Courtesy:
Dr. Walid K Yassir
Children’s Hospital of Michigan Pediatric Emergency Department www.chmpem.com

Epidemiology and Mechanism

Pediatric forearm fractures

• Account for approximately 40 percent of pediatric long bone fractures.
• Most commonly occur after a fall on an outstretched hand.
• The ulna is subcutaneous and is prone to direct trauma, producing a nightstick injury.
• Increasing incidence is related to greater sports participation and rising childhood obesity.

Anatomy and Growth

Ossification

• Distal radial epiphysis appears at approximately 1 year of age.
• Distal ulnar epiphysis appears at approximately 5 years of age.

Growth contribution

• Distal physes contribute most of the forearm growth.
• Proximal physes contribute relatively little.

Clinical significance

• Distal fractures have excellent remodeling potential.
• Proximal fractures remodel poorly.

Distribution of Fractures

• Distal forearm: Approximately 75 percent.
• Midshaft: Approximately 20 percent.
• Proximal forearm: Approximately 4 percent.

Types of Forearm Fractures

Plastic deformation

• Permanent bending without cortical disruption.
• Periosteum remains intact.
• No callus formation.
• May restrict forearm rotation.
• Remodeling is unreliable.
• Correction is indicated for angulation greater than 20 degrees, functional limitation, or age greater than 8 years.

Greenstick fracture

• One cortex is broken while the opposite cortex remains intact.
• Includes buckle (torus) fractures.
• Intact cortex tends to recoil after reduction.
• Usually treated with a well molded long arm cast.
• Completion of the fracture under anesthesia may occasionally be required.

Complete fracture

• Both cortices are disrupted.
• Highly unstable.
• Proximal fragment is usually supinated by the biceps.
• Distal fragment is pronated by the pronator muscles.

Goals of Treatment

• Restore alignment and cosmetic appearance.
• Preserve soft tissues.
• Relieve pain.
• Achieve functional forearm rotation.
• Minimum functional motion is 50 degrees each of pronation and supination.
• Normal motion is approximately 90 degrees each of pronation and supination.

Principles of Closed Reduction

• Apply traction and countertraction.
• Exaggerate the deformity to unlock the fragments.
• Correct rotational deformity.
• Point the thumb toward the apex of the deformity.
• Apex volar deformity requires pronation.
• Apex dorsal deformity requires supination.

Acceptable Alignment

• Avoid angulation greater than 25 degrees whenever possible.
• Acceptable alignment depends on age, fracture location, and remodeling potential.
• Preserve the interosseous space between the radius and ulna.

Remodeling Potential

Factors affecting remodeling

• Younger age.
• Fractures closer to the physis.
• Sagittal plane deformities remodel best.
• Coronal deformities remodel less.
• Rotational deformities do not remodel.

Remodeling rate

• Approximately 1 degree per month.

Follow Up After Reduction

• Weekly radiographs for the first 3 weeks.
• Shaft fractures may be remanipulated up to 3 weeks.
• Distal physeal fractures should be remanipulated only within 7 to 10 days.

Principles of Casting

• Three point molding.
• Cast index should be less than 0.8.
• Maintain a straight ulnar border.
• Maintain an interosseous mold.

Cast saw burns

• Caused by heat transfer through a wet cast.
• More common in sedated children and wet fiberglass casts.
• Prevent by allowing the cast to dry, using a protective strip, and cooling the saw blade frequently.

Complications

• Malunion is the most common complication.
• Refracture.
• Compartment syndrome.
• Radioulnar synostosis.
• Neurovascular injury.

Indications for Surgery

• Open fractures.
• Compartment syndrome.
• Irreducible fractures.
• Loss of reduction.
• Polytrauma or floating elbow.
• Neurovascular compromise.
• Refracture.

Surgical Options

Intramedullary nailing

• Preferred surgical technique.
• Titanium elastic nails are commonly used.
• Causes minimal soft tissue injury.
• Provides good stability.
• Nails should be prebent to approximately three times the bone diameter.

Plate fixation

• Preferred for older children.
• Useful for comminuted fractures.
• Indicated for some open injuries.
• Higher refracture risk after implant removal.

Galeazzi Fracture

Definition

• Radial shaft fracture associated with distal radioulnar joint disruption.

Clinical features

• Prominent distal ulna.
• Distal radioulnar joint instability.

Management

• Reduce the radial fracture.
• Assess distal radioulnar joint stability.
• Fix the distal radioulnar joint if instability persists.

Distal Radius Fractures

Types

• Metaphyseal fractures are the most common.
• Physeal fractures, with Salter Harris Type II being the most common.
• Buckle (torus) fractures.

Management

Non displaced fractures

• Short arm cast for approximately 3 weeks.
• Buckle fractures are treated with a removable splint.

Displaced fractures

• Closed reduction followed by casting.
• Hematoma block is a useful anesthetic technique.

Important Points

• Avoid repeated reductions because of the risk of growth arrest.
• Up to 15 to 20 degrees of angulation may be accepted if substantial growth remains.
• Bayonet apposition is acceptable in young children with good remodeling potential.

Complications

• Growth arrest in approximately 5 percent.
• Malunion is uncommon because of excellent remodeling.
• Ulnar overgrowth may produce positive ulnar variance.

Exam Pearls

• Distal radius fracture is the most common pediatric fracture.
• Greenstick and buckle fractures are the most common fracture patterns.
• Remodeling is best in younger children, near the physis, and in the sagittal plane.
• Rotational deformity does not remodel.
• Bayonet apposition is often acceptable in younger children.
• Avoid repeated reductions of physeal fractures to minimize the risk of growth arrest.