The etiology and assessment of subscapularis tendon tears: a case for subcoracoid impingement, the roller-wringer effect, and TUFF lesions of the subscapularis.

With the advent of arthroscopy and arthroscopic repair techniques, the diagnosis and treatment of subscapularis tears have been significantly advanced. The precise etiologic factors related to subscapularis tears remain unclear. We propose that subcoracoid stenosis and subcoracoid impingement cause a "roller-wringer effect" on the subscapularis tendon. This effect increases the tensile loads on the articular surface of the subscapularis tendon that may lead to tensile undersurface fiber failure (TUFF) of the subscapularis insertion. Collectively, these factors may in part contribute to the pathogenesis of subscapularis tears.