Tendon Degeneration in the Rotator Cuff

Overuse injuries of the rotator cuff are a significant source of pain and morbidity.1 Despite an aging population and documented associations between rotator cuff tears and increasing age, the pathogenesis of rotator cuff tendinopathy remains poorly understood.1-9 The natural history of rotator cuff tears is unfavorable, as these lesions fail to spontaneously heal and progress in size over time.10,11 This progression in tear size is accompanied by fatty infiltration and atrophy of the rotator cuff musculature and no evidence of reversal or repair of the degeneration process.12-14 Furthermore, recurrent tears after surgical repair remain a significant issue for large and massive tears, with documented failure rates ranging from 11% to 94%.15-19 While arthroscopic surgical techniques have considerably evolved, including the use of double-row repair to improve time-zero biomechanics, our understanding and ability to improve the biologic milieu for tendon-to-bone healing has lagged behind. This chapter reviews the current understanding of the pathogenesis and biology of rotator cuff tendinopathy and outlines various treatment modalities and future directions for research into biologic augmentation of tendon-to-bone healing after rotator cuff repair.