Femoral Shaft Fractures - Pediatric - Pediatrics

Introduction

Overview
- pediatric femoral shaft fractures are one of the most common pediatric orthopedic fractures and are the most common reason for pediatric hospitalization due to orthopedic injury
  - treatment may be casting or operative depending on the fracture pattern and age of patient.
  - any femur fracture in a child not yet walking should raise concern for non-accidental trauma
Epidemiology
- incidence
  - 1.6-2% of all pediatric fractures
    - bimodal distribution
      - increased rate in toddlers age 2-4 years and adolescents
  - most common reason for pediatric hospitalization due to orthopaedic injury
- demographics
  - males more commonly affected 2.6:1
Pathophysiology
- mechanism of injury
  - fall is the most common cause under 10 years
  - a motor vehicle accident is the most common cause over 10 years
- correlated with age due to the increased thickness of the cortical shaft during skeletal growth and maturity
Associated conditions
- high suspicion for child abuse required
  - abuse must be considered if the child is < 3 years and especially if present in a patient before walking age
  - femur fractures are one of the most common fractures associated with child abuse
- medical conditions and comorbidities
  - osteogenesis imperfecta
  - osteopenia secondary to neuromuscular disorders
  - benign or malignant bone tumors
Prognosis
- high rate of fracture union if appropriate treatment is selected based on patient age and fracture pattern

Anatomy

Osteology
- anterior bow to femur
- isthmus is the narrowest portion of the femur
Muscles
- iliopsoas creates a flexion and external rotation force on the proximal fragment
- adductors create a shortening and varus force on the distal fragment
Biomechanics
- femoral shaft cortical diameter and cortical thickness increase with age

Classification

Descriptive classification
- characteristics of the fracture
  - transverse
  - comminuted
  - spiral
  - Others
- location of the fracture
  - proximal, middle, or distal third
- integrity of the soft-tissue envelope
  - open vs closed fracture
Stability
- stable fractures
  - typically transverse or short oblique
- unstable fractures
  - long spiral (fracture length > 2 X bone diameter at that level) or comminuted fractures

Presentation

Symptoms
- thigh pain
- inability to walk
- report of deformity or instability
Physical exam
- gross deformity
- shortening
- swelling of the thigh

Imaging

Radiographs
- AP and lateral of the femur
  - allow for complete evaluation of the fracture location, configuration, and amount of displacement
- ipsilateral AP and lateral of knee and hip
  - to rule out associated injuries

Treatment

Nonoperative
- Pavlik harness
  - indications
    - children up to 6 months
    - any fracture pattern
- spica casting
  - indications
    - children 0 - 5 years
    - relatively contraindicated with polytrauma, open fractures and shortening > 2-3 cm
- traction + delayed spica casting
  - indications
    - younger patients with significant shortening
    - rarely utilized
Operative
- flexible intramedullary nails
  - indications
    - most length stable fracture patterns in children 5 - 11 years weighing < 49kg (100 lbs)
- submuscular bridge plate fixation
  - indications
    - unstable fractures in children 5 or older and >49kg (100lbs)
    - very proximal or very distal fractures
    - severe comminution
- antegrade rigid intramedullary nail fixation
  - indications
    - in patients >11 years or approaching skeletal maturity
    - unstable fractures
    - fractures in patients weighing > 49kg (100 lbs)
- external fixation
  - indications
    - damage control orthopedics in a polytrauma patient
    - open fractures
    - associated vascular injuries requiring revascularization
    - segmental or significantly comminuted fractures

Treatment Table by Age
< 6 months	Any fracture pattern	Pavlik harness early spica casting
6m - 5 years	stable fracture pattern	early spica casting
6m - 5 years	unstable fracture pattern polytrauma/multiple fx/open fx	traction with delayed spica casting external fixator
5 - 11 years	length stable fx (transverse or oblique fx patterns) patient weighs < 49kg (100 lbs)	flexible intramedullary nails
5 - 11 years	length unstable fx (comminuted or spiral) very proximal or distal fx any weight	ORIF with submuscular bridge plating external fixation
11 or greater years	patient weight < 49kg (100 lbs)	flexible intramedullary nails
	patient weight > 49kg (100 lbs)	antegrade rigid intramedullary nail fixation
	proximal or distal fracture severe comminution	ORIF with submuscular bridge plating

Surgical Techniques

Pavlik harness
- technique
  - avoids the need for sedation or anesthesia
- complications
  - can compress femoral nerve if excessive hip flexion is used in presence of a swollen thigh
    - identified by decreased quadriceps function
Immediate spica casting
- technique
  - applied with reduction under sedation or with general anesthesia
  - single-leg spica or one-and-one-half spica (to control rotation)
    - distal femoral buckle fracture may be treated with long leg cast alone (not spica)
  - hips flexed 60-90° and approximately 30° of abduction
  - external rotation is typically needed to correct a rotational deformity
  - molded into recurvatum and valgus as the muscular forces will pull fracture into procurvatum and varus
  - molds along the distal femoral condyles and buttocks help to maintain reduction
  - acceptable limits are based on age
    - the goal of reduction should include obtaining < 10° of coronal plane and < 20° of sagittal plane deformity with no more than 2cm of shortening or 10° of rotational malalignment
  - a special car seat is sometimes needed for transport (often can use a regular car seat if single-leg spica is used)
- complications
  - compartment syndrome
    - decreased with applying smooth contours around popliteal fossa, limiting knee flexion to < 90° and avoiding excessive traction
    - Decreased by avoiding applying short leg cast first followed by traction on poplitea fossa
    - monitored for by observing the child's neurovascular exam and level of comfort
- outcomes
  - healing times vary from 4 - 8 weeks based on age
Traction + delayed spica casting
- technique
  - placed in distal femur proximal to distal femoral physis
    - proximal tibial traction can cause recurvatum due to damage to the tibial tubercle apophysis
  - used for 2-3 weeks to allow early callus formation
  - spica casting then applied until fracture healing
- more complications than immediate spica casting
Flexible intramedullary nails
- approach
  - all distal approach
    - 2cm incision medially and laterally at level of distal physis
    - spread with hemostat to starting point 2cm proximal to physis
  - distal and proximal approach
    - 2cm incision laterally at level of distal physis and 2cm incision proximally at greater troch apophysis
- instrumentation
  - nail size determined by multiplying the width of the isthmus of femoral canal by 0.4
  - the goal is 80% canal fill
- complications
  - the most common complication is pain at insertion site near the knee
    - in up to 40% of patients
    - recommended that < 25mm of nail protrusion and minimal bend of the nail outside the femur are present
  - increased rate of complications in patients 11 years or up or > 50 kg
  - malunion
    - increased rates with comminuted, shortened, or very proximal/distal fractures
- outcomes
  - generally good outcomes
  - time to union is typically 10 - 12 weeks
  - removal of the nail can be performed at 1 year
Submuscular bridge plate fixation
- approach
  - laterally based incision and plating with minimal disruption of soft tissue envelope
  - small proximal and distal incisions and plate is placed between periosteum and vastus lateralis on the lateral side of the femur
- fracture is provisionally reduced with closed or percutaneous techniques
- instrumentation
  - typically use 12-16 hole 4.5mm narrow LC-DC plate with 3 screws proximal and 3 screws distal to the fracture. the plate may need to be bent to accommodate the natural bend of the femur
  - Contoured femur plates are also an option
- complications
  - hardware removal
  - refracture following hardware removal
- outcomes
  - favorable time to union, weight bearing, hardware irritation, and limp outcomes
Antegrade rigid intramedullary nail fixation
- approach
  - trochanteric entry nail
  - lateral entry nail
    - avoid piriformis entry due to risk of injury to vascularity to femoral head
- soft tissue
  - lateral incision proximal to the greater trochanter
  - sharp or electrocautery through fascia lata to obtain starting point at the tip of the greater trochanter
- closed versus open reduction of the fracture
- instrumentation
  - with fracture reduced follow steps to insert intramedullary nail with caution to not cross distal physis
- complications
  - osteonecrosis risk is 1-2% with piriformis start in a patient with open proximal physes
  - the exact risk of osteonecrosis with greater trochanter and lateral entry nails is unknown
  - secondary deformities of the proximal femur can occur after greater trochanteric insertions
    - narrowing of the femoral neck
    - premature fusion of greater trochanter apophysis
    - coxa valga
    - hip subluxation
- outcomes
  - decreased risk of angular malunion
  - favorable outcomes in adolescents
External fixation
- technique
  - applied laterally
    - avoid disruption and scarring of quadriceps
  - weight-bearing as tolerated can be considered with stiff constructs
- complications
  - more complications than internal fixation
  - pin tract infections are frequent
    - as high as 50% of fixator related complications
    - treated with oral antibiotics and pin site care
  - higher rates of delayed union, nonunion and malunion
  - increased risk of refracture (1.5-21%) after removal of fixator especially with varus malunion

Complications

Leg-Length Discrepancy
- overgrowth
  - the most common complication in younger patients
  - 0.7 - 2 cm is common in patients <10 years
  - typically occurs within 2 years of injury
- shortening
  - is acceptable if less than 2 - 3 cm because of anticipated overgrowth in young patients
  - can be symptomatic if greater than 2 - 3 cm
    - temporary traction or fixation used to prevent persistent shortening
Osteonecrosis (ON) of the femoral head
- reported with both piriformis and greater trochanter entry nails
- femoral nailing through the piriformis fossa is contraindicated in adolescents with open physes because of the risk of osteonecrosis of femoral head
- main supply to femoral head is deep branch of the medial femoral circumflex artery
  - branches into superior retinacular vessels that supply the femoral head
  - vulnerable as it lies near the piriformis fossa
Nonunion and malunion
- higher risk with load bearing devices
  - external fixator or submuscular plates
- can occur after flexible intramedullary nailing in patients
  - aged over 11 years old
  - who weigh >49 kg (>108 lb)
- the typical deformity is varus + flexion of the distal fragment
- remodeling is greatest in the sagittal plane
- rotational malalignment does not remodel
- nearly 50% of fractures treated with flexible nails have 15 degrees of malalignment
Refracture
- most common after external fixator removal with varus alignment

Femoral Shaft Fractures - Pediatric

Spica Casting for Femur Fractures

Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.

Flexible IMN for Femur Fractures

Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.

Core Webinar - PEDIATRIC HIP AND FEMUR TRAUMA - by CHLA

Pediatric Femur Flexible Intramedullary Nail Fixation

Spica Cast Technique

Subtrochanteric fracture extended to the neck in female child (C2348)

Hip fracture-dislocation - Femoral head necrosis (C1877)

femur fracture (C1439)

Femoral Shaft Fractures - Pediatric

Spica Casting for Femur Fractures Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.

Flexible IMN for Femur Fractures Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.

Core Webinar - PEDIATRIC HIP AND FEMUR TRAUMA - by CHLA

Pediatric Femur Flexible Intramedullary Nail Fixation

Spica Cast Technique

Subtrochanteric fracture extended to the neck in female child (C2348)

Hip fracture-dislocation - Femoral head necrosis (C1877)

femur fracture (C1439)

Spica Casting for Femur Fractures

Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.

Flexible IMN for Femur Fractures

Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.