Meaningful Clinical Improvement and Failure Rates 5 years Following Hip Arthroscopy in Adolescents

Abstract

To define hip-specific survey score thresholds for achieving minimal clinically important difference (MCID) in the adolescent population, and identify rates of clinical success and failure 5-years after undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Data from consecutive adolescent patients (age≤21) who underwent hip arthroscopy for the treatment of FAIS between January 2012 and April 2014 were collected. Baseline data, clinical outcomes including Hip Outcome Score–Activities of Daily Living (HOS-ADL), HOS–Sports Subscale (HOS-SS), modified Harris hip score (mHHS), international Hip Outcome Tool (iHOT-12), and clinical failure rates were recorded at 5-years postoperatively. Clinical failure was defined by revision hip arthroscopy or conversion to total hip arthroplasty (THA). Clinical success was defined as achieving MCID on a hip specific outcome measure at five-year follow-up. A total of 67 patients were included in the final analysis, with an age and BMI average of 17.2(SD+2.2) years and 22.1(SD+3.1) kg/m2 respectively. The majority of the patients were female (80.6%) and participated in sports (86.9%). The HOS-ADL, HOS-SS, mHHS, and iHOT-12 threshold scores for achieving MCID were 9.5, 13.5, 9.6, and 15.1 respectively. There was significant difference between preoperative and postoperative score averages across every reported outcome (p<0.001). Sixty patients (89.6%) had maintained clinically successful outcome at a minimum of five years; five patients had clinical failure, with two (2.9%) undergoing conversion to THA and three undergoing revision (4.5%). Both patients undergoing THA conversion had a history of pediatric hip pathology (SCFE and Perthes), and underwent conversion due to significant osteoarthritis. This study demonstrated that a majority (89.6%) of pediatric patients treated for symptomatic FAIS with hip arthroscopy achieved MCID. Furthermore, a small number of patients had clinical failure, with 4.5% requiring revision hip arthroscopy due to continued pain and 2.9% undergoing THA conversion due to complications from pre-existing pediatric hip pathology.