Dislocation, Glenohumeral

© Reed Group

Risk: Individuals at risk of glenohumeral dislocation include those who have shoulder instability, a history of shoulder dislocation, or seizures (e.g., epilepsy). Approximately 96% of all dislocations result from trauma such as falls and sports injuries. Elderly women are at increased risk of shoulder dislocation associated with falls, as are young athletes who participate in sports (Park). Males are affected more frequently than females, quite possibly because of their higher rate of participation in contact sports.

Incidence and Prevalence: The shoulder is the most commonly dislocated joint in the body and glenohumeral dislocation accounts for more than half of all joint dislocations in the US. Approximately 95% of the glenohumeral dislocations are anterior dislocations, and 4% are posterior dislocations (Park). An international estimate of the annual incidence of glenohumeral dislocation is 17 per 100,000 individuals (Wilson).

History: A thorough history should be obtained including circumstances surrounding the injury, prior injuries to the affected shoulder including dislocations, medical conditions, family history of dislocations and/or ligamentous laxity, and medication use. The individual usually reports trauma from a fall, having the arm jerked backwards, or trying to catch something heavy. Pain is extreme, immediate, and worsened by any motion. The individual may report a sensation of slipping or tearing in the joint at the time of injury. Usually, individuals are unable to move the shoulder and may carry the arm with the elbow bent and arm held slightly away (abducted and externally rotated) from the body if an anterior dislocation has occurred. In a posterior dislocation, individuals may carry the affected arm with the elbow held toward the body (adduction and internal rotation). If this is a recurrent dislocation, the individual may have attempted to pop the shoulder back into place.

Physical exam: Physical examination should begin with observation of the two shoulders, which may reveal an abrasion, bruising (ecchymosis), swelling (edema), or obvious deformity on the affected side. Any atrophy of the muscles of the rotator cuff and upper arm should be noted. With a glenohumeral dislocation, a dimple in the skin occurs below the shoulder joint and the head of the humerus that can be felt with the hands (palpated). This can be accentuated by pulling down on the affected arm (sulcus sign). Active and passive shoulder range-of-motion should be tested and any restrictions or hypermobility noted. Attempting to move the arm in a throwing motion may reveal abnormal shoulder function and cause a high level of anxiety (positive apprehension sign) in the individual. Lower arm (distal) pulses may be faint, and there may be sensory changes. A thorough motor and sensory examination before and after the joint is restored to its normal anatomical position (reduction) is important since injuries to the axillary nerve can occur in up to 40% of cases (Seade).

Tests: Plain x-rays demonstrate the position of the humeral head that defines the direction of the dislocation. A minimum of 2 orthogonal views is necessary, and anterior-posterior (AP) and axillary views are usually ordered. X-ray examination also shows any fractures. CT is performed if the diagnosis is unclear after viewing the plain films. MRI is indicated to assess soft tissue injuries or if a tear of the rotator cuff is suspected.

The goal of rehabilitation after glenohumeral dislocation is to decrease pain and to restore full function of the affected shoulder. The main focus of rehabilitation for glenohumeral dislocation is stabilizing the shoulder through strengthening and proprioceptive exercises (Hayes; Walton), while maintaining range of motion. The key to establishing a successful progression of rehabilitation is to understand the direction of instability (e.g., anterior, posterior, or multidirectional). Initial and intermediate therapeutic protocols are essentially the same for all dislocations; however, when exercises become more functional, directional issues must be addressed.

After reduction of the humerus the arm is immobilized in an arm sling for up to 2 weeks. Local ice application can help to reduce pain. During this period of immobilization, the individual can begin pendulum exercises. After immobilization, passive and active assisted range of motion exercises can be initiated. Six weeks after the dislocation the goal is to progressively regain function of the affected shoulder. Range of motion and strengthening exercises should be progressed as tolerated, and proprioceptive exercises should be added. Care must be taken to avoid positions that place the shoulder at risk for a recurrent dislocation. In an anterior dislocation, the most common type of shoulder dislocation, movements including abduction of the humerus above 90° combined with simultaneous external rotation should be avoided.

Because of the risk of recurrence, surgery is recommended after a first time dislocation in young, active patients (Wen). After surgery, passive and active assistive range of motion exercises may be started, with limitations of motion determined by the surgical repair. Special attention should be paid to protect soft tissue and to avoid re-dislocation. Rehabilitation may then proceed as in a closed reduction.

Up to twelve weeks of rehabilitation may be needed when an individual experiences a glenohumeral dislocation for the first time. Rehabilitation from surgery to rectify frequent dislocation of the humeral head can take up to 5 months for full recovery.

Additional information may provide insight into the rehabilitation needs of these individuals (McMahon).