Acromio-Clavicular Joint OsteoArthritis

If you’re experiencing pain reaching your arm across your body, or when lifting your arm above head height as well as pain and tenderness at the top of your shoulder, there’s a chance you may be experiencing acromioclavicular arthritis.

This form of arthritis is named for the acromioclavicular (AC) joint, which sits on the top of our shoulders joining the scapula (shoulder blade) and the clavicle (collarbone).

Acromioclavicular arthritis is one of the more common locations of shoulder arthritis, and the joint is affected by osteoarthritis, the most common osteoarthritis, with other arthritis types being inflammatory arthritis, such as rheumatoid arthritis.

Like other sites of osteoarthritis, AC Joint osteoarthritis is a degenerative disease of the joint and leads to joint’s cartilage breaking down and abnormal bony growths, called osteophytes or bone spurs, developing in the joint.

Osteoarthritis is the most common form of arthritis and affects millions of people worldwide. It causes structural changes within a joint or multiple joints, resulting in pain and loss of function. It can be incredibly painful.

Who’s most at risk?

The exact cause of acromioclavicular osteoarthritis is still now known, but there are traits generally present with an increased risk of the condition.

Trauma to the AC joint

The main cause of AC joint osteoarthritis (ac joint OA) is trauma and injuries.

It can occur after a serious injury (for example, an AC Joint sprain or separation) although there may be many years between the injury and developing the condition.

While the trauma may come about as a one-off injury, the joint can also become damaged by years of ‘mini- traumas’ – years of smaller wear and tear on the shoulder muscles. People who have spent years weightlifting or participating in high-impact sports, such as football and rugby, also can be particularly prone to acromioclavicular osteoarthritis.


Unfortunately, sometimes you can take all the precautions in the world and still develop AC osteoarthritis. A family history of the condition increases your chances, as does being born with poor shoulder alignment. Certain metabolic disorders, episodes of gout or infection (septic arthritis) can also increase your risk.


Statistics show that as we age, we become more at risk of developing AC osteoarthritis. The condition is most likely to present in people over the age of 50.

Symptoms of AC OsteoArthritis

The key symptoms of AC OsteoArthritis involve:

  • Pain in the shoulder. This pain most commonly involves tenderness at the top and front of the shoulder. It may be low-level and consistent and have occasional flare-ups of more severe pain. This pain may be present all the time, disrupting quality of life and particularly affecting sleep patterns.
  • Others may experience pain in the shoulder with certain activities, including reaching the arm across the body. This may lead to limited movement in the arms.
  • A clicking or creaking noise when using the shoulder joint.

How is AC osteoarthritis diagnosed?

If you believe you may have AC osteoarthritis, the best tests that can be undertaken to see if the condition is present are:

  • X-rays
  • MRI scans


AC osteoarthritis is a degenerative condition, but there are a number of treatments available to ease the pain and reduce the symptoms of the condition.

  • A steroid injection under ultrasound control can temporarily ease the symptoms and confirm the diagnosis
  • Surgery is a key treatment option and involves an arthroscopic (minimally invasive key hole surgery) excision of the end of the clavicle (collar bone) with immediate motion afterwards (no need for a sling) and has excellent results.

Our shoulder joints are complex, so make sure you’re getting the best specialist treatment before proceeding with treating your AC osteoarthritis.

The team at Glenelg Orthopaedics works towards gaining the best outcome for you, the patient – priding ourselves on providing a quality and individualised experience.

Call (08) 8376 9988 for all appointment bookings.