EP1.25 Three-Dimensional Coverage Analysis Can Help Predict Short-Term Outcomes Following Hip Arthroscopy for Borderline Hip Dysplasia

Abstract

Abstract Introduction The role of isolated hip arthroscopy for patients with borderline hip dysplasia [BHD; lateral center edge angle (LCEA) 19-25] remains an ongoing topic of debate. Our previous study has identified the low-volume acetabulum (LVA) morphology, defined as an acetabular coverage of <51.5%, as a possible variant of dysplasia. The primary purpose of the present study is to compare short-term patient-reported outcomes measures (PROM) in patients with BHD undergoing primary hip arthroscopy for femoroacetabular impingement (FAI) with concomitant LVA compared to a control group of BHD patients without LVA. Methods Data was reviewed for patients with BHD who underwent primary hip arthroscopy for FAI between December 2019 and November 2022. Patients were eligible for inclusion in the study if they had preoperative 3D imaging and minimum 2-year follow-up or a documented endpoint. Patients were excluded from the study if they had previous ipsilateral hip surgery or a previous hip condition. Functional outcome scores and reoperation rates were compared between the two groups. Results A total of 54 patients with BHD were included in the study, 37 in the LVA group and 17 in the non-LVA group. The groups were comparable with regards to patient demographics, intraarticular pathology, and surgical procedures (p > 0.05). Notably, there were significant differences in LCEA (23.6 vs 22.5) and Tonnis Angle (10.9 vs 13.8) on the preoperative CT scans between the normal coverage and LVA group. Both groups saw significant improvement from the preoperative timepoint to 2-year follow-up, however, the non-LVA group tended to have higher postoperative scores, and the LVA group saw significantly lower improvement in VAS pain scale as well as lower satisfaction. Furthermore, the LVA group had a 3.2-fold (95% CI: 0.4-24.1) relative risk of revision surgery with 7 (18.9%) major revision surgeries compared to 1 (5.9%) in the normal coverage group. Conclusion Although BHD patients in the LVA group demonstrated significant improvement across all PROs, they tended to have lower postoperative scores and a 3.2-fold (95% CI: 0.4-24.1) relative risk of revision surgery (18.9% vs 5.9%). These findings emphasize the importance of 3-D hip modeling preoperatively, as well as further support that LVA morphology impacts outcomes following isolated hip arthroscopy for subjects with radiographic borderline dysplasia.