AC Joint Arthritis | All You Need to Know About The Condition

Written by on October 29, 2021 — Medically reviewed by John Doe

Reaching for a seatbelt, lying on your side, scratching your back. Trivial as they may seem, these are tasks that we do daily with our shoulders. These same movements become painful and tiresome if you have AC joint arthritis.

When we think of arthritis, we rarely consider our shoulder joint. But, if you’re older than 50 years of age, pain from the tip of your upper arm bone is something you might be familiar with. (1)

So why do we even have arthritis in our shoulders? And, what can we do about it?

What is acromioclavicular arthritis?

Acromioclavicular Arthritis (AC arthritis) happens when there is a breakdown of your joint cartilage. Thinning or loss of cartilage can happen from overuse, previous injuries, and even from the normal aging process.

Cartilage is what protects your shoulder joint from friction between moving bones.

What is the AC joint?

The AC joint is the meeting point between the end of your collar bone and the tip of your shoulder blade. Surrounding it are different muscles, ligaments, and its joint capsule.

It also has different functions, such as:

  • Allow more range for the arm via the shoulder blade,
  • Allows adjustments for the shoulder blade to adapt to the movements of the arm, and
  • Permits transmission of forces from the arm to the collar bone

While these functions allow for freedom of movement, it also makes the joint prone to overuse injuries. If done for a long time, it can develop into AC joint arthritis.

Causes of AC arthritis

Classifying the cause of your arthritis depends on your previous activities and injuries. These are (2):

  • Primary Arthritis: This is the degeneration of the articular cartilage. This is due to constant wear and tear to the joint.
  • Secondary Arthritis: This comes from previous injury or trauma to the AC joint. It can also be from underlying diseases such as rheumatoid arthritis.

Risk factors 

These are the types of activities that may lead to AC joint arthritis (3):

  • Inflammatory arthropathies
  • Manual work
  • Occupational heavy lifting
  • Repetitive microtraumas
  • Joint infection
  • Trauma

Signs and symptoms

You might have AC joint arthritis if you have one or a few of the following complaints:

  • Pain and limitation when reaching across your body
  • Shoulder and/or neck pain when lying on your affected shoulder
  • Tenderness on the tip of your shoulder
  • Decreased range of motion
  • Clicking/grating noise during arm movement
  • Gradual shoulder weakness
  • More prominent tip of the shoulder

So, how can you tell for sure if you have arthritis on your AC joint?

Only your physician can give your painful condition an accurate diagnosis.

Here are tests/questions to expect during your appointment:


Your doctor will ask you about any history of strenuous activities, trauma, or injury to your shoulder. All these help estimate the amount of damage your AC joint has accumulated over the years.

Physical Examination

Your physician will check for any asymmetries, swelling, and tenderness on both of your shoulders. He may also perform provocative tests that may elicit symptoms typical of AC joint arthritis.

Ancillary Procedures

Your clinician might refer you for an X-ray and/or steroid injection.

These are done to further increase the accuracy of diagnosing any AC joint arthropathy. Decrease in joint space, presence of bone spurs, presence of scar tissue, and positive reaction to steroids are indicative of AC joint arthritis.

How to treat arthritis of the AC joint

Now, you might be asking:

How do you get your AC joint osteoarthritis to stop hurting?

There are 2 major treatment options you can take here: Non-surgical and surgical treatments.

Non-surgical treatment for AC joint arthrosis

Fortunately, most patients who have AC arthritis do well with a conservative treatment program.  Here’s what that generally looks like:

  • Rest: Adequate time to rest allows your body to repair itself.
  • Activity Modification: Avoid repetitive overhead and cross-body movements to prevent flare-ups.
  • Medication: Anti-inflammatory, oral analgesic, and local anesthetic medications address shoulder pain and swelling.
  • Corticosteroid Injections: This is both a treatment and diagnostic tool for AC joint arthritis. Corticosteroid injections have shown pain relief even after 5 years post-injection (4). But, the frequency of injections is limited to prevent soft tissue complications. (5)
  • Physical Therapy: This helps assess and fix your muscle imbalance.  It also addresses your symptoms with different treatment modalities

Surgical route for AC arthritis

 If symptoms persist even after a series of treatments, surgery may be necessary.

Distal clavicle excision is the most common surgery for AC joint arthritis. It can either be done through open or arthroscopic surgery.

  • Open surgery is quicker but has a longer recovery time.
  • Arthroscopic surgery is less invasive. So, it also takes less time to heal.

As with any surgery, there’s always the risk of damaging other shoulder ligaments and other complications.

But, all in all, both approaches offer good long-term clinical outcomes for pain relief and return to function. (6)


How should I sleep with shoulder arthritis?

It is best to sleep on your back and unaffected side to avoid aggravating your joint pain. 

  • For back sleepers: Use a pillow under your head and knees. This promotes the natural alignment of your spine.
  • For sleeping on your unaffected side: Place a pillow between your arms and knees.

Will a shoulder brace help relieve my symptoms?

Yes, a shoulder brace provides added support and protection. Look for a brace that is specifically made to help patients with AC joint arthritis.


Although not as huge as our neighboring glenohumeral joint, AC joint osteoarthritis can still have a big impact on our daily lives. We hope that this article guides you in dealing with AC joint arthritis.


  1. Docimo, Salvatore Jr et al. “Surgical treatment for acromioclavicular joint osteoarthritis: patient selection, surgical options, complications, and outcome.” Current reviews in musculoskeletal medicine vol. 1,2 (2008): 154-60. doi: 10.1007/s12178-008-9024-5
  2. Menge, Travis J et al. “Acromioclavicular osteoarthritis: a common cause of shoulder pain.” Southern medical journal vol. 107,5 (2014): 324-9. DOI: 10.1097/SMJ.0000000000000101
  3. Mall, Nathan A et al. “Degenerative joint disease of the acromioclavicular joint: a review.” The American journal of sports medicine vol. 41,11 (2013): 2684-92. DOI: 10.1177/0363546513485359
  4. Hossain, Saqif et al. “The long-term effectiveness of steroid injections in primary acromioclavicular arthritis: a five-year prospective study.” Journal of shoulder and elbow surgery vol. 17,4 (2008): 535-8. DOI: 10.1016/j.jse.2007.12.001
  5. Lemos, Mark J, and Eric T Tolo. “Complications of the treatment of the acromioclavicular and sternoclavicular joint injuries, including instability.” Clinics in sports medicine vol. 22,2 (2003): 371-85.  DOI: 10.1016/s0278-5919(02)00102-3
  6. Flatow, E L et al. “Arthroscopic resection of the outer end of the clavicle from a superior approach: a critical, quantitative, radiographic assessment of bone removal.” Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association vol. 8,1 (1992): 55-64. DOI: 10.1016/0749-8063(92)90136-y