An acromioclavicular (AC) joint injury, commonly referred to as a shoulder separation, happens when the ligaments that hold the collarbone (clavicle) and the shoulder blade (acromion) together become stretched or torn. Despite the name, a shoulder separation is different from a shoulder dislocation, which affects a different part of the joint. These injuries often occur after a fall onto the outer shoulder, especially when the arm is at the side. The pain is typically focused right at the top of the shoulder, and symptoms can vary depending on how severe the damage is to the ligaments.
Symptoms of an AC Joint Injury
Pain at the top of the shoulder is the most common symptom, especially when moving the arm. You might also notice swelling and bruising, and in more serious cases, a bump or deformity at the top of the shoulder. Some people experience limited movement, weakness in the arm, or pain that radiates up toward the neck or upper back.
How To Know If Your AC Joint Is Separated
To diagnose an AC joint injury, a doctor will typically start with a physical exam. Pressing on the joint may cause discomfort, and your range of motion might be limited. X-rays are often used to determine how much damage has occurred and whether the bones are out of alignment. In some cases, doctors may perform specific tests, like having you move your arm across your chest to pinpoint the exact source of the pain.
Types of AC Joint Injuries (Grades 1–3)
AC joint injuries are categorized into three grades based on severity. A Grade 1 injury is considered a mild shoulder sprain. It involves stretching or a partial tear of the ligaments but doesn’t cause instability or visible changes to the joint. Symptoms usually include mild pain and swelling, and recovery typically takes between two to six weeks with rest, ice, and anti-inflammatory medications.
A Grade 2 injury is more serious. It involves a full tear of the AC ligaments and allows partial displacement of the collarbone from the shoulder blade. This can result in more noticeable swelling and pain, and sometimes a slight bump at the top of the shoulder. Treatment is similar to a Grade 1 injury but often takes longer to heal, typically six to twelve weeks.
The most severe form, a Grade 3 injury, involves complete tearing of both the AC and the coracoclavicular (CC) ligaments. This often results in a significant and visible shift of the collarbone upward and backward. People with this injury experience intense pain, swelling, and difficulty moving the arm. While many Grade 3 injuries can be managed without surgery, some severe cases may require surgical repair to stabilize the joint and reconstruct the torn ligaments. Recovery after surgery can take several months.
Whether or not surgery is needed, treatment for an AC joint injury usually begins with rest, ice, pain relief, and physical therapy. In some cases, a shoulder brace is recommended to keep the joint stable while the ligaments heal. Avoiding overhead exercises, heavy lifting, bench presses, and dips is important during recovery, as these movements can aggravate the injury.
When surgery is necessary—typically in the more severe Grade 3 injuries—the torn ligaments are reconstructed and the joint is stabilized. Results are generally good, but the recovery time is longer due to both the extent of the injury and the rehabilitation process.
What Happens If an AC Joint Injury Is Left Untreated?
If left untreated, AC joint injuries can lead to ongoing shoulder pain, reduced range of motion, and even long-term instability or arthritis in the joint. That’s why early treatment and a guided rehabilitation program are so important. Rehab focuses on restoring shoulder motion, strength, and control, and becomes even more essential for more severe injuries.
Rehabilitation: The Key to Recovery
Rehabilitation is an important part of the recovery process and becomes more important and prolonged with the more severe Grade 2 and 3 injuries. The patient must be guided through a program designed to recover range of motion, strength and neuromuscular control of the shoulder.
In summary, an AC joint injury, or shoulder separation, can range from a mild sprain to a serious ligament rupture. Most injuries heal well with conservative treatment, but severe cases may require surgery and a longer recovery period. With proper care, rehab, and a little patience, most people can return to their normal activities.
If you’re experiencing shoulder pain, swelling, or limited mobility, the orthopedic experts at OrthoConnecticut are here to help with personalized care and proven treatment options tailored to your needs.
