PURPOSE: To evaluate patient-reported outcomes (PROs), achievement of clinically significant outcomes (CSOs), and reoperation-free survivorship at long-term follow-up after primary hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in patients with and without preoperative low back pain (LBP). METHODS: A repository was reviewed to identify patients who underwent primary HA for FAIS between January 2012 and May 2014 with 10-year follow-up. Exclusion criteria included previous ipsilateral hip surgery, concomitant procedures, congenital hip disorders, non-FAIS hip pathologies, Tönnis grade >
1, history of platelet-rich plasma injections, and missing 10-year follow-up. Patients who self-reported preoperative, concomitant LBP were propensity-matched 1:1 to patients without LBP by age, sex, and body mass index. PROs collected included Hip Outcome Score-Activities of Daily Living and Sports Subscale (HOS-ADL/HOS-SS), 12-item International Hip Outcome Tool (iHOT-12), modified Harris Hip Score (mHHS), and visual analog scale (VAS) for pain and satisfaction. Minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) were compared. Subgroup analysis was conducted comparing female and male patients with LBP. Reoperation-free survivorship was compared with Kaplan-Meier analysis. An a priori power analysis determined sample size. RESULTS: Overall, 69 hips in 67 patients with LBP were matched to 69 hips in 67 patients without LBP. Demographics were similar between groups, including age (39.22 ± 10.3 vs 38.99 ± 10.7 years, P = .90), sex (55.1% vs 55.1% female, P = 1.0), and body mass index (26.15 ± 4.6 vs 26.36 ± 5.1, P = .80). Average follow-up duration was 10.43 ± 0.4 years. The most common cause of LBP was degenerative lumbar or sacral conditions, including degenerative disc disease, degenerative joint disease, or spondylosis, accounting for 38.8% (26/69) of the cohort. Mean preoperative HOS-ADL (62.38 ± 18.7 vs 64.45 ± 21.1, P = .57), HOS-SS (37.83 ± 22.6 vs 45.67 ± 24.7, P = .09), mHHS (53.63 ± 14.6 vs 57.01 ± 14.6, P = .22), iHOT-12 (33.29 ± 19.0 vs 39.49 ± 15.8, P = .27), and VAS-Pain (71.88 ± 18.3 vs 71.87 ± 19.1, P = 1.0) were similar between patients with and without LBP. In addition, the mean 10-year follow-up HOS-ADL (81.48 ± 21.2 vs 79.57 ± 22.0, P = .66), HOS-SS (66.87 ± 31.3 vs 67.36 ± 30.4, P = .94), mHHS (74.15 ± 18.8 vs 73.19 ± 17.7, P = .79), iHOT-12 (77.77 ± 23.3 vs 69.63 ± 29.3, P = .13), VAS-Pain (23.98 ± 25.0 vs 32.19 ± 28.4, P = .11), and VAS-Satisfaction (83.47 ± 25.3 vs 81.43 ± 29.7, P = .73) were similar between patients with and without LBP. Patients with and without LBP had comparable MCID achievement for HOS-ADL (72% vs 56%, P = .13), HOS-SS (74% vs 50%, P = .06), mHHS (74% vs 65%, P = .47), iHOT-12 (83% vs 72%, P = .67), VAS-Pain (89% vs 75%, P = .10), and any PRO (98% vs 93%, P = .32). Similarly, patients with and without LBP had comparable PASS achievement for HOS-ADL (64% vs 65%, P = 1.0), HOS-SS (66% vs 69%, P = .83), mHHS (64% vs 60%, P = .84), iHOT-12 (65% vs 61%, P = .84), VAS-Pain (55% vs 50%, P = .71), and any PRO (76% vs 80%, P = .81). Subgroup analysis revealed no significant differences between female and male patients with LBP in preoperative or 10-year follow-up PROs as well as MCID and PASS achievement rates. Reoperation-free survivorship was comparable (P = 1.0). CONCLUSIONS: Patients undergoing primary HA for FAIS with concomitant LBP may achieve comparable PROs, CSOs, and reoperation-free time-dependent survivorship to patients without LBP at long-term follow-up. LEVEL OF EVIDENCE: Level III, retrospective, matched case-control study.