The grade of preoperative subscapularis muscle atrophy as a prognostic factor for postoperative retears: A double-center retrospective series

The aim of the study was to investigate whether subscapularis muscle atrophy is a negative prognostic factor leading to increased risk of retears in patients treated with an arthroscopic subscapularis tendon repair. We hypothesized that fatty infiltration of the subscapularis muscle deteriorates the clinical and sonographic outcome of the arthroscopic repair and inhibits reparability of the ruptured tendons. A double- center, multinational, retrospective, blind (in the follow-up) clinical study regarding 32 patients who underwent an arthroscopic subscapularis repair was conducted. Patients were divided into two groups according to the preoparative fatty infiltration grade of subscapularis muscle (group A: grade<II, group B: grade II or higher). Reparability was not influenced by the grade of preoperative fatty infiltration of subscapularis muscle. The preoperative MRI scans showed significantly higher grades of fatty infiltration (group B) in the subscapularis muscle of patients with clinical evidence of retear after the arthroscopic repair. Low grades of preoperative subscapularis muscle atrophy are significantly correlated with low clinical and sonographic retear’s rate after subscapularis arthroscopic repair, while high grades were a clear negative prognostic factor for the clinical outcome of the aforementioned patients.