Clinically Significant Outcome Improvement After Hip Arthroscopy in Patients With Femoroacetabular Impingement Syndrome and Severe Femoral Torsion

Abstract

Background: The influence of femoral torsion on clinically significant outcome improvement after hip arthroscopy for femoroacetabular impingement syndrome (FAIS) has not been well-studied. Purpose: To quantify femoral torsion in FAIS patients using magnetic resonance imaging (MRI) and explore the relationship between femoral torsion and clinically significant outcome improvement after hip arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: Included were patients who underwent hip arthroscopy for FAIS between January 2012 and August 2018 and had 2-year follow-up and preoperative MRI scans containing transcondylar slices of the knee. Participants were categorized as having severe retrotorsion (SR; <0°), normal torsion (NT; 0°-25°), and severe antetorsion (SA; >25°) as measured on MRI. Patient-reported outcomes (PROs) included the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sports Subscale, modified Harris Hip Score, 12-item International Hip Outcome Tool (iHOT-12), and visual analog scale (VAS) for pain and satisfaction. Achievement of Patient Acceptable Symptom State (PASS) and substantial clinical benefit (SCB) were analyzed among cohorts. Results: Included were 183 patients (SR, n = 13; NT, n = 154; SA, n = 16) with a mean age, body mass index, and femoral torsion of 30.6 ± 12.1 years, 24.0 ± 4.4 kg/m2, and 12.55° ± 9.58°, respectively. The mean torsion was –4.5° ± 2.6° for the SR, 12.1° ± 6.8° for the NT, and 31.0° ± 3.6° for the SA group. There were between-group differences in the proportion of patients who achieved PASS and SCB on the iHOT-12, pain VAS, and any PRO (P