The acromioclavicular (AC) joint is located on the upper part of the shoulder. There are three major ligaments that contribute to stability of the joint. These ligaments can be injured during a traumatic event. An injury to this joint is termed an “AC joint separation”. This is often injured with a fall directly on this side of the shoulder or with an outstretched hand. Sports with a higher incidence of AC joint separation are biking, hockey, and football.
Symptoms include pain and swelling over the upper portion of the shoulder, a displacement of the clavicle causing a prominence on the upper part of the shoulder, pain with reaching across the chest, or even instability or popping of the clavicle with arm motion. Diagnosis is obtained through a careful history and physical exam by your physician. X-rays are often obtained to evaluate the degree of separation and to evaluate for any fractures. An MRI is often obtained to evaluate for any injury to the rotator cuff. There are six grades of AC joint separations, depending on the degree of ligament injury and resulting separation of the joint. Low grade separations are treated very conservatively. Grade 3 sprains may heal with conservative care, such as rest, ice, and physical therapy. However, certain athletes with Grade 3 separations may need to elect for surgical reconstruction in order to return to full activities.