Teres Minor Fatty Degeneration Progression by Magnetic Resonance Imaging Analysis Is Associated With Graft Failure After Arthroscopic Superior Capsule Reconstruction

PURPOSE: To investigate risk factors, including rotator cuff fatty degeneration, for postoperative graft failure within 1 year after arthroscopic superior capsule reconstruction using a fascia lata autograft in shoulders with an intact or reparable subscapularis tendon. METHODS: Patients who underwent arthroscopic superior capsule reconstruction for massive or irreparable rotator cuff tears between June 2016 and December 2022, with a minimum 12-month follow-up, were retrospectively reviewed. Radiological evaluations included measurement of acromiohumeral distance and fatty degeneration of the rotator cuff muscles using the Goutallier classification. The Goutallier grades were classified into none-to-mild (grades 0-1) and moderate-to-severe fatty infiltration (grades 2-4). Graft integrity was assessed using the Sugaya classification on postoperative magnetic resonance imaging obtained 1 year after surgery, and patients were categorized into a nonfailure group (Group I) and graft failure group (Group GF). Univariate and multivariate logistic regression analyses were performed to identify the significant risk factors for graft failure. RESULTS: Eighty-seven shoulders were included: 70 in Group I and 17 in Group GF. The mean radiological follow-up (range) was 22.2 (12-72) in Group I versus 25.5 (12-65) months in Group GF (P = .163). Similarly, patient-reported outcome measure follow-up was 22.3 (12-48) versus 22.6 (12-47) months (P = .839). Group GF showed significantly greater fatty degeneration of the teres minor and a higher prevalence of moderate-to-severe fatty infiltration (58.8% vs 25.7%, P = .012). Multivariate logistic regression identified teres minor fatty degeneration and the preoperative acromiohumeral distance as risk factors for graft failure. Clinical outcomes improved significantly in both groups, although the magnitude was lower in Group GF. CONCLUSIONS: This study showed that moderate-to-severe fatty degeneration of the teres minor and a smaller preoperative acromiohumeral distance are significant risk factors for graft failure after arthroscopic superior capsule reconstruction in shoulders with an intact or reparable subscapularis tendon. LEVEL OF EVIDENCE: Level III, retrospective cohort study.