Rotator cuff injury

In high school my close friend who I played softball with tore one of her rotator cuff tendons.  She recieved injections of cortisone into the tendon.  I would make fun of her for taking steroids because cortisone is a type of steroid.  The cortisone provided her with some relief from the pain but it did not heal it.  Our rotator cuff is made up of muscles and tendons that give our arms a wide range of motion.  The muscles connect to the tendons which then connect your shoulder blade to the upper arm(see link below).  In class we learned how muscles do not touch the bone directly and they touch the bones through the tendons.  A tendon is formed out of three different types of collagen fibers coming together at the ends of muscles.  The epimysium fiber surrounds the whole muscle.  The perimysium surrounds the groups of muscle fibers known as a fascicle.  The endomysium surrounds the individual muscle fibers.  http://www.mayoclinic.com/health/rotator-cuff-injury/DS00192