AC Joint Arthritis

AC Joint arthritis

What is it?
The acromio-clavicular joint (ACJ) is where the outer end of the clavicle (collarbone) meets the shoulder bone (acromion) and forms the point on top of the shoulder. Cartilage normally covers the ends of these bones and forms a smooth gliding surface. Arthritis occurs when these smooth cushioned layers become thinned and roughened.


The main cause of AC joint arthritis is thought to be use. As we use our arm and shoulder, stress is placed on the joint, which can lead to wear of the joint cartilage over time. This can occur with normal use of the arm over many years (age related wear). In some people this degenerative process becomes painful, the joint can be inflamed, and the end of the clavicle can develop a prominent bone spike (osteophyte).

Occupations or activities that involve prolonged or repetitive overhead lifting or shoulder impacts are associated with an increased risk of ACJ arthritis. These include construction workers, contact sports athletes or weightlifters. Cartilage damage may occur because of a previous injury such as ACJ dislocation.

What are the Symptoms?

The AC joint is often tender and swollen in the early stages. Pain is often vaguely located over the shoulder area. This pain is often made worse by lying on the affected side or by using the arm, especially undertaking activities that place the hand high above the shoulder (termed high arc pain). Taking the arm across the chest will often also make the pain worse.


AC Joint arthritis is usually diagnosed based on your symptoms and examination findings. In most cases the diagnosis is confirmed with X-rays. Advanced diagnostic imaging, such as CT (computed tomography) or MRI (magnetic resonance imaging), are typically not needed, but may be requested if the diagnosis is in doubt or there is suspicion of other problems.

Treatment options

Here are treatments for AC joint pains:

Treatment options depend on the severity of your symptoms and also the extent of the wear and tear in the joint. These will be discussed with you at your consultation. They are outlined in brief below:

Nonsurgical Treatment
For the early stages of osteoarthritis of the AC joint, the most common treatment is nonsurgical. This includes oral analgesics and non-steroidal anti-inflammatories (NSAID’s ), to reduce or alleviate pain. This is combined with rest, modification of activities and sometimes physiotherapy.

Corticosteroid injections are sometimes used to treat osteoarthritis symptoms. Steroid medication has typically been used with good results. Although the effects of injections are temporary, they can provide significant pain relief until symptoms progress enough to need additional treatment.

Surgical Treatment
In the majority of people AC joint arthritis, the symptoms can be successfully controlled by the above interventions. If these fail to provide sufficient improvement, then surgery in the form of AC joint excision may be considered. This procedure involves removing a small amount (less than 1cm) of the end of the clavicle (collarbone). This takes away the painful rubbing of the bone ends with the empty space being replaced over time with scar tissue. This is very effective in alleviating the symptoms of pain and provides excellent shoulder function. This procedure can be undertaken either through a small incision (open) or via keyhole techniques (arthroscopic).

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