AC Joint Injury

Acromioclavicular (AC) joint injuries account for around 40% of all shoulder injuries that occur in contact sport. Our physiotherapist Laura Scott investigates physiotherapy treatment and what to do if you have an AC joint injury.

What is the AC joint?

The joint itself is one of four major joints which make up the shoulder. It is where the clavicle (collar bone) and the acromion (part of the shoulder blade) articulate. The joint is held together by two main ligaments; coracoclavicular ligament and the acromioclavicular ligament. Together these ligaments work to prevent dislocation of the joint.

How can you injure your AC joint?

You may commonly see AFL footballers suffer such an injury after falling onto an outstretched hand or elbow. The joint can also be affected by a direct blow to the joint or similarly falling onto the AC joint. The joint functions to absorb the force coming from the upper limb, thus if we fall onto our elbow or outstretched hand, the AC joint is responsible for absorbing this force. Disruption of the ligaments will occur when the force translated is greater than the capacity of ligaments.

Along with AFL players, this injury is often seen in hockey and rugby players, cyclists as well as skiers/snowboarders.

Injury to the AC joint can range from minor to severe based upon the level of impact and instability present thereafter. Diagnosis will be based upon a combination of factors including; subjective history i.e. trauma, objective testing i.e. special tests and palpation and if required imaging results such as an x-ray or MRI.

If injury to the AC joint is suspected, your physiotherapist will perform a series of test to determine the level of severity.

Type 1: presence of swelling, with pain on abduction only (moving arm out to he side)

Type 2: presence of swelling, pain in all directions of movement

Type 3: visible step deformity showing complete disruption of ligament fibres

Physiotherapy for AC joint injury

Conservative management is often the recommendation for type 1 and 2 AC joint injuries. In the initial stages treatment will focus on the acute management of symptoms i.e. Pain, preserving/regaining range of motion, and maintaining muscle length. In these stages your physiotherapist may also look to tape the shoulder to assist with stability and avoidance of aggravating positions.

Once full range of motion is regained, treatment will focus on both stability and strength around the shoulder prior to then sport specific exercises and rehab.

Surgery for AC joint injury

Surgery may be indicated for the more severe cases or where conservative management has failed. Surgical management may involve a joint fixation or ligament reconstruction to insure the stability of the joint. In more severe cases, the risk of early degeneration of the joint increases.

If you suspect you have injured your acromioclavicular joint, book in to see one of our physiotherapists for a thorough assessment.