DISLOCATION OF THE ELBOW

Dr. D. N. Bid [PT]

• Dislocation of the ulno-humeral joint is fairly common – more so in adults than in children.

• Injuries are usually classified according to the direction of displacement.

• However, in 90% of cases the radioulnar complex is displaced posteriorly or posterolaterally, often together with fractures of the restraining bony processes.

Mechanism of injury and pathology

• The cause of posterior dislocation is usually a fall on the outstretched hand with the elbow in extension.

• Disruption of the capsule and ligaments structures alone can result in posterior or posterolateral dislocation.

• However, provided there is no associated fracture, reduction will usually be stable and recurrent dislocation unlikely.

• The combination of ligamentous disruption and fracture of the radial head, coronoid process or olecranon process (or, worse still, several fractures) will render the joint more unstable and, unless the fractures are reduced and fixed, liable to re-dislocation.

• Once posterior dislocation has taken place, lateral shift may also occur.

• Soft tissue disruption is often considerable and surrounding nerves and vessels may be damaged.

• Although certain common patterns of fracture-dislocation are recognized (based on the particular combination of structures involved), high-energy injuries do not necessarily follow any rules.

• A classic example is the so-called side-swipe injury which occurs, typically, when a car-driver’s elbow, protruding through the window, is struck by another vehicle.

• The result is forward dislocation with fractures of any or all of the bones around the elbow; soft-tissue damage (including neurovascular injury) is usually severe.

Clinical features

• The patient supports his forearm with the elbow in slight flexion.

• Unless swelling is severe, the deformity is obvious.

• The bony landmarks (olecranon and epicondyles) may be palpable and abnormally placed.

• However, in severe injuries pain and swelling are so marked that examination of the elbow is impossible.

• Nevertheless, the hand should be examined for signs of vascular or nerve damage.

X-ray

• X-ray examination is essential:– (a) to confirm the presence of a dislocation and – (b) to identify any associated fractures.

• It is often only when the elbow is screened at the time of surgery that the full extent of the injury can be established.

Treatment• UNCOMPLICATED DISLOCATION• The patient should be fully relaxed under anaesthesia.

• The surgeon pulls on the forearm while the elbow is slightly flexed.

• With one hand, sideways displacement is corrected, then the elbow is further flexed while the olecranon process is pushed forward with the thumbs.

• Unless almost full flexion can be obtained, the olecranon is not in the trochlear groove.

• After reduction, the elbow should be put through a full range of movement to see whether it is stable.

• The distal nerves and circulation are checked again.

• In addition, an x-ray is obtained to confirm that the joint is reduced and to disclose any associated fractures.

• The arm is held in a collar and cuff with the elbow flexed above 90 degrees.

• After 1 week the patient gently exercises his elbow; at 3 weeks the collar and cuff is discarded.

• Elbow movements are allowed to return spontaneously and are never forced.

• The long-term results are usually good.

• DISLOCATION WITH ASSOCIATED FRACTURES• Coronoid process • Coronoid fractures have been classified by Regan

and Morrey as: – Type I : Avulsion of the tip. A benign enough injury, but it

can represent a substantial soft-tissue injury of the elbow– Type II : A single or comminuted fracture of the coronoid

with 50 per cent or less involved. This is usually not repaired surgically, as the elbow remains stable

– Type III : A single or comminuted fracture involving more than 50 per cent. If the elbow is unstable after reduction, then fixation is usually needed.

• Medial epicondyle : • An avulsed medial epicondyle is, for practical

purposes, a medial ligament disruption.

• If the epicondylar fragment is displaced, it must be reduced and fixed back in position.

• The arm and wrist are splinted with the elbow at 90 degrees; after 3 weeks movements are begun under supervision.

• Head of radius : • The combination of ligament disruption and a type II or III

radial head fracture is an unstable injury;

stability is restored only by healing or repair of the ligaments and restoration of the radial pillar – either by fracture fixation or (in the case of a comminuted fracture) by prosthetic replacement of the radial head.

• The medial collateral ligament may also be repaired to protect the radial head fixation or implant from undue valgus stress.

• Olecranon process : • In the rare forward dislocation of the elbow, the

olecranon process may fracture;

a large piece of the olecranon is left behind as a separate fragment.

Open reduction with internal fixation is the best treatment.

• Side-swipe injuries : – These severe fracture-dislocations are often

associated with damage to the large vessels of the arm.

– The priorities are repair of any vascular injury, skeletal stabilization and soft tissue coverage.

– This is demanding surgery, necessitating a high level of expertise, and is best undertaken in a unit specialising in upper limb injuries.

• Persistent instability • In cases where the elbow remains unstable

after the bone and joint anatomy has been restored, a hinged external fixator can be applied in order to maintain mobility while the tissues heal.

Complications

• Complications are common; some are potentially so serious that the patient with a dislocation or a fracture-dislocation of the elbow must be observed with the closest attention.

• EARLY COMPLICATIONS

• Vascular injury • The brachial artery may be damaged.• Absence of the radial pulse is a warning. • If there are other signs of ischaemia, this should be treated as an

emergency. • Splints must be removed and the elbow should be straightened

somewhat. • If there is no improvement, an arteriogram is performed; the

brachial artery may have to be explored.

• Nerve injury • The median or ulnar nerve is sometimes injured. • Spontaneous recovery usually occurs after 6-8 weeks.

• LATE COMPLICATIONS• Stiffness – Loss of 20 to 30 degrees of extension is not uncommon

after elbow dislocation; fortunately this is usually of little functional significance.

– The most common cause of undue stiffness is prolonged immobilization.

– In the management of all elbow injuries the joint should be moved as soon as possible, with due consideration to stability of the fractures and soft tissues and without undue passive stretching of the soft tissues.

• For injuries requiring prolonged splintage,

– a hinged elbow brace, or

– on some occasions a hinged external fixator, can allow some movement in the flexion-extension plane whilst protecting against collateral stress.

– Persistent stiffness of severe degree can often be improved by anterior capsular release.

– However, operative treatment should not be rushed;

– remember that sometimes the stiffness is due to myositis ossificans, which is usually undetectable on plain x-ray examination until a month or more after injury.

• Heterotopic ossification (myositis ossificans) – Heterotopic bone formation may occur in the damaged soft

tissues in front of the joint.

– It is due to muscle bruising or haematoma formation; however the precise pathogenesis is not known.

– In former years ‘myositis ossificans’ was a fairly common complication of elbow injury, usually associated with forceful reduction and overenthusiastic passive movement of the elbow.

– Nowadays it is rarely seen, but it is as well to be alert for signs such as slight swelling, excessive pain and tenderness around the front of the elbow, along with tardy recovery of active movements.

– X-ray examination is initially unhelpful; soft-tissue ossification is usually not visible until 4–6 weeks after injury.

– If the condition is suspected, exercises are stopped and the elbow is splinted in comfortable flexion until pain subsides; gentle active movements and continuous passive motion are then resumed.

– Anti-inflammatory drugs may help to reduce stiffness; they are also used prophylactically to reduce the risk of heterotopic bone formation.

– A bone mass which markedly restricts movement and elbow function can be excised,

though not before the bone is fully ‘mature’, i.e. has well-defined cortical margins and trabeculae (as seen on x-ray).

• Unreduced dislocation • A dislocation may not have been diagnosed; or only

the backward displacement corrected, leaving the olecranon process still displaced sideways.

• Up to 3 weeks from injury, manipulative reduction is worth attempting but care is needed to avoid fracturing one of the bones. Other than this, there is no satisfactory treatment.

• Open reduction can be considered, but a wide soft tissue release is required, which predisposes to yet further stiffness.

• Alternatively, the condition can be left, in the hope that the elbow will regain a useful range of movement.

• If pain is a problem, the patient can be offered an arthrodesis or an arthroplasty.

• Recurrent dislocation • This is rare unless there is a large coronoid fracture or

radial head fracture.

• If recurrent elbow instability occurs, the lateral ligament and capsule can be repaired or re-attached to the lateral condyle.

• A cast with the elbow at 90 degrees is worn for 4 weeks.

• Osteoarthritis • Secondary osteoarthritis is quite common

after severe fracture-dislocations.

• In older patients, total elbow replacement can be considered.

ISOLATED DISLOCATION OF THERADIAL HEAD

• A true isolated dislocation of the radial head is very rare; if it is seen, search carefully for an associated fracture of the ulna (the Monteggia injury).

• In a child, the ulnar fracture may be difficult to detect if it is incomplete, either green-stick or plastic deformation of the shaft;

it is very important to identify these incomplete fractures because even a minor deformity,

if it is allowed to persist, may prevent full reduction of the radial head dislocation.

Thank you …..4…your attention…..