Poster 221: Revision Hip Arthroscopy Outcomes at an Average 5 year Follow-Up: FAI and Capsular Complications

OBJECTIVES: Femoroacetabular impingement (FAI) has become an increasingly recognized diagnosis contributing to morbidity in the adolescent and young adult population over the past decade. Our ability to treat such pathology with hip arthroscopy has grown in parallel. As the number of hip arthroscopy cases performed annually continues to rise, so will the number of patients requiring revision surgery. Trending outcomes and indications for revision hip arthroscopy is essential to improve surgical techniques, facilitate accurate diagnoses and address pathology appropriately. The purpose of this study was to report outcomes for revision hip arthroscopy and assess if outcomes vary by indication. METHODS: A single-center hip preservation registry was reviewed to identify patients who underwent revision hip arthroscopy for the treatment of FAI between 2012 and 2019. Patient demographics and primary indications for revision hip arthroscopy were determined, patient reported outcomes were collected preoperatively and at an average follow-up of 5.2 years post-operatively. RESULTS: A total of 239 patients met inclusion criteria for this study. The top 4 primary indications for revision were: Residual FAI 67.8%, instability 14.6%, heterotopic ossification (HO) 4.6% and adhesions 4.2%, trends in indication did not vary over time. On average patients improved significantly from pre- to post-operatively in mHHS 20.4(95% CI: 16.6 - 24.1), HOS ADL 15.0 (95%CI: 11.9 -18.2), HOS SS 23.8 (95% CI: 18.8 – 28.9), iHOT-33 30.2 (95% CI: 26.0 – 34.3), p<0.001. Rates of achieving MCID varied from 62.9%-78.3%, SCB 44.9-56.6% and SCB by absolute value at final follow-up of 32.1-65.9%. In a subgroup analysis, significantly lower pre-operative function was noted in the instability cohort compared to the impingement cohort as measured by HOS SS only, p=0.004. Post-operatively this instability cohort demonstrated significantly worse outcomes as measured by mHHS, HOS ADL and iHOT33. Rate of re- revision arthroscopy was 6.4% and 8.7% of patients required THA or were planning soon. CONCLUSIONS: The most common indication for revision hip arthroscopy in the treatment of femoroacetabular impingement remains residual impingement. Capsular complications have significant consequence for function and may represent a subset of patients who demonstrate more dysfunction both before and after revision arthroscopy. Lastly, heterotopic ossification is third most common reason for revision hip arthroscopy underlining the importance of postoperative prophylaxis.