Courtesy: Kaye Wilkins MD, Lynn Staheli MD
www.global-help.org

Supracondylar Fracture of the Humerus in Children

Epidemiology

• Most common elbow fracture in children.
• Peak incidence between 5 and 7 years of age.
• More common in boys.

Reasons for increased incidence

• Maximum ligamentous laxity.
• Weak metaphyseal bone with a thin cortex during remodeling.
• Fall on an outstretched hand is the common mechanism.

Mechanism of Injury

Extension type

• Accounts for approximately 95 to 98 percent of cases.
• Caused by a fall on an extended elbow resulting in hyperextension.
• Failure begins on the anterior cortex under tension.

Flexion type

• Rare.
• Caused by a fall on a flexed elbow.

Types

Based on displacement

• Extension type.
• Flexion type.

Gartland Classification (Extension Type)

Type I

• Undisplaced fracture.
• Minimal or acceptable displacement.
• Anterior humeral line passes through the capitellum.

Type II

• Angulated fracture with an intact posterior cortex.
• Posterior cortex acts as a hinge.
• Length is maintained.

Type III

• Completely displaced fracture.
• No cortical contact.
• Loss of length with angulation.
• Posteromedial subtype.
• Posterolateral subtype.

Type IV

• Multidirectional instability.
• Unstable in both flexion and extension.
• Less commonly used in routine clinical practice.

Radiological Evaluation

Anterior humeral line

• Should pass through the capitellum.
• Failure to intersect the capitellum indicates unacceptable sagittal angulation.

Fat pad sign

• Posterior fat pad is always abnormal.
• Indicates an occult elbow fracture until proven otherwise.

Baumann angle

• Assesses coronal alignment.

Crescent (half moon) sign

• Suggests varus malalignment.

Acceptable Deformity

• Sagittal angulation of approximately 20 degrees may remodel.
• Coronal plane deformity, particularly varus, does not remodel reliably.

Treatment

Type I fractures

• Above elbow cast.
• Elbow flexed to approximately 90 degrees.
• Immobilization for about 3 weeks.

Pitfall

• Missed medial column collapse may result in cubitus varus.

Type II fractures

Reduction

• Closed reduction under general anesthesia.
• Correct coronal plane deformity first.
• Correct sagittal plane deformity next.

Immobilization

• Stable fractures may be treated with casting.
• Unstable fractures require percutaneous pin fixation.
• Current practice increasingly favors pin fixation.

Type III fractures

• Closed reduction and percutaneous pinning is the treatment of choice.

Reduction principles

• Restore limb length.
• Correct angular deformity.
• Maintain reduction with elbow flexion.

Pin Configuration

Cross pinning

• Medial and lateral K wires.
• Provides maximum mechanical stability.
• Higher risk of iatrogenic ulnar nerve injury.

Lateral pinning

• Two or three lateral K wires.
• Lower risk of ulnar nerve injury.
• Slightly less rotational stability.
• Three lateral pins provide stability comparable to crossed pins in most fractures.

Posteromedial versus Posterolateral Displacement

Posterolateral displacement

• Increased risk of brachial artery injury.
• Increased risk of median nerve and anterior interosseous nerve injury.
• May become irreducible because of brachialis muscle interposition.

Posteromedial displacement

• Increased risk of radial nerve injury.

Indications for Open Reduction

• Irreducible fracture.
• Puckering sign indicating soft tissue interposition.
• Vascular compromise.
• Nerve entrapment.

Surgical approach

Posterolateral displacement

• Anteromedial approach.

Posteromedial displacement

• Anterolateral approach.

Flexion Type Fractures

Features

• Distal fragment displaced anteriorly.
• Tendency to develop valgus deformity.
• Frequently associated with ulnar nerve injury.

Treatment

Type I

• Cast immobilization.

Type II

• Closed reduction.

Type III

• Open reduction is frequently required.

Complications

Early complications

• Median nerve and anterior interosseous nerve injury.
• Radial nerve injury.
• Ulnar nerve injury in flexion type fractures.
• Compartment syndrome.
• Volkmann ischemic contracture.

Late complications

• Cubitus varus due to malunion.
• Elbow stiffness.
• Myositis ossificans, particularly after delayed surgery.

Exam Pearls

• A posterior fat pad sign indicates an occult fracture until proven otherwise.
• Cubitus varus results from malunion rather than growth disturbance.
• Type II fractures are increasingly managed with percutaneous pin fixation.
• Flexion type fractures have a higher rate of open reduction.
• A delay of 6 to 8 hours before surgery is acceptable in the absence of vascular compromise.

Healing

• Fracture union usually occurs within 3 weeks.
• Full range of elbow motion is generally regained within 4 to 6 weeks.