AC joint separation – an injury to the shoulder
AC joint separation – also known as shoulder separation – is an injury to the shoulder joint, more specifically the acromioclavicular (AC) joint. The joint connects the collarbone (clavicula) with the top of the shoulder blade (acromion). Separation occurs when the ligaments that stabilise the connection get overstretched or tear completely.
The severity of separation can vary – from minor ligament stretches to completely torn ligaments. There are usually two methods used to assess AC joint separation: the Tossy classification and the Rockwood classification. The Tossy classification focuses on certain ligaments, and divides them into three different degrees (grades) of damage. The Rockwood classification also looks at other structures, such as the surrounding muscles, the change in the joint gap, and the extent of joint instability.
AC joint separation Rockwood I
AC joint separation Rockwood II
AC joint separation Rockwood III
Risks and causes: How does AC joint separation happen?
Pre-existing shoulder strain and insufficient muscle strength in the shoulder and neck area can put more of a burden on the AC joint and increase the risk of injury. In addition, muscular imbalances can lead to an uneven load distribution on the shoulder joint and increase the risk of AC joint separation.
Typically, AC joint separation is caused by trauma – a heavy blow to the shoulder either from the side or the front. The most common causes and risk factors are:
- Falling on the shoulder: If a person falls on their shoulder – either during an everyday activity or while playing sports – the AC joint can separate.
- Sports injuries: Sports that may involve close physical contact or falls, such as e.g. football, hockey, cycling or extreme sports, increase the risk of AC joint separation.
- A blow to the shoulder: A direct blow to the shoulder, such as a collision, can cause the AC joint ligaments to overstretch or tear.
How do you prevent AC joint separation?
Preventative measures, particularly strengthening the shoulder muscles, can help reduce the risk of AC joint separation. Those who already have existing risk factors are advised to seek medical advice in order to obtain personalised recommendations on how they can prevent AC joint separation. Prevention approaches may include:
Warm up
Warming up before doing any sports: It is important to warm up appropriately before doing sports in order to loosen up the muscles and increase blood circulation. This prepares the joint for the pending workout, and reduces the risk of injury.
Risk avoidance
Avoiding risky activities: Sports involving a high risk of injury require particular caution. Wearing protective clothing, especially during contact sports, can reduce the force of any impact.
Correct technique & movement
Correct technique and movements: Doing exercises and sports movements with the proper form minimises the risk of injury. Getting professional advice from a trainer can improve your technique in any sport.
Ergonomics in everyday life & work
Ergonomic home and workplace setups: A healthy posture can help us to avoid uneven weight distribution across the muscles and minimise the strain on the shoulder joint.
Symptoms and signs of shoulder separation
Symptoms of AC joint separation can vary, depending on the severity of the injury. Typical signs can include:
- Pain and swelling: AC joint separation is a painful injury. Depending on the severity, the pain can vary in intensity. Touching or pressing the AC joint can intensify the pain. In addition, the affected shoulder might swell up.
- Raised collarbone position: Sometimes there can be a visible deformity around the AC joint. This is especially the case with severe joint separation.
- Piano-key sign: If the end of the collarbone near the shoulder can be pressed downwards, like pressing a piano key, and it springs back up when released, it can indicate AC joint separation.
- Impairments of movement: The injury can cause impaired mobility in the shoulder joint. Spreading and lifting the arm sideways, and moving the shoulder, can be painful.
If AC joint separation is suspected, a medical examination is essential. It provides details to aid an exact diagnosis, and enables the subsequent treatment to be tailored to the individual patient.
Diagnosing AC joint separation: How is AC joint separation confirmed?
To assess the severity of the injury and to make a diagnosis, doctors use a combination of a medical examination and diagnostic scans. Common diagnostic procedures are:
Physical examination
Doctors carefully press (palpate) the shoulder area, particularly the AC joint, to look for swelling, deformities, or areas painful to the touch. Depending on the individual situation, suitable joint function tests can be performed to check the mobility and stability of the shoulder and to determine if there is any impaired function and/or pain. For instance, the "piano test" shows whether the piano-key phenomenon is present: Doctors press on the raised end of the collarbone closest the shoulder. If it bounces back, it might indicate AC joint separation.
Diagnostic imaging
X-ray scans are often the imaging procedure of first choice to confirm the diagnosis and assess the severity of AC joint separation. The X-ray scans can reveal signs such as a displacement of the collarbone relative to the shoulder blade. MRI (magnetic resonance imaging) gives a more detailed view of the ligaments, soft tissues and the joint, which can provide particularly helpful information if the fracture is complex.
Once an accurate medical diagnosis has been made, the patient can start treatment – either conservatively or, in more severe cases, by surgery.
Therapy and treatment of AC joint separation
The treatment depends on the severity of AC joint separation – as well as on the age and physical fitness of the person concerned. More minor cases can be treated conservatively, while serious injuries may require surgery. Most patients with shoulder separation can regain their normal joint functioning and mobility following appropriate treatment and rehabilitation. The first-aid response should be to immobilise and cool the shoulder. If using ice to cool the shoulder, it is important not to place the ice directly onto the skin, but to protect it with a cloth or a compress to avoid frostbite.
Shoulder separation – conservative treatment options
- Shoulder braces and rest: In mild cases, patients can rest the affected shoulder by immobilising it with e.g. an arm sling.
- Cool compresses and anti-inflammatories: Applying cold, and taking anti-inflammatory medication, can reduce any swelling and pain.
- Physiotherapy: Targeted physiotherapy exercises are a key part of follow-up treatment. These exercises strengthen the muscles around the shoulder joint and improve joint mobility.
Shoulder separation – surgical treatment options
- Arthroscopic stabilisation: If the separation is severe, or if conservative measures do not suffice, arthroscopy may be considered. During an arthroscopy, the surgeon repairs or reconstructs the torn ligaments to restore the stability of the joint.
- Collarbone fixation: In some cases, the clavicle will need to be fixed to the shoulder blade with screws or other implants in order to put the joint back into its normal position.
Rehabilitation exercises for shoulder separation
Physiotherapy is crucial in aiding the recovery from AC joint separation. Whether after an operation or as part of conservative treatment, targeted exercises strengthen the muscles and increase mobility, which accelerates rehabilitation.
What kind of doctors treat AC joint separation?
An orthopaedic accident & emergency centre is the right place to go to get treatment for AC joint separation. Orthopaedists and surgeons are the right people to contact to get AC-joint separation diagnosed or treated.
medi products for shoulder separation
Special shoulder orthoses or slings can be used to assist healing. medi offers an extensive range of suitable products.
