The AC joint is where the highest point of the shoulder blade (acromion) meets the collarbone (clavicle).
What causes an AC separation?
Separation of the collarbone from the acromion at the AC joint is usually caused by falling onto the shoulder, causing injury to the ligaments that stabilise the joint. It is more common among people who take part in contact sports as well as horse riders, cyclists, and skiers. The extent of the injury depends on the force of the impact. Recovery is usually successful, even after a serious injury.
What are the symptoms?
Pain, tenderness, swelling, weakness, bruising and a bump on top of the shoulder are common symptoms.
How is it diagnosed?
Injuries that cause an obvious deformity are easy to diagnose; in cases where there is less of a deformity, the specialist will ask questions about your injury, identify where there is pain, and back the diagnosis up with an X-ray or MRI scan to show the extent of the damage.
How is it treated?
Non-operative treatment: this includes wearing a sling, applying ice (crushed and wrapped in a towel) several times a day to reduce inflammation, and taking anti-inflammatory medication if advised by your doctor. For most people this is enough to be able to return to their everyday activities, even if they still have a slight deformity.
Surgery: if your symptoms don’t improve, you may be offered surgery – usually carried out via arthroscopy - to trim the end of the collarbone to prevent it from rubbing against the acromion and, in some cases, ligament repair surgery to reconstruct ligaments beneath the collarbone. Afterwards, a gentle exercise programme will help you to regain your strength, flexibility and range of movement.
Important: This information is only a guideline to help you understand your treatment and what to expect. Everyone is different and your rehabilitation may be quicker or slower than other people’s. Please contact us for advice if you’re worried about any aspect of your health or recovery.