EP1.24 Midterm Outcomes of Revision Hip Arthroscopy in Patients with Borderline Dysplasia: A Propensity-Matched Comparison to a Nondysplastic Control Group

Abstract Background Hip arthroscopy for borderline hip dysplasia (BHD) remains controversial, particularly in the revision setting. Limited data exist on mid-term outcomes in this population, and few studies have compared them with patients without dysplasia undergoing revision arthroscopy. The purpose of this study is to report minimum 5-year patient-reported outcomes (PROs) and survivorship in patients with BHD who underwent revision hip arthroscopy and to compare these outcomes with those of a propensity-matched control group without dysplasia. Methods Prospectively collected data were reviewed. Inclusion criteria were revision hip arthroscopy, lateral center-edge angle (LCEA) 18°–25°, capsular plication, labral treatment of any kind, and minimum 5-year follow-up with available PROs. Exclusion criteria included prior hip conditions, preoperative Tönnis grade >1, and LCEA <18°. Controls had normal coverage (LCEA 26°–40°) and met identical surgical and follow-up criteria. Groups were matched 1:2 for age, sex, BMI, and follow-up. Rates of minimal clinically important difference and reoperations were recorded. Results 31 patients with BHD (LCEA 22.4° ± 2.0) were matched to 62 controls (LCEA 31.3° ± 3.5), with comparable age, sex, BMI, and follow-up time (79.6 ± 29.1 vs 83.2 ± 27.4 months). Both groups demonstrated significant improvement from preoperative to latest follow-up in all PROs (p < 0.001). Postoperative PROs, magnitude of improvement, MCID, and satisfaction were comparable between groups (p > 0.05). The BHD group demonstrated a lower arthroplasty free survival rate (64.5% vs 88.7%, p = 0.005), while tertiary arthroscopy rates were comparable (12.9% vs 14.5%, p > 0.99). Conclusion At minimum 5-year follow-up, patients with borderline dysplasia undergoing revision hip arthroscopy achieved significant and durable improvements in PROs, with MCID and PASS rates comparable to those of a matched control group without dysplasia. Although the borderline dysplasia group demonstrated higher rates of conversion to THA, overall outcomes and patient satisfaction remained favorable.