Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 64 8 2026 07 12 494 498 Ashraf Alhusseini Hammurabi College of Medicine, University of Babylon, Babylon, Iraq 2026 04 07 2026 05 02 - Bilateral total hip replacement (BTHR) is an effective surgical solution for patients with bilateral hip osteoarthritis and avascular necrosis. The procedure can be performed either as a single-stage operation or as two staged session surgeries. To compare single-stage bilateral total hip replacement with staged two-session bilateral total hip replacement, with particular emphasis on functional outcomes and early postoperative recovery. A prospective comparative observational study. Sixty patients aged 45-65 years with bilateral hip osteoarthritis or avascular necrosis and without any major comorbidity were enrolled. Thirty patients were operated on in a single stage, and 30 had the two hips replaced separately with an interval of 6-12 weeks. All surgeries were conducted through a posterolateral approach. Measures were total hospital stay, total rehabilitation time, and time to symmetric normal gait 12 months post-surgical follow-up using the OHS. Baseline demographic characteristics and underlying diagnoses were comparable between groups. The single-stage group demonstrated a significantly shorter hospital stay, reduced rehabilitation duration, and earlier achievement of symmetric normal gait compared with the staged group (P<0.001). Additionally, functional outcome was significantly higher in the single-stage group, as reflected by superior OHS scores at 12 months (P<0.001). Single-stage bilateral total hip replacement provides a better early functional recovery, shorter hospital stays, and faster rehabilitation than staged two-session surgery in properly selected patients. Our results justify single stage BTHR as a safe and effective option when selection of patients and preoperative optimization are well thought out. https://acta.tums.ac.ir/index.php/acta/article/view/12000 https://acta.tums.ac.ir/index.php/acta/article/download/12000/6094