Comparison of Clinical and Structural Outcomes by Subscapularis Tendon Status in Massive Rotator Cuff Tear

Abstract

Background: The subscapularis tendon is essential in maintaining normal glenohumeral biomechanics. However, few studies have addressed the outcomes of tears extending to the subscapularis tendon in massive rotator cuff tears.

Purpose: To assess the clinical and structural outcomes of arthroscopic repair of massive rotator cuff tears involving the subscapularis.

Study design: Cohort study; Level of evidence, 3.

Methods: Between January 2010 and January 2014, 122 consecutive patients with massive rotator cuff tear underwent arthroscopic rotator cuff repair. Overall, 122 patients were enrolled (mean age, 66 years; mean follow-up period, 39.5 months). Patients were categorized into 3 groups based on subscapularis tendon status: intact subscapularis tendon (I group; n = 45), tear involving less than the superior one-third (P group; n = 35), and tear involving more than one-third of the subscapularis tendon (C group; n = 42). All rotator cuff tears were repaired; however, subscapularis tendon tears involving less than the superior one-third in P group were only debrided. Pain visual analog scale, Constant, and American Shoulder and Elbow Surgeons scores and passive range of motion were measured preoperatively and at the final follow-up. Rotator cuff integrity, global fatty degeneration index, and occupation ratio were determined via magnetic resonance imaging preoperatively and 6 months postoperatively.

Results: We identified 37 retears (31.1%) based on postoperative magnetic resonance imaging evaluation. Retear rate in patients in the C group (47.6%) was higher than that in the I group (22.9%) or P group (20.0%) ( P = .011). Retear subclassification based on the involved tendons showed that subsequent subscapularis tendon retears were noted in only the C group. The improvement in clinical scores after repair was statistically significant in all groups but not different among the groups. Between-group comparison showed significant differences in preoperative external rotation ( P = .021). However, no statistically significant difference was found in any shoulder range of motion measurements after surgery.

Conclusion: Arthroscopic repair of massive tears results in substantial improvements in shoulder function, despite the presence of combined subscapularis tears. However, this study showed a high failure rate of massive posterosuperior rotator cuff tear repair extending more than one-third of the subscapularis tendon. When combined subscapularis tendon tear was less than the superior one-third of the subscapularis tendon, arthroscopic debridement was a reasonable treatment method where comparable clinical and anatomic outcomes could be expected.

Keywords: fatty degeneration; functional and structural outcomes; massive rotator cuff tear; rotator cuff; subscapularis tear; tendon integrity.