The 4 fibrocartilagenous transition zones of the rotator cuff insertion site are not recreated following surgical repair. Instead, a layer of scar tissue is formed between the tendon and the bone, which makes repairs prone to failure. Growth factors are a group of cytokines that induce mitosis, extracellular matrix production, neovascularization, cell maturation, and differentiation. Research has focused on their ability to augment rotator cuff repairs. Studies have shown that several factors are capable of increasing the strength of repairs in animal models. However, this appears to be accomplished through the production of more scar tissue, as opposed to regeneration of native tissue. It is becoming clear that multiple factors may be needed to regenerate the native tendon-bone insertion site. The optimal timing and vehicle for growth factor delivery have remained elusive. Gene therapy and tissue scaffolds provide promising options for the future, but the engineering still needs to be optimized for clinical use. Growth factor therapy for rotator cuff repairs remains a promising therapeutic for the future; however, much work needs to be done to optimize its effectiveness.
