Ac Joint Injuries

An acromioclavicular (AC) joint injury is commonly referred to as "shoulder separation".
AC Joint is the joint at the top of your shoulder between your clavicle (collarbone) and your scapula (shoulder blade). The AC joint is important in allowing overhead and across the body movements of your arm, as well as transmitting forces from the arm to the rest of the body during activities such as pushing, pulling and lifting. There are a number of ligaments which help to stabilise this joint.

Causes -

Direct forces can injure your AC joint when a person collides with a solid object or surface such as a fall from a bicycle or during a football tackle where the shoulder hits the ground.
Your AC joint may also be injured indirectly when a person falls on an outstretched arm. The contact force is transmitted up through the arm, which forces a separation of the acromion and clavicle. The ligaments are overstretched and damaged in the process.

Symptoms -

Your physiotherapist will suspect an acromioclavicular ligament sprain when you report:

Treatment -

Most patients with acromioclavicular joint injury start to feel better within a few days or a week of the injury. However, full ligament healing will take at least six weeks. During this time it is important to protect your AC joint ligaments from overstretching the immature scar tissue. It can be helpful to use a sling, taping or a shoulder brace that de-loads your AC joint.


In severe cases, some patients choose to undergo AC joint surgery to pin the AC joint or repair the damaged ligaments surrounding the AC joint. Post-operative rehabilitation is one of the most important, yet too often neglected, aspects of surgery. The quickest and most successful outcomes result from the guidance and supervision of an experienced shoulder physiotherapist.
Risks of surgery include infection, persistent instability and pain, stiffness, and difficulty returning to your previous level of activity.