The labrum is a ring of tissue around the cup of the shoulder joint. It helps keep the ball of the joint centered in the cup. During sports or after an injury, a person can dislocate the shoulder joint and tear the bottom of the labrum. A tear at this location is often called a Bankart tear. If the labrum does not heal, the shoulder can remain unstable, and the ball of the shoulder can dislocate during simple activities.
The labrum is also where the biceps tendon attaches to the shoulder joint. Repetitive activities, like throwing a baseball, put a lot of stress on the biceps tendon, which can lead to tears on the top of the labrum. Tears at this location, called SLAP (Superior Labrum from Anterior to Posterior) tears, are painful, while tears on the bottom of the labrum usually cause shoulder instability, but not pain.
Another type of tear of the labrum is a degenerative tear. This type of tear occurs as we age, but it usually does not cause pain. Studies show that patients with degenerative tears usually have normal shoulder function. Based on this information, a tear of the labrum does not always need to be repaired. The decision whether or not to repair the labrum is complex and requires a complete evaluation by a surgeon.
An MRI should be used to confirm the diagnosis of a labrum tear. Some doctors inject a dye into the shoulder joint in order to see the tear more clearly. The dye surrounds the labrum, making the outline of the tissue easier to see. If the MRI shows a tear but the patient's history or physical exam is inconsistent with a labrum tear, then the doctor may inject the shoulder joint with lidocaine, a local anesthetic, to determine whether the labrum is the source of the pain.
A torn labrum does have the potential to heal. Physical therapy can help, especially if the patient has pain rather than instability of the shoulder joint. Surgery for pain should be considered if a minimum of 8 weeks of physical therapy does not lessen the discomfort. Surgery for instability can be considered right away if the labrum tear occurred after a shoulder dislocation. SLAP tears can be treated by either repairing the labrum or reattaching the biceps tendon outside of the shoulder joint. The treatment varies depending on the patient's age. If the patient is 40 or older, then it is better to reattach the biceps tendon outside of the shoulder joint, because this type of surgery will heal better than a repair of the labrum.