Hip Arthroscopic Surgery for Femoroacetabular Impingement With Capsular Management: Factors Associated With Achieving Clinically Significant Outcomes.

BACKGROUND: There has been increasing interest in defining clinically meaningful outcomes in patient reported outcomes following orthopaedic surgery. Little is known about the factors associated with clinically meaningful outcomes after hip arthroscopy for femoroacetabular impingement.

STUDY DESIGN: Case-control study; Level of evidence, 3.

PURPOSE: To report on a large, prospectively collected consecutive series of patients who underwent comprehensive arthroscopic treatment of femoroacetabular impingement (FAI) and capsular management with greater than 2-year follow-up. The objectives were to determine (1) what percentage of patients achieve clinically significant outcomes after hip arthroscopic surgery for FAI as determined by the minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) and (2) what factors are associated with achieving the MCID and PASS.

METHODS: Data from an institutional repository of consecutive patients undergoing primary hip arthroscopic surgery with routine capsular closure for FAI that had failed nonsurgical management between January 2012 and January 2014 were prospectively collected and analyzed. Of 474 patients during the enrollment period, 386 (81.4%) patients were available for a minimum 2-year follow-up. Demographics, radiographic measurements, intraoperative characteristics, and patient-reported outcome scores were collected. The primary outcome measure was achieving published thresholds for the MCID and PASS for the Hip Outcome Score (HOS)-Activities of Daily Living (ADL) in patients with FAI. The HOS-Sport-Specific Subscale (SSS), complications, and reoperations were secondary outcome measures. Multivariate regression analyses were conducted to identify factors associated with achieving the MCID and PASS.

RESULTS: At a minimum of 2-year follow-up, the patients had statistically significant improvements in all patient-reported outcomes (HOS-ADL, HOS-SSS, and modified Harris Hip Score [mHHS]; P < .001 for all), with a 1.2% rate of revision hip arthroscopic surgery and 1.7% rate of conversion to total hip arthroplasty. The MCID was achieved by 78.8% of patients for the HOS-ADL, and the PASS was achieved by 62.5% for the HOS-ADL. Younger age ( P = .008), Tönnis grade 0 ( P = .022), and lower preoperative HOS-ADL score ( P < .001) were associated with successfully achieving the MCID for the HOS-ADL. Younger age ( P < .001), larger medial joint space width ( P = .028), and higher preoperative HOS-ADL score ( P < .001) were associated with achieving the PASS for the HOS-ADL. Younger age ( P < .001), lower body mass index ( P = .006), non-workers' compensation status ( P = .020), and lower preoperative HOS-SSS score ( P < .001) were associated with achieving the MCID for the HOS-SSS. Younger age ( P = .001), Tönnis grade 0 ( P = .014), running ( P = .008), and higher preoperative HOS-SSS score ( P < .001) were associated with achieving the PASS for the HOS-SSS. Overall, 49.4% of patients achieved all 4 clinically significant outcomes: both the MCID and PASS for the HOS-ADL and HOS-SSS.

CONCLUSION: The majority of patients undergoing hip arthroscopic surgery with routine capsular closure for FAI experienced clinically significant outcomes that met the MCID or PASS criteria, with low rates of revision and conversion to total hip arthroplasty. Factors associated with these successful outcomes on multivariate analyses included younger age with a normal joint space. Patients with lower preoperative HOS scores were more likely to achieve the MCID, whereas patients with higher preoperative HOS scores were more likely to achieve the PASS.