Defining Minimal Clinically Important Difference After Open Hip Abductor Repair

BACKGROUND: Open repair for gluteus medius and minimus tears is a common surgical treatment for patients with lateral hip pain associated with abductor tears; however, clinically meaningful outcomes have not been described after open surgical treatment. PURPOSE: To define the minimal clinically important difference (MCID) in patient-reported outcome measures (PROMs) in patients undergoing open gluteus medius or minimus repair, and to identify preoperative patient characteristics predictive of achieving MCID postoperatively. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective review of prospectively collected data from a consecutive series of patients undergoing open abductor repair between July 2010 and April 2019 was conducted. Perioperative patient data collected included patient characteristics and preoperative and postoperative modified Harris Hip Score (mHHS) and International Hip Outcome Tool (iHOT-33) score. Paired t tests were utilized to compare preoperative and postoperative PROMs and MCID was calculated for both PROMs. Multivariate logistical regression analysis was used to assess the association between preoperative variables and the likelihood for achieving MCID. RESULTS: A total of 47 patients were included in the study. The majority of patients were female (78.7%), with an average age of 63 ± 10.7 years. The average follow-up for both the mHHS and the iHOT-33 surveys was 37.8 ± 27.9 months (range, 10-102 months). Patients demonstrated statistically significant improvements on the mHHS and iHOT-33 postoperatively (P < .001 for both). The MCIDs of mHHS and iHOT-33 were calculated to be 9.9 and 14.3, respectively. Overall, 82.9% of patients achieved MCID for mHHS and 84.1% of patients achieved MCID for iHOT-33 postoperatively. Multivariate logistical analysis demonstrated younger patients were less likely to achieve MCID for both outcome measures. Four patients (8.5%) suffered postoperative complications after open repair. CONCLUSION: This study defined MCID for mHHS and iHOT-33 for patients undergoing open repair of hip abductor tears, with a large percentage of patients (>80%) achieving meaningful outcomes for both outcome measures. There was a low complication rate. Younger patients were less likely to achieve MCID compared with older patients.