EP1.86 Identifying Independent Radiographic Predictors of Failure in Young Females with Borderline Hip Dysplasia Undergoing Contemporary Hip Arthroscopy

Abstract

Abstract Background Hip arthroscopy, predominantly performed in females, has previously shown favorable outcomes in appropriately selected patients with borderline hip dysplasia (BHD). However, select dysplastic populations may demonstrate inferior outcomes, and management of this population remains controversial. Identifying radiograph parameters that predict suboptimal outcomes may be of utility in preoperative patient work-up. Methods Female patients ≤30 years old (mean=21.0±4.7) who underwent hip arthroscopy between 1/2015-3/2019 with mean 5-year follow-up were identified and had BHD (lateral center-edge angle [LCEA] = 18.0-25.0°). Cohort-specific patient acceptable symptom state (PASS) thresholds were determined from the cohort. Patients who failed to achieve PASS for any patient reported outcome (Hip Outcome Score [HOS] - Activities of Daily Living, HOS-Sports Specific Subscale, 12-Item International Hip Outcome Tool, Visual Analog Scale for Pain) or underwent any reoperation were deemed clinical failures. Patient characteristics were compared using univariate analyses. Radiographic parameters that were significantly different between failures and non-failures were included in multivariate logistic regression with least absolute shrinkage and selection operator (LASSO) elimination. Results A total of 105 patients were included, 28 of which were clinical failures (n=16 PASS non-achievement, 4 revision surgery, 1 total hip arthroplasty, 6 periacetabular osteotomy, 1 derotational femoral osteotomy). Clinical failures had a higher proportion of patients with symptom duration >2 years (42.9% vs. 18.2%; P=.020), lower external rotation (33.0±8.0° vs. 37.6±10.2°; P=.049), greater internal rotation (20.6±9.3° vs. 17.7±7.1°; P=.037), lower LCEA (21.6±1.8° vs. 22.4±2.0°; P=.035), greater Tönnis angle (12.3±4.2° vs. 10.5±3.9°; P=.046), greater femoro-epiphyseal acetabular roof (FEAR) index (-1.7±5.4° vs. -5.6±7.4°; P=.011), lower apical joint space width (JSW) (4.2±0.6 mm vs. 4.5±0.7 mm; P=.044), and a higher proportion of combined acetabular retroversion signs (crossover+posterior wall+ischial spine sign) (25.0% vs. 6.5%; P =.014). FEAR index (OR=1.1; P=.019), apical JSW (OR=0.4; P=.041), and combined acetabular retroversion signs (OR=6.1; P=.013) were independent radiographic predictors of failures. Conclusions Young female patients with BHD undergoing hip arthroscopy that have clinical failure, compared to non-failures, have greater preoperative symptom duration, less acetabular coverage , reduced apical JSW, and radiographic evidence of acetabular retroversion. FEAR index, apical JSW, and combined acetabular retroversion signs are independent radiographic predictors of failure.