The signs and symptoms of acromioclavicular arthritis (AC joint arthritis) tend to progress gradually. The pain may seem to get better only to return worse later.
Many people initially attribute shoulder soreness or stiffness to lack of exercise or getting older. Early recognition of symptoms and appropriate activity modification and treatment can sometimes slow or eliminate progression of AC joint osteoarthritis symptoms. By doing so, people can guard against other shoulder joint problems that can result from AC joint arthritis, such as tendinitis and shoulder impingement syndrome.
Learn more about Shoulder Impingement on Sports-health.com.
Pain with certain motions
People with acromioclavicular arthritis have difficulty with cross-body arm movement—holding the arm out straight and then moving it in a horizontal plane across the body, toward the other shoulder. Reaching up and across the body to put on a car seat belt can pose a challenge.
A person may also have pain when performing a bench press or push up, reaching behind the back, or reaching overhead.
Joint tenderness and pain
The spot where the scapula and clavicle meet, located at the front and top of the shoulder, may feel tender and painful. (Alternatively, tenderness and pain that is isolated to the back of the shoulder may be a sign of arthritis in the glenohumeral joint, commonly known as the shoulder’s ball-and-socket joint.)
For symptoms and treatments for another common type of shoulder arthritis (Glenohumeral Arthritis), see Shoulder Osteoarthritis Symptoms
It is possible for arthritis pain that originates at the AC joint to radiate into the rest of the shoulder, the base of the neck, or arm.1 Pain that radiates to the base of the neck may lead to headaches.2
Inactivity makes it worse
The joint area can become stiff after long periods of inactivity and get better after short bouts of activity.
Laying on the affected shoulder can be painful. Many people decide to go to the doctor when shoulder pain begins to interrupt sleep.1
When arthritis causes friction between bones, the surrounding soft tissue can become irritated and swell. Swelling at the top and front of the shoulder is sometimes seen in people with AC joint arthritis.
The shoulder may produce a clicking, popping, snapping, or crunching sensation when stress is put on it.1 The medical term for this symptom is called crepitus.
In most but not all cases, the symptoms of AC joint osteoarthritis come and go, becoming worse and more frequent over months or years. Acromioclavicular osteoarthritis pain may flare up after high-intensity activities, such as tennis or weightlifting.