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

 

Pediatric Foot Fractures and Dislocations

Overview

Pediatric foot fractures

• Rare because the immature foot is highly flexible.
• Thick cartilage absorbs impact forces.
• Forces are often transmitted proximally to the ankle, tibia, or knee rather than causing foot fractures.

Minor Foot Fractures

Metatarsal base fractures

• Usually result from trivial trauma.
• Treated with immobilization alone.
• Healing is rapid with excellent outcomes.

Talus Fractures

Mechanism of injury

• Forced dorsiflexion combined with pronation.
• Anterior tibia impacts the talar neck causing fracture.

Imaging

• Canale view is the preferred radiographic view.
• Foot is pronated approximately 15 degrees.
• X ray beam is angled approximately 75 degrees.
• Best demonstrates talar neck alignment and displacement.

Acceptable displacement

• Less than 5 mm displacement.
• Less than 5 degrees angulation.

Reduction principle

• Reverse the injury mechanism.
• Plantarflexion.
• Supination.

Blood supply

• Talus has a retrograde blood supply.
• High risk of avascular necrosis after fracture.

Hawkins classification

• Type I: Undisplaced fracture with 0 to 13 percent risk of avascular necrosis.
• Type II: Subtalar subluxation with 20 to 50 percent risk.
• Type III: Associated ankle dislocation with high risk.
• Type IV: Associated talonavicular dislocation with very high risk.

Hawkins sign

• Subchondral lucency of the talar dome.
• Indicates preserved blood supply.
• Suggests a good prognosis.

Complications

• Avascular necrosis.
• Subtalar arthritis.
• Malunion.

Osteochondral Lesions of the Talus

Clinical features

• May be traumatic or atraumatic.
• Pain.
• Clicking.
• Joint effusion.

Treatment

• Only symptomatic lesions require treatment.
• Arthroscopy.
• Open reduction and internal fixation or bone grafting for large lesions.

Calcaneal Fractures

Mechanism

• Usually caused by axial compression following a fall from height.

Associated injuries

• Always evaluate for lumbar spine fractures.

Types

Stress fracture

• Common in athletes.
• Pain increases with activity.
• Bone scan is useful early.
• X rays may become positive later.

Extra articular fracture

• Usually treated conservatively.

Intra articular fracture

• Involves the subtalar joint.
• CT scan is recommended.

Bohler angle

• Normal is 20 to 40 degrees.
• Decreased angle indicates calcaneal collapse.

Treatment

• Mild displacement: Conservative treatment.
• Significant displacement: Open reduction and internal fixation or screw and pin fixation.

Special Calcaneal Injury

Nutcracker fracture of the cuboid

Mechanism

• Forefoot abduction compresses the cuboid between the calcaneus and metatarsals.

Treatment

• Restore lateral column length.
• Bone grafting.
• Internal fixation.

Midfoot Injuries

Lisfranc injury

• Involves the base of the second metatarsal with tarsometatarsal disruption.
• Requires anatomical reduction.
• Usually managed with internal fixation.

Metatarsal Fractures

Base of the fifth metatarsal

• Differentiate avulsion fracture from Jones fracture.

Jones fracture

• Occurs at the proximal diaphysis.
• Poor blood supply.
• High risk of delayed union and nonunion.
• Often treated with intramedullary screw fixation.

Metatarsal neck fractures

• Excellent remodeling potential in children.
• Usually managed conservatively.

Phalangeal Fractures

Management

• Commonly caused by crush injuries.
• Buddy taping is sufficient in most cases.
• Surgery is rarely required.

Baseball toe

• Avulsion fracture of the distal phalanx.
• Often requires fixation similar to mallet finger.

Complications

• Avascular necrosis of the talus.
• Subtalar arthritis.
• Growth arrest.
• Malunion.
• Nonunion, especially in Jones fractures.
• Foot compartment syndrome requiring medial and dorsal fasciotomy.

Exam Pearls

• Pediatric foot fractures are uncommon because of the flexibility of the immature foot.
• Talus fracture is the most important pediatric foot fracture because of the risk of avascular necrosis.
• Canale view is the preferred radiographic view for talar neck fractures.
• Hawkins sign indicates preserved talar vascularity.
• Always evaluate the lumbar spine in patients with calcaneal fractures.
• Nutcracker fracture refers to compression fracture of the cuboid.
• Jones fractures have a high risk of delayed union and nonunion.
• Lisfranc injuries usually require anatomical reduction and fixation.