Download Information leafletShoulder separations (AC joint injuries)
What is it?
The ‘Acromioclavicular’ joint is located at the end of the collarbone (clavicle), at the top of the shoulder. This joint can be injured after a fall.
Is it called by any other name?
Shoulder separations.
What is its cause?
The most common cause for injuring the AC joint is a fall on to the point of the shoulder, elbow or hand, or a direct impact to the point of the shoulder. This can result in a sprain, partial or total dislocation of the joint.
What are the symptoms and how is the injury diagnosed?
Immediate severe pain is felt over the shoulder. Any attempt to lift the arm up or carry anything will make the pain worse. A bony bump may be felt or seen if the joint has partially or totally dislocated.
Diagnosis is mainly by physical assessment and is usually obvious to a specialist.
Will further tests or investigations be needed?
An x-ray of the shoulder is always recommended. Sometimes the patient is asked to hold a weight in the hand during x-ray. The x-rays will grade the injury.
The injury can range from a sprain (Grade I), partial dislocation (Grade II) or full dislocation (Grade III). The full dislocations can be more severe and are further graded as IV, V and VI.
What is the treatment?
- The treatment for grade I & grade II injuries is a sling to rest the joint for a few days, followed mobilization of the shoulder. Within about 6-8 weeks the pain will settle. Grade III injuries are usually treated with a sling followed by exercises; some patients with grade III injuries may need surgery to stabilise the joint.
- Grade IV, V and VI injuries will need surgery to stabilize the joint and help the torn ligaments heal.
- Acromioclavicular joint stabilisation surgery (open): In acute injures the aim of the operation is to reduce the separated joint. This will help the torn ligaments heal. The traditional operation needs a long incision. The joint is reduced and then stabilised by using some form of internal fixation like a hook plate, a wiring technique or an artificial ligament.
- Arthroscopic Acromioclavicular joint stabilisation surgery (keyhole surgery): In recent years the operation is more often carried out with the aid of a telescope (keyhole surgery). Using a special jigging system and strong sutures (Tightrope) the joint is stabilised with 3 small incisions.
- Acromioclavicular joint stabilisation surgery in old injuries (open): In patients who neglected the original injury (see picture below) or in some patients who were initially treated non-surgically, the joint remains deformed, painful or weak, causing functional problems.
Such patients may require surgery during which the torn ligaments are reconstructed using a part of another neighbouring ligament (coraco-acromial ligament) or a part of a tendon (conjoint tendon).
- Arthroscopic excision of the AC joint (keyhole): This procedure is advised for patients who continue to have problems after grade I or II injuries.
What happens if it is not treated?
Patients with Grade I, II and III generally recover very well. Rarely the patient will be left with a bump, but pain and functional problems will vary. In some people, pain and shoulder weakness will persist. This is more likely to occur with patients who perform regular overhead work (e.g. athletes, builders).
Patients with grade III – VI may also develop additional symptoms due to joint instability. They will complain of a deformity that results in the shoulder dropping (see picture above). This may lead to shoulder weakness and pain, neck pain and symptoms in the upper limb (Brachial neuralgia).
What is the success of surgical treatment?
The surgical treatments for both acute and old injuries has a generally successful outcome. More than 80% patients will achieve a full range of movement and full strength after joint stabilization.
What are the complications of surgical treatment?
- The surgical scar may be tender for a few weeks but will nearly always settle. There is a small possibility that the scar may remain unattractive. An area of numbness can occur around the scar but this rarely causes any problems.
- Infection of the wound is possible but can usually be successfully treated with antibiotics. Very rarely infection may spread.
- Failure of the ligaments to heal, resulting in incomplete reduction of the joint.
- Fracture of the collar bone may rarely occur.
- Deltoid or trapezial muscle detachment following open surgery.
- Any surgical intervention has the risk of developing complications / setbacks which are unpredicted. These complications may have the potential to leave the patient worse than before surgery.
Is there anything I can do to improve the outcome?
- Keep the wounds dry and clean until they have healed.
- After the operation you need to wear a sling for a period of 3-6 weeks.
- The therapist will see you to start rehabilitating your shoulder. It is important that the advice with regards to use of the sling and exercises are followed. These instructions will vary according to the type of surgery performed.
- It is advised not to wear rings on the operated side for 4-6 weeks after surgery.
When can I do various activities?
Return to work depends on many factors including the nature of the job and hand dominance.
- Patients may be able to return to a desk job within 7-14 days. However if use of the sling is recommended, patients will need to adapt their activities accordingly.
- Light lifting with the affected arm can be started at 6 weeks. Manual work after surgery should be avoided for 8-12 weeks.
- Breast stroke swimming can be started at about 8 weeks, but overhead work and freestyle swimming are best avoided for 12 weeks.
- Driving should be possible after about 8 weeks of surgery. Before driving, do check that you can manage all controls and start with short journeys.
