Courtesy: Prof Nabile Ebrahiem, University of Toledo, Ohio, USA

Supracondylar Fracture of the Humerus in Children

Introduction

• Most common elbow fracture in children, accounting for approximately 50 percent of pediatric elbow fractures.
• Occurs through the supracondylar region, the weakest part of the distal humerus.

Types of Fracture

Extension type

• Accounts for approximately 95 percent of cases.
• Caused by a fall on an outstretched hand.
• Distal fragment is displaced posteriorly.

Flexion type

• Uncommon.
• Caused by a fall on a flexed elbow.
• Distal fragment is displaced anteriorly.

Nerve Injuries

Extension type

• Anterior interosseous nerve injury is the most common.
• Inability to make the “OK” sign.
• Weakness of the flexor pollicis longus.
• Weakness of the flexor digitorum profundus to the index finger.
• Radial nerve injury is the second most common.
• Wrist and finger extension weakness may be present.

Flexion type

• Ulnar nerve injury is the most common.
• Sensory loss over the little finger.
• Weakness of the intrinsic muscles of the hand.
• Clawing may develop.

Gartland Classification

Type I

• Undisplaced fracture.

Type II

• Angulated fracture with an intact posterior cortex.

Type III

• Completely displaced fracture.

Type IV

• Multidirectional instability due to complete periosteal disruption.

Radiological Evaluation

Fat pad sign

• Posterior fat pad is always abnormal.
• Suggests an occult elbow fracture.

Anterior humeral line

• Should pass through the middle third of the capitellum.
• In extension type fractures, the capitellum lies posterior to the line.

Baumann angle

• Assesses coronal alignment.
• A decreased Baumann angle indicates an increased risk of cubitus varus deformity.

Clinical Examination

Neurovascular assessment

Anterior interosseous nerve

• Assess with the “OK” sign.

Radial nerve

• Assess wrist and finger extension.

Ulnar nerve

• Assess sensation over the little finger.
• Assess intrinsic hand muscle function.

Treatment

Nonoperative treatment

Indications

• Gartland Type I fractures.

Management

• Above elbow cast or splint.
• Immobilization for 3 to 4 weeks.
• Avoid elbow flexion greater than 90 degrees to prevent vascular compromise.

Operative treatment

Indications

• Gartland Type II fractures.
• Gartland Type III fractures.
• Associated neurovascular compromise.

Technique

• Closed reduction followed by percutaneous pinning.
• Elbow flexion is used to maintain reduction.
• Forearm pronation helps correct varus displacement.
• Fixation with two or three divergent lateral K wires.
• Cross pinning provides greater stability but carries a higher risk of ulnar nerve injury.

Open reduction

Indications

• Failed closed reduction.
• Vascular injury.
• Entrapped soft tissues such as the brachialis muscle.

Surgical principle

• Avoid extensive posterior dissection to preserve blood supply.

Complications

Early complications

• Neuropraxia.
• Compartment syndrome.
• Vascular injury.

Late complications

• Cubitus varus (gunstock deformity) caused by malunion.
• Volkmann ischemic contracture secondary to brachial artery compromise.
• Increased risk with hyperflexion casting beyond 90 degrees.

Pulseless Supracondylar Fracture

Pink pulseless hand

• Hand remains warm and well perfused.
• Treat with closed reduction and percutaneous pinning.
• Observe with serial neurovascular examinations.

Pale pulseless hand

• Hand is cold with poor perfusion.
• Perform urgent closed reduction and percutaneous pinning.
• Proceed to vascular exploration if perfusion does not improve.

Exam Pearls

• The anterior interosseous nerve is the most commonly injured nerve.
• Cubitus varus is the most common late deformity.
• A posterior fat pad sign indicates an occult fracture until proven otherwise.
• Do not immobilize the elbow in more than 90 degrees of flexion.
• Closed reduction and percutaneous pinning is the treatment of choice for displaced supracondylar fractures.