55 y/o man reports with 3 weeks of right shoulder pain. He is a contractor and states he was lifting a piece of wood when he felt a sharp pain in his right shoulder. He relays minor aches and pains in his right shoulder over the last few years. Following a set of provocative tests, he is scheduled for an ultrasound. A few days later the ultrasound shows a possible tear in his supraspinatus tendon, an MRI confirmed the result and he elected to treat his tear with PRP injections.
Rotator cuff tears have an incidence in the general population of approximately 16% to 34% with the likelihood increasing as you age. They are one of the most common causes of acute and chronic shoulder pain.  The rotator cuff is made up of 4 separate muscles that are responsible for holding the shoulder joint in place and moving the arm in several directions. A rotator cuff tear can include 1 or many of the muscles in the group and can be a partial or complete tear. The rotator cuff is assessed first by a series of provocative tests that will include the physician placing your shoulder in several different positions and any reproduction of pain counting as a positive test.
A positive test signals a need for imaging to determine location and degree of tear. Ultrasound provides a fast and non-invasive way to determine if there is a tear and the approximate location. A positive ultrasound scan will typically lead to an MRI to properly assess the exact location and degree of tear that will help guide treatment options. Options can include the use of nonsteroidal anti-inflammatory drugs and physical therapy referral, trial of steroid injections, PRP injections or referral to an orthopedic surgeon.
Treatment options should be explored, and decisions made based on recommendations and patient preference. PRP injections are less invasive than surgery have been shown to be effective for partially torn rotator cuff tendons. They can lead to significant improvements in both pain and functionality at the shoulder joint. 
 Graham, P.Rotator Cuff Tear, Orthopedic Nursing: March/April 2018 – Volume 37 – Issue 2 – p 154-156.