The labrum is a rim of cartilage attached to the glenoid cavity in the shoulder blade that lines and reinforces the ball and socket joint of the shoulder. The shoulder socket is rather shallow; however the labrum adds strength and stability to the shoulder joint by deepening the socket where the humeral head attaches to the joint. The labrum also serves as the attachment site for several ligaments within the shoulder joint.
Common Causes of a Labral Tear
Damage to the labrum can occur from acute trauma, such as a falling on an outstretched arm, a direct blow to the shoulder, a sudden pull. Another common cause of labrum injuries is wear and tear from overuse, such as repetitive overhead motion, improper throwing techniques in athletes, or strenuous weightlifting.
Symptoms of a labral tear are similar to other shoulder injuries, such as:
- Pain, usually related to overhead movements
- Catching, locking, popping, or grinding
- Occasional night pain
- Instability in the shoulder
- Decreased range of motion
- Loss of strength
Diagnosing a labrum tear can be difficult. Your physician will begin by discussing the history of the injury. Next, they will perform a series of physical tests to check range of motion, stability, strength, and pain. The doctor will also request x-rays to help rule out any other reasons for the shoulder pain. Due to the rim of cartilage being so deep in the shoulder joint, an MRI scan is needed to properly diagnosis a labrum tear. Contrast may be injected into the joint to help enhance the images from the scan. This area of the body is very complex and can be difficult to get good reliable pictures with an MRI. The best way to diagnose a torn labrum is with a shoulder arthroscopy.Labrum tears often occur with other shoulder injuries, such as a dislocation. Tears to the cartilage can be located above (superior) or below (inferior) the middle of the glenoid socket. The two most common types of labrum tears are:
- SLAP Lesion (superior labrum, anterior [front] to posterior [back]) is a tear of the cartilage above the middle of the shoulder socket that may also involve the biceps tendon
- Bankart Lesion is a tear of the cartilage below the middle of the shoulder socket that also involves the inferior glenohumeral ligament
Treatment of a labrum tear depends on the kind of tear. Tears due to subluxation or dislocations require the labrum to be reattached to the rim of the shoulder socket. This surgery can be done either by arthroscopic techniques or an open incision in the front of the shoulder. If the labrum is frayed and is asymptomatic, no treatment is needed unless there is a tear large enough where the torn portion should be cut out, trimmed, or repaired. Tears of the labrum involving the biceps tendon (SLAP lesions) will need to be reattached or trimmed. This is usually best performed by arthroscopic surgery.
Recovery from a labrum tear depends on location and severity of the tear, and how it was able to be repaired. It usually takes four to six weeks for the labrum to reattach itself to the rim of the bone, and usually another four to six weeks to regain strength. Most patients will have full function of the shoulder after full recovery of the labrum repair.