AC Joint Injury: Understanding, Treatment, and Rehabilitation

How to heal an AC joint?

Healing an AC joint injury, typically a separation or sprain, involves a structured, phased rehabilitation process focused on rest, pain management, progressive strengthening, and restoring full function, often guided by the injury's specific grade.

Understanding the AC Joint and Its Injuries

The acromioclavicular (AC) joint is a small but crucial articulation located at the top of the shoulder, where the collarbone (clavicle) meets the highest part of the shoulder blade (acromion). This joint is stabilized by several ligaments: the acromioclavicular (AC) ligaments, which connect the clavicle directly to the acromion, and the coracoclavicular (CC) ligaments (conoid and trapezoid), which connect the clavicle to the coracoid process of the scapula. Its primary function is to allow for a wide range of shoulder motion and to transmit forces from the arm to the axial skeleton.

An AC joint injury, commonly referred to as an AC joint separation or sprain, occurs when these ligaments are stretched or torn, often due to a direct fall onto the shoulder or a direct blow to the top of the shoulder.

Grading AC Joint Separations

The severity of an AC joint injury is classified into grades, which dictate the appropriate course of treatment and rehabilitation.

• Grade I: A mild sprain of the AC ligaments. The joint remains stable, and the clavicle maintains its normal position. There is stretching but no significant tearing of the ligaments.
• Grade II: A complete tear of the AC ligaments and a partial tear or significant stretching of the CC ligaments. This results in some instability and a slight upward displacement of the clavicle.
• Grade III: A complete tear of both the AC and CC ligaments. This leads to noticeable instability and a significant upward displacement of the clavicle, often creating a visible bump on top of the shoulder.
• Grades IV-VI: More severe and rare injuries involving complete ligamentous disruption and more pronounced displacement of the clavicle, often requiring greater force and potentially involving muscle detachment. These typically necessitate surgical intervention.

Immediate Management: The Acute Phase

For most Grade I, II, and many Grade III AC joint injuries, initial treatment focuses on pain control and protection of the healing tissues. This phase typically lasts for the first 1-3 weeks, depending on the injury's severity.

• Rest: Avoid activities that exacerbate pain or stress the AC joint. This often means refraining from lifting, pushing, pulling, or overhead movements.
• Ice: Apply ice packs to the affected area for 15-20 minutes every 2-3 hours to reduce pain and swelling. Ensure a barrier between the ice and skin to prevent frostbite.
• Compression: While direct compression on the AC joint itself is difficult, a sling or shoulder immobilizer can provide gentle compression and support, helping to reduce swelling and restrict unwanted movement.
• Elevation: Keeping the arm elevated, especially during rest, can assist in reducing swelling.
• Pain Management: Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen can help manage pain and inflammation. Always consult with a healthcare professional before starting any medication regimen.
• Immobilization: A sling may be used for a period ranging from a few days for Grade I injuries up to 2-4 weeks for Grade II and some Grade III injuries to protect the joint and facilitate initial healing. The duration will be determined by your physician.

The Rehabilitation Process: A Phased Approach

Rehabilitation is crucial for restoring full shoulder function and preventing chronic issues. This process should be guided by a physical therapist or exercise physiologist and progresses based on pain levels, healing, and functional improvement.

Phase 1: Protection and Early Mobility (Typically Weeks 1-3)

The primary goals in this phase are to reduce pain and inflammation, protect the healing ligaments, and begin to restore pain-free passive range of motion (ROM) in the shoulder.

• Pain and Swelling Control: Continue with ice and pain medication as needed.
• Gentle Passive Range of Motion: Once pain allows, begin very gentle, passive movements where the arm is moved by the unaffected arm or by gravity (e.g., pendulum swings) without active muscle contraction of the injured shoulder.
• Scapular Awareness: Begin gentle isometric exercises for the muscles stabilizing the shoulder blade (scapula). This might include gentle scapular squeezes or depressions without resistance.
• Avoid: Lifting, carrying, pushing, pulling, or any movements that cause pain.

Phase 2: Progressive Strengthening and Restoring Full Range of Motion (Typically Weeks 3-8)

As pain subsides and passive ROM improves, the focus shifts to restoring active ROM and initiating progressive strengthening.

• Active Range of Motion: Gradually progress to active range of motion exercises, moving the arm through its full, pain-free range in all directions (flexion, extension, abduction, internal and external rotation).
• Scapular Stabilization Exercises: Strengthen the muscles that control the shoulder blade (rhomboids, trapezius, serratus anterior). Examples include:
  • Scapular Retractions: Squeezing shoulder blades together.
  • Wall Slides: Sliding arms up a wall while keeping shoulder blades depressed and retracted.
  • Y-T-W-L Exercises: Performed prone on a bench or floor to target different scapular muscles.
• Rotator Cuff Strengthening: Begin with light resistance (resistance bands, light dumbbells) for internal and external rotation, focusing on controlled movements.
• Deltoid Strengthening: Gradually introduce exercises for the deltoid muscle, starting with lighter weights and controlled movements, such as front raises, lateral raises, and eventually overhead presses, as tolerated.
• Core Stability: Incorporate core strengthening exercises, as a strong core provides a stable base for shoulder movement.

Phase 3: Advanced Strengthening and Return to Activity (Typically Weeks 8-16+)

This phase focuses on achieving full strength, power, and endurance, and preparing the individual for a safe return to sport or demanding occupational activities.

• Progressive Resistance: Increase the intensity, volume, and complexity of strengthening exercises. This includes heavier weights, more challenging resistance band exercises, and multi-joint movements.
• Power and Plyometrics: For athletes, introduce exercises that mimic sport-specific movements and require power, such as medicine ball throws, plyometric push-ups, and rotational drills.
• Sport-Specific Drills: Gradually reintroduce activities specific to the individual's sport or occupation, starting with low intensity and progressing as tolerance allows. This might include throwing mechanics, overhead pressing, or simulated work tasks.
• Endurance Training: Focus on muscular endurance through higher repetitions and sustained activity.
• Gradual Return to Activity: The return to full activity or sport should be gradual and guided by a professional. It's crucial to avoid rushing the process to prevent re-injury or chronic pain. The shoulder should feel strong, stable, and pain-free through a full range of motion before returning to high-impact or overhead activities.

When to Seek Professional Medical Advice

While conservative management is often successful, it's vital to seek professional medical advice in certain situations:

• Significant Pain or Deformity: If you suspect a higher-grade injury (Grade III or above) due to severe pain, a visible bump on the shoulder, or significant loss of function.
• Lack of Progress: If pain or limited range of motion persists or worsens despite weeks of conservative management.
• Neurological Symptoms: Numbness, tingling, or weakness in the arm or hand, which could indicate nerve involvement.
• Concern for Other Injuries: If you suspect other injuries, such as a fracture, rotator cuff tear, or labral tear.

Surgical Considerations for AC Joint Injuries

While most AC joint separations heal well with conservative treatment, surgery may be considered for certain cases.

• High-Grade Injuries (Grades IV-VI): These often involve significant displacement and instability, making surgical stabilization more likely.
• Persistent Instability or Pain (Grade III): In some active individuals, a Grade III injury that results in persistent pain or functional instability despite adequate conservative rehabilitation may be considered for surgery.
• Non-Union or Chronic Instability: In rare cases, if the ligaments do not heal properly or if chronic instability develops, surgical reconstruction may be necessary.

Surgical procedures aim to reduce the clavicle back into alignment and stabilize the joint, often using screws, plates, or grafts to reconstruct the torn ligaments. Post-surgical rehabilitation is typically more prolonged and structured.

Prevention Strategies

While not all AC joint injuries are preventable, certain measures can reduce risk:

• Strengthen Supporting Musculature: Focus on strengthening the rotator cuff, deltoids, and scapular stabilizers to improve overall shoulder stability and resilience.
• Proper Technique: Learn and utilize correct form for exercises, sports, and occupational tasks to minimize undue stress on the shoulder joint.
• Fall Prevention: Be mindful of surroundings and take precautions to prevent falls, especially in sports or activities with a high risk of impact.

Conclusion

Healing an AC joint injury is a journey that requires patience, adherence to a structured rehabilitation program, and often, the guidance of healthcare professionals. Understanding the grade of your injury, committing to the phased rehabilitation process, and recognizing when to seek further medical intervention are key to a successful recovery and a return to full, pain-free function.