Acromioclavicular (AC) Joint Dislocation or Separated Shoulder

“A separated shoulder, also known as acromioclavicular joint injury, is a common injury to the AC joint. The AC joint is located at the outer end of the clavicle where it attaches to the acromion of the scapula. Symptoms include pain which may make it difficult to move the shoulder and often a deformity. It is most commonly due to a fall onto the front and upper part of the shoulder when the arm is by the side. They are classified as type I, II, III, IV, V, or VI with the higher the number the more severe the injury. Diagnosis is typically based on physical examination and X-rays.” In Wikipedia.

What is the AC Joint?

The AC joint is where the acromion process and the clavicle meet and form a joint. See the shoulder anatomy section. It is a small joint, but commonly sprained in car accidents, bicycling and in contact sports. There are several ligaments surrounding the joint and depending on the severity of your injury you may have torn one or all of the ligaments.


AC Joint Separation – Bike Crash Video

This is one of Edward Seade, M.D.’s patients who is a professional cyclist who fell and sustained an AC joint dislocation or separation by landing onto his shoulder during this fall. His riding partner happened to have a video camera on his helmet and captured the accident on tape. The rider received a grade III AC joint separation from this fall. His bike tire actually gets caught under the car tire and blows-up. On the slow motion portion of the video, you can see and hear the tire exploding. The car involved did stop to assist the rider. This type of motor vehicle / bike accident, in which the car turns in front of the biker in this manner, is very common.

What are the different injuries one can get around the AC joint?

The ligaments can either partially tear or fully tear around the AC joint. When you fully tear the ligaments the clavicle “rides” up and is seeing/felt higher at the top of the shoulder.

You can also fracture the outer part of the clavicle and/or the acromion process and this may also look like the clavicle is riding up. Luckily, most of the injuries are mild ligament strains and not full fledged tears causing the upward displacement of the clavicle.

What is the treatment for the AC joint injuries?

Proper diagnosis is imperative. With this we can tailor your therapy accordingly. A large majority of the patients do great with a sling for comfort and early range of motion with physical therapy.

There are some fractures and or ligament injuries that need to have surgical intervention. Again, these patients are the minority, but the goal is the same and that is to get you back to your pre-injury state.

This resource has been provided by Edward Seade, M.D. as general information only. Additional information can be found by visiting our clinic. Please call for an appointment at 512-583-0219

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