SUPRACONDYLAR FRACTURES IN CHILDREN

Abstract

Introduction: Closed reduction and percutaneous pinning techniques for displaced supracondylar fractures of the humerus in children have overcome disastrous ischemic complications and long inpatient treatment. Closed reduction of those highly unstable fractures and the demanding pin placement itself are potential sources of failure for the inexperienced reflected by the rate of cubitus varus which is still about 5 to 15% in recent series. Rotational primary and residual displacement has to be appreciated to prevent permanent cosmetic deformity. Malrotation is the major source of instability since bicolumnar support is lost which allows the distal fragment to tilt.

Anatomy: The transverse section of the distal humerus is the key to all stability related problems faced in supra-condylar fractures of the humerus in children. In the supracondylar region the radial and ulnar column are only connected by a thin bony wafer which results from the presence of the cubital and olecranon fossa. In case of a fracture. In case of a fracture rotation leads to decrease of bony contact and hence to instability.

Epidemiology: Elbow fractures account for 7–10% of all pediatric fractures whereof 80–90% are located at the distal humerus with 80% involvement of the supracondylar region. Most of the supracondylar fractures occur between ages 5 and 10 years.

Mechanism of injury: Fall from a height, usually from a household object in the age group < 3 years or from a playground equipment in children > 4 years on the outstretched nondominant arm (indirect elbow trauma). 96% of all supracondylar fractures are extension type injuries. Open fractures, mostly grade 1, occur when the anterior spike of the proximal fragment pierces through the brachialis muscle and the skin of the cubital fossa. Their incidence is about 1–3% in major referral centers.

Differential diagnosis: Supracondylar fractures have to be differentiated from transcondylar fractures and dislocations of the elbow. In a supracondylar fracture the fracture line stays proximal to the distal humerus physis. If it runs across it, it is most likely a supracondylar fracture. Dislocations of the elbow typically after the age of 10 years.

Neurologic compromise: Fracture related peripheral neuropathies have an incidence of 10 to 17%. With rare exceptions concomitant nerve lesion recover spontaneously within a time range of 1 to 4 months. The rate of iatrogenic nerve injuries is 3%–16% with the ulnar nerve being the most susceptible due to inadvertent pinning. Despite a high recovery rate, they are a nuisance for the patients.

Vascular compromise: Early recognition of vascular compromise with subsequent reduction and fixation of the fracture and avoidance of extreme flexion at the elbow have decreased the incidence of ischemic complications. An initially absent radial pulse is found in up to 19% in displaced fractures. Closed reduction restores pulsation in about 80%. Patients with postreduction lack of pulse or poor capillary refill should undergo vascular revision. There is still controversy regarding the management of a post reduction pink, warm but pulse less hand with adequate capillary refill. Simple observation and conservative management leads to a favourable clinical outcome in most cases but cold intolerance or exercise induced ischemic symptoms is a potential sequel.

Treatment:

Undisplaced fractures: simple immobilisation e.g. collar and cuff

Incomplete displacement: in case of malrotation and/or age-related unacceptable extension (> 20° in patients older than 6 years) closed reduction and pinning otherwise conservative management

Complete displacement: Attempt for closed reduction and percutaneous pinning. Irreducibility is found in up to 22%. Open reduction is most widely as a last resort.

Complications:

Infection

Occasionally, superficial infection after pinning occurs despite all preventive measure (wires left protruding through the skin should not be covered by plaster to prevent rubbing; pin care instruction for the parents; regular follow-up for pin site inspection)

Cubitus varus

Most common complication with an overall incidence of about 20%. As a malunion in the coronal plane it has no capacity for remodelling. Although this deformity is mainly a cosmetic problem and does not interfere with the range of motion, it may be a functional problem in some activities e.g. in apparatus gymnastics.

Malunion/Stiffness

Even after perfect reduction, lack of full extension is common and usually takes over 6 months to improve. Impaired range of motion may be prolonged or even persistent due to an underlying pathology. Malunion is the most common one. In the sagittal plane, antecurvation leads to hyperextension and reduced flexion of the elbow. Significant remodelling with growth can only be expected below the age of 6 and in antecurvations of less than 20°. Rotatory malunion with an anterior spur restrains flexion. Complete remodelling of the spur usually takes place even in older children. Volkmann’s contracture represents the most severe complication after supracondylar fractures. Fortunately, it has become a rarity.

Conclusion:

The human factor, in view of the particular anatomy of the supracondylar region and the extreme fracture instability seems to be more decisive for the end result than any biomechanical differences of various pin configurations. Repeat instruction by an experienced surgeon for proper reduction technique, assessment of achieved reduction and technically correct pin placement is crucial to further improve the outcome of this challenging fracture.