AC Joint Injury – A “Separated” Shoulder
What makes up the acromioclavicular joint?
The acromioclavicular (AC) joint is where your collarbone, or clavicle, meets with a part of the scapula, the flat triangular bone on the either side of your back. Where these two bones meet there is a joint, reinforced by soft tissue ligaments. This is a joint that only moves a few degrees and serves as a pivot point for the shoulder. If you injure this joint, you may have trouble raising your arm above your head.
How does the AC joint get injured?
Because of the highly exposed position of this joint, it is very easy to injure with a direct blow to the side of the shoulder. You see this type of injury in contact sports when players fall directly onto their shoulder, such as after getting tackled in soccer or football.
What are the different types of AC joint injury?
We classify injury to the AC joint based on which of the supporting ligaments were sprained (stretched and damaged) or torn, which correlates to how separated the collarbone is from the scapula after injury. This is why you may have heard this type of injury referred to as a shoulder “separation.”
What are the symptoms of an AC joint injury?
- Tenderness directly over the AC joint, right at the lateral end of your collar bone
- Often a visible deformity or separation between the collar bone and the shoulder
- Swelling and discoloration or bruising
- Increased pain when trying to touch the opposite shoulder
It is important to note that a fracture to the distal (most lateral) end of the collar bone can present very similarly to an AC joint injury and the two injuries are easily confused. A thorough assessment by someone from the OSS team can help ensure that the injury is properly diagnosed and treated.
How is an AC joint injury treated?
In addition to a careful physical exam, your provider will likely order x-rays to assess the degree of damage to the AC joint. This will help inform the best approach to treatment. For the mildest injuries, when there is no visible deformity and the trauma was low-impact, your provider may decide an x-ray is not necessary. Treatment may range from conservative treatment with rest and medication to surgery. The choice of repair methods and surgical approach are very dependent on the details of the case and can be discussed with you in detail by one of our excellent OSS surgeons.