Acromioclavicular joint dislocation

Acromioclavicular joint dislocation manifests as acute pain immediately after the trauma, often associated with a cracking sensation. The patient reports significant functional discomfort and limited arm movement. Examination often reveals localized swelling, sometimes accompanied by visible deformation with protrusion of the outer end of the clavicle. Palpation reveals marked sensitivity at the joint and, in more severe cases, instability of the clavicle.

Acromioclavicular joint dislocation usually occurs as a result of direct trauma to the shoulder. The most common mechanism is a fall onto the shoulder, which causes the acromion to shift relative to the clavicle and puts tension on the surrounding ligamentous structures.
 
In addition to falls, violent impacts during contact or high-speed sports (rugby, football, cycling, skiing) are often to blame. In severe cases, displacement of the clavicle can cause damage to surrounding tissues, particularly the brachial plexus, although this is rare.

Although anyone exposed to shoulder trauma can develop acromioclavicular dislocation, certain situations significantly increase the risk.
Young adults who are particularly active and athletic are the most at-risk population. Activities involving physical contact or a high risk of falling increase the likelihood of injury.
Recurrence is also a notable risk factor. A person who has already suffered a shoulder dislocation or severe sprain of the ligaments of the acromioclavicular joint has residual instability that weakens the joint. Certain body types characterized by natural ligament laxity can also promote repeated injuries. Finally, men are more likely to suffer shoulder dislocations, probably due to greater exposure to contact sports and high-risk activities.

The diagnosis is based on a thorough clinical examination supplemented by imaging tests. During the consultation, the doctor looks for sharp pain localized at the acromioclavicular joint, possible deformation with elevation of the end of the clavicle, and abnormal mobility.
Specific tests, such as forced adduction of the arm in front of the chest (cross-body adduction test), isolate the joint and reproduce the pain, thereby confirming the suspected diagnosis. X-rays are the gold standard for confirming dislocation and determining its type. These tests allow the dislocation to be classified according to the Rockwood classification, which distinguishes six stages based on the degree of displacement of the clavicle and ligament damage.
In more complex cases or when associated ligament or cartilage damage is suspected, an MRI may be recommended. It provides better visualization of soft tissues and helps guide the treatment strategy

Treatment depends on the type of dislocation, classified according to severity. In mild cases (types I and II), treatment is generally conservative. It involves immobilizing the arm with a sling for a few days, combined with painkillers and ice to relieve pain and limit inflammation. As soon as the pain allows, the shoulder should be remobilized. Rehabilitation begins quickly to prevent the joint from stiffening.
For type III dislocations, initial treatment is often non-surgical, but surgery may be considered, especially in young athletes, to reduce the risk of chronic instability. Patients who do not undergo surgery may experience persistent symptoms for up to three months.
For the most severe forms (types IV, V, and VI), surgery is indicated. The procedure aims to restore the alignment between the clavicle and the acromion and to repair or reconstruct the coracoclavicular ligaments. Surgical treatment must be performed in a timely manner to avoid lasting functional sequelae.
Rehabilitation plays a central role in all forms of treatment. It helps restore mobility, strengthen the shoulder muscles, and stabilize the joint. Active patients can resume sports when the pain has disappeared and strength and range of motion are equivalent to the unaffected side.

In most cases, the outcome after an acromioclavicular dislocation is favorable, especially for mildly displaced forms. Patients regain a functional and pain-free shoulder within a few weeks. However, certain complications may arise, particularly if the injury has not been correctly diagnosed or treated.

Chronic instability of the joint may develop, causing pain in the shoulder during physical activities or everyday movements. This instability can progress to acromioclavicular osteoarthritis, characterized by progressive wear and tear of the joint and persistent pain.

It is not possible to prevent acromioclavicular dislocation, but certain measures can reduce the risk. Regular muscle strengthening exercises, particularly for the rotator cuff and shoulder blade stabilizing muscles, help to protect the joint.

Any sharp pain, associated with visible deformation of the shoulder or immediate limitation of movement, particularly after trauma, should prompt a prompt visit to the doctor. An acromioclavicular dislocation must be assessed quickly by a healthcare professional. It is not advisable to attempt to put the joint back in place yourself, as this may aggravate the injury and lead to complications.

Hôpital de La Tour provides comprehensive care for acromioclavicular joint dislocations. Orthopedic and trauma specialists make an accurate diagnosis through clinical and radiographic examinations, then recommend appropriate conservative or surgical treatment depending on the type of dislocation. Rehabilitation is provided by physical therapists to promote a quick and safe return to daily activities and sports.

What is an acromioclavicular dislocation?
It is an injury to the joint between the collarbone and the acromion of the shoulder blade. It occurs after direct trauma, such as a fall on the shoulder.

What are the initial symptoms?
The pain is immediate and intense, often accompanied by swelling and sometimes visible deformation above the shoulder.

Is it the same as a shoulder dislocation?
No. An acromioclavicular dislocation affects the joint between the collarbone and the acromion, while a glenohumeral dislocation affects the main shoulder joint where the humerus comes out of its socket.

How does the doctor make the diagnosis?
Through a targeted clinical examination, supplemented by specific X-rays. In some cases, an MRI is useful for visualizing the ligaments and soft tissues.

Is surgery always necessary?
No. Mild cases heal with simple immobilization and rehabilitation. Surgery is reserved for severe dislocations or very active patients whose shoulder is likely to remain unstable.

How long does recovery take?
Depending on the severity, recovery can take from a few weeks for a mild case to several months for a severe dislocation requiring surgery.

Can this type of injury be prevented?
Good shoulder muscle strengthening, practicing appropriate techniques, and wearing protective equipment in certain sports reduce the risk.

What should you do immediately after a suspicious fall?
Immobilize the shoulder and seek medical attention immediately. It is not recommended to try to put the joint back in place yourself.