Courtesy: Nirav Pandya MD, Associate Professor, UCSF, SanFrancisco, California

 

Pediatric Femoral Fractures

Proximal Femur Fractures (Femoral Neck)

Epidemiology

• Rare in children.
• Usually result from high energy trauma such as road traffic accidents or falls from height.
• Always evaluate for associated injuries.
• Always exclude pathological lesions such as bone cysts.

Blood supply

• The medial circumflex femoral artery is the principal blood supply.
• Injury to this vessel increases the risk of avascular necrosis of the femoral head.

Classification (Delbet)

• Type I: Transphyseal fracture with the highest risk of avascular necrosis.
• Type II: Transcervical fracture.
• Type III: Cervicotrochanteric fracture.
• Type IV: Intertrochanteric fracture.
• More proximal fractures have a higher risk of avascular necrosis.

Complications

• Avascular necrosis.
• Nonunion.
• Coxa vara.
• Physeal arrest.

Management principles

• Treat as an orthopaedic emergency with urgent fixation.
• Aim for anatomical reduction.
• Achieve stable fixation.
• Crossing the physis is acceptable if required for stable fixation.

Surgical considerations

• Leave room for femoral head collapse if avascular necrosis develops.
• Early implant removal may be necessary in selected patients.

Femoral Shaft Fractures

Epidemiology

• Most common femoral fracture in children.
• High energy trauma is the usual mechanism in older children.
• Falls are a common mechanism in younger children.

Healing characteristics

• Excellent union rates.
• Nonunion is uncommon.
• Remodeling is excellent in children younger than 5 years.
• Remodeling is limited after 10 years of age.

Remodeling principles

• Mild angulation is acceptable.
• Shortening of 1 to 2 cm is acceptable because of overgrowth.
• Rotational deformity does not remodel and should be corrected.

Age based treatment

Children younger than 2 to 3 years

• Pavlik harness in selected cases.
• Hip spica cast.

Children 6 months to 5 years

• Early hip spica casting is the preferred treatment.

Children 5 to 11 years weighing less than 49 kg

• Titanium Elastic Nailing System (TENS).
• Flexible intramedullary nails.

Children older than 11 years or weighing more than 49 kg

• Rigid intramedullary nail.
• Plate fixation.

Flexible intramedullary nailing (TENS)

Principles

• Two elastic nails provide three point fixation.
• Stable fixation with controlled micromotion promotes callus formation.

Technical points

• Each nail should occupy approximately 40 percent of the canal diameter.
• Combined canal fill should be about 80 percent.
• Oversized nails may cause iatrogenic fractures.

Indications

• Stable fracture patterns.
• Length stable fractures.

Limitations

• Comminuted fractures.
• Length unstable fractures.
• Obese children.

Complications

• Nail irritation.
• Malalignment.
• Loss of reduction.

Special situations

Heavier children younger than 11 years

• Stainless steel nails may provide greater strength than titanium nails.

Comminuted fractures

• Submuscular plating is preferred.

Open fractures or polytrauma

• External fixation.

Rigid intramedullary nailing

Key point

• Lateral trochanteric entry is preferred.
• Avoid piriformis entry because of the risk of avascular necrosis.

Indications

• Older children and adolescents.

Complications of femoral shaft fractures

• Limb length discrepancy.
• Malunion.
• Refracture after plating.
• Rare nonunion.

Distal Femur Fractures

Importance

• Approximately 50 percent risk of growth disturbance.
• Distal femoral physis contributes about 70 percent of femoral growth.
• Growth rate is approximately 10 mm per year.

Mechanism

• High energy trauma.
• Sports injuries.
• Hyperextension or varus valgus injuries.

Clinical features

• Severe swelling.
• Deformity.
• May mimic ligament injuries.

Important point

• Obtain radiographs before diagnosing a ligament injury.

Complications

• Growth arrest.
• Varus or valgus deformity.
• Limb length discrepancy.

Treatment

Conservative treatment

• Closed reduction and casting for undisplaced fractures.

K wire fixation

• Salter Harris Type I and II fractures.
• Follow with cast immobilization.

Screw fixation

• Salter Harris Type II to IV fractures.
• Requires anatomical reduction.
• CT planning is often helpful.

Plate fixation

• Unstable fractures.
• Near skeletal maturity.

Surgical principles

• Minimize passes across the physis.
• Use the least amount of hardware necessary.
• Achieve stable fixation.

Neurovascular assessment

• Always assess distal pulses.
• Consider CT angiography when popliteal artery injury is suspected.

Management of growth disturbance

• Shoe lift.
• Epiphysiodesis.
• Limb lengthening.

Exam Pearls

• Proximal femoral fractures have a high risk of avascular necrosis.
• Femoral shaft fracture management depends on age and weight.
• Distal femoral fractures have the highest risk of growth disturbance.
• Rotational deformity does not remodel.
• An intact posterior cortex indicates a length stable fracture suitable for TENS fixation.

Quick Summary

Age	Preferred Treatment
Younger than 5 years	Hip spica cast
5 to 11 years and less than 49 kg	TENS
Older than 11 years or more than 49 kg	Rigid intramedullary nail or plate fixation