Shoulder Acromioclavicular Joint (ACJ) Sprain

What is it?

The AC Joint or acromioclavicular joint is a small joint between the acromium of the shoulder blade and the collarbone. It forms an important link between the arm and the skeleton and plays an important role when elevating the arm.


The AC Joint has a capsule and small AC Joint ligaments, which provide stability. Although the AC Joint ligaments are relatively weak, there are also two much stronger ligaments that attach the clavicle to a different point on the shoulder blade called the coracoid. These ligaments are termed the conoid and trapezoid ligaments and are collectively known as the coracoclavicular ligaments. They hold the clavicle in place and prevent it from being displaced upward.


Mechanism of Injury

Traumatic AC Joint injuries are most commonly caused by a direct impact to the shoulder but can also occur due to a fall on an outstretched hand, cyclists after falls from their bike and in contact sports such as rugby and football.


Acute AC Joint Injury Symptoms:

AC Joint injuries are traumatic in nature resulting in significant pain at the point of injury. The pain is localised but may extend upward into the neck or down into the front of the shoulder. Depending of the severity of the AC Joint injury, there may be swelling and/or a bump at the end of the clavicle. There is usually an inability to raise the arm above shoulder height due to pain.

 Semi-Acute AC Joint Injury Symptoms:

Common Management Techniques

Physiotherapy Treatment for AC Joint Injuries:


Grade 1 AC Joint Injury Treatment:


Grade 2 and 3 AC Joint Injury Treatment:


Medical Treatment for AC Joint Injuries:


Surgical Treatment for AC Joint Injuries:



For some people a course of physiotherapy for 6 weeks may be suitable, for other it may be ongoing. Some patients who do not respond to conservative management may need to go on to having surgery or the use of injection to aid in management of the disorder combined with exercise therapy.