Mechanisms of fatty degeneration in massive rotator cuff tears.

Fatty degeneration of chronically injured muscle is a commonly recognized consequence of massive rotator cuff tears. Current surgical treatments are unable to alter or reverse the progression of fatty degeneration and are associated with poor functional outcomes in these patients. Therefore, a better understanding of the pathophysiology of fatty degeneration is required. As such, recent discoveries in stem cell biology and new animal models have significantly advanced our understanding of the cellular and molecular basis of fatty degeneration. Future studies will facilitate development of novel treatments to prevent the progression of fatty degeneration and improve muscle regeneration in patients with massive rotator cuff tears.