Arthritis More Arthritis Types & Related Conditions Acromioclavicular (AC) Joint Arthritis: What to Know How It Feels, Causes, and Symptoms By Jonathan Cluett, MD Jonathan Cluett, MD LinkedIn Twitter Jonathan Cluett, MD, is a board-certified orthopedic surgeon with subspecialty training in sports medicine and arthroscopic surgery. Learn about our editorial process Updated on May 23, 2022 Medically reviewed Verywell Health articles are reviewed by board-certified physicians and healthcare professionals. These medical reviewers confirm the content is thorough and accurate, reflecting the latest evidence-based research. Content is reviewed before publication and upon substantial updates. Learn more. by Riteesha G. Reddy, MD Medically reviewed by Riteesha G. Reddy, MD Riteesha G. Reddy, MD, is a board-certified rheumatologist and internist at a private practice in Dallas, Texas. Learn about our Medical Expert Board Print Table of Contents View All Table of Contents Shoulder Conditions Symptoms Causes Treatment Recovery Frequently Asked Questions AC arthritis is chronic inflammation of the acromioclavicular (AC) joint, one of the four joints that work together in the complex system that makes up the shoulder. Like most cases of osteoarthritis (OA), AC arthritis happens when the cartilage protecting certain bones within the joint wears thin. Recognizing AC arthritis as the unique condition that it is is important when it comes to treatment. Though shoulder arthritis occurs in the same region, the conditions are not the same. Cultura RM Exclusive / PhotoStock-Israel / Getty Images AC Joint vs. Shoulder Arthritis To understand how AC joint arthritis and shoulder arthritis are different, you need to know a little about the shoulder joints. The term shoulder arthritis means arthritis in the glenohumeral joint. That's the ball-and-socket joint most people think of when they think of the shoulder. The shoulder blade (scapula) forms the socketThe ball is at the top of the upper arm bone (humerus) The acromioclavicular joint is formed by: The acromion, which is a finger-like projection of the scapulaAn end of the collar bone (clavicle) AC arthritis refers to inflammation and cartilage loss in this joint. These two conditions cause different symptoms and complications, and they're treated differently as well. In both cases, however, an X-ray (along with a physical exam) is often enough to help diagnose the condition and reveal how severe it is. Other Shoulder Joints The other two shoulder joints of the shoulder are the:Sternoclavicular (SC) joint, which joins the clavicle to the breastbone (sternum)Scapulothoracic joint, which connects the scapula to the back ribs AC Joint Arthritis Symptoms If you have AC joint arthritis, you may feel tenderness and pain at the top of the shoulder early on. Other possible symptoms of AC joint arthritis include: More pain after sleeping on that sideLost range of motion in your shoulderMore pain when the joint is compressed (like when crossing an arm across your chest)Visible inflammation and increased prominence around the AC joint AC arthritis pain is most often tied to shoulder motion, but neck and arm pain may also play a part. That can complicate diagnosis, as several types of arthritis and some other conditions may cause similar symptoms. Specific movements tend to exacerbate the symptoms. The typical test for AC joint pain is to bring the affected arm across your chest. That compresses the AC joint and usually recreates the pain. Causes AC arthritis is usually osteoarthritis, the result of repeated movements that wear away cartilage in the acromioclavicular joint. Because the shoulder is used so commonly, it is not surprising that joint surface may wear thin after years of use. However, other problems may bring on symptoms: Inflammatory conditions: Autoimmune diseases like rheumatoid and psoriatic arthritis can attack the AC joint. Septic arthritis: This stems from an infection in the joint that can be transmitted via the bloodstream or by an injury delivering germs directly to the joint (a puncture, for example). Injuries: Shoulder trauma, such as shoulder separation, may contribute to the development of AC arthritis. AC Joint Arthritis Treatment AC joint arthritis treatment depends on the severity of symptoms and the presence of other shoulder problems, including: Impingement syndrome Glenohumeral arthritis Muscular injury (e.g., rotator cuff tear) For Mild-to-Moderate Symptoms If the symptoms of AC arthritis are mild to moderate, anti-inflammatory medications and physical therapy are the most common conservative measures. Your healthcare provider may inject the AC joint with a local anesthetic or steroids to see if your symptoms improve. For Severe or Unresponsive Symptoms If the symptoms do not respond to conservative treatment, or if the pain is too severe, you may need surgery. Your healthcare provider may suggest an arthroscopic procedure called an isolated AC joint resection. In this procedure, the surgeon removes the tip of the clavicle. This allows for normal movement of the AC joint (which is minimal even in healthy shoulders) while stopping the exposed bones from rubbing together. Usually, the incision is about an inch long and they remove less than a centimeter of bone. Then, over time, the AC joint fills up with scar tissue. Recovery After an AC joint resection, you can usually go home the same day. You'll likely start shoulder motion right away, possibly with physical therapy. While you recover, you may have pain and/or fatigue in your shoulder with heavy lifting or strenuous activity. Most people can return to full activity within the three months after surgery. Frequently Asked Questions Does AC joint arthritis go away? No. AC joint arthritis won't go away because it comes from a loss of cartilage, which can't be replaced. But AC joint arthritis can be well managed and have a minimal impact on your life. What foods should you avoid if you have AC joint arthritis? Try to avoid or limit foods that increase inflammation. Examples include red meat, processed meats, fried foods, refined carbs, and sweets. Learn More: 12 Foods to Avoid on an Arthritis Diet Was this page helpful? Thanks for your feedback! Dealing with chronic inflammation? An anti-inflammatory diet can help. Our free recipe guide shows you the best foods to fight inflammation. Get yours today! Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit 4 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Chaudhury S, Bavan L, Rupani N, et al. Managing acromio-clavicular joint pain: a scoping review. Shoulder Elbow. 2018;10(1):4-14. doi:10.1177/1758573217700839 Menge TJ, Boykin RE, Bushnell BD, Byram IR. Acromioclavicular osteoarthritis: a common cause of shoulder pain. South Med J. 2014;107(5):324-9. doi:10.1097/SMJ.0000000000000101 Johns Hopkins Medicine. AC joint problems. Harvard Health Publishing. Foods that fight inflammation.