. The total-BT rate was significantly higher for SimBTHA-DAA than for StaBTHA-DAA (p < .0001). The allogeneic BT rate was significantly higher in SimBTHA-DAA in the supine position (32.3%) than in StaBTHA-DAA (8.3%) (p = .007). However, no patient who received autologous BT required allogeneic BT. CONCLUSIONS Clinical and radiographic outcomes were equivalent between SimBTHA-DAA and StaBTHA-DAA. The allogeneic BT rate was significantly higher in SimBTHA-DAA than in StaBTHA-DAA. Autologous BT reduced the use of allogeneic BT in SimBTHA-DAA. Auto-BT may be useful for avoiding allo-BT in SimBTHA.