AC Joint Pain: What is it and how do I fix it?

AC joint pain and injury is a common problem among athletes, especially rugby players, of which we have seen a few of over this busy winter sports season! So how do you know when you have injured your AC joint and what can you do about it?

Where is your AC joint?

The AC joint, or acromioclavicular joint, is the joint between you collar bone (clavicle) and your acromion (shoulder blade). It therefore is the only bony joint holding your entire arm to the rest of your body!

How does it get injured?

It is injured mostly from impact from another player or the ground, or possibly when your arm is pulled down or away from your body. If you have pain over the front of your shoulder in a localised spot and it hurts to touch directly over that spot, then it is likely you have injured your AC joint.

There are 6 grades of AC joint injury, with the first two being minor strain to the ligaments and no displacement of the joint. The last four grades however have some degree of displacement due to a large rupture of the AC joint ligaments. If you have a more severe AC joint injury, there will likely be a ‘step’ deformity in your shoulder, where one part of the joint is sitting higher than the other.

How can we fix AC joint pain?

Sometimes, if the injury is severe enough, it may be best to operate to ensure good stability in your shoulder in the future. This is rare however, and even if you have a step deformity, it is likely that it will be managed conservatively with exercises and rest.

As mentioned previously, this joint is the only bony one connecting your arm to your body, so it holds a lot of weight and therefore can be a very painful injury. In the initial stages it is best to rest it completely and wear a sling to avoid too much weight through the joint.

As the joint begins to heal, it is important to slowly strengthen the muscles surrounding your shoulder, to take the pressure off the AC joint and to ensure the shoulder is strong and stable. Doing this will also limit the amount of step deformity and movement through the AC joint once it is fully healed. You should be guided by your physiotherapist through these exercise progressions.

How long does it take?

This depends on the severity of your injury, however it can take anywhere from 4 weeks to 3 months to heal completely and be strong enough to return to sport. You should discuss this with your physio.