Shoulder dislocation

A shoulder dislocation, more commonly referred to as a “dislocated shoulder,” is the partial (subluxation) or complete loss of contact between the humerus and the joint surface of the shoulder blade. In most cases, the head of the humerus dislocates by moving forward in front of the joint surface of the shoulder blade. More rarely, usually in cases of generalized ligament laxity or neurological impairment, it may move backward or downward. During a dislocation, several structures of the shoulder can be injured. In fact, ligament tears, labral tears — the labrum being a cartilaginous rim that helps stabilize the shoulder — or fractures of the joint surfaces are commonly found.

 

Who is affected by this injury?

Anyone can experience a dislocation, but young people under the age of 30 are generally more affected because they are more likely to have a certain degree of ligament laxity. Individuals with neurological conditions that affect muscle tone, such as a stroke, as well as those who practise contact sports or high-risk activities, are also more frequently affected.

 

How does it happen?

A shoulder dislocation can occur through two types of mechanisms. First, there are traumatic dislocations, which can happen following a body check in hockey, a car accident, a fall onto an outstretched arm, or any impact or excessive traction on the humerus. Second, there are non-traumatic dislocations, which occur during everyday movements in individuals with ligament laxity — ligaments that are more elastic than normal — or a neurological impairment. In these individuals, a dislocation can occur during daily activities, such as throwing a ball, leaning on the hand with the arm extended, stretching into a movement beyond the normal range of motion, applying pressure to the humeral head, lightly pulling downward on the arm, etc.

 

What are the symptoms?

For a complete dislocation: This injury involves very intense pain in the shoulder, visible deformity of the joint, and significant inability to perform any movement with the shoulder. A dislocation often causes major muscle spasms, making reduction without anesthesia more difficult. In some cases, there may be inflammatory signs, such as redness or warmth, in the shoulder if certain structures are torn. A dislocation may also cause numbness in the affected upper limb if the humeral head puts pressure on a blood vessel or nerve.

For a subluxation: Symptoms are more subtle. There may be intense pain or only discomfort if the subluxations are chronic. The affected individual may report a sensation that the bone has shifted, but the humeral head returns to its place on its own, with only the ligaments having been stretched. There are generally no inflammatory signs. Shoulder movements may be limited by pain. Muscle spasms in the shoulder and shoulder blade muscles may also occur.

 

What is the treatment?

For a complete dislocation that has not reduced spontaneously:

Immediate consultation at the emergency department is required to reduce the dislocation, meaning to return the joint to its normal position. The emergency physician will generally request an X-ray to determine the severity of the injury and ensure there is no fracture. The reduction will then be performed with pain medication, with or without anesthesia.

After the reduction, the physician may refer you to an orthopedist to establish the appropriate treatment plan for your condition, depending on the injured structures. Some cases may require surgery to prevent recurring dislocations in the future. A sling may also be prescribed to immobilize the arm for a few days. Finally, patients are referred to physiotherapy to begin rehabilitation, which will include an exercise program focused on joint stabilization, motor control, and strengthening of weak muscles. The physiotherapist will also be able to support the individual in returning to sport, if needed.

For a subluxation or a dislocation that has reduced without medical intervention:

For these injuries, it is not necessary to go to the emergency department. If there is pain, you can use a sling to immobilize the affected arm close to the body for a few days, and you may consult a pharmacist to obtain appropriate medication to help manage symptoms. However, it is important to consult a physiotherapist quickly, since a subluxation or dislocation will often lead to joint instability, which greatly increases the risk of a second dislocation in the future, especially in individuals under the age of 30. The physiotherapist will prescribe an exercise program adapted to your needs and will be able to determine whether a consultation with an orthopedist is appropriate in cases of significant instability. Finally, as in the previous case, the physiotherapist will be able to support you in returning to sport safely.

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