An intact subscapularis tendon and compensatory teres minor hypertrophy yield lower failure rates for non-operative treatment of irreparable, massive rotator cuff tears.

<bold>Purpose: </bold>To investigate whether subscapularis integrity and compensatory teres, minor hypertrophy is associated with maintaining relatively good function and tolerable pain levels during non-operative treatment.<bold>Methods: </bold>This study included 108 patients with irreparable, massive rotator cuff tears involving at least two tendons and stage III or IV muscle hypotrophy and fatty infiltration on oblique sagittal magnetic resonance imaging, in which even a partial repair does not seem feasible. All supraspinatus and infraspinatus muscles were grade IV; if the subscapularis was involved, only stage III or IV was included. Patients were divided into two groups: group A consisted of 67 patients with both an intact subscapularis and teres minor hypertrophy; group B consisted of 41 patients lacking either one or both. The Visual Analogue Scale pain score, the American Shoulder and Elbow Surgeons score, the University of California at Los Angeles shoulder score, and active range of motion (ROM) were assessed.<bold>Results: </bold>During the follow-up period, failure of non-operative treatment was found in 29 (43%) patients in group A and 28 (68%) in group B (p = 0.012). Conversion to surgery was noted in 26 (39%) patients in group A and 27 (66%) in group B (p = 0.006). Among the remaining nonsurgical patients, there were no significant differences in clinical outcomes between the groups except ROM in internal rotation at final follow-up.<bold>Conclusions: </bold>Although conservative treatment was not always successful in patients with irreparable, massive cuff tears, patients with both an intact subscapularis tendon, and teres minor hypertrophy experienced significantly lower incidences of failure and conversion to surgery, since force couple is maintained in the setting of minimal arthritis.<bold>Level Of Evidence: </bold>III. [ABSTRACT FROM AUTHOR]