Specialized Shoulder Care in Colorado Springs

Acromioclavicular (AC) Joint Injuries

Colorado Springs Orthopaedic Group

Your shoulder is one of the body's most mobile joints, allowing you to reach, lift, rotate, and perform countless everyday movements. Because of this mobility, the shoulder can also be susceptible to injuries, overuse, arthritis, and other conditions that cause pain and limit movement.

CSOG provides comprehensive evaluation and treatment for a wide range of shoulder conditions, from sports injuries and tendon problems to arthritis, instability, and fractures. Depending on your condition, treatment may include physical therapy, activity modification, medications, injections, minimally invasive procedures, or surgery.

Our shoulder specialists take the time to understand your symptoms, activity level, and goals so you can receive treatment designed to reduce pain, improve function, and help you get back to the activities that are important to you.

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What is an AC Joint Injury?

The acromioclavicular (AC) joint in the shoulder is very important for shoulder strength, motion, and maintaining shoulder position. The joint is stabilized by various ligaments and a capsule, which can cause pain and affect normal joint function if damaged.

What is the Anatomy of the AC Joint?

The AC joint is located at the highest point of the shoulder, where the acromion, a bony projection on the shoulder blade, connects to the clavicle or collarbone. This joint enables you to lift your arm above your head and is important for overall shoulder control, motion, and strength.

The AC joint is stabilized by the following structures:

• Capsular ligaments: These ligaments are called the acromioclavicular ligaments. They have upper and lower components and resist separation of the joint in the horizontal direction.
• Extracapsular stabilizers: These are ligaments extending from the bony process of the scapula called the coracoid process to the clavicle (coracoclavicular ligaments) and the acromion (coracoacromial ligaments). These ligaments resist vertical forces from separating the joint.
• Muscular attachments: The deltoid muscle on the outside of the shoulder and the trapezius muscle in the upper back and neck also help stabilize the acromioclavicular joint.

An injury to the AC joint, particularly the ligaments, can result in instability or separation of the AC joint (shoulder separation), causing pain and discomfort and limiting shoulder function.

What Causes AC Joint Injuries?

Injuries to the AC joint commonly occur due to:

• Falling onto the shoulder
• Lifting heavy objects or weights

What are the Risk Factors for AC Joint Injuries?

Various situations which can result in an AC joint injury include:

• Participating in contact sports
• Participating in activities that increase your risk of falls, such as skiing, biking, or skating.
• Weightlifting
• Physically strenuous jobs

What are the Symptoms of AC Joint Injuries?

Signs and symptoms of AC joint injuries include:

• Pain over the AC joint at the top of the shoulder
• Tenderness at the top of the shoulder
• A bump over the shoulder
• Swelling
• Bruising
• Shoulder tightness and loss of motion
• Pain with lifting the arm

How are AC Joint Injuries Diagnosed?

Your doctor will review your symptoms and medical history. A thorough physical examination is performed to check for a range of motion, blood flow, stability, and strength of the joint. Other diagnostic tests include:

• X-ray
• MRI
• CT scan or ultrasound for a detailed evaluation of the joint.

What is the Treatment for AC Joint Injuries?

In most cases, the following conservative treatment methods are quite effective in treating the injury:

• Resting the joint for prolonged periods
• Application of an ice pack at regular intervals to reduce pain and swelling
• Use of anti-inflammatory medications
• Physical therapy to help strengthen the shoulder muscles and improve range of motion.