Rotator Cuff Tears
The rotator cuff is a group of four muscles (supraspinatus, infraspinatus, teres minor, and subscapularis) that work together to rotate the shoulder and to hold the humerus in the center of the glenoid socket. These muscles are small, and lie underneath the larger muscles of the shoulder such as the deltoid, trapezius, and pectoral muscles. They connect to the humerus via tendons. It is the tendon part of the rotator cuff that is usually inflamed or torn.
Rotator Cuff Tendonitis
Anytime a muscle / tendon is overworked, it will become inflamed. The rotator cuff is frequently inflamed in throwers, along with the bursa that sits on top of the cuff. This tendonitis and bursitis is usually not dangerous but can be painful. The diagnosis requires a physical examination by a qualified Sports Medicine physician, and occasionally an MRI. The MRI is actually to rule out more severe problems such as a rotator cuff tear. The treatment is usually relative rest (decreasing but not stopping activities), anti-inflammatory activities, and physical therapy. The idea is to allow the overworked cuff a chance to recover and heal, diminish the inflammation, and strengthen the cuff so it can better tolerate the activities in the future.
If the rotator cuff is overworked for a long time, it may start to fray or tear, just as a rope that is pulled too hard too many times may fray and tear. In the thrower it is rare for the cuff to suddenly tear through and through, but it can happen gradually. Usually, the pain gets too great to pitch long before the tear penetrates all the way through the cuff tendon. It is interesting that this fraying is not always painful. Sometimes it is the inflammation (rather than the fraying) that hurts. Most Major League pitchers will have some visible evidence of fraying of the rotator cuff on their MRIs, but this is not always painful! A thorough evaluation by an experienced shoulder physician is necessary to determine this. A MRI can tell us if the rotator cuff is frayed or partially torn, but it can’t tell us if that actually hurts! The history and physical examination are just as important in diagnosing a shoulder problem in a thrower.
Internal impingement is one of the problems seen in throwers’ shoulders. If the shoulder goes too far in ER/extension during the cocking phase (i.e. elbow behind the chest with the shoulder externally rotated), the rotator cuff will get pinched inside the shoulder (impinged internally) between the glenoid and humerus. This can result in some partial tearing of the rotator cuff which can progress to a serious tear. The internal impingement is made worse by an unstable shoulder, “SICK” Scapula, and also by loss of internal rotation (GIRD, see below). Since most of these risk factors can be addressed by physical therapy and improving throwing mechanics, surgery can be avoided if it is detected early enough.