internal impingement syndrome

What is it?
The main tendon of the rotator cuff is called the supraspinatus. The muscles are the red and the tendons are the white structures attaching to the bone in this diagram, which you can also review on the anatomy page. The supraspinatus is the uppermost of the 4 tendons of the rotator cuff. During throwing, specifically during the follow-through phase of throwing, it can rub on the labrum, the red circle surrounding the socket in the third anatomy diagram. This causes the labrum to tear and the rotator cuff to fray. This is called internal impingement. It is thought to be made worse by anterior instability since anterior looseness allows the ball to slide too far forward and this brings the supraspinatus tendon into contact with the posterior-superior labrum.

What does this feel like?
This is causes pain during release, deceleration, and follow-through. Throwers lose pitch velocity and location, and endurance and thus can't throw as well or for as long.

How are they treated?
Nonoperative treatment is usually successful if this is diagnosed early, before complete tearing of the labrum or rotator cuff. This involves time away from throwing, anti-inflammatory medicines, physical therapy, and sometimes cortisone injections.

Operative treatment is required for tears that are through either the full thickness of the rotator cuff, or the labrum. It is sometimes needed for the few patients that do not get better with nonoperative treatment. It is arthroscopic surgery with very small skin incisions and many advantages over older open surgery techniques.

How long will I be out of throwing?
If nonoperative treatment is successful, about 3 months.
If surgery is required, about 9-12 months.