Acromioclavicular (AC) Joint Separation: Causes, Symptoms, and Treatment

What is an Acromioclavicular (AC) Joint Separation?

The AC joint is located at the top of the shoulder, where the clavicle (collarbone) meets the acromion, a part of the scapula. A separation occurs when the ligaments supporting the joint are damaged, often resulting in the collarbone moving upward, causing pain and visible deformity. The severity of the injury depends on the extent of the ligament damage.

Types of AC Joint Separation

AC joint separations are graded based on the severity of the injury:

1. Grade 1 (Mild):

   • In this type, the ligaments are stretched but not torn. There is mild pain and swelling, but the bones remain in alignment.

2. Grade 2 (Moderate):

   • The ligaments are partially torn, leading to some misalignment of the collarbone. There is moderate pain, swelling, and bruising.

3. Grade 3 (Severe):

   • Both the acromioclavicular and coracoclavicular ligaments are completely torn, causing significant misalignment of the collarbone. This is the most severe form of AC joint separation and often requires surgical intervention.

4. Grade 4, 5, and 6:

   • These are rare, more severe cases where the clavicle is displaced significantly, often behind or beneath the acromion or the coracoid process.

Causes of AC Joint Separation

An AC joint separation is typically caused by direct trauma or force to the shoulder, such as:

1. Falling onto an Outstretched Hand:

• When you fall on an outstretched arm, the force can travel up the arm to the shoulder, causing damage to the AC joint.

2. Direct Blow to the Shoulder:

• A direct impact or fall onto the top of the shoulder, such as in contact sports (e.g., rugby, football), can separate the acromion and clavicle.

3. Repetitive Stress:

• Athletes involved in sports that require overhead movements or contact may be more prone to AC joint separation due to repetitive strain on the ligaments.

Symptoms of AC Joint Separation

The symptoms of an AC joint separation vary based on the grade of the injury, but the most common signs include:

1. Pain at the Top of the Shoulder:

• Immediate pain is felt at the AC joint, which worsens with movement, particularly overhead or across the body movements. The pain is often sharp, especially after the initial injury.

2. Swelling and Bruising:

• Swelling and bruising may appear around the shoulder and collarbone area, particularly with moderate to severe separations.

3. Deformity:

• In more severe cases (Grades 2-3), the collarbone may be visibly raised or displaced, creating a bump at the top of the shoulder. This is a hallmark sign of an AC joint separation.

4. Limited Range of Motion:

• Movement of the shoulder is often restricted, particularly lifting the arm overhead or across the body. This is due to pain and joint instability.

5. Instability:

• A feeling of weakness or instability in the shoulder is common, especially in Grade 3 injuries, where the ligaments are torn.

Diagnosing AC Joint Separation

A healthcare provider will typically diagnose an AC joint separation through:

1. Physical Examination:

• The doctor will assess the shoulder for tenderness, swelling, and deformity. They may also perform special tests to determine the level of separation and instability.

2. Imaging Tests:

• X-rays: X-rays are the primary diagnostic tool used to assess the severity of the AC joint separation. They can show the alignment of the clavicle and acromion, confirming the extent of the injury.

• MRI: An MRI may be used to evaluate soft tissue damage to the ligaments and muscles around the joint, especially in severe cases where surgery is being considered.

Treatment for AC Joint Separation

Treatment for an AC joint separation depends on the severity of the injury and may range from conservative methods to surgical intervention.

Non-Surgical Treatment (for Grade 1 and Grade 2)

1. Rest and Ice:

   • Initially, rest and ice therapy are recommended to reduce pain and swelling. Ice packs should be applied to the affected area for 15-20 minutes every few hours during the first 48 hours after the injury.

2. Pain Management:

   • Over-the-counter pain relievers, such as NSAIDs (Nonsteroidal Anti-Inflammatory Drugs), can help reduce pain and inflammation.

3. Shoulder Sling or Brace:

   • A shoulder sling or brace may be used to immobilize the shoulder and reduce stress on the injured ligaments, particularly during the healing phase.

4. Physical Therapy:

   • Once the acute pain subsides, a physical therapist will guide you through a rehabilitation program that focuses on restoring strength, flexibility, and function to the shoulder. This may involve:

     • Range-of-motion exercises

     • Strengthening exercises to support the shoulder

     • Proprioception training to enhance joint stability

5. Activity Modifications:

   • Modifying activities to avoid overhead movements or contact sports during the healing process is essential for preventing further injury.

Surgical Treatment (for Grade 3 and Severe Injuries)

If the injury is severe (Grade 3 or higher), surgery may be required to repair the damaged ligaments and restore normal joint function. Surgical options include:

1. Acromioclavicular Joint Reconstruction:

   • This involves using sutures, grafts, or metal plates to repair or replace the torn ligaments and restore the normal alignment of the clavicle and acromion.

2. Clavicle Fixation:

   • In some cases, a clavicle fixation surgery may be performed to realign the collarbone and secure it in place using screws, pins, or plates.

3. Post-Surgical Rehabilitation:

   • After surgery, rehabilitation is crucial to regain mobility, strength, and function. Physical therapy will focus on gradual return to activity, starting with passive range-of-motion exercises and progressing to active strengthening.

Recovery and Prognosis

The recovery time for an AC joint separation depends on the severity of the injury and the treatment method:

• Grade 1 and Grade 2: Recovery can take several weeks, with most people returning to normal activity within 4 to 6 weeks after the injury.

• Grade 3: If treated conservatively, recovery may take 6 to 8 weeks. If surgery is required, full recovery can take several months, with a gradual return to activity after rehabilitation.

• Post-Surgical Recovery: Full recovery after surgery may take anywhere from 3 to 6 months, depending on the extent of the surgery and the individual’s rehabilitation process.

Prevention of AC Joint Separation

While it’s not always possible to prevent an AC joint separation, the following strategies may help reduce the risk of injury:

1. Proper Technique:

   • Ensure proper technique when participating in sports or activities that may put stress on the shoulder joint, especially contact sports.

2. Strengthening Exercises:

   • Regularly engage in shoulder strengthening exercises to support the muscles and ligaments around the AC joint, helping to prevent injury.

3. Protective Equipment:

   • In high-contact sports, wear appropriate protective gear, such as shoulder pads, to reduce the impact on the shoulder.

4. Warm-up:

   • Always warm up before engaging in physical activities, especially those that involve overhead motions or physical contact.

Expert Care at Palms Physiotherapy & Allied Health

At Palms Physiotherapy & Allied Health, our expert physiotherapists specialize in the treatment and rehabilitation of Acromioclavicular (AC) joint separations. Whether you are dealing with a mild injury or a severe AC joint separation, we offer tailored treatment plans that may include physical therapy, pain management, and post-surgical rehabilitation. If you're experiencing shoulder pain or suspect an AC joint injury, contact us today for a comprehensive assessment and treatment plan.