Hand
The shoulder is a ball and socket joint. The ball is called the humeral head; it is the head of the bone of your upper arm, the humerus. The socket is called the glenoid.
The shoulder is the most mobile joint in the body. This great mobility allows you move your arm with a great degree of freedom. But the shoulder pays for this great mobility by having the least amount of bony stability of any joint in the body. The humeral head is like a golf ball balanced on a tee (the glenoid socket), and is highly dependent on soft tissue structures, such as ligaments and muscles, to stay in joint.
The shoulder ligaments can be stretched out by either a single traumatic event, such as a dislocation, or by multiple minor insults without trauma, such as excessive swimming or throwing. Shoulder instability can cause pain, weakness, and impairment.
Diagnosis
Shoulder instability exists as a spectrum. However, it is easier to understand it by looking at either end of this spectrum. “Traumatic” instability means that the shoulder becomes unstable following a dislocation that is caused by a significant injury. These shoulders usually dislocate out the front as the arm is levered up over the head.
As the force increases on the ligaments, they begin to stretch. Eventually they may tear off the bone of the (glenoid) socket. This ligament tear off of bone is called a “Bankart” lesion.
Shoulder instability that comes from swimming, tennis, throwing, overhead work, and other repetitive, non-violent activities is called “atraumatic” instability. These individuals are typically “loose jointed” to start, and stretch their shoulder ligaments out over time until their ligaments are so loose that they can’t fully control the shoulder any more.
Treatment
For atraumatic instability, the initial treatment involves strengthening the muscles around the shoulder. The hope is that the strengthened muscles will be able to stabilize the shoulder enough to make up for the stretched ligaments. This is effective in decreasing symptoms in 80% of shoulders with atraumatic instability.
Muscle strengthening is not as effective for those individuals who have sustained traumatic dislocations. For these individuals, the chance of re-dislocation or of developing instability problems is more related to their age at the time of the first dislocation. The younger the patient, the greater the risk. The literature varies on exactly how great this risk is: In athletes less than 20 years, the rate of recurrent dislocation is as high as 90-96%.
The rate of recurrence drops to 50-75% in those 20-25 years old. In patients >40 years, recurrent instability is uncommon. The length of time you’re immobilized in a sling following dislocation makes almost no difference.
In older patients or non-active patients, nonoperative management should be initially tried. However, because of the high rate of recurrent instability, arthroscopic stabilization should be performed in young athletes who have sustained a shoulder dislocation. Arthroscopic stabilization has been shown to decrease the rate of recurrent instability following initial shoulder dislocation by 70-80%. Patients who undergo arthroscopic stabilization have significantly higher satisfaction, a higher rate of return to spots, and an improved quality of life.
Allowing multiple instability events to occur by not stabilizing the shoulder in young athletes may cause significant damage to the joint capsule and its ligaments and lead to arthritis and bone loss. Once significant bone loss has occurred, arthroscopic procedures will no longer be predictably effective and open surgery will be needed to place new bone in the glenoid socket. Early arthroscopic stabilization significantly decreases the chances of developing these future problems.
Surgery
Arthroscopic Bankart repair (stabilization) following initial acute traumatic dislocation is warranted for young patients who are unwilling to give up high-demand activities. Arthroscopic stabilization is also effective treatment for individuals who continue to have symptoms of instability that affect their quality of life, such as the ability to play sports, work, enjoy themselves, etc. despite the completion of an appropriate shoulder strengthening program.
Modern arthroscopic techniques are just as effective in preventing recurrent instability as the older open procedures, with less pain and stiffness. Suture anchors (little harpoons with suture in them) are placed into the glenoid (socket) bone and the ligaments repaired to them. Any stretching of the capsular ligaments can be tightened up. After surgery you can type and use computers starting the day after surgery. The arm is in a sling for 4 weeks. Motion is started after 2 weeks. Therapy is used as needed
A word of caution: Lasers and radiofrequency (heat-generatgin) devices that shrink the ligaments were popular a few years ago. However, they have an extremely high rate of failure, up to 25-50%. In addition, these devices can cause serious complications, such as arthritis, destruction of the ligaments, and severe untreatable pain and stiffness. Because of these significant problems, lasers and radiofrequency are no longer recommended for use in the shoulder.
Patients with a history multiple dislocations, or instability with the arm held low or during simple activities of daily living or while asleep, or who have failed surgical repair should have a CT scan performed to make sure that no bone loss has occurred to either the glenoid socket or the humeral head. MRI cannot be relied upon for this, as it often underestimates (misses) the degree of bone loss. Patients with significant bone loss (25% or more of the socket) need an open procedure called the modified Laterjet procedure to replace bone back into the shoulder. These procedures do well, but they’re bigger open surgeries.
| Suture passing devices are used to shuttle the sutures around the labrum (ligament) tissue. | ||
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Suture passed around the labrum (ligament attachment) |
Repaired labral (ligament) tissue |
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