Younger Age, Capsular Repair, and Larger Preoperative Alpha Angles are Associated With Earlier Achievement of Clinically Meaningful Improvement Following Hip Arthroscopy for Femoroacetabular Impingement Syndrome
Purpose: The purpose of the study was to analyze demographic, radiographic, and intraoperative factors that influence the time to achieve the minimal clinically important difference (MCID) and maximum outcome improvement satisfaction threshold (MOIT) after primary hip arthroscopy for femoroacetabular impingement syndrome (FAIS) and labral tear.
Methods: Included patients had undergone hip arthroscopy with labral repair or reconstruction for FAIS with labral tear between February 2008 and October 2018. Patients were excluded if they had a prior ipsilateral hip surgery, prior hip conditions, a Tonnis grade > 1, or were unwilling to participate. Multiple demographic, radiographic, and intraoperative variables were collected. The modified Harris Hip Score (mHHS) and Non-Arthritic Hip Score (NAHS) were collected before surgery and at 3 months, 1 year, and 2 years after surgery. The MCID and MOIT for the mHHS and NAHS were either calculated or determined through previously published values. A time-to-event analysis was performed to determine variables predictive of early or delayed achievement of MCID or MOIT. Early achievement was defined as achieving MCID or MOIT at the 3-month timepoint.
Results: Six hundred thirty-two hips (632 patients) were included. Of those that achieved MCID and MOIT, 428 (73.0%) and 414 (73.0%) patients achieved MCID and 253 (47.9%) and 264 (52.5%) patients achieved MOIT by 3 months after surgery for mHHS and NAHS, respectively. Younger age, capsular repair, and increasing alpha angle were associated with earlier achievement for either MCID or MOIT. Increasing age, worker's compensation claims, and higher baseline patient-reported outcome measure scores were associated with delayed achievement for either MCID or MOIT.
Conclusions: Most of the patients who achieved MCID and MOIT for mHHS and NAHS did so by 3 months after surgery. Younger age, capsular repair, and increasing alpha angle were associated with earlier achievement of MCID and MOIT after hip arthroscopy.