In order for the shoulder to generate the high torque necessary to throw hard overhand, the arm must rotate externally, bringing the hand behind the body like the end of a whip. This position tends to lever the ball (humerus) off the front of the socket (glenoid). If the ball slides too far to the front (anterior), the shoulder is unstable. Even though the humerus rarely slides off the glenoid, any movement off-center may be painful.
Most of the time, therapy can address the painful shoulder in thrower's--treating such problems as scapular dysfunction and GIRD-glenohumeral internal rotation deficit. SICK Scapula responds well to a rehabilitation program, but often requires the help of a therapist skilled in caring for throwers. Some of the exercises can be done on your own, but some need the supervision of a therapist. The exercises focus on stretching the posterior capsule (behind the shoulder) and strengthening the scapular rotator muscles. However, this requires not just simple strengthening but also re-training of the muscles so that they get out of the habit of moving the scapula incorrectly. Similarly, loss of internal rotation predisposes throwers to shoulder injuries such as labral tears and rotator cuff tears.
When therapy is not successful,superior labral tears, internal rotation deficits, partial cuff tears and subtle anterior laxity can be addressed arthroscopically. This may include SLAP repair, PASTA debridement, Posterior capsular release and occasional anterior capsular plication/rotator interval plication.
