Minimum 5-Year Outcomes After Arthroscopic Subspine Decompression in Patients With Femoroacetabular Impingement: A Propensity-Matched Study

Background: Subspine impingement (SSI) is a frequently coexisting pathology in patients undergoing hip arthroscopy for femoroacetabular impingement (FAI). While short-term outcomes after arthroscopic subspine decompression (SSD) are promising, midterm outcomes remain unclear. Purpose: To evaluate minimum 5-year patient-reported outcomes (PROs), survivorship, and rates of clinically meaningful improvement after arthroscopic SSD in patients undergoing hip arthroscopy for FAI; and to compare these results to a matched cohort without SSD. Study Design: Cohort study; Level of evidence, 3. Methods: The data of patients undergoing primary hip arthroscopy for FAI between 2009 and 2019 were retrospectively reviewed. Inclusion criteria included a confirmed diagnosis of FAI and SSI and complete PROs (modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score–Sports-Specific Subscale, International Hip Outcome Tool–12 score, and visual analog scale score) at a minimum of 5 years. Exclusion criteria included prior ipsilateral hip surgery, workers’ compensation claims, and Tönnis grade >1. Patients with SSD were matched 1:2 to a control group without SSI. Matching variables included age, sex, body mass index, follow-up duration, lateral center-edge angle, alpha angle, Tönnis grade, acetabular labrum articular disruption grade, and labral treatment. Outcomes were compared between groups, including survivorship and achievement of the minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS). Results: A total of 94 patients with SSD were matched to 188 control patients. Patients who underwent SSD demonstrated significant improvements in all PROs at a minimum 5-year follow-up ( P < .0001). MCID and PASS achievement rates were comparable between groups ( P > .05). The SSD cohort also demonstrated favorable survivorship, with 5.3% converting to total hip arthroplasty or hip resurfacing. Compared to patients with type 1 morphology who did not undergo SSD, outcomes in the SSD group were comparable in terms of postoperative PROs, satisfaction ( P > .05), and conversion rates to further surgery ( P = .61). Notably, time to revision arthroscopy was significantly longer in the SSD group (52.0 vs 32.8 months; P = .04). The mean time to conversion (arthroplasty) was similar between both cohorts ( P = 0.71). Conclusion: Arthroscopic SSD performed concurrently with FAI correction yields durable improvements in hip function and pain relief at a minimum 5-year follow-up. Outcomes and survivorship are comparable to those of patients without SSI undergoing FAI correction alone, supporting the use of SSD in appropriately selected patients with SSI.