EP1.74 Femoral Derotation Osteotomy With or Without Arthroscopy is Associated With Superior Outcomes Compared with Isolated Hip Arthroscopy in Excessive Femoral Anteversion

Abstract

Abstract Background There remains no consensus regarding the threshold at which femoral derotation osteotomy (FDO) should be performed instead of hip arthroscopy (HA) in patients with excessive femoral anteversion (EFA) presenting with features of both instability and impingement. Additionally, the role of combining HA with FDO to address residual impingement after derotation remains unclear. The purpose of this study was to compare patient-reported outcomes among patients with EFA undergoing isolated FDO, isolated HA, and combined FDO+HA. Methods An institutional hip preservation registry was queried for patients ≤60 years old with femoral version >20° on preoperative computed tomography and minimum 1-year follow-up. Patients underwent isolated FDO, isolated HA, or combined FDO+HA. Patients with acetabular dysplasia (lateral center-edge angle ≤18°) or prior/concomitant periacetabular osteotomy were excluded. The primary outcome was change in modified Harris Hip Score (mHHS). Rates of achievement of minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptom state (PASS) were evaluated. Continuous variables were compared using ANOVA or Kruskal–Wallis tests with appropriate post hoc analyses, and categorical variables using chi-square tests with Bonferroni-adjusted pairwise comparisons (p < 0.017). Results A total of 199 patients (FDO: 66, FDO+HA: 27, HA: 106), predominantly female (71.4%) and aged 25.6 [19, 34.9] years with a median follow-up of 1.4 [1, 2.3] years were included. Preoperatively, femoral version was greater in the FDO (39.0°) and FDO+HA (38.0°) cohorts than in the HA cohort (25.0°) (p < 0.01), whereas alpha angle was higher in the HA cohort (65.0° vs 59.2° and 58.6°, respectively; p < 0.01). Despite lower baseline mHHS in the FDO cohort (59.2 vs 64.9 (both cohorts), p = 0.02), improvement in mHHS was greater in the FDO (29.2) and FDO+HA (24.7) cohorts compared with HA (20.9, p < 0.01), with no difference between FDO and FDO+HA. MCID achievement was similar between FDO and FDO+HA (95.5% vs 88.9%), but lower in the HA cohort (79.1%, p < 0.01). SCB achievement also differed across groups (74.2% vs 74.1% vs 57.1%; p = 0.04). PASS achievement was highest in the FDO+HA cohort (70.4%) compared with FDO (65.2%) and HA (55.2%), without statistically significant differences. Conclusion In patients with excessive femoral anteversion, femoral derotation osteotomy, with or without hip arthroscopy, results in greater clinical improvement compared with arthroscopy alone. Despite similar rates of achieving an acceptable symptom state, the magnitude of improvement was higher in the derotation cohorts, supporting correction of version-driven instability as a key determinant of outcomes. These findings emphasize the importance of dominant pathology-based surgical decision-making.