Hip Arthroscopy Patients with Lower Back Pain Show Delayed Clinical Improvement and Inferior Time-Dependent Survivorship: A Propensity Matched Study at Mid-Term Follow-Up.

PURPOSE: To evaluate patient-reported outcomes (PROs) and survivorship at mid-term follow-up after hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in patients with and without preoperative lower back pain (LBP).

METHODS: Patients with self-endorsed preoperative LBP who underwent HA for FAIS with mid-term follow-up were identified and propensity matched 1:1 to patients without back pain by age, sex, and body mass index. PROs collected preoperatively and at postoperative years 1, 2, and 5 included: Hip Outcome Score Activities of Daily Living (HOS-ADL) and Sports Subscale (HOS-SS), International Hip Outcome Score 12 (iHOT-12), modified Harris Hip Score (mHHS), Visual Analog Scale (VAS) for Pain. Achievement of minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) were compared. Survivorship was compared with Kaplan-Meier analysis.

RESULTS: 119 patients with LBP were matched to 119 patients without LBP. Group demographic factors were as follows, age (37.4±11.9 years vs 37.6±12.6, p=0.880), sex (64.4% female vs 67.7%, p=0.796), and BMI (25.3±5.1 kg/m2 vs 25.3±5.4, p=0.930). Average follow-up duration was 6.0 ± 1.9 years. LBP patients showed similar preoperative PROs, yet lower 1-year scores for all PROs (p ≤ 0.044). At final follow-up, similar PROs were shown between groups (p ≥ 0.196). LBP and non-LBP patients had similar MCID achievement for HOS-ADL (59.3%vs.63.1%,p=0.640), HOS-SS (73.9%vs.70.8%,p=0.710), mHHS (66.7%vs.73.4%, p=-.544), iHOT-12 (85.1%vs.79.4%,p=0.500), and VAS-Pain (75.6%vs.69.9%,p=0.490). Groups also had similar PASS achievement for HOS-ADL (63.5%vs.61.3%,p=0.777), HOS-SS (57.0%vs.62.5%,p=0.461), mHHS (81.9%vs.79.1%, p=0.692), iHOT-12 (54.6%vs.61.2%,p=0.570), and VAS-Pain (51.0%vs.55.4%,p=0.570). with similar MCID (p ≥ 0.490) and PASS (p ≥ 0.386) achievement. Conversion to total hip arthroplasty occurred in 3.4% of hips with LBP and 0.8% of hips without LBP (p=0.370), Back pain patients demonstrated inferior time-dependent survivorship compared to patients without back pain on Kaplan-Meier survival analysis (p = 0.023).

CONCLUSIONS: Patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome with LBP achieve comparable PROs and CSOs to patients without back pain at mid-term, despite lower 1-year PRO scores. LBP patients show inferior reoperation-free time-dependent survivorship compared to those without LBP.