AC Joint Pain: Causes, Treatment, and Recovery

How to treat AC joint pain?

Treating AC joint pain typically involves a multi-faceted approach, beginning with acute pain management and progressing through structured rehabilitation exercises to restore strength and function, often guided by the severity of the injury.

Understanding the AC Joint and Its Pain

The acromioclavicular (AC) joint is a small, yet critical, articulation located at the top of the shoulder, where the lateral end of the clavicle (collarbone) meets the acromion process of the scapula (shoulder blade). This joint is stabilized by strong ligaments, including the acromioclavicular ligaments and the coracoclavicular ligaments (conoid and trapezoid), which are vital for shoulder stability and overhead movement.

Common Causes of AC Joint Pain:

• AC Joint Sprain/Separation: This is the most common cause, typically resulting from a direct blow to the shoulder (e.g., fall onto the shoulder, tackle in sports). The severity is graded from I to VI based on the degree of ligamentous damage and displacement of the clavicle relative to the acromion.
  • Grade I: Mild sprain, ligaments intact but stretched.
  • Grade II: Partial tear of AC ligaments, minimal displacement, coracoclavicular ligaments intact.
  • Grade III: Complete rupture of AC and coracoclavicular ligaments, significant displacement.
  • Grades IV-VI: More severe injuries involving posterior/inferior displacement, often requiring surgical intervention.
• AC Joint Osteoarthritis: Degenerative changes in the joint cartilage, common in older adults or those with a history of shoulder trauma or repetitive overhead activities.
• Distal Clavicle Osteolysis: A condition where the end of the clavicle begins to resorb or break down, often seen in weightlifters or those engaged in repetitive heavy lifting.

Initial Management: The Acute Phase

For most AC joint injuries, especially Grade I and II sprains, conservative management is the initial cornerstone of treatment.

• Rest: Immediately cease activities that aggravate the pain. Protect the joint from further stress.
• Ice: Apply ice packs to the affected area for 15-20 minutes, several times a day, particularly in the first 24-48 hours, to reduce pain and swelling.
• Compression: While direct compression on the AC joint is difficult, gentle compression around the shoulder with a bandage might offer some support, though this is less common than for other joint injuries.
• Elevation: Keep the arm elevated if possible, especially when resting, to help reduce swelling.
• Pain Management:
  • Over-the-counter NSAIDs: Non-steroidal anti-inflammatory drugs like ibuprofen or naproxen can help manage pain and inflammation. Always follow dosage instructions and consult a healthcare professional if unsure.
  • Immobilization: A sling may be used for a short period (typically 1-3 weeks for Grade I/II injuries) to provide support, reduce movement, and promote healing. Prolonged immobilization should be avoided to prevent stiffness.

Rehabilitation: Restoring Function and Strength

Once acute pain and swelling subside, a progressive rehabilitation program is crucial for restoring full shoulder function, preventing stiffness, and minimizing recurrence. This should ideally be guided by a physical therapist.

Phase 1: Pain Control and Early Mobility (Weeks 1-3, depending on injury severity)

Focus on gentle, pain-free movement to prevent stiffness and maintain range of motion.

• Pendulum Swings: Lean forward, letting the injured arm hang freely. Gently swing it in small circles, forward/backward, and side-to-side.
• Passive/Assisted Range of Motion: Use the uninjured arm or a pulley system to gently move the injured arm through its available range, avoiding pain.
• Scapular Isometric Holds: Gently contract the muscles that pull the shoulder blade back and down without moving the arm. Hold for a few seconds, relax. This helps activate stabilizing muscles.

Phase 2: Progressive Strengthening (Weeks 3-8+)

Once pain is minimal and basic range of motion is restored, begin strengthening exercises, focusing on the rotator cuff, scapular stabilizers, and deltoid muscles. Start with light resistance and gradually increase.

• Rotator Cuff Strengthening:
  • Internal/External Rotation: Use a light resistance band or small dumbbell, keeping the elbow tucked at the side.
  • Scaption: Raise the arm to the side at a 30-degree angle forward (in the plane of the scapula), thumb up, no higher than shoulder height initially.
• Scapular Retraction and Depression:
  • Rows: Seated cable rows or resistance band rows, focusing on squeezing the shoulder blades together.
  • Face Pulls: Using a cable machine or resistance band, pull towards the face, emphasizing external rotation and scapular retraction.
• Deltoid Strengthening (Gradual):
  • Front Raises/Lateral Raises: Start with very light weights, ensuring no pain in the AC joint. Avoid overhead movements initially.
• Core Stability: A strong core supports overall movement and can indirectly benefit shoulder mechanics.

Phase 3: Return to Activity (Weeks 8+)

This phase focuses on sport-specific or activity-specific movements, increasing load, and preparing the shoulder for the demands of daily life or athletic performance.

• Progressive Loading: Gradually increase weight, repetitions, or resistance in exercises.
• Overhead Movements: Slowly reintroduce overhead pressing, throwing, or reaching activities, ensuring proper form and no pain.
• Proprioceptive Training: Exercises that challenge balance and joint position awareness (e.g., stability ball push-ups, plyometric throws) to enhance neuromuscular control.
• Sport-Specific Drills: For athletes, gradually reintroduce drills specific to their sport, starting with low intensity and progressing.

When to Seek Professional Medical Advice

While many AC joint injuries respond well to conservative treatment, it's crucial to consult a healthcare professional (doctor, orthopedic surgeon, physical therapist) if:

• You experience severe pain or significant deformity.
• There's a complete inability to move the arm or significant loss of strength.
• Pain persists or worsens despite conservative measures.
• You suspect a higher-grade injury (Grade III or above).
• You have concerns about the diagnosis or treatment plan.

Advanced Treatments and Surgical Considerations

For more severe injuries (Grade III and above, especially IV-VI) or chronic pain that doesn't respond to conservative management, advanced treatments may be considered.

• Corticosteroid Injections: Can provide temporary relief for AC joint osteoarthritis or inflammatory conditions, but are not a long-term solution and should be used judiciously.
• Platelet-Rich Plasma (PRP) Injections: A newer treatment involving injecting concentrated platelets from the patient's own blood into the joint to promote healing. Evidence is still developing.
• Surgical Interventions: For severe separations (Grade III with persistent symptoms, or Grades IV-VI) or chronic pain from osteoarthritis/osteolysis, surgery may be recommended.
  • Distal Clavicle Excision (DCE) / Mumford Procedure: Removes a small portion of the end of the clavicle to create more space and alleviate pain, commonly used for osteoarthritis or osteolysis.
  • AC Joint Reconstruction: Various techniques to stabilize the joint by repairing or reconstructing the torn ligaments, often using grafts or synthetic materials.

Prevention Strategies

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

• Proper Lifting Mechanics: Use legs and core, maintain good posture, and avoid excessive weight, especially in overhead movements.
• Balanced Strength Training: Ensure a balanced strength development around the shoulder girdle, focusing on rotator cuff, scapular stabilizers, and deltoids. Avoid over-emphasizing anterior muscles.
• Warm-up and Cool-down: Prepare muscles and joints for activity and aid recovery.
• Protective Gear: Athletes in contact sports should wear appropriate protective padding.
• Fall Prevention: Be mindful of surroundings to prevent falls, especially among older adults.

Conclusion and Long-Term Outlook

Treating AC joint pain requires patience and a structured approach. Most lower-grade injuries heal well with conservative management and a diligent rehabilitation program, allowing a return to full activity. Higher-grade injuries or chronic conditions may necessitate more advanced interventions. Understanding the nature of the injury and working closely with healthcare professionals and exercise specialists is key to a successful recovery and long-term shoulder health.