What is the acromioclavicular joint?

The shoulder is made up of three bones: the humerus (upper arm bone), the clavicle (collarbone) and the scapula (shoulder blade). The part of the scapula that connects with the clavicle is known as the acromion, and where the acromion and clavicle meet is called the acromioclavicular (AC) joint. All of the bones in the joint are connected and supported by ligaments, which are strong bands of fibrous tissue.

Ultimately, this joint is responsible for allowing the shoulder to move freely.

What are common AC joint injuries and conditions?

Some of the more common injuries involving the AC joint include:

  • AC joint separation, which occurs when the ligaments in the joint become injured or torn, resulting in a dislocation or separation of the acromion from the clavicle
  • Osteoarthritis of the AC joint—also known as degenerative joint disease—a wearing down of the cartilage covering the tops of the bones that make up the joints, causing the bones to grind against one another

These conditions cause symptoms including pain, inflammation and difficulty moving the shoulder. The joint may also make clicking or snapping sounds as it moves, and a visible bump may appear over the joint.

What causes these injuries?

These types of injuries are usually the result of acute trauma or overuse. Trauma can include falling directly on the shoulder or an injury following an event such as a motor vehicle accident. Overuse injuries occur when the same motion is repeated again and again, which causes wear over a period of time. In the case of the AC joint, it’s the constant lifting of heavy amounts overhead—such as performed by weightlifters or shelf stockers, for example—that leads to injury.

How are AC joint injuries treated?

Nonsurgical Options

In many cases, an AC joint injury can be managed with physical therapy to strengthen and restore movement, as well as medication to reduce pain and inflammation. Medication can include over-the-counter medications like aspirin and ibuprofen or corticosteroid injections into the joint.

Surgical Options

Should conservative methods of treatment fail to alleviate symptoms within a reasonable amount of time—or if the injury is too severe—surgery may be required to effectively repair the damage.

Surgery for AC Joint Osteoarthritis
The most common surgical method for repairing the damage from AC joint osteoarthritis is distal clavicle resection. With this procedure, the surgeon removes a portion of the clavicle so that just enough space is left between it and the acromion, allowing the joint to maintain its flexibility without the bones rubbing together. This is typically done arthroscopically, using a camera and small instruments through small skin portals.

Surgery for AC Joint Separation
For joint separation, the ligaments can potentially be repaired or reconstructed. A distal clavicle resection is often performed along with ligament treatment.

Come to the Upper Extremity Specialists

At IGEA, our orthopaedic surgeon specializes in treating shoulder injuries, including AC joint damage, using advanced treatment options. These and other specialties are part of our practice’s full continuum of care for patients living with brain, spine, neuroendovascular and orthopaedic conditions.

For more information about the superior care and services we provide or to schedule an appointment with one of our experts, contact us today.