Clinical and structural results of arthroscopic repair of isolated subscapularis tear.

BACKGROUND: Even though the frequency of arthroscopic repair of isolated lesions of the subscapularis tendon has increased, few studies have presented clinical and anatomical outcomes of this treatment. We hypothesized that, after an arthroscopic repair, structural outcomes in the muscle have an influence on functional results.

METHODS: A retrospective study was performed on twenty-two patients who had undergone arthroscopic repair of an isolated tear of the subscapularis tendon and had a mean follow-up of thirty-six months. Patients were evaluated preoperatively and postoperatively with use of the Constant-Murley score, a subjective shoulder value, the lift-off test, the belly-press test, and magnetic resonance imaging or computed tomography arthrography. The results were compared with those of a cohort of thirteen patients who underwent open repair of the subscapularis tendon tear.

RESULTS: In the arthroscopic group, the Constant-Murley score improved from a mean of 66 points preoperatively to a mean of 85 points postoperatively (p < 0.05). The subscapularis tendon was healed in 86% of the patients. Three patients (14%) had a partial rupture limited to the superior tendon. Postoperatively, progression of fatty infiltration of the subscapularis muscle was observed in 55% of the patients. Ten patients (45%) had a severe but localized fatty infiltration area of the subscapularis muscle related to the larger tears. Subjective and functional outcomes were not influenced by tendon-healing or postoperative fatty infiltration (p > 0.05). Clinical testing was significantly improved, but incomplete corrections remained frequent. Although open repair resulted in higher subjective shoulder scores and better strength scores, most other clinical parameters, postoperative subscapularis testing results, and structural outcomes were comparable between the arthroscopic repair and the open repair group.

CONCLUSIONS: Arthroscopic repair of isolated subscapularis tears was associated with improved shoulder function and improved results on clinical testing. The tendon-healing rate was high but resulted in incomplete correction of the results of clinical testing. Progression of fatty infiltration in the subscapularis muscle was observed on magnetic resonance imaging but did not influence the clinical outcomes.