Architectural gear ratio and their accompanying tendons. These muscles form a cuff around the glenohumeral joint and function to stabilize and manipulate the shoulder. The pennation angle of the rotator cuff myofibers, the angle at which fibers connect to the associated tendon, affects the contractile properties and function of the whole pennate muscle. For example, the pennation angle determines the architectural gear ratio at which a pennate muscle operates. A large initial pennation angle results in a large AGR and velocity amplification. A 2011 study on human cadaveric shoulders suggests tendon tears may affect the pennation angle of the rotator cuff muscles. Researchers
Rotator cuff tear which they use grafted tissues rather than stitching to reconnect tendon segments. This can result in a complete repair. Other options are a partial repair, and reconstruction involving a bridge of biologic or synthetic substances. Partial repairs typically are performed on patients with retracted cuff tears. Two methods of promoting rotator cuff healing are injecting patients' own stem cells (or other growth factors) into the site of the repair, and installing scaffolds (natural or artificial supports that maintain tissue contour). The results of using PRP (platelet rich plasma) to augment the healing of rotator cuff repair at the time of