Shoulder Dislocation/Instability and Stabilisation

What is it?

The shoulder joint is a ball and socket joint, where the socket is naturally quite shallow. The labrum is a cartilage rim that surrounds the socket to enhance stability of the joint. Together with the joint capsule (and condensations of the capsule: ligaments), they resist movement of the humeral head out of the socket – dislocation.

ball and shallow socket of the shoulder joint and labrum

When the capusle or the labrum are stretched or torn, the humeral head can dislocate more readily, which is known as instability. A tear in the labrum is known as a Bankart lesion. This commonly occurs at the front of the shoulder (3 o’clock to 6 o’clock position), as the majority of shoulder dislocations are when the humeral head falls out of joint down and forwards.

Subluxation is abnormal movement of the humeral head within the socket but not frank dislocation. There can be several reasons as to why this occurs and these determine the treatment modality.

How the shoulder dislocates for the first time is important as this has a bearing on the subsequent management. There are two main categories:

  • Traumatic – a large force is imparted on the shoulder joint that is violent enough to displace the ball out of the socket e.g. rugby tackle, significant fall etc. More often than not, the dislocation needs to be reduced in an A & E department. Bankart lesions are often created by this mechanism of dislocation, which predisposes the shoulder to recurrent dislocations.
  • Atraumatic – this dislocation occurs as a result of a small force being imparted on the shoulder joint e.g. turning in bed, reaching above head height for an object. Reduction in A & E is not often required. It is common in people who have generalised joint laxity or hypermobility i.e. many joints are lax, especially knees, hands, elbows. A change in the muscles around the shoulder that normally coordinate to keep the shoulder in joint ensues. Loss of muscle interaction in certain positions of the arm occurs causes repeated instability. Because abnormal muscle coordination or patterning is responsible this is often best treated with sustained physiotherapy and re-training of correct muscle patterning.

It should be noted that overlap does exist between these two groups, particularly over time, as some patients may start in the traumatic group but eventually end up in the atraumatic group i.e. continue to dislocate with low energy mechanisms.

Stabilisation procedures aim to prevent further shoulder dislocation; repair of the Bankart lesion and tightening of the capsule is the mainstay of this type of surgery and can be done by shoulder arthroscopy.

Who should have stabilisation surgery?

The best method to prevent repeated shoulder dislocation is to strengthen and coordinate the muscles of the rotator cuff and shoulder girdle. This is best supervised by an experienced physiotherapist.

Surgical stabilisation is an option when non-operative management fails. Success of stabilisation surgery is greater in patients with no inherent physiological factors i.e. hypermobility, voluntary dislocations.

Current evidence suggests that patients that sustain their first dislocation traumatically may be at high risk of re-dislocation if they:

  • Are young active patients (<30yrs)
  • Intend to continue to participate in athletic overhead activity or contact sports

For patients that continue to dislocate over a long period of time, bony damage to the socket may occur (glenoid erosion). X-ray or CT scan can detect this pre-operatively. In the case of confirmed glenoid bone loss, arthroscopic Bankart repair may no longer be a suitable surgical procedure and a bone block stabilisation procedure (Bristow-Latarjet) should be considered. This is open surgery and Mr Patel will discuss the likelihood of this with you at your consultation.

coracoid process and Bristow-Latarjet procedure

Will I need any tests/scans?

It is likely that X-rays and a CT scan will be requested for shoulder dislocation. A MR arthrogram may also be requested. This is like a standard MRI but prior to the investigation, dye is injected into the joint under local anaesthesia to increase the sensitivity of the scan to demonstrate a Bankart lesion. Please see the section Surgery FAQs to see if you will need any other tests e.g. blood tests before your surgery.

How is it done?

Arthroscopic stabilisation (Bankart repair) is carried out under general and/or regional anaesthesia.

Three portals (incisions <1cm) are made around the shoulder. If a Bankart lesion is present this is reattached to the glenoid rim by using 2-3 small bone anchors (devices that are inserted into bone and have very strong suture attached). If the capusle is excessively loose (also a cause for recurrent dislocation which can occur in isolation with atraumatic dislocations or with a Bankart lesion in traumatic dislocations) this can be tightened (capsular plication) using the same technique.

view inside shoulder joint

At the end of the operation, steri-strips or one stitch is used to close each portal. Waterproof dressings and then a bulky dressing pad are applied to absorb the natural ooze from the joint. The arm is always placed into a polysling for comfort and to immobilise the shoulder to allow tissues to heal.

The Bristow-Latarjet procedure is an open procedure also carried out under general and/or regional anaesthesia. An incision is made at the front of the shoulder. The coracoid process is transferred to the deficient area of the glenoid with its muscles attached; this replaces the deficient bone and the muscles act as a further dynamic restraint to further dislocation. The coracoid is fixed in place with a screw and washer.

The wound is closed with a dissolvable stitch; the area should be kept clean and dry for 2 weeks. A dressing and polysling are then applied.

Can I go home the same day?

More often than not, as with most arthroscopic surgery, this is a day case procedure. Occasionally an overnight stay is advised depending on post-operative comfort levels and time of day of the surgery.

What about after the operation?

You will see a physiotherapist before discharge to be instructed on simple exercises to carry out in the short term. This usually involves simple pendulum exercises out of the polysling and light stretches, often with assistance (e.g. your other arm or your physiotherapist) and you will be instructed on axillary hygeine. You should aim to exercise the shoulder 3-4 times a day; although the shoulder will be sore to start, there should be no lasting pain or pain that is not alleviated by the analgesia prescribed to take home. Sleeping with a pillow under the shoulder is recommended. It will be painful to sleep on the side of the operated arm for several weeks.

Restrictions of movement: for 6 weeks Mr Patel recommends no combined abduction and external rotation and restriction of forward flexion to shoulder height. These apply to the Bristow-Latarjet procedure also.

You will be prescribed analgesia to take home and Mr Patel strongly advocates its use to keep pain to a minimum; it should be noted that pain is more difficult to control if allowed to establish itself. Mr Patel recommends the regular application of ice as an adjunct to relieve pain and swelling in the acute post-operative period.

You will see Mr Patel two weeks after surgery for a wound check (and stitch removal) and a physiotherapy program will ensue thereafter which is paramount to the success of the operation. You are likely to have been seeing a physiotherapist before the operation and Mr Patel will liaise with him/her in detail to advise on the post-operative exercise program. For this procedure, Mr Patel recommends return to work (sedentary) when you feel able; for manual work this may be 3-4 months. Driving can resume after 6-8 weeks, as can swimming breastroke. Return to freestyle swimming, overhead athletic activity and contact sport is recommended at 3-4 months. These apply to the Bristow-Latarjet procedure also.

What are the potential complications?

All surgery carries a risk. Specific risks to arthroscopic shoulder stabilisation are:

Infection – this can be either superficial (portals) or within the joint. You will be given antibiotics to reduce this risk.

Stiffness – It is very important that some mobility of the shoulder is maintained after surgery. The physiotherapist will advise on simple exercises that can be carried out at home. Mr Patel also recommends that you take regular analgesia and use ice (see Surgery FAQs) to help minimise post-operative discomfort and facilitate early movements.

Bleeding – this may require a return to the operating room for removal of blood clots and to stop the bleeding.

Neurological – patients often describe a patch of numbness or a heavy feeling around the shoulder in the early post-operative phase. This is commonly swelling related and resolves as swelling reduces and full shoulder mobility is recovered

Non-union – this applies to the Bristow-Laterjet procedure. Despite good fixation, very ocassionally the bone transfer does not heal. Re-operation and stimulation may be required in this instance.

Device failure – rarely, the bone anchors used for arthroscopic stabilisation can migrate (move out of position). They will need to be retrieved if this happens as if they are not flush with the glenoid surface or left to float around the joint, they can cause damage to the articular surfaces. The screw used for the Bristow-Latarjet procedure may also migrate; re-operation to revise the fixation will be necessary in this circumstance.

Recurrence – redislocation can and does occur. Good compliance with post-operative rehabilitation will reduce your risk greatly. Contact sports carry a higher risk for redislocation.