Simultaneous bilateral total hip arthroplasty results in smaller Leg length discrepancy than staged bilateral procedures.

Introduction: The purpose of this study was to compare leg length discrepancies (LLD) between simultaneous and staged bilateral total hip arthroplasty (BTHA).

Materials And Methods: This retrospective cohort study included 150 consecutive patients who underwent BTHA (60 simultaneous and 90 staged BTHA). To adjust for preoperative patient characteristics between groups, 1:1 propensity score matching was performed based on age, sex, body mass index, American Society of Anesthesiologists Physical Status, Tönnis classification, Crowe classification, preoperative range of motion (flexion and abduction), LLD, and Harris Hip Score (HHS). Finally, 66 patients (33 pairs) with comparable preoperative backgrounds were analyzed. Postoperative LLD and clinical outcomes, including HHS, range of motion (flexion and abduction), operative time, intraoperative blood loss, and complications, were compared between the simultaneous and staged BTHA groups.

Results: The LLD in the simultaneous BTHA group was significantly smaller than that in the staged BTHA group (simultaneous BTHA, 3.5 ± 3.2 mm; staged BTHA, 6.2 ± 4.5 mm, p < 0.001). The rate of LLD ≤ 7 mm was significantly higher in simultaneous BTHA (84.8%) compared to staged BTHA (57.6%) (p = 0.028). Other outcomes, including the HHS, range of motion (flexion and abduction), operative time, intraoperative blood loss, and complication rates were similar between the groups.

Conclusion: Simultaneous BTHA has the potential to provide smaller LLD than staged BTHA because simultaneous surgery enables intraoperative comparison of bilateral leg lengths based on both extra- and intra-articular measurements. This approach may be advantageous for postoperative patient satisfaction.