LAUSR

Background The association of simultaneous bilateral total hip arthroplasty (THA) with postoperative deep venous thrombosis (DVT) remains controversial. The aim of the study is to determine whether simultaneous bilateral THA without chemoprophylaxis has a higher risk than unilateral THA without chemoprophylaxis. Methods This is a population-based retrospective cohort study of all adults who underwent primary THA without any anticoagulant or antiplatelet therapy between July 2012 and March 2021 at the Department of Orthopedic Surgery, Toranomon Hospital, Tokyo, Japan. The association of simultaneous bilateral THA with postoperative DVT was examined by unadjusted analysis and overlap propensity score weighting. The primary outcome was the incidence of DVT (confirmed by ultrasonography of the lower limb veins) within 7 days postoperatively. Results Of the 557 consecutive patients who underwent primary THA in the study period, 458 met the inclusion criteria. The mean (standard deviation) age of these patients was 67 (11.7) years, and 364 (79.5%) were women; 75 (16.4%) of the 458 patients underwent simultaneous bilateral THA, and 383 (83.6%), unilateral THA. A total of 64 patients (14.0%) developed a postoperative venous thromboembolism, all of which were a distal DVT. The overlap weighting analysis found no significant difference in the incidence of postoperative DVT complications among patients who underwent simultaneous bilateral THA and those who underwent unilateral THA (31.1 [13.6%] vs 22.9 [10.0%], respectively; risk ratio, 1.36; 95% confidence interval, 0.67 to 2.77; P = .40). Conclusions Our findings indicate that the occurrence of DVT within 7 days after surgery is not significantly different between patients undergoing simultaneous bilateral THA or unilateral THA without any anticoagulant or antiplatelet therapy. Level of Evidence Level II-III.