The outcomes and affecting factors after arthroscopic isolated subscapularis tendon repair

Background This study evaluated clinical outcomes for isolated subscapularis tendon tears treated by arthroscopic repair, the factors affecting clinical outcomes, and changes in tendon structural integrity using magnetic resonance imaging. Methods Between 2005 and 2013, 45 patients with isolated subscapularis tendon tears were enrolled from two institutions. Clinical outcomes were assessed using the pain visual analog scale, American Shoulder and Elbow Surgeons, and Simple Shoulder Test scores. We evaluated factors affecting clinical outcomes: trauma history, tear classification, sex, age, symptom duration, preoperative fatty infiltration grade, cross-sectional area (CSA), cranial-transversal diameter, and caudal-transversal diameter. Subscapularis tendon integrity and fatty infiltration grade were evaluated using magnetic resonance imaging. Results No complications occurred except for tendon rerupture in 1 patient. No significant changes in tendon structural integrity occurred except for those related to CSA. Tendon structural integrity was significantly different between tears less than one-fourth of the entire subscapularis tendon and those exceeding one-fourth. However, there were no statistically significant differences in clinical outcomes between the 2 types of tear. Age was significantly associated with clinical outcomes, including Constant, American Shoulder and Elbow Surgeons, and Simple Shoulder Test scores. Men experienced better outcomes than women in Constant and Simple Shoulder Test scores. As the postoperative period progressed, the difference in CSA, cranial-transversal diameter, and caudal-transversal diameter decreased to the point of no statistical significance. Conclusion Arthroscopic repair of isolated subscapularis tear provided significant functional improvements with a low rerupture rate. Age was significantly associated with clinical results.