Time zero stability immediately after the rotator cuff repair is important, however, contemporary research has also focused on the cascade that influences biologic healing of these rotator cuff repairs and if augmentation can improve functional results. Specifically, various authors have looked at the cytokines, growth factors and stem cells involved in the process. The question remains of what role these factors play and whether there are techniques that can facilitate their use and improve healing of rotator cuff repairs. Data exists in a animal models that does show that some of these growth factors can improve tendon healing.