Abstract
Acromioclavicular joint osteoarthritis is often a cause of shoulder pain. On the other hand, imaging frequently leads to such a diagnosis, especially in elderly patients, and some authors believe it to have a poor correlation with the clinical picture. It is, however, widely accepted that such a condition can be the cause of rotator cuff impingement. In the case of shoulder pain, it is important to distinguish between symptomatic acromioclavicular osteoarthritis and other causes, especially rotator cuff pathology, which is more common. Sometimes, the clinical picture does not allow for differential diagnosis; in these cases, the injection of a local anesthetic into the acromioclavicular joint or into the subacromial bursa can be of great help. Ultrasonography can easily detect acromioclavicular osteoarthritis and rotator cuff pathology, and it is highly effective in guiding the articular or bursal injection of a local anesthetic to assess the origin of the pain. In addition, in conservative therapy, ultrasonography can guide the articular or bursal injection of corticosteroids and hyaluronic acid.