Glenohumeral Dislocations

Anterior dislocation is the most common shoulder dislocation and is generally caused by abduction with external rotation.

Posterior dislocation is rare and is the most commonly missed major dislocation. It may be caused by a sudden, forceful muscle contraction (e.g., epilepsy or electric shock) or direct blow. Luxatio erecta is a rare dislocation that occurs when the superior aspect of the humeral head lies below the inferior rim of the glenoid fossa.

Causes

Anterior-inferior shoulder dislocations usually occur when there is contact with the arm while the arm is away from the body in an outward rotated position. Traumatic contact from the back of the shoulder can also cause this type of dislocation even when the arm is by the side of the body. These traumatic events will cause the head of the humerus to be displaced out of the glenoid fossa.

Signs

• Anterior: may feel mass anterior, inferior, or medial to normal glenohumeral joint with posterior sulcus. Internal rotation is restricted.
• Posterior: note a prominent coracoid with an anterior sulcus. External rotation is restricted.
• Luxatio erecta: patient may have arm locked overhead in abduction

Treatment

Anterior-inferior shoulder dislocations are treated by doctors. Doctors trained in treating emergencies are also trained in making sure that the head of the humerus is put back into it's correct position. Sometimes the head of the humerus does not want to return to it's correct position and an Orthopedic Surgeon is consulted on whether surgery is required.

After an anterior-inferior shoulder dislocation the long term goal is to return the individual back to their previous level of activity. Achieving this goal will depend on the function and stability of the shoulder and any complications that have occurred. After a period of immobility, a general shoulder rehabilitation program such as includes strengthening exercises, flexibility exercises, aerobic conditioning, technique refinement and proprioceptive retraining is the important factor in improving shoulder function and stability. Stability may be improved by an anterior-inferior shoulder dislocation brace.