Bilateral Hip Arthroscopy Compared with Unilateral Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Propensity-Matched Analysis of Long-term Outcomes and Procedural Timing

BACKGROUND: Bilateral hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) has demonstrated favorable short-term outcomes. However, the long-term results remain unclear and warrant further investigation. HYPOTHESIS/PURPOSE: To compare 10-year patient-reported outcomes (PROs), clinically significant outcomes (CSOs), and reoperation-free survivorship between bilateral and unilateral HA. It was hypothesized that both groups would demonstrate comparable PROs, CSO achievement, and survivorship. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A prospective repository was retrospectively reviewed to identify patients undergoing bilateral HA for FAIS between January 2012 and January 2015 with 10-year follow-up. Patients were propensity-matched 1:1 to unilateral HA patients controlling for age, sex, body mass index, and Tönnis grade. Exclusions included revision HA, concomitant procedures, congenital hip disorders, non-FAIS pathologies, staged periacetabular osteotomy, Tönnis grade >1, and missing 10-year follow-up. Hip Outcome Score (HOS) subscale for Activities of Daily Living and the HOS Sports Subscale (HOS-SS), International Hip Outcome Tool, modified Harris Hip Score, and visual analog scale (VAS) for pain/satisfaction were collected. Minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and reoperation-free survivorship were compared. Improvements from baseline to 10 years were correlated between hips. Analysis of variance evaluated differences based on bilateral HA timing. RESULTS: = .70). Change in index hip scores positively correlated with contralateral hip changes. A 0- to 3-month interval demonstrated superior preoperative HOS-SS compared with 6 to 12 months, whereas a 3- to 6-month interval demonstrated superior 10-year VAS-Pain score compared with 0 to 3 months. CONCLUSIONS: Bilateral HA achieved long-term outcomes and reoperation-free survivorship comparable to those of unilateral HA. Index and contralateral hip outcomes were positively correlated. Shorter intervals between procedures were associated with better preoperative function, whereas intermediate intervals were associated with lower long-term pain, but finding this requires further investigation with larger sample sizes.