The shoulder joint is the most mobile joint in the human body. However there is a price to be paid for this mobility- it is also the most commonly dislocated large joint in the body.
How does the shoulder dislocate?
Usually a significant injury is required to dislocate a shoulder. In some people however the shoulder can dislocate due to abnormal muscle contraction. Shoulder dislocation is not uncommon in sports such as rugby or football. Usually the shoulder dislocates in a forward direction. Less commonly the shoulder can dislocate in a backwards direction particularly in people suffering from epilepsy.
How is it treated?
Usually the shoulder needs to be pulled back into a joint by a healthcare professional. This is often possible in the accident and emergency department. Before putting the shoulder back, an x-ray of the shoulder may be taken. This is useful to rule out any associated breaks of the bone. Sometimes the shoulder fails to go back into joint despite all attempts. Such patients will require admission to hospital for manipulation of the shoulder under a general anaesthetic. In some people the shoulder goes back into joint spontaneously without the need for medical intervention.
What happens after the shoulder is put back into joint?
Initially the shoulder will be rested in a sling or brace. Painkillers are given and an appointment arranged with an orthopaedic surgeon. The sling is used for between 2 rule of law that to 6 weeks depending upon a number of factors such as age and number of previous dislocations.
What happens next?
Those patients above the age of about 40 will be thoroughly assessed for any associated muscle tears (rotator cuff tears) which are not uncommon in this age group. An MRI scan may be ordered if there is a strong suspicion of a tear. All age groups are assessed for any associated nerve injury.
If no muscle tear is found, then the treatment is usually nonoperative and involves Physiotherapy and an exercise programme to strengthen the shoulder.
If a muscle tear is found, then in most cases this will require repair by keyhole surgery.
In the younger, more athletic patient, keyhole surgery to stabilise the shoulder may be considered. There is mounting clinical evidence that such patients do better following keyhole surgery compared to nonoperative treatment.
Those patients whose shoulder keeps on dislocating will require surgery in order to stabilise it. This may be performed by keyhole surgery or by open surgery. The choice of method depends on the training of the surgeon and the type of damage seen on the MRI scan and at the time of surgery.
What are the complications of shoulder dislocation?
The main complications are:
- Recurrent dislocation- the younger the patient at the time of the first dislocation, the greater the chance of a second dislocation. 80% of those under 20 years of age have a recurrence within two years. This falls to only 10 to 15% in those aged over 40 years.
- Muscle (rotator cuff) tears- this is more common in the older patient.
- Nerve injury- this is also more common in the older patient and almost always recovers spontaneously with time.
- Fractures- fractures of the ball or the socket can occur when a shoulder dislocates. Sometimes these will need an operation to fix back the broken piece of bone.
What does keyhole surgery involve?
This involves being admitted to hospital as a day case. The surgery is performed either under a general anaesthetic ( the patient is put to sleep) Or a regional anaesthetic (the arm is put to sleep). Usually three tiny 5 mm incisions are made and a special telescopic camera is inserted into the shoulder. The damage is repaired using special “thermoplastic” anchors inserted into the socket. They shoulder sling is worn for about 4 to 6 weeks after surgery. Physiotherapy is usually started 3 to 4 weeks after surgery. The advantage of keyhole surgery is that minimal damage done to surrounding structures and therefore there is a quicker recovery.
When it is open surgery required?
Sometimes the damage done is too extensive to repair by keyhole surgery. For example there may be a large chunk of the socket missing. In such patients an open operation involving bone grafting to the socket (Bristow-Laterjet procedure) is usually required.
What is the success rate of surgery?
Using the latest keyhole surgery techniques, the success rate for prevention of further dislocation is approximately 90%.