Acromio-clavicular Joint Dislocation


An acromioclavicular (AC) joint dislocation refers to the separation of the acromion process of the scapula (shoulder blade) from the clavicle (collarbone). The AC joint is located at the top of the shoulder, where the clavicle meets the acromion process of the scapula. This joint is supported by ligaments and surrounded by soft tissues.

AC joint dislocations commonly occur as a result of a direct blow to the shoulder or a fall onto the shoulder. The severity of the dislocation can vary, ranging from mild to severe depending on the extent of ligament damage and can be classified accordingly. A grade 1 injury is a ‘sprain’ of the joint without ligament damage. A grade 2 injury is a ‘partial separation’ with some structural damage to ligaments. Grade 3 injuries are complete dislocations with extensive ligament damage.

Immediate Symptoms of AC joint dislocation may include pain, swelling, and a visible deformity or prominence at the top of the shoulder. Treatment depends on the severity of the dislocation and may include conservative measures such as rest, ice, pain management, and physical therapy for mild cases. More severe cases may require surgical intervention to stabilise the joint, especially in higher-grade dislocations.

Medical evaluation, including imaging studies such as X-rays, is typically necessary to diagnose and determine the appropriate course of treatment for an AC joint dislocation.

Clinical Presentation

The clinical presentation of an acromioclavicular (AC) joint dislocation can vary depending on the severity of the injury. Here are some common signs and symptoms associated with AC joint dislocations:

  • Pain: Pain is a predominant symptom and is often localised to the top of the shoulder, near the AC joint. The intensity of the pain may vary, and it can be exacerbated by movement or palpation of the affected area.
  • Swelling: Swelling typically occurs around the AC joint as a result of the injury. This swelling can contribute to the visible deformity of the shoulder.
  • Visible Deformity: In more severe cases, there may be a noticeable deformity or prominence at the top of the shoulder. This can result from the displacement of the clavicle in relation to the acromion process.
  • Limited Range of Motion: The range of motion in the affected shoulder may be restricted due to pain and instability caused by the dislocation. Patients may find it challenging to move their arm or raise it overhead.
  • Tenderness to Palpation: The area around the AC joint is often tender to touch. Healthcare professionals may perform palpation to assess for specific points of tenderness and to better understand the nature of the injury.

All of these symptoms will be most severe at the time of the injury and will improve with time. More severe dislocations however may cause ongoing or chronic symptoms including pain, loss of function, and a visible deformity.

It’s important to note that the severity of symptoms can vary, and a thorough clinical examination along with imaging studies (such as X-ray and MRI) is typically necessary to confirm the diagnosis and assess the extent of the AC joint dislocation. Treatment options will depend on the severity of the injury, ranging from conservative measures like rest and physical therapy to surgical intervention in more severe cases. Early and accurate diagnosis is crucial for determining the most appropriate course of treatment.

Treatment Options

The treatment for an acromioclavicular (AC) joint dislocation depends on the severity of the injury, level of ongoing symptoms, occupation, arm dominance, and other lifestyle factors.

Immediate Management:

  • Rest and Immobilisation. Grade 1 and 2 AC joint dislocations may be treated conservatively. Rest and avoiding activities that worsen symptoms are crucial. Immobilisation with the use of a sling may be recommended initially to allow the ligaments to heal.
  • Ice: Applying ice to the affected area can help reduce pain and swelling.
  • Pain Management: Over-the-counter pain medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may be recommended to manage pain and inflammation.


  • Physical therapy is often a crucial component of the rehabilitation process. Therapists work on restoring range of motion, strengthening the shoulder muscles, and improving overall shoulder function. Rehabilitation exercises focus on restoring stability and preventing long-term complications.

Surgical Intervention:

  • In cases of complete (grade 3) AC joint dislocations, especially those classified as surgical intervention may be considered. Surgical procedures may involve reconstructing the torn ligaments, stabilising the joint, or using implants to realign the clavicle and acromion.
  • Surgery is often considered for individuals who require a higher level of shoulder function, such as athletes, overhead manual workers, or those with persistent pain and functional limitations.

It’s crucial for individuals with a suspected AC joint dislocation to seek prompt medical attention for a proper diagnosis and appropriate treatment. The choice between conservative and surgical approaches is individualised and depends on factors such as the patient’s age, activity level, and the severity of the dislocation.

Overall, the goal of treatment is to relieve pain, restore shoulder function, and prevent long-term complications such as chronic instability or arthritis.

To schedule an appointment with Dr Matthew Evans to discuss your AC joint injury, please contact us by phone – (03) 9529 3820, or email

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