Gluteus Repair Yields Satisfactory Clinically Significant Outcome Achievement By One Year in Mostly Partial-Thickness Tears with Preoperative Hip Abduction Weakness Associated with Delayed Achievement.

PURPOSE: The purposes of this study were (1) to define the time to achievement of clinically significant outcomes (CSOs) following primary gluteus medius and/or minimus (GM) repair and (2) to identify factors associated with delayed CSO achievement.

METHODS: Patients who underwent primary GM repair between January 2012 and June 2021 with complete preoperative, 6-month, 1-year, and 2-year Hip Outcome Score - Activities of Daily Living (HOS-ADL) were retrospectively identified. Cohort-specific minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) were calculated. The time to achievement of MCID and PASS were analyzed using Kaplan-Meier survival analysis. Median time to MCID and PASS achievement were recorded. Multivariate stepwise cox regressions were used to identify factors associated with delayed CSO achievement.

RESULTS: Fifty GM repairs were identified (age 59.4 ± 9.7 years, BMI 27.9 ± 6.2 kg/m2 , 94% female). Tears were Grade 1 in 39 cases, Grade 2 in 7 cases, and Grade 3 in 4 cases. Endoscopic repair was performed in 35 cases, and open repair was performed in 15 cases. Labral debridement and repair were each performed in 15 cases. Median time to CSO achievement was 5.7 months for MCID and 11.0 months for PASS. The 2-year cumulative probability of MCID and PASS achievement was 92.7% and 66.7%, respectively. Preoperative hip abduction weakness on physical exam was associated with delayed achievement of MCID (Hazard Ratio (HR) = 2.27, Confidence Interval (CI) 1.067 - 7.41, p = 0.039) and PASS (HR= 3.89, CI 1.341 - 11.283, p = 0.012).

CONCLUSIONS: This study demonstrated that in patients undergoing repair of primarily Grade 1 GM tears, most achieved MCID by 6 months and over half achieved PASS by 12 months. Preoperative hip abduction weakness on physical exam was associated with delayed CSO achievement.

LEVEL OF EVIDENCE: Retrospective Case Series, IV.