Irreparable rotator cuff tears: the impact of tear morphology on active shoulder function

Background Irreparable rotator cuff tears account for up to 40% of all rotator cuff tears. The clinical complaints vary as well as the injury morphology. Accordingly, this study investigates the influence of rupture morphology on active shoulder range of motion. Materials and methods In this multicenter study, 178 cases of irreparable rotator cuff tears were retrospectively examined. Tear morphology was determined by MRI and divided into anterosuperior and posterosuperior 2- or 3-tendon tears. Furthermore, tendinous injury was described in terms of tendon retraction, rupture extension, and fatty muscle degeneration. Active range of motion mobility was measured clinically. Results Three-tendon irreparable rotator cuff tears are associated with a higher limitation of abduction ability and, to a lesser extent, also flexion ability than 2-tendon irreparable rotator cuff tears. Hereby especially posterior located tears involving the teres minor tendon play a significant role for flexion and elevation limitation. Lesions of the subscapularis tendon significantly affect internal rotation, especially in 2-tendon ruptures. Ability to externally rotate does not correlate with tear morphology. Conclusion Abduction ability is related to the number of affected tendons. Here, the involvement of the teres minor tendon has a significant influence. Internal rotation ability is significantly influenced by subscapularis tendon lesion. In contrast, rotator cuff quality (muscle and tendon status) of the affected tear components was shown to be less relevant for active shoulder range of motion.