AC Joint Injury

AC Joint Injury 364 200 Dr Paul Annett

I see Josh Dugan of the Canberra Raiders has succumbed to an AC joint injury of his shoulder, reported as being grade 3 injury.

The AC joint is formed between the clavicle (collarbone) and the acromion (shoulder blade) at the front of the shoulder. It is most commonly injured when a patient lands directly on the point of their shoulder, such as a footballer being tackled into the ground. Another term for this is a ‘separated shoulder’.

The injury is classified in increasing severity from 1-3, 3 being the most severe. A grade 1 injury reflects a simple sprain with no joint separation, a grade 2 injury involves a partial separation of the joint, but reflects continuity of the stabilizing ligaments – the coracoclavicular ligaments. A grade 3 injury involves a rupture of these ligaments leading to a complete separation of the joint. In this case there is an obvious ‘step’ deformity of the AC joint. On X-ray this includes a greater than 100% separation of the clavicle from the acromion. A weight bearing view of the joint (with the patient holding onto some weights) will demonstrate this more clearly.

A grade 3 AC joint separation with displacement of the clavicle on the acromion

Historically all grades of AC joint injuries have been treated conservatively. A grade 3 injury may take a good 8-12 weeks to fully settle down and allow a return to contact sport. In recent times the treatment of these injuries has involved surgery. Aside from the ongoing cosmetic deformity from this injury, patients do describe difficulty with overhead activities, and particularly lifting. As such a simple procedure to stabilize the joint will prevent this being a problem. This is important in rugby league players who need to lift weights as part of their training and also sustain considerable contact to the joint. The overall recovery from the surgery is similar to the time taken to return from the original injury, so little is lost with this procedure, and there is a greater guarantee of a functional joint in the future.

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