Tendon induce endothelial cell proliferation and migration, and VEGF mRNA has been shown to be expressed at the site of tendon injuries along with collagen I mRNA. Bone morphogenetic proteins (BMPs) are a subgroup of TGF-β superfamily that can induce bone and cartilage formation as well as tissue differentiation, and BMP-12 specifically has been shown to influence formation and differentiation of tendon tissue and to promote fibrogenesis. In animal models, extensive studies have been conducted to investigate the effects of mechanical strain in the form of activity level on tendon injury and healing. While stretching can disrupt healing during the initial
Tendon transfer or positional transfers. Power transfers are done to perform motion, and therefore requires relatively more powerful donor muscles. Positional transfers, on the other hand, do not require powerful donors. The strength of the antagonist muscle should be similar to the donor to avoid overcorrection and to maintain correct posture. Tendon excursion, or distance a tendon travels upon movement, should be similar to that of the recipient to adequately restore the function. Any transfer of a tendon for another function will generally lose one grade of power. For example, M4 muscle power grade will become M3. A single tendon should be