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AC Joint Injury

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Injury to the joint at the top of the shoulder where the collarbone meets the shoulder blade

An AC (acromioclavicular) joint injury refers to damage to the joint located at the top of the shoulder where the collarbone (clavicle) meets the shoulder blade (acromion). These injuries, often caused by trauma or overuse, can range from mild sprains to complete dislocations. Dr Ben McGrath, an orthopaedic specialist, provides expert diagnosis and comprehensive treatment options to help patients recover from AC joint injuries and restore shoulder function.

What is an AC Joint Injury?

The AC joint is a small joint at the top of the shoulder where the clavicle meets the acromion of the shoulder blade. An AC joint injury occurs when the ligaments stabilising this joint are sprained, stretched, or torn. These injuries are common in contact sports and activities that involve falls onto the shoulder.

Common Symptoms of AC Joint Injuries

Patients with AC joint injuries often experience:

  • Shoulder Pain: Pain at the top of the shoulder, worsening with overhead movements or lifting.
  • Swelling and Bruising: Localised inflammation and discolouration around the joint.
  • Visible Deformity: In severe cases, the collarbone may protrude or appear misaligned.
  • Limited Range of Motion: Difficulty moving the arm, particularly during overhead or cross-body movements.
  • Tenderness: Sensitivity to touch at the top of the shoulder.

Causes and Risk Factors for AC Joint Injuries

AC joint injuries can result from:

  • Trauma: Direct blows to the shoulder, such as falling onto the point of the shoulder during sports or accidents.
  • Repetitive Overuse: Overhead activities, such as throwing or heavy lifting, can strain the AC joint over time.
  • Contact Sports: Rugby, football, and wrestling carry a high risk due to frequent impacts.
  • Previous Shoulder Injuries: A history of shoulder trauma may increase susceptibility to AC joint injuries.

Dr McGrath evaluates these factors when diagnosing and treating AC joint injuries.

Types of AC Joint Injuries

AC joint injuries are classified into six types based on the severity of damage to the joint and surrounding ligaments:

  1. Type I: Mild sprain of the AC ligaments without displacement.
  2. Type II: Partial tear of the AC ligaments with slight displacement of the clavicle.
  3. Type III: Complete tear of the AC and coracoclavicular (CC) ligaments with significant displacement.
  4. Type IV: Dislocation of the clavicle posteriorly into surrounding muscles.
  5. Type V: Severe displacement with significant tearing of surrounding structures.
  6. Type VI: Rare injury where the clavicle is displaced inferiorly beneath the acromion or coracoid process.

The type of injury determines the appropriate treatment approach.

Diagnosis of AC Joint Injuries

Dr Ben McGrath uses a detailed diagnostic process to confirm AC joint injuries:

  • Medical History and Physical Examination: Assessment of pain, swelling, and shoulder deformity, as well as range of motion and stability tests.
  • Imaging Tests:
    • X-rays: Used to confirm the diagnosis and classify the injury type.
    • Ultrasound or MRI: May be recommended to assess soft tissue damage, particularly in complex or chronic cases.

Accurate diagnosis ensures effective treatment tailored to the severity of the injury.

Non-Surgical Treatments for AC Joint Injuries

Non-surgical management is often sufficient for mild to moderate AC joint injuries:

  • Rest and Immobilisation: Using a sling to stabilise the joint and allow for healing.
  • Physiotherapy: A tailored program to restore strength, range of motion, and stability.
  • Ice Therapy: Applying ice to reduce pain and swelling in the initial stages.
  • Medication: NSAIDs or other pain relief options may help manage symptoms. Consult a healthcare provider before starting any medication.
  • Activity Modification: Avoiding activities that aggravate symptoms and gradually returning to normal function under guidance.

These treatments aim to reduce pain and support the healing process without invasive interventions.

Surgical Treatments for AC Joint Injuries

Surgery may be required for severe or chronic AC joint injuries:

  • AC Joint Reconstruction: Restoring joint stability by repairing or reconstructing damaged ligaments, often using surgical grafts.
  • Clavicle Resection (Distal Clavicle Excision): Removing the end of the clavicle to relieve pain and prevent further joint irritation in chronic cases.
  • Fixation Techniques: Use of plates, screws, or sutures to stabilise the joint in severe dislocations.

Dr McGrath discusses surgical options based on the patient’s injury type, lifestyle, and recovery goals. Post-operative rehabilitation is essential for optimal outcomes.

When to See Dr Ben McGrath for Shoulder Pain

If you experience persistent shoulder pain, visible deformity, or difficulty moving your arm after an injury, a consultation with Dr McGrath can provide an accurate diagnosis and personalised treatment plan to restore comfort and function.

FAQs About AC Joint Injuries

Many mild to moderate injuries heal with rest, physiotherapy, and non-surgical treatments. Severe cases may require surgical intervention.

Recovery times vary, but mild injuries may heal within 4–6 weeks, while severe injuries requiring surgery may take 3–6 months.

While not entirely preventable, using proper techniques during physical activities and strengthening shoulder muscles can reduce the risk.

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