Acromioclavicular Joint Injury

The Acromioclavicular joint is the small joint between the outer edge of the collar bone (clavicle) and the shoulder blade (acromion).

Injuries to the capsule alone result in pain without significant swelling. This typically lasts for days to a few weeks and seldom requires surgical intervention. Injuries that tear the strong ligaments between the clavicle and the coracoid result in dislocation of the ac joint. This is apparent as a bony swelling at the site of the acromioclavicular joint.

The Acromioclavicular joint is typically injured in shoulder to shoulder or shoulder to ground contact. Acute pain is localized to the top of the shoulder and may be associated with a bony swelling if the clavicle is dislocated. In most sport associated AC joint injuries it is not possible to continue playing on after the injury due to pain.

Fracture of the clavicle may cause similar symptoms.

Definitive diagnosis is made from clinical examination x-rays or imaging such as MRI.

Treatment depends on the degree of displacement and patient symptoms. Most frequently the individual can return to contact sport 6-12 weeks after injury without surgery. Displaced acromioclavicular joint injuries will tend to function well without pain despite the prominent appearance of the lateral clavicle. Surgery is seldom required to regain normal function even in contact sport.

If pain due to the Acromioclavicular joint injury persists or the individual is unhappy with the appearance injections or surgery can be performed. To restore the clavicle into a more anatomic position would require surgery.

Surgery is usually a combination of open and arthroscopic surgery that replaces the damaged coraco-clavicular and acromio-clavicular ligaments with a form of synthetic ligament.

Recovery aims to protect the healing soft-tissues and allow ingrowth of the synthetic tape. A sling is worn for 6 weeks following surgery. There may be a small amount of re-displacement either early or later.  Return to sport is between 4-6 months following surgery.