OP5.4 Primary and Revision Hip Arthroscopy in Borderline Hip Dysplasia Shows Comparable Outcomes at Minimum 5-Year Follow-Up

Purpose: To compare patient-reported outcomes (PROs), achievement of clinically significant outcomes (CSOs), and reoperation-free survivorship between primary and revision hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in patients with borderline hip dysplasia (BHD) at minimum 5-year follow-up.

Methods: Patients with BHD, characterized by a lateral center edge angle 18°-25°, who underwent HA for FAIS with capsular repair by a single surgeon between 01/2012 and 06/2018 with minimum 5-year follow-up were identified. Cases of revision HA were propensity-matched 1:2 to cases of primary HA, controlling for age, sex, and body mass index (BMI). Collected PROs included: Hip Outcome Score-Activities of Daily Living and Sport Subscales, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Achievement of minimal clinically important difference (MCID), patient acceptable symptom state (PASS), and substantial clinical benefit (SCB) for any measured PRO were compared between groups along with reoperation-free survivorship using Kaplan-Meier survival analysis.

Results: Thirty-six revision HA hips (34 patients) were propensity-matched to 72 primary HA hips (70 patients). The groups were similar in age (31.5±10.3 years vs. 30.5±11.2, P=0.669), sex (69.4% female vs. 70.8%, P=0.656), and BMI (25.7±4.0 kg/m2 vs. 25.5±3.7, P=0.849). The revision group showed a greater prevalence of prolonged preoperative pain (50.0% vs. 27.8%, P=0.032) compared to the primary group. A significant improvement in all PROs was observed for both groups with comparable PROs preoperatively and at 5-year follow-up between groups (P≥0.086). The revision and primary groups showed comparable MCID (95.0% vs. 95.7%, P=1.000), PASS (80.0% vs. 83.6%, P=0.757), and SCB (62.5% vs. 70.7%, P=0.603) achievement for any PRO. Comparable reoperation-free survivorship was observed (P=0.151).

Conclusion: Propensity-matched patients with BHD undergoing primary and revision hip arthroscopy for FAIS achieved similar minimum 5-year PROs, CSOs, and reoperation-free survivorship.

Level of Evidence: Level III, Retrospective Comparative Case Series