Shoulder Dislocation

What Is A Shoulder Dislocation?

The shoulder joint is a ball and socket joint and is the most movable joint in the body, having the capability to move in many directions. Because the shoulder joint allows for significant movement, it is an unstable joint and is commonly injured. The shoulder joint is made up of the humerus, clavicle, and scapula. The humeral head sits in a fossa (socket), known as the glenoid fossa. Structures around the shoulder joint, including the labrum, capsular tissues, and rotator cuff tendons and muscles, are needed for stability as the glenoid fossa is a very shallow socket.

Shoulder dislocations happen when the humeral head is forcefully removed from the glenoid fossa socket. Shoulder dislocations can occur in various directions; however, they usually dislocate anteriorly and inferiorly. An anterior dislocation occurs when the head of the humerus is moved in front of the joint. A Bankart lesion results from detachment of the anterior inferior labrum from the underlying glenoid. Bankart lesions are usually the result of a previous anterior shoulder dislocation. Conversely, a posterior dislocation occurs when the head of the humerus is moved backward, toward the scapula. After a shoulder dislocation occurs, the shoulder joint may become unstable and may be more susceptible to future dislocations.

Individuals with shoulder dislocations will usually report significant pain. Furthermore, patients often refuse to move the shoulder in any direction. The surrounding musculature may go into spasm after a dislocation, making movement of the shoulder extremely painful. With anterior dislocations, patients will often hold the affected arm slightly away from the body while supporting it with the other hand. The shoulder will often look squared off as the humeral head has moved out of its normal position. On occasion, a bulge may be seen or felt in front of the shoulder joint.

Causes of Shoulder Dislocation

Dislocations that occur in younger individuals are usually the result of trauma associated with sports injuries or falls. Dislocations are commonly seen in contact sports, such as hockey and American football, as well as in sports where there is the risk of falling such as skiing or gymnastics. Anterior dislocation usually occurs when the shoulder is in an exposed position, involving external rotation of the shoulder. Anterior dislocations can also be the result of a fall on an out-stretched hand. Posterior dislocations of the shoulder are commonly associated with particular injuries (i.e. fall with your arm straight out in front of you, electrical injury, epileptic seizures, high energy trauma, etc.). However, in the elderly, posterior shoulder dislocations can occur with a minor injury. Posterior shoulder dislocations are sometimes misdiagnosed, as there is less displacement of the bones compared to what is seen with anterior dislocations. Obtaining correct radiographic views, including axillary views, is of the utmost importance when evaluating a patient with a history of shoulder trauma.

Treatments for Shoulder Dislocation

Some physicians may try closed reduction to address dislocated shoulder joints. This involves applying gentle maneuvers to help the bones of the shoulder go back into their proper position. Patients will usually be given a muscle relaxant or sedative prior to this procedure. In the acute phase of injury, the shoulder should be iced and the arm should be immobilized in a sling. Once the sling is removed, physical therapy exercises including active and passive range of motion exercises should be initiated, progressing to additional stretching and strengthening for the shoulder joint, including rotator cuff exercises. During this phase, pain medication as well as non-steroidal anti-inflammatory medications may also be warranted.

Surgical management should be considered for individuals with recurrent shoulder instability or those who have continued instability during physical therapy. Arthroscopy is a procedure that is used to inspect, diagnose, and repair problems in the shoulder joint. During an arthroscopic procedure, the surgeon inserts a small camera through tiny incisions in the shoulder joint. Tiny surgical instruments are then used to perform any necessary repairs. If a Bankart lesion is found, a procedure called arthroscopic anterior shoulder stabilization will be performed. This procedure involves reattaching and tightening the torn labrum and ligaments of the shoulder arthroscopically. While risks with arthroscopic surgery are rare, they do exist and include infection, nerve and blood vessel injury, joint stiffness, rotator cuff tear, pain, persistent instability, and the need for additional surgeries.

Conclusion

The shoulder joint is a complex ball and socket joint that is prone to dislocation because of its ability for a wide range of movements. Young athletes who participate in contact sports and sports where the risk of falling is high commonly suffer from shoulder dislocations. Anterior dislocations account for the majority of shoulder dislocations. Treatment ranges from conservative measures such as rest and immobilization to more aggressive treatment options including arthroscopy. Patients are encouraged to discuss their symptoms with their physicians to determine the best course of treatment for their injury.

References

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