SLAP Tears (Superior Labrum Anterior-Posterior Tears)
The labrum surrounds the socket like a rubber ring or washer. Throwers often tear the labrum at the top of the socket (usually between 11:00 and 1:00 on clock face). The bicep tendon attaches to the labrum at the top and the pull of the bicep during the deceleration phase of the throw contributes to this injury.
…the labrum is subject to the highest stress during the deceleration phase.
I recently co-authored a paper published in the American Journal of Sports Medicine in March 2005 examining this using computer modeling of throwing and found that the labrum is subject to the highest stress during the deceleration phase. Other studies indicate that the labrum may be “peeled off” during the cocking phase. In truth, it probably happens through a combination of the motions pulling back and forth on the superior labrum. Once the labrum as partially detached, it may progress to the point that is painful to throw. Most often this pain is behind the shoulder during the cocking phase and possibly as the thrower “finishes” his throw. The detachment of the labrum can increase the instability of the shoulder and increase the strain on the rotator cuff. This can contribute to tearing of the rotator cuff, adding to the problem. If the cuff begins to tear, this is a bad sign and surgery is often needed. If the pain is too great, even without a cuff tear, surgery may be needed if therapy does not provide enough relief.
For additional information on these injuries to the labrum, please visit my website at www.DrLintner.com.
Like the rotator cuff, the bicep tendon helps stabilize the shoulder and is under tremendous stress with throwing. It may get inflamed or even torn from repetitive throwing. The pain is usually in front of the shoulder. Bicep exercises with weights don’t always reproduce the pain even if the bicep is partially torn. The usual sign is pain with throwing. It is difficult to see on MRI scans. If rest doesn’t resolve the problem, surgery is needed. Sometimes the surgery involves reattachment of the superior labrum (SLAP tear) if that portion of the labrum has detached. Sometimes the tendon itself needs to be reattached in a different location. In some athletes, the tendon is simply released. Which operation is performed is determined by what the structural damage is and the athlete’s preferences.