FP6.2 Pre-Operative Acetabular Cysts are Associated with Inferior Outcomes in Hip Arthroscopy for Femoroacetabular Impingement Syndrome at 15-year Follow-up

Abstract

Abstract ICLA06 - Finetuning FAI Surgery: Advanced Corrections and Avoiding Yatrogenic Instability, Auditorium A (BMCC Level 1), October 8, 2026, 14:00 - 16:00 Background Hip arthroscopy for femoroacetabular impingement syndrome (FAIS) in appropriately selected patients has been shown to yield favorable outcomes. Acetabular subchondral cysts typically reflect underlying chondral damage and may be associated with inferior surgical outcomes. Purpose The purpose of this study is to compare 15-year outcomes of patients with and without isolated subchondral acetabular cysts undergoing hip arthroscopy for FAIS. It is hypothesized that patients with acetabular cysts will demonstrate lower patient-reported outcomes and increased conversion to total hip arthroplasty. Methods A retrospective review was performed of patients who underwent primary hip arthroscopy for FAIS by a single surgeon between 2009 and 2012. Patient-reported outcomes were gathered at baseline and at 15 years using the Non-Arthritic Hip Score (NAHS) and modified Harris Hip Score (mHHS). Patients were categorized based on the presence of acetabular cysts on pre-op MRI as noted by radiology reports. Included patients underwent primary hip arthroscopy, preoperative MRI, and had a minimum of 14.5-year follow-up. Patients with acetabular cysts were matched 1:4 with patients without cysts, while also matching for sex, age, BMI, Kellgren-Lawrence grade, and preoperative lateral center edge angle (LCEA). 15-year outcomes were compared between the two groups, and linear regression models were run to determine the relationship. Results In the matched cohort of 45 patients, 15-year NAHS and mHHS scores were similar between those with and without acetabular cysts (p = 0.16, p = 0.141), with significantly better change scores in those without acetabular cysts (p = 0.038, p = 0.006). Rate of conversion to total hip arthroplasty was significantly higher in patients with acetabular cysts (22.2% versus 2.8%, p = 0.041). Baseline-adjusted linear regression demonstrated that presence of an acetabular cyst was independently associated with lower 15-year mHHS (β = –15.3; p = 0.015) and increased rate of conversion to THA (β = 0.194; p = 0.037) Conclusion Patients with subchondral acetabular cysts on preoperative MRI demonstrated significantly less improvement in patient-reported outcomes and increased rate of conversion to total hip arthroplasty, 22% versus 2%. Even though the change in patient-reported outcome scores was lower, the overall 15-year outcome scores were comparable.