The acromioclavicular joint, commonly known as the AC joint, is where the clavicle or collarbone joins with the acromion— part of the scapula or shoulder blade. This joint plays an integral part in maintaining shoulder strength, balance, position, and motion. Surrounding the acromioclavicular joint are tendons, muscles, and ligaments (acromioclavicular ligament and coracoclavicular ligament) that support and stabilise the joint, allowing for full range of motion and flexibility.
Acromioclavicular joint injury, also known as shoulder separation, occurs when damage is inflicted onto any of the structures that make up the joint and surrounding tissues. This injury can result in pain, shoulder instability, and reduced range of motion and flexibility.
Acromioclavicular joint injury or shoulder separation often occurs when the ligaments get damaged by injury.
Type 1: partial tear or sprain of the acromioclavicular ligament while the coracoclavicular ligament remains intact.
Type 2: completely torn acromioclavicular ligament and minimal or no damage to the coracoclavicular ligament.
Type 3: both the acromioclavicular and coracoclavicular ligament are completely torn, causing the clavicle to separate from the scapula.
Types 4-6: rare but severe and involves the complete tearing of both ligaments and surrounding muscles.
An acromioclavicular joint injury is categorised based on severity and which ligaments are affected.
What causes acromioclavicular joint injury?
Acromioclavicular joint injury can occur in two ways:
Injury: the most common cause of acromioclavicular joint injury. A sprain or separation of the AC joint may occur by falling on an outstretched arm or when lifting heavy objects.
Arthritis: characterised by the gradual loss of cartilage within the joint, arthritis is a common wear and tear issue observed in weightlifters.
What are the symptoms of acromioclavicular joint injury?
The symptoms of acromioclavicular joint injury depends on its severity and may vary between individuals.
General symptoms of an acromioclavicular joint injury include:
Joint pain when raising your hand to the side or reaching one hand across to the other
Swelling or bump at the injury site
Reduced range of motion
Reduced shoulder flexibility and strength
Severe cases of acromioclavicular joint injury can cause the collarbone to separate from the shoulder blade, causing a bump.
If you notice any of the symptoms, make an appointment with an orthopaedic specialist to get an accurate diagnosis and treatment.
Dr Puah KL is our Senior Consultant Orthopaedic Surgeon at Artisan Sports & Orthopaedic Surgery. He used to serve the sports service of Singapore General Hospital - the highest volume trauma centre for orthopaedics in Singapore.
Yes. An acromioclavicular joint injury is characterised by intense pain and swelling, in conjunction with swelling, reduced range of motion, and reduced shoulder strength and flexibility.
Who is at risk of acromioclavicular joint injury in Singapore?
Anyone can get an acromioclavicular joint injury, however, there are several factors that may increase your risk, these are:
Athletes: weightlifters are more prone to an AC joint injury.
Occupation: individuals with jobs that involve a lot of overhead lifting.
Age: an AC joint injury is more common in individuals under the age of 35.
Gender: males are more prone to an AC joint injury than females.
How is acromioclavicular joint injury diagnosed?
Diagnosis of an acromioclavicular joint injury occurs in the following ways:
Physical examination: medical history will be obtained and a physical examination will be conducted to check for pain, swelling, bruising, range of motion, shoulder flexibility and strength, etc.
Imaging tests:x-rays, magnetic resonance imaging (MRI), or computed tomography scans (CT-scans) will be performed to identify the severity and type of AC joint injury.
What are the treatment options for acromioclavicular joint injury in Singapore?
Depending on the severity and cause, an acromioclavicular joint injury can be treated using both surgical and non-surgical ways such as:
Physiotherapy:physiotherapy involves gentle therapeutic exercises to rehabilitate and strengthen the muscles. Effective for individuals with type 1-3 AC joint injury.
Injections:corticosteroid injections can be administered to alleviate pain and swelling. Effective for individuals with AC joint injury caused by arthritis.
Medication:non-steroidal anti-inflammatory drugs (NSAIDs) and painkillers can be administered to reduce inflammation and alleviate the pain. Effective for individuals with all types of AC joint injury caused by both trauma and arthritis.
Surgery: surgeryisoften the only treatment option for individuals with type 4-6 AC joint injury.
A brace or sling will be used in your recovery from an acromioclavicular joint injury.
Frequently asked questions
How long does it take for an acromioclavicular joint injury to heal?
How do you treat an acromioclavicular joint injury?
Is an AC joint injury permanent?
our process
Feeling aches and pains?
Book a consultation with us for a more comprehensive diagnosis and a personalised treatment plan best suited to your needs.
