AC Shoulder Joint Arthritis


One of the most critical joints in your body is the shoulder. It allows you to raise your arms and execute basic but frequently unassumed movements like carrying groceries or shaking hands.

Sometimes, frequent usage can lead to shoulder injuries due to the amount of stress applied there. Besides those injuries, you can also get AC joint arthritis.


The AC joint (AcromioClavicular joint) is positioned at the tip of the shoulder, where the shoulder blade (scapula) and the collarbone (clavicle) meet at a point on the upper part of the shoulder blade called the acromion. Ligaments connect these two bones. The acromioclavicular ligaments surround the joint to create a capsule.

Another collection of ligaments (coracoclavicular ligaments) stabilizes the shoulder by linking the clavicle to a bony protrusion on the surface of the shoulder blade called the coracoid process. In the joint between the two bones, a cartilage disk helps guide the joints. The AC joint facilitates movement between the clavicle and scapula when you move your shoulder.


Acromioclavicular injury or arthritis (also known as AC joint arthritis) is an unpleasant condition that affects the upper “surface” of the shoulder, where the collarbone (clavicle) meets the shoulder blade (scapula).

Osteoarthritis is caused by the joints’ breakdown and loss of articular cartilage. Articular cartilage covers and protects the ends of bones where they meet in the AC joint and is very slippery and flexible.

During the development of osteoarthritis, the amount of cartilage decreases. The body may try to make new cells, but it won’t produce enough to replace the lost cartilage.

If you have AC joint arthritis or an injury, you may have discomfort while moving or swinging your arm across your body, such as when swinging a tennis racket or golf club. This condition occurs mainly in middle-aged and older people.

Cartilage doesn’t have any nerves, so the loss of cartilage in the AC joint doesn’t necessarily cause pain.


Arthritis is characterized by pain and stiffness in the joint. Shoulder pain and soreness on the top or front of the shoulder and discomfort and stiffness while performing specific shoulder motions, such as extending across your body or stretching or reaching up, are common symptoms of AC joint arthritis.

As the joint’s inflammation progresses, you may occasionally sense a minor swelling in the affected region. Symptoms often advance slowly, and they are frequently assumed to be a normal part of the aging process, which allows the illness to continue unnoticed and untreated.

Having shoulder pain symptoms addressed as soon as possible may help reduce the advancement of the illness and avoid developing other linked issues such as shoulder impingement later in life.


Your shoulder anatomy is complicated and prone to a range of issues. It is not unusual for two or more disorders to occur simultaneously. Acromioclavicular osteoarthritis, for example, may coexist with shoulder impingement syndrome or glenohumeral osteoarthritis.

Because no specific test can conclusively identify acromioclavicular osteoarthritis, doctors use a multidisciplinary approach to rule out other possible origins of pain, such as rotator cuff issues or cervical degenerative disc disease, which may induce referred pain.

Most people over the age of 50 will develop some form of osteoarthritis in their main joints, which may show up on an x-ray, even if they have no pain or other symptoms. For that reason, an x-ray, MRI, or other diagnostic investigation should not be used to make a diagnosis on its own. On the other hand, diagnostic imaging is best used to confirm a clinical diagnosis.

Several investigative methods are used to achieve an accurate diagnosis:

  • Interaction with the Patient – Your doctor will inquire about your occupation, lifestyle, hobbies, and past shoulder injuries. They will also ask about your family history and when shoulder problems started, the pattern of discomfort, limits in range of motion, and what causes the symptoms to improve or worsen. The answers to these questions are critical for diagnosis and therapy.
  • Physical Examination – The joint is evaluated for symptoms of past damage, tenderness and pain spots, and muscle weakness. The doctor will also look for differences between the affected and unaffected shoulders.
  • Medical Diagnostics – Follow-up testing may be ordered to determine the degree of acromioclavicular arthritis and rule out other issues:
Local Anesthetic Injection

Putting a local anesthetic like lidocaine into the aching joint may help diagnose arthritis. If the patient’s discomfort is briefly eased, arthritis is proven. If the pain continues, it is likely due to another shoulder issue, such as a rotator cuff injury.

Lab Testing

While lab testing cannot diagnose AC joint osteoarthritis, they can rule out other causes of shoulder discomfort, such as rheumatoid arthritis. A blood draw or a shoulder joint aspiration may be required.


An MRI (Magnetic Resonance Imaging) scans soft tissue (ligaments, tendons, and muscle) as well as bone. If x-rays are ambiguous or the doctor feels symptoms are due to anything other than osteoarthritis, including rotator cuff injury, MRI images of the shoulder joints may assist. An MRI frequently indicates excess fluids and unusual inflammation at and around the acromioclavicular joint.


An x-ray showing the acromioclavicular joint’s bones closer together than usual suggests cartilage degeneration (osteoarthritis). An x-ray may reveal alterations in the bone, such as bone spurs. X-rays may reveal strong evidence of acromioclavicular osteoarthritis and slight pain in some persons while showing few signs and severe discomfort in others. One research revealed no significant difference between patients with and without osteoarthritis symptoms on their AC joint x-rays.

Treatment (Overview)

Many non-surgical therapies, such as rest and medication, may ease the discomfort associated with acromioclavicular osteoarthritis (AC joint arthritis). Shoulder surgery may be an alternative when non-surgical treatments fail to cure chronic, moderate-to-severe pain.

Non-Surgical Treatments

Most people with AC joint arthritis will never need surgery. The following are some of the non-surgical therapies that are suggested:

  • Changes in Activity – Certain activities and exercises may aggravate the acromioclavicular joint. If weightlifting, golfing, or other practices that demand cross-body arm movement create discomfort, they should be avoided. Alternatives to other everyday activities may need to be considered.
  • Warm or Cold Presses – Using moist heat, such as a warming pad or whirlpool, for several minutes before exercise can release a tight AC joint. After a workout, icing the shoulder joint for 15 to 20 minutes may help reduce swelling and give some immediate pain relief. These therapies reduce the symptoms of AC joint osteoarthritis and do not address the condition’s underlying causes.
  • Physical Therapy – Exercises that concentrate on stretching and strengthening muscles and preserving the shoulder’s range of motion may be beneficial depending on the patient, coexisting diseases, and the individual physical therapy program. Physical therapy has been proven to be less helpful for persons with isolated acromioclavicular arthritis than hip and knee osteoarthritis treatment, which prioritizes physical therapy.
  • Medications – They include the following:

Acetaminophen (Tylenol) is a pain medication with minimal adverse effects.

Non-steroidal anti-inflammatory drugs (NSAIDs) – Osteoarthritis of the AC joint may be relieved by anti-inflammatory drugs such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), or cox-2 inhibitors (Celebrex).

Topical creams – Topical medicines are applied directly to the skin over the affected joint. They come in many forms. The brain is distracted from joint pain by topical NSAIDs, whereas topical lidocaine is a numbing agent that inhibits pain signals. Topical medicines may be preferable to oral drugs for persons with acromioclavicular osteoarthritis who wish to avoid gastrointestinal side effects.

Surgical Procedures/Treatments

Surgery may be an option if nonoperative therapy and activity adjustment does not relieve your osteoarthritis symptoms.

The most often used procedure is a resection of the distal clavicle. Distal clavicle resection, also known as the Mumford surgery, involves removing a tiny part of the clavicle’s end to eliminate friction between the clavicle and scapula. Scar tissue eventually covers the space between the two bones. The AC joint’s ligaments are kept in place during this operation to minimize postoperative joint instability.

Next Steps

If you have shoulder pain and suspect that you’re suffering from AC joint arthritis, call for an appointment with Dr. Peter Howard to have it checked.