A Comparison of Open and Endoscopic Repair of Full-Thickness Tears of the Gluteus Medius Tendon at a Minimum of 2 Years Follow-up

OBJECTIVES: Historically, tears of the gluteus medius tendon were repaired via an open approach yielding excellent outcomes. With the advent of hip arthroscopy, endoscopic techniques have been developed to repair abductor tears which have shown favorable early outcomes. The open technique may still be preferred for large tears with retraction (>4cm), but there is a paucity of data comparing open and endoscopic approaches. The purpose of this study was to compare the outcomes of open and endoscopic repair of full-thickness tears of the gluteus medius tendon. We hypothesized that the outcomes of the two approaches would be similar but that the open technique would have shorter surgical times. METHODS: Between March 2010 and June 2012, 1267 patients (1518 hips) undergoing a hip preservation procedure were prospectively entered into a registry. From this cohort, we identified 27 patients (30 hips) that had undergone repair of the gluteus medius tendon with a minimum of 2 years follow-up. Nine patients (9 hips) had an open repair and 18 patients (21 hips) had an endoscopic repair. Patient-reported outcome scores, including the Modified Harris Hip Score (mHHS), the Hip Outcome Score-Activity of Daily Living (HOS-ADL), and the Sport-specific Subscale (HOS-SSS) were obtained preoperatively and at 1, 2, and 3 years postoperatively. Surgery time was obtained using operating room records. The femoral neck shaft angle (FNSA) and lateral center-edge angle (LCEA) were measured on preoperative radiographs. Continuous and categorical variables were compared between endoscopic and open abductor repair patients using independent-samples t-tests and chi-square or Fisher's exact tests (as appropriate), respectively. Given the limited sample size, no adjusted or matched analyses were performed. RESULTS: The mean age (±SD) of the open and endoscopic groups was 62.0 ± 9.9 years and 51.6 ± 13.6 years respectively (p=0.05). There were 6 females (67%) in the open group and 17 females (94%) in the endoscopic group (p=0.09). Seven hips (78%) in the open group had varus necks (FNSA30°) compared to 15 hips (54%) in the endoscopic group (p=0.93). At a mean follow-up of 38.1 months (range, 24-87 months), there were large (> 35 points) and significant improvements (p0.8). One patient (11.1%) in the open group had a poor clinical outcome compared to 2 patients (11.1%) in the endoscopic group that required revision abductor repairs at 5 and 24 months respectively. The mean surgical time was 98.7 ± 21.3 minutes in the open and 122.0 ± 26.8 minutes in the endoscopic group (p=0.003). CONCLUSION: This study demonstrates that an open gluteus medius tendon repair results in a significant improvement in clinical outcome, that is similar to the scores seen after endoscopic repair. Varus femoral necks and acetabular overcoverage are common features of hips with abductor tears and may be useful diagnostic aids. The surgical time for an open technique is significantly shorter than the endoscopic technique. We recommend an open technique where an intra-articular hip arthroscopy is not required, or in those patients with large and retracted tears.