Arthroscopic Treatment of Femoroacetabular Impingement in Adolescents Provides Clinically Significant Outcome Improvement

Abstract

To define minimal clinically important difference (MCID) and substantial clinical benefit (SCB) for adolescents undergoing arthroscopic femoroacetabular impingement (FAI) surgery. A prospective institutional hip preservation registry was reviewed to identify hip arthroscopies performed for FAI. Patients with pre-existing hip conditions such as slipped capital femoral epiphysis and Legg-Calve-Perthese were excluded. Included patients were 18years and younger. The modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the international Hip Outcome Tool (iHOT-33) were administered as part of the registry. MCID was calculated using a distribution-based method, and SCB was calculated using a physical function anchor question. Receiver operating characteristic analysis with area under the curve (AUC) was used for psychometric analyses. Forty-seven adolescents were identified. The majority of patients were female (n= 32, 68.1%) with a mean age of 16.5 (±1.1) years. The MCID (% achieving) for the mHHS, HOS activities of daily living (ADL), HOS Sport, and iHOT-33 was 9.5 (85%), 9.8 (79%), 12.1 (85%), and 10.7 (94%), respectively. Ninety-two percent of adolescents reported some form of improved hip physical ability on the anchor question. The following 1-year absolute outcome scores were significantly representative of an SCB state on the mHHS, HOS ADL, HOS Sport, and mHHS, respectively (AUC): 93.5 (0.79), 98.5 (0.84), 96.9 (0.81), and 85.9 (0.76). Adolescents undergoing arthroscopic FAI surgery achieve clinically significant outcome improvement. We found that the vast majority of adolescents achieve MCID on hip-specific patient-reported outcome tools. However, although adolescents readily achieve MCID, a considerable improvement in postoperative outcome score is often needed to perceive a substantial benefit (SCB). The available hip outcome tools may be subject to ceiling effects for measuring clinically significant outcome improvement in adolescents. Level IV, case series.