Acromioclavicular Joint Dislocation Specialist Singapore

Dr Bryan Tan, orthopaedic surgeon in Singapore.
Dr. Bryan Tan

MBBS (SINGAPORE) MMED (ORTHO) FRCS ED (ORTH)

Acromioclavicular joint (ACJ) dislocations are injuries often experienced by athletes. They are often mistaken to be glenohumeral joint dislocations (see section on shoulder dislocations).

However this certainly does not mean some who is not an athlete cannot suffer such an injury. Majority of ACJ dislocations occur in males in their thirties. Although many patients with untreated ACJ dislocations do well and eventually suffer few functional deficits, more severe untreated ACJ dislocations can result in chronic pain.

Some knowledge of the anatomy of the shoulder is required to understand ACJ dislocations.

Man experiencing shoulder pain in gym, possibly due to AC joint dislocation

What is Acromioclavicular Joint Dislocation?​

Acromioclavicular (AC) joint dislocation occurs when the clavicle (collarbone) is displaced from its normal position at the acromion (part of the scapula). The AC joint helps connect the shoulder blade to the collarbone. Typically, dislocations result from a fall onto the shoulder or direct impact. This injury is common in contact sports but can also affect individuals from various backgrounds.

While both AC joint and shoulder dislocations involve the shoulder region, the key difference lies in the joint affected. AC joint dislocation involves the separation of the clavicle from the acromion. On the other hand, a shoulder dislocation occurs when the ball of the upper arm bone (humerus) leaves the socket of the shoulder blade. AC joint dislocations may be less severe than shoulder dislocations. However, the condition can still cause significant pain and limited mobility.

What Causes A Acromioclavicular Joint Dislocation?

The common causes of acromioclavicular joint dislocation include:

  • Falling Directly onto the Shoulder

One of the most frequent causes of AC joint dislocation is a fall onto the shoulder, particularly when the arm is not in a protective position.

In this scenario, the force of the fall directly impacts the shoulder, causing the clavicle to be forced upwards and out of alignment with the acromion.

This type of injury is common in activities such as cycling, skiing, or any other sport where falls onto the shoulder are likely.

  • Violent Blow to the Shoulder Area

A direct, violent blow to the shoulder, such as being struck by a heavy object or during a collision, can cause the AC joint to dislocate.

This can occur when an individual is hit by an object like a falling piece of equipment, or during high-impact activities like martial arts, rugby, or boxing.

The intense force from the blow may cause the ligaments around the AC joint to tear or stretch, leading to the dislocation of the clavicle.

  • Sports Injuries

Contact sports such as football, rugby, hockey, and wrestling are particularly prone to causing AC joint dislocations.

These sports often involve tackles, falls, and collisions where the shoulder is exposed to sudden, high-impact forces that can cause displacement of the AC joint.

Even non-contact sports like cycling, skateboarding, or skiing can result in AC joint dislocations. The risk increases if the athlete falls awkwardly or is involved in a crash.

Types of Shoulder Separation Injuries

Shoulder separations occur when the ligaments connecting the collarbone (clavicle) to the shoulder blade (scapula) are damaged, typically at the acromioclavicular (AC) joint. These injuries are classified into types based on the severity of ligament damage and the displacement of the clavicle.

Shoulder Separation (AC Joint Dislocation):

Occurs when the clavicle (collarbone) displaces from the acromion (part of the shoulder blade).   

Classified by the Rockwood Classification system into six types (I-VI) based on severity.   

 

Types of Shoulder Separation:

Type I (Mild): Sprained AC ligaments, minimal displacement. Treated conservatively.

Type II (Partial): Partial tear of AC ligament, some displacement. Treated conservatively or with immobilization.

Type III (Complete): Complete tear of AC and CC ligaments, significant displacement. May require surgery.   

Type IV (Posterior): Clavicle displaced backwards, typically requiring surgery.   

Type V (Severe): Significant elevation of the clavicle, requiring surgery and extensive rehabilitation.

Type VI (Inferior): Rare, severe injury with downward clavicle displacement, requiring surgery and complex rehabilitation.

What Are The Symptoms Of Acromioclavicular Joint Dislocation?​

Common symptoms of acromioclavicular joint dislocation include:

  • An obvious deformity of the shoulder
  • Intense pain in the AC joint
  • Inability to move the shoulder joint
  • Decreased range of motion
  • The end of the collarbone may appear to be sticking up under the skin

How Is A Acromioclavicular Joint Dislocation Diagnosed?

During a physical examination, your doctor may inspect the affected area for pain, tenderness or any deformities. Furthermore, they may test your shoulder’s mobility by asking you to perform specific simple exercises to determine whether or not the AC joint is dislocated.

An X-ray of your shoulder joint may also be performed to reveal the dislocation and other damages to your AC joint. An MRI scan may be required to fully assess the extent of the injury.

It is essential to avoid attempting to put the joint back yourself because of the risk of aggravating the injury. Also, the joint will not stay in place because of the pull of gravity on the arm.

​​Is acromioclavicular joint dislocation affecting your quality of life, and your ability to perform everyday activities such as working, playing sports and wearing your clothes?
Dr. Bryan will assess your symptoms in detail before recommending the right treatment plan for your condition.

How Is A Acromioclavicular Joint Dislocation Treated?

For Type I and Type II injuries (mild to moderate dislocations), non-surgical treatments may be performed. These methods focus on managing pain and inflammation, promoting healing, and restoring function gradually.

1. Rest and Ice Therapy

Resting the shoulder and avoiding movements that may exacerbate the pain (such as lifting or overhead activities) is crucial in the initial stages.

Applying ice to the affected area can help reduce swelling and alleviate pain. Ice packs should be applied for 15-20 minutes every 2-3 hours during the first 48 hours following the injury.

2. Sling or Shoulder Immobilisation

A sling or shoulder immobiliser is often recommended, especially in the early stages of recovery. Besides restricting movement and supporting the injured joint, this method also prevents further irritation.

Immobilisation typically lasts for 2-4 weeks, depending on the severity of the injury.

3. Physical Therapy

As healing progresses, physical therapy becomes an essential part of the recovery process. A physical therapist will guide the patient through exercises to:

  • Improve range of motion.
  • Strengthen the surrounding muscles, including the rotator cuff and shoulder stabilisers.
  • Prevent stiffness and improve flexibility.
  • Prevent the recurrence of injury once healing is complete.

For Type III injuries or more severe dislocations (Types IV, V, and VI), surgery is recommended for younger and active patients.

1. Surgical Repair for Severe Dislocations

For types IV-VI injuries, surgery is typically required to stabilise the joint and repair torn ligaments. The procedure may involve reattaching the acromioclavicular ligament, repairing the coracoclavicular ligament, or using screws, plates, or suture anchors to hold the bones in place.

2. Open Reduction and Internal Fixation (ORIF)

In cases of severe displacement, an open surgical approach may be needed to manually reposition the clavicle and secure it using plates, screws, or other hardware. This approach is typically used for Type IV, V, and VI injuries.

After surgery, patients are usually required to wear a sling to limit movement and allow the joint to heal.

3. Arthroscopic Surgery

In certain cases, minimally invasive arthroscopic surgery can be performed. This involves the use of small incisions and a camera to guide the surgeon in repairing the torn ligaments or reattaching the dislocated joint. This approach may be less invasive than traditional open surgery.

 

Prevention Strategies:

Maintain a Healthy Weight: Reducing excess weight to minimise joint strain.

Stay Active: Engaging in low-impact exercises like swimming and walking.

Nutrition: Consuming omega-3 fatty acids, vitamin D, calcium, and joint supplements.

Early Diagnosis: Regular monitoring to catch symptoms early and prevent further damage.

Anatomy of the Shoulder Joint

The shoulder joint is made up of 3 bones: the shoulder blade (scapula), the humeral head and the collar-bone (clavicle).

Labeled shoulder joint model highlighting acromioclavicular joint, relevant to AC joint dislocation

Movements around the shoulder involve 3 separate articulations: the glenohumeral joint, the acromioclavicular joint and the scapulothoracic articulation. When the arm is raised, the majority of movement occur at the glenohumeral joint and the scapulothoracic articulation.

Anatomical illustration of the shoulder highlighting the AC joint, relevant to AC joint dislocation

The ACJ is a rather small joint between the clavicle and a part of the scapula known as the acromion. The acromion forms a roof over the glenohumeral joint which is often regarded as the “main” shoulder joint.

When we raise our arms, majority of movement occurs at the glenohumeral joint and scapulothoracic articulation. Only small gliding and rotatory movements occur at this joint. Despite the fact that such little amount of movement occur through this joint, this small joint has to deal with large forces.

Anatomical model illustrating an intact AC joint and CC ligaments, relevant to AC joint dislocation

The joint is held in place by several structures:

1. The joint capsule (the covering of the joint)
2. Ligaments found within the capsule of the joint (known as the AC ligaments)
3. Ligaments that are attached, on one end to the coracoid process (part of the scapula) and on the other end, to the clavicle. These ligaments are called the coraco-clavicular (CC) ligaments.

Sports injuries are the most common cause of ACJ dislocation. Often times it is the result of direct impact on the point of the shoulder.

The most common scenarios I see are when patients trip while running fast causing them to tumble “head over heels” or when cyclists pitch over the handlebars after having hit a pothole or a branch on the road. In almost all of these scenarios, the patient lands hard directly on their shoulder.

Cyclist crashes onto shoulder, highlighting AC joint dislocation risk

Frequently Asked Questions

When should I visit a doctor for acromioclavicular joint dislocation?

What will the doctor do?

What does surgery for ACJ dislocations entail?

Will I be able to participate in sports after the surgery?

How to prevent acromioclavicular joint dislocation?

What are the common symptoms of an acromioclavicular joint dislocation?

What are the different types of AC joint dislocations, and how do they affect treatment options?

What are the risks of untreated AC joint dislocations?

Are there any lifestyle changes or modifications required during recovery from an AC joint dislocation?

Billing & Payment

Medisave & Insurance Claims

The following are accredited For Singaporeans, Singapore Permanent Residents and Foreigners. If your insurance is not listed, you will still be able to make claims for eligible procedures! We have experience processing claims from many other various insurance providers. Please contact us if you have any queries.

WHAT’S THE FIRST STEP?

Embark on Your Road to Recovery With Dr Bryan Tan

OrthoSports: Dr. Bryan Tan's Clinic
STEP 1

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With Dr. Bryan

Our friendly clinic staff will assist you with your registration, ensuring an efficient and hassle-free process for you. Fill up this form to schedule an appointment with Dr. Bryan.

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STEP 2

Initial Consultation & Diagnosis of your Condition

During your consultation, Dr. Bryan will evaluate your medical history and the pain you are experiencing. You may also ask Dr. Bryan any questions you may have about your condition.

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STEP 3

Treatment & Follow Up Visits With Dr. Bryan

After your consultation with Dr. Bryan, our friendly clinic staff will assist you with your follow-up appointment, and provide you with instructions/information for any prescribed treatment plans from Dr. Bryan.

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