Arthrosis of the acromioclavicular joint


AC joint arthrosis; Shoulder joint arthrosis


Arthrosis is a sign of wear in a joint. Often this wear is of a degenerative nature, i.e. it is a kind of symptom of old age. However, the likelihood of the occurrence of arthrosis can be significantly increased, for example, by a trauma (accident) with joint involvement in younger years. The AC joint is the joint between the outer part of the collarbone (clavicle) and a bony protrusion on the upper part of the shoulder blade, the so-called acromion. The AC joint is a part of the shoulder joint and is also known as the acromioclavicular joint.


In most cases, AC joint arthrosis is purely degenerative in nature. The joint is one of the most frequently affected by arthrosis, which can be partly explained by the fact that it is subject to strong mechanical stress. Almost all people over 50 years of age have arthrotic changes in the acromioclavicular joint, but these often remain without symptoms.

Various previous traumas can increase the risk of arthritis in the acromioclavicular joint: Both events can occur in falls on the shoulder or arm. – Previous fracture of the clavicle

  • Fracture of the acromioclavicular joint

Those affected report a gradual onset and a gradual increase in pain, especially the lifting of the arm is perceived as painful. However, pain can also occur at rest, some of which radiates into the neck. Various symptoms indicate arthrosis of the acromioclavicular joint:

  • High painful arch: the lateral elevation of the arm from a lift of about 120° is considered painful. – Positive hyperadduction test: Here the patient feels pain in the shoulder when the affected arm is jerked in front of the body towards the centre of the body.


The diagnosis is made clinically (i.e. by the patient’s description of his symptoms and physical examination), the presence of a high painful arc and a positive hyperadduction test, as well as a punctual pressure pain in the area of the AC joint make the diagnosis likely. In addition, local swelling can often be observed, which is caused by bony attachments or soft tissue swelling. An x-ray helps to make a reliable diagnosis, as it shows the changes typical of osteoarthritis: However, there is often a clear discrepancy between the X-ray image and the patient’s symptoms, so patients with severe osteoarthritis can be clinically completely free of symptoms in the X-ray image. – Narrowed joint space

  • Bony extensions (osteophytes)


Treatment is initially conservative, i.e. non-surgical: If the above-mentioned procedures fail to improve the situation, there is the possibility of surgical removal of the outer part of the clavicle (resection arthroplasty). – In addition to the use of painkillers (mostly in the form of NSAIDs, i.e. non-steroidal anti-rheumatic drugs, but also in the form of occasional direct cortisone injections into the affected joint space)

  • Especially physical therapy is in question. HieCortisone therapy for joint diseases includes, for example, iontophoresis, in which a drug substance applied to the skin is absorbed into the underlying tissue by means of a weak electric current. Ultrasound therapy, in which heating of the tissue is intended to help relieve symptoms, can also be part of the therapy.