Coracoclavicular Ligament

What is the Acromioclavicular Joint?

The acromioclavicular joint is the point where the collar bone (clavicle) meets the flat bone at the top of the shoulder blade, known as the acromion. The joint is located on the tip of the shoulder and moves when your arm is overhead or stretching across your chest. The ACJ is held in position by two ligaments (the coracoclavicular ligaments) and cushioned by a thick pad of cartilage, known as the meniscus.

What are the common acromioclavicular joint problems?

The three most common conditions that can affect the acromioclavicular joint are arthritis, stress fractures (osteolysis) and dislocations.

  1. ACJ arthritis is a degenerative disease that can cause a loss of cartilage around the joint. This can lead to irritation, the development of bony spurs, inflammation and pain around the joint.
  2. Stress fractures of the ACJ (also known as ACJ osteolysis) can happen at the outer end of the collar bone, at the point where it joins the shoulder blade.
  3. The acromioclavicular joint can dislocate, just like the shoulder can. It normally happens due to a traumatic injury which causes the ligaments holding the bones of the joint in place to break.
Normal Acromioclavicular Joint Dislocated Acromioclavicular Joint

Why do acromioclavicular joint problems happen?

Worn out joint between the Acromion and the Clavicle
  • ACJ arthritis: The most common cause of acromioclavicular joint arthritis is wear and tear through over use. For this reason it is most common in people who are aged 50 or older and in athletes who place a lot of stress on the joint – such as rugby players and weight lifters.
  • ACJ dislocations: The acromioclavicular joint can be dislocated by trauma such a fall directly onto the tip of the shoulder, or by a fall onto an outstretched hand. The degree of dislocation is determined by how many of the ligaments are torn and how far the collar bone has been moved. The severity of the injury can be graded from I-VI
Acromioclavicular Joint Dislocations Acromioclavicular Joint Dislocation Severity
Acromioclavicular Joint Dislocation Stress Fracture

What is an ACJ stress fracture?

Repetitive overhead activities that put an excessive weight on the edge of the collar bone can lead to erosion or stress fractures (osteolysis). ACJ stress fractures are most commonly seen in athletes such as rugby players and weightlifters and in people whose work includes heavy overhead activities, such as builders and plasterers.

How common are acromioclavicular joint problems?

Acromioclavicular joint injuries are most common in athletes who have to carry weight on their shoulders, such as weightlifters, wrestlers and rugby players. This type of injury is also more common in builders and plasterers, who may carry weights overhead, and in older people who may suffer from additional wear and tear and arthritic change to their joints.

What type of imaging tests is done?

  • X-rays are the initial choice. A variety of images may be required to assess the degree of AC joint disruption.

How does my doctor treat AC-Joint problems?

Video Procedure:

There is controversy about the success of surgery versus non-operative intervention for grade III type injuries. Grade I and II injuries seem to respond favourably to conservative management. Grade IV, V, and VI separations often require surgical reconstruction.

AC Joint Disruption

  1. Types I and II injuries are managed conservatively with ice, a sling for 1-3 weeks and non-steroidal anti-inflammatory drugs (NSAIDs) followed by physiotherapy to strengthen muscles and ligaments after the acute phase.
  2. Type III injuries should be managed conservatively but carefully selected cases may benefit from surgical intervention if conservative therapy fails.
  3. Types IV to VI are nearly always treated with open reduction and internal fixation.
  4. All acute lesions thought to be worse than type II should be referred urgently for an orthopaedic opinion.


  1. Activity modification, physiotherapy and NSAIDs/other analgesia.
  2. Cortisone injections may provide relief of symptoms for up to three months in expert hands. Currently there is no consensus in terms of dosage, and injections should be limited to fewer than four per year. Duration of analgesia is very variable with ranges of two hours to three months reported.
  3. In severe cases of OA or osteolysis, removal of the end of the clavicle may need to be considered. This can be performed arthroscopically. In OA, consider surgery for severe cases where there is failure of response to conservative management after six months.