Understanding AC Joint Injuries

The shoulder contains two joints, the glenohumeral joint, and the acromioclavicular joint, or AC joint. The glenohumeral joint is where the arm and shoulder blade connect, which provides a wide range of motion. The AC joint does not move much but is critical for shoulder stability and allowing the arm to move freely. It connects the clavicle (collarbone) and shoulder blade, containing ligaments, cartilage, and synovial fluid. Injuring this joint from trauma or wear and tear can affect overall shoulder and arm function.

AC joint injuries can happen suddenly or slowly over time. Extending the arm puts the most strain on the AC joint – landing on an outstretched arm is the most common way the AC joint is fractured or separated. The following are types of AC joint injuries, their symptoms, and possible treatments.

AC Joint Sprain

One of the most common injuries to the AC joint is a sprain. This occurs when the ligaments are stretched and torn when the arm and shoulder are impacted. The ligaments are damaged but still connect to the bones within the joint. Symptoms include pain on the top of the shoulder which increases when you lift your arm above your head.

Treatment for AC joint sprains can include rest and immobilization initially, then followed by physical therapy and rehabilitation. Most AC joint sprains do not require surgery.

AC Joint Separation

When the ligaments are completely torn in the AC joint, the bones can be separated. This is a more severe injury that requires immediate medical attention. If the clavicle is displaced, it can cause nerve damage. Symptoms include pain at the front top of the shoulder, bruising, tenderness, swelling, and shoulder deformity.

Treatment for AC joint separation depends on the severity of the injury. There are several grades of separation – minor separation may be treated similarly to a sprain, but more severe injuries may require surgery.

AC Joint Fractures

Fractures to the clavicle are common injuries often occurring in contact sports or motor vehicle accidents. Acromion fractures are less common but can happen when there is severe trauma to the shoulder. Fractures of the AC joint cause pain, swelling, and bruising. There may be deformity if the bone is displaced. It will be painful to move the arm.

AC joint fractures do not always require surgery, only if the bones are displaced. Immobilization followed by rehabilitation can be used for less severe injuries.

AC Joint Wear and Tear (Arthritis)

Like any joint, AC joints can slowly deteriorate from wear and tear, resulting in worn-away cartilage. AC joint arthritis causes many patients pain, limited shoulder motion, and swelling. Treatment can include anti-inflammatory medications, injections, physical therapy, and other conservative therapies.

If you have a severe AC joint injury, you may need the expertise of an orthopedic surgeon. Call our office in Los Angeles, CA, to schedule an appointment at Robotic Hip and Knee Replacement LA with Dr. Kabaei.