Growth Factorsfor Rotator Cuff Repair

regenerated. Normally, the rotator cuff inserts into bone through 4 distinct transition zones: tendon, unmineralized fibrocartilage, mineralized fibrocartilage, and bone. Af-ter repair, the tendon heals to bone with an interposed layer of fibrovascular scar tis-sue that persists (Fig. 2A and B).7–9 The mechanical properties of this fibrous tissue are weaker than the native insertion site and may render repairs prone to failure