Influence of fatty degeneration on functional result of endoscopic gluteus medius repair

Abstract

Purpose To report the early outcomes of endoscopic repair of partial and full thickness tears of the gluteus medius tendon and to determine whether the fatty degeneration had an influence on clinical results. Methods Between October 2012 and June 2014, data was prospectively collected and retrospectively reviewed for all patients undergoing endoscopic gluteus medius repair. Patients were assessed pre- and postoperatively using the modified Harris Hip Score, the Non-Arthritic Hip Score and Visual Analogic Scale for pain. Gluteus minimus and the 3 distinct parts of the Gluteus medius (Anterior, Middle and Posterior) were assigned a grade of fatty degeneration on preoperative magnetic resonance imaging scans. Results Twenty-two hips (in 20 patients) were assessed with 31.7 months mean follow-up (range: 24 to 47 months). No patient was lost to follow-up. The mean age at the time of surgery was 66 years (range: 45 to 82 years). Of the 20 MRI assessed hips included in the study, fourteen hips (70 %) had fatty degeneration of gluteus medius. Mean gluteus medius fatty degeneration index was 1.57 (range: 0.33 to 3.33). Postoperative improvement was seen in mHHS (33.7 points vs. 80.2 points, P = 0.0001), NAHS (47.7 points vs. 76.8 points, P = 0.0001) and in the visual analog scale for pain (7.2 vs. 3.2, P > 0.05). Increasing preoperative fatty degeneration index of the Gluteus medius correlated with decreased postoperative functional hip score values (regression coefficient, 0.5839; P > 0.0001). Conclusions This study suggests that endoscopic surgical repair can be an effective treatment of gluteus medius tears in the short term. Fatty degeneration of gluteus medius and minimus has a negative impact on clinical outcomes of endoscopic gluteus medius repair. Level IV, therapeutic case series (no control group).