Glenohumeral dislocation is a shoulder dislocation, which may be caused by a traumatic injury such as a sports injury, or by weakening of the capsular ligaments which stabilize the shoulder joint. The term glenohumeral refers to the name of the bone and socket of the shoulder. The bone which fits into the shoulder socket is the humerus, and the socket is called the glenoid. In a glenohumeral dislocation the bone and socket become separated, and the head of the humerus lifts entirely out of the socket.
The glenohumeral shoulder joint is the most commonly dislocated joint in the human body. Anterior glenohumeral dislocation, in which the head of the humerus is displaced above the joint, is the most common type of shoulder dislocation. Posterior dislocation, in which the head of the humerus is displaced below the shoulder joint, is much less common. Around 95% of cases of shoulder dislocation occur as a result of a traumatic injury. Dislocation is extremely painful, and may require initial sedation with narcotic analgesics, followed by several days of medication for pain management.
People who have had one episode of shoulder dislocation have an increased risk of further dislocation occurring. Young people up to around 20 years of age have a higher risk of further dislocation after an initial episode. This is thought to be due to the higher activity level of younger people, rather than factors relating directly to age. Severe injury during an initial dislocation also increases the risk. Such injuries include fracture of the glenoid socket, or tearing of the rotator cuff muscles which support the joint.
First line treatment glenohumeral dislocation involves replacing the humerus bone in the glenoid socket, which is often as painful as the dislocation itself. During the two to three weeks afterwards, the arm is held in a sling to immobilize the shoulder joint and allow healing to take place. Physical therapy is very limited during this time and involves exercises to improve the range of motion of the hand, wrist, and elbow.
The next phase of treatment for glenohumeral dislocation begins two or three weeks after the initial injury. Older people with this injury are usually advised to begin shoulder exercises sooner, to alleviate stiffness of the joint. The goal of physical therapy is to improve the range of motion of the shoulder with exercises that gradually increase the rotation and flexion of the joint.
Around six weeks after glenohumeral shoulder dislocation, vigorous exercises are safe for most people. Young adults are the exception, due to the high risk of another dislocation episode. These patients are advised to wait three months before adding strenuous exercise to the physical therapy routine. Exercises to strengthen the rotator cuff muscles are particularly helpful, especially for people who damaged the muscles during the dislocation episode. Swimming is also recommended as an exercise which helps strengthen the joint without further risk of injury.