PURPOSE: This study aims to evaluate patient-reported outcomes (PROs) and reoperation rates in patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) over a minimum 10-year follow-up stratified by sex, age, and body mass index (BMI). METHODS: Primary hip arthroscopies performed for FAIS between 2010 and 2013, with a minimum 10-year follow-up, were reviewed. Procedures consisting of microfracture, or labral debridement without repair, were excluded. Ten-year PROs were assessed using the modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS). Patients were categorized into three groups by age (<
30, 30-44, >
45 years) and BMI (<
25.0, 25.0-29.9, ≥ 30). Minimum clinically important difference (MCID) was set to half the preoperative standard deviation of the cohort. Reoperation rates and PROs were compared, and regression analysis identified independent predictors of PROs. RESULTS: At minimum 10-year follow-up (mean: 11.6 [10.0-13.9] years), 59.2% follow-up was achieved, representing 154 hips (141 patients). The cohort had a mean age of 38.5 years, BMI of 24.4, and was 68.2% female. At follow-up, 91.6% of the cohort achieved MCID with a 9.7% reoperation rate. In the middle-aged group, males had higher mHHS (mean: 92.8 vs 85.2
P = .015) and NAHS (mean: 91.6 vs 83.4
P = .008) scores compared to females. In the BMI ≥30 group, males had higher mHHS (mean: 83.3 vs 66.4
P = .030) and NAHS scores (mean: 83.0 vs 58.5
P = .035). Only 72.7% of females with BMI ≥30 achieved MCID for mHHS and NAHS, compared to BMI <
25 (96.6% and 94.9%, respectively) and 25-29.9 (87.5% and 83.3%) (mHHS: P = .016
NAHS: P = .038). Similarly, 78.8% of females aged ≥45 achieved MCID for NAHS, compared to 92.9% of those aged <
30 and 97.1% of those 30-44 (P = .040). Multivariable regression identified older age (mHHS: P = .019
NAHS: P = .042) and higher BMI (mHHS: P = .007
NAHS: P <
.001) as independently predictive of worse 10-year PROs. CONCLUSION: Older age and greater BMI independently predicted poorer long-term functional outcomes after hip arthroscopy for FAIS. Female sex, while not independently predictive, may make patients more susceptible to the negative effects of older age and BMI. No significant association was observed for reoperation rates. LEVEL OF EVIDENCE: Level IV, retrospective therapeutic case series.