Acromioclavicular (AC) joint dislocation

A dislocation of the joint where the front of the shoulder blade (acromion) meets the collarbone (clavicle).

About

Your shoulder blade (scapula) has a slim bone that extends over the top of your shoulder called the acromion. This links to your collarbone (clavicle) in the front of your shoulder at the acromioclavicular (AC) joint.

The joint is held together by strong, fibrous tissue called ligaments, which can be stretched (sprained), causing the bones to separate or dislocate.

Causes of AC joint dislocation

An AC dislocation is most commonly caused by:

  • impact to your shoulder - such as in contact sports or a car accident
  • fall onto the tip of your shoulder
  • weightlifting
  • degenerative bone conditions such as arthritis

Most AC dislocation injuries heal on their own in six to 12 weeks, with the help of rest and gentle exercises.

If the damage is more severe, it might be necessary to have surgery to reconnect, stabilise or reconstruct the joint.

Symptoms of AC joint dislocation

  • Pain at the moment the injury occurs
  • Limited movement in the shoulder area because of pain
  • Swelling and bruising
  • Tenderness over the AC joint on top of your shoulder
  • Bump at the top of your shoulder

Diagnosis of AC joint dislocation

Your doctor can usually diagnose an AC dislocation with a physical exam and assessment of your symptoms.

If your symptoms are severe or may be related to another condition such as arthritis, an X-ray can be used to show the extent of the damage.

However, imaging is invariably required including stress X-rays and an MRI scan to more accurately assess the extent of the damage.

Treatments for AC dislocation

Non surgical options

Most minor AC joint dislocation injuries can be treated at home, and heal within a few weeks. More severe damage can take up to 12 weeks.

Avoid activities that aggravate your shoulder.

Use ice and anti-inflammatories to manage swelling and pain.

Your doctor might suggest strengthening and stretching exercises to restore strength and motion in your shoulder as it heals.

Surgical options

If your symptoms don’t improve, you may be offered AC joint reconstruction surgery.

This is usually carried out using minimally invasive but open surgery.

Your surgeon will reconstruct the stretched ligaments beneath your collarbone. This may involve anchoring the ligaments back into the bone, or using a tendon (from your body or from a donor) to replace damaged ligaments.

“I had a great experience at the Cromwell Hospital; the staff were amazing, and is another level of professionalism compared to other hospitals I’ve stayed in.”

Lorne, patient

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Published: 6 February 2020 | Review: 6 February 2023

Disclaimer: This information is published by Cromwell Hospital and is based on reputable sources of medical evidence and experience from over 30 years of treating patients. It has been peer reviewed by Cromwell Hospital doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional. If you have any feedback on the content of this patient information document please email info@cromwellhospital.com or telephone 020 7460 5901.