A 6 year old boy attended the emergency department with an isolated injury to his left elbow after falling on his outstretched left arm. On examination, the left elbow joint was swollen and clinically deformed with diffuse tenderness. The skin was intact and there was no neurovascular deficit in the left upper limb. We x rayed the elbow (figure).

X ray of the boy's elbow

Questions

1. What does the x ray film show?
2. What should the assessment of such an incident include?
3. What is the classification of supracondylar fractures of the humerus?
4. What are the potential complications of supracondylar fractures?
5. How should this fracture be managed?

Answers

1. The x ray film shows a displaced supracondylar fracture of the left humerus with the distal fragment of the humerus displaced posteriorly.
2. Assessment should include a quick general evaluation of the patient to ensure that the airways are patent, breathing is not compromised, and that the patient is cardiovascularly stable. Then, assess the level of consciousness and cognitive function. Once the patient is stable, assess for any further injuries. It is important not to miss any head, chest, or abdominal injuries, as contusion or internal bleeding can damage major organs. Examination of the affected limb should include inspection for swelling, erythema, deformities, and any skin breach. Neurovascular examination is essential to exclude nerve or arterial damage. You should then palpate the whole limb up to the clavicle looking for bony tenderness, as any part may have sustained a fracture or joint dislocation.
3. There are two types of supracondylar fracture--the extension type (95%), in which the anterior cortex fails first with resultant posterior displacement of the distal fragment, and the flexion type, in which the opposite occurs. Extension type supracondylar fractures are classified using Gartland's classification: type I fractures are nondisplaced, type II fractures are displaced but hinged on the posterior cortex, and type III fractures are completely displaced, as in this case.
4. Supracondylar fractures of the humerus, especially Gartland's type III, have potentially serious complications, which can occur early or late.
5. In this case, the fracture was treated with closed reduction, under radiological guidance, and percutaneous pins. Reduction is achieved by first correcting the lateral-medial displacement, and then the posterior angulation. Crossed pins provide the most secure fixation, better if they do not cross at the fracture side. Undisplaced fractures can be treated in a backslap with the elbow flexed for three weeks or in a collar and cuff.

Early complications

Vascular damage

As the distal fragment and forearm are pushed backward, the brachial artery and median nerve are pulled violently against the sharp lower edge of the proximal fragment. Circulation must be assessed looking for pulselessness, pallor, pain, paraesthesia, and paralysis (the five p's), and capillary refill.

Compartment syndrome

The intracompartmental pressures in the forearm may rise due to interstitial oedema, requiring fasciotomy to prevent neurovascular compromise. In this case, reduced passive finger extension, due to anterior compartment oedema, was relieved by gentle extension of the elbow joint.

Nerve damage

The median, radial, and ulnar nerves may be injured, with potential long term pain and functional deficit. Fortunately, the injury is usually a neuropraxia, which recovers with conservative treatment.

Myositis ossificans

This is calcification in the haematoma that forms in the brachialis muscle, which covers the anterior aspect of the elbow joint. This can lead to mechanical block to flexion. Complete rest is necessary to minimise the mass of the material formed, which may be excised at a later stage if quiescent (stable in size and symptoms) for many months.

Late complications

Volkmann's ischaemic contracture

If the compartment syndrome is not detected and remains untreated, muscle necrosis and fibrosis can occur, causing finger flexion and wrist flexion and pronation.

Malunion

Varus deformity may occur due to malunion. At best the result is loss of carrying angle and at worst a gunstock deformity, which may require corrective osteotomy after completion of growth.

Marios Tryfonidis preregistration house officer in general medicine, Manchester Royal Infirmary
Email: martryfon1@hotmail.com

Charalambos Charalambous specialist registrar in orthopaedics and trauma, Blackburn Royal Infirmary

Suggested Reading

• Hammond WA, Kay RM, Skaggs DL. Supracondylar humerus fractures in children. AORN J 1998;68:186-99, quiz 203, 205-6, 208-10.
• Wilkins KE. Supracondylar fractures: what's new? J Pediatr Orthop B 1997;6:110-6.
• Ristic S, Strauch RJ, Rosenwasser MP. The assessment and treatment of nerve dysfunction after trauma around the elbow. Clin Orthop 2000;370:138-53.
• Botte MJ, Gelberman RH. Acute compartment syndrome of the forearm. Hand Clin 1998;14:391-403.
• Papandrea R, Waters PM. Posttraumatic reconstruction of the elbow in the pediatric patient. Clin Orthop 2000;370:115-26.
• David JD, Denis JE. Essential orthopaedics and trauma. 3rd ed. Edinburgh: Churchill Livingstone,1998:195-7.