To compensate for the shallow socket, the shoulder joint has a cuff of cartilage called a labrum that forms a deeper socket for the ball of the top of the arm bone (humerus) to move within. This cuff of cartilage makes the shoulder joint much more stable, yet allows for a very wide range of movements (in fact, the range of movements of your shoulder far exceeds any other joint in the body).
Bankart TearsWhen the labrum of the shoulder joint is torn, the stability of the shoulder joint may be compromised. A specific type of labral tear is called a Bankart tear. A Bankart tear occurs when an individual sustains a shoulder dislocation. As the shoulder pops out of joint, it often tears the labrum, especially in younger patients. The tear is to part of the labrum called the inferior glenohumeral ligament. When the inferior glenohumeral ligament is torn, this is called a Bankart tear.
Typical symptoms of a Bankart tear include:
- a sense of instability
- repeat dislocations
- catching sensations
- aching of the shoulder
Diagnosis of a Bankart TearMost young patients (under the age of 30) who sustain a shoulder dislocation will sustain a Bankart tear; therefore, there is a high suspicion of this injury whenever a young patient dislocates their shoulder. On examination, patients will often have a sense their shoulder is about to dislocate if their arm is placed behind their head.
X-rays are sometimes normal, but they may show an injury to the bone called a Hill-Sachs lesion. This is a divot of bone that was injured when the shoulder dislocation occurred. An MRI may also be obtained in patients who have dislocated their shoulder. Bankart tears do not always show up well on MRI scans. When a MRI is performed with an injection of contrast solution, a Bankart tear is much more likely to be seen.
Treatment of a Bankart TearThere are two general options for the treatment of a Bankart tear. One option is to allow the arm to rest, and the inflammation to subside with the use of a sling. This is usually followed by physical therapy to regain motion of the extremity. The potential downside of this option is that people who dislocate a shoulder once are much more likely to dislocate the shoulder again.
The other option is to perform surgery to repair the torn labrum. When surgery is performed, the torn ligament is reattached to the socket of the shoulder. The results of surgery are usually very good, with over 90% of patients returning to their activities without any further dislocations. More and more commonly this surgery is being performed arthroscopically; however, there are some patients who should have a Bankart repair performed through a standard incision.