Does Femoral Anteversion Play a Role in the Pathomechanics and Subsequent Surgical Treatment of Femoroacetabular Impingement? (SS-44)

Abstract

Introduction While much attention has been given to variations in proximal femoral and acetabular anatomy in femoroacetabular impingement (FAI), less attention has been focused on the role of femoral version. We hypothesized that patients with significant variations in femoral version would have differing preoperative examinations and intraoperative hip pathology. The study purpose was to (1) describe values for femoral anteversion in FAI patients measured by MRI, (2) report the relationship between physical examination findings in patients undergoing hip arthroscopy for FAI and femoral version, and (3) report the relationship between increased and decreased femoral anteversion and intraoperative findings during hip arthroscopy. Methods After IRB approval was obtained, we retrospectively reviewed prospectively collected data on 188 patients (204 hips). Data analyzed included patient demographics, physical examination measurements, radiographic data, and intra-operative findings. Femoral version was measured on MRI by a fellowship trained musculoskeletal radiologist. Results The mean age of the patient population was 35 years (range, 18-62 years); 100 patients were males and 88 were females. Mean femoral version was 9 degrees (range, −10 to 27). No relationship was found between femoral version and patient demographics (age, gender, weight, height and BMI). There was a significant correlation between version degrees and external rotation and internal rotation degrees, respectively (r=−0.208; p=0.027 and r=0.231; p=0.002). Intra-operative findings demonstrated that femoral version greater than 15 degrees was related to larger labral tears; patients with anteversion greater than 15 degrees had a mean tear size of 38mm, while patients with less than 5 degrees of anteversion had tear sizes of 30mm and patients with angles between 5 and 15 degrees had tear sizes of 34mm (p=0.008). Hips with femoral version greater than 15° were 2.2 times more likely (95% CI: 1.2 to 4.1) to have labral tears that extended beyond the 3 o'clock position (normalizing all hips as right hips), denoting more anterior tears. Patients requiring a psoas release were more likely to have higher version angles (8 vs. 11 degrees, p=0.023). Conclusion Femoral neck version angles are similar between FAI patients and the normal population. Patients with increased anteversion may be more likely to develop “psoas impingement” causing larger labral tears that extend more anteriorly and frequently require a psoas release. Femoral version plays a role in FAI pathomechanics and should be taken in consideration during treatment planning.