Open and Endoscopic Gluteus Medius and/or Minimus Repair Achieves Clinical Success Regardless of Tear Grade: High-Grade Fatty Infiltration Portends Worse Outcomes

Purpose: To evaluate minimum 2-year gluteus medius and/or minimus repair clinical success rates stratified by the 3-grade magnetic resonance imaging (MRI)–based classification (MRI grade) and to evaluate clinical success rates by the surgical approach used at each MRI grade and by the Goutallier-Fuchs (GF) classification. Methods: A retrospective review identified patients who underwent primary endoscopic or open gluteus medius and/or minimus repair from 2012 to 2021 performed by a single surgeon. Preoperative MRI scans were classified using the MRI grade and GF classification. Patient-reported outcomes were collected preoperatively and at minimum 2-year follow-up. Cohort-specific minimal clinically important difference and patient acceptable symptom state achievement was recorded. Rates of clinical success, defined as achievement of the 2-year minimal clinically important difference or patient acceptable symptom state with avoidance of revision surgery, were compared by MRI grade, by surgical approach at each MRI grade, and by GF classification. Results: A total of 112 patients (71 with MRI grade 1, 19 with grade 2, and 22 with grade 3) were included. MRI grade 1 patients underwent endoscopic repair (P < .001) more often than the other groups. The overall clinical success rate was 90%. Clinical success rates by MRI grade were 93% for grade 1, 95% for grade 2, and 77% for grade 3 (P = .087). Clinical success rates by the endoscopic and open surgical approaches used at each MRI grade were 93% versus 90% for grade 1 (P = .543), 91% versus 100% for grade 2 (P > .999), and 60% versus 92% for grade 3 (P = .135). GF grade 1 tears achieved a higher rate of clinical success than GF grade 4 tears (100% vs 71%, P = .030). Conclusions: Primary repair of gluteus medius and/or minimus tears resulted in clinical success in most patients irrespective of MRI grade and irrespective of the surgical approach used at each MRI grade, yet GF grade 1 tears showed a significantly higher clinical success rate than GF grade 4 tears. Level of Evidence: Level IV, prognostic retrospective case series.