Principles of Paediatric Fractures

Overview

*Revisit embryology of bone!

• As a rule, the younger the patient, the greater the bone remodeling potential
• Incidence of pediatric fractures rising due to increased sports participation – approximately 50% of children fracture at least one bone during childhood
• The leading cause of death in children aged 1-14 years is accidental trauma
• Skeletal trauma accounts for 10-15% of all childhood injuries
• Open fractures in this population are rare: <5%

Pediatric vs adult bone

Pediatric	Adult
Higher water content	Lower water content
Lower mineral content	Higher mineral content
Less brittle (more elastic)	More brittle
Higher strain-to-failure	Lower strain-to-failure
Stronger in tension than compression	Stronger in compression than tension
4 regions:
Diaphysis – shaft/primary ossification center
Metaphysis
Physis – growth plate
Epiphysis – secondary ossification center	2 regions:
Diaphysis
Metaphysis

Mechanism of injury

• Pediatric fractures usually occur at lower energy than adult fractures
• Most are as a result of:
  • Compression
    • Compression fractures ( “buckle” or “torus” fractures) mostly occur at the metaphyseal diaphyseal junction
    • Rarely cause physical injury, but may result in angular deformity
    • Are impacted and hence stable, rarely requiring manipulative reduction
  • Torsion
    • Torsional injuries result in 2 kinds of fracture patters, depending on the physeal maturity:
      • Long spiral fracture – very young child with thick periosteum, thus the diaphyseal bone fails before the physis
      • Physeal fracture – older child
  • Bending
    • Result in “greenstick fractures”
      • Here the bone is incompletely fractured, resulting in a plastic deformity on the concave side of the fracture
      • The fracture may need to be completed to obtain adequate reduction
    • May also result in microscopic fractures
      • These create plastic deformation of the bone with no visible fracture lines on plain radiographs
      • Permanent deformity can result
    • In older children, may result in transverse or short oblique fractures
      • May present with small butterfly fragment, however, there may only be a buckle of the cortex as pediatric bone fails more easily in compression

Clinical evaluation

• Full trauma evaluation according to ATLS protocol, if possible with pediatric specialist present
• History challenges – children may not be the best historians, and parents may not have been present at time of injury, hence patient must be evaluated thoroughly
• Neurovascular evaluation is mandatory both before and after manipulation
• Periodically evaluate for compartment syndrome
• Explain as much to the children as possible listen to their suggestions, STOP when they ask you to
• When to suspect child abuse
  • Transverse femur fracture in child <1 year old
  • Transverse humerus fracture in child <3 years old
  • Metaphyseal corner fractures (caused by traction/rotation mechanism)
  • History/mechanism of injury inconsistent with fracture pattern
  • Unwitnessed injury that results in a fracture
  • Multiple fractures in various stages of healing
  • Skin stigmata suggestive of abuse: multiple bruises in various stages of resolution, cigarette burns
    • IF ABUSE IS SUSPECTED admit the child + notify social worker

Radiographic evaluation

• Normal ossification patterns must be thoroughly understood to adequately evaluate plain radiographs
• Ensure radiographs are ADEQUATE!
  • Views should include an orthogonal projection (obtained 90° from the original view) of involved bone, as well as joints proximal and distal to suspected area of injury
  • Comparison views of opposite extremity may aid in appreciating minimally displaced fractures or subtle deformities (when necessary)
• ‘Soft signs’ e.g. posterior fat pad sign of the elbow should be closely evaluated
• Skeletal survey may aid in identifying other fractures in cases of suspected child abuse or multiple traumas
• CT may help in evaluating complicated intro-articulate fractures in older children
• MRI can be of value in preop evaluation of a complicated fracture, or evaluation of a fracture not clearly identifiable on plain films due to lack of ossification
• Bone scans may be used to evaluate tumor or osteomyelitis
• Ultrasound can be useful for identification of epiphyseal separation in infants
• Arthrograms are valuable in intraoperative assessment of intraarticular fractures, as radiolucent cartilaginous structures will not be apparent on fluoroscopic or plain radiographs

Classification

Salter-Harris/Ogden Classification

• Pediatric physeal fractures have traditionally been described by the five-part Salter-Harris classification
• This has been extended by the Ogden classification to include periphyseal fractures, which do not radiologically appear to involve the physis, but may interfere with physeal blood supply + result in growth disturbance
• Salter-Harris Types I-V
  • Type I
    • Transphyseal fracture involving hypertrophic and calcified zones
    • Reserve and proliferative zones are preserved hence prognosis is generally excellent
    • Complete or partial growth arrest may occur in displaced fractures
    • Radiographs may be unremarkable – diagnosis is clinical
  • Type II
    • Transphyseal fracture that exits through the metaphysis
    • Metaphyseal fragment = Thurston-Holland fragment
    • The periosteal hinge is intact on the side with the Thurston-Holland fragment
    • Prognosis is excellent, however complete or partial growth arrest may occur in displaced fractures
  • Type III
    • Transphyseal fracture that exits epiphysis
    • Causes intraarticular disruption, as well as disruption of reserve and proliferative zones
    • Anatomic reduction and fixation without violating the physis are essential
    • Common complications include partial growth arrest and resultant angular deformity
  • Type IV
    • Fracture that traverses epiphysis and physis, exiting the metaphysis and disrupting all four zones of the physis
    • Anatomic reduction and fixation without violating the physis are essential
    • Common complications include partial growth arrest and resultant angular deformity
  • Type V
    • Crush injury to they physis
    • Diagnosis usually made retrospectively
    • Poor prognosis as growth arrest and partial physeal closure are common complications
• Ogden Types VI-IX
  • Type VI
    • Injury to the perichondral ring at the periphery of the physis
    • Usually results from an open injury
    • There may be a peripheral physeal bar to be excised
    • Common complication is formation of peripheral physeal bridges
  • Type VII
    • Involves epiphysis only, including:
      • osteochondral fractures
      • epiphyseal avulsions
    • Prognosis depends on location of fracture and amount of displacement
  • Type VIII
    • Metaphyseal fracture
    • There is disruption of primary circulation to the remodeling center of the cartilage cell columns
    • Angular overgrowth may result from hypervascularity
  • Type IX
    • Diaphyseal fracture
    • There is disruption of the mechanism for appositional growth (the periosteum)
    • Prognosis is generally good if reduction is maintained
    • Can complicate with cross-union between the tibia and fibula and between the radius and ulna if there is intermingling of the respective periosteums

Treatment

• Children have a thick periosteum in case of diaphyseal fractures and an open physis in case of metaphyseal fractures, thus:
  • The tough periosteum may help in reduction by serving as a hinge (the periosteum on the concave side for the deformity is usually intact) and preventing overreduction
  • To disengage fragments and retain traction, controlled recreation and exaggeration of the fracture deformity may be necessary, as longitudinal traction is inadequate
  • Adequate reduction may be prevented by:
    • a periosteal flap entrapped in the fracture site
    • buttonholing of a sharp fracture end through the periosteum
  • Physeal injuries should not be re-manipulated after 5-7 days
• Children (especially when younger) have great remodeling potential, hence considerable fracture deformity may be permitted
  • In general, fractures closer the the joint (physis) tolerate deformity better – e.g. in a proximal humeral fracture, 45-60 degrees of angulation is permissible, however, a midshaft radial or tibial fracture must be brought to within 10 degrees of normal alignment
  • Rotational deformity should be avoided even in young children, as it does not spontaneously correct or remodel to an acceptable extent
• Severely shortened or comminuted fractures may require skin or skeletal traction
  • Traction pins should be placed proximal to the nearest distal physis
  • Care should be taken not to place the traction pin through the physis
• Fracture reduction should be performed under conscious sedation, followed by immobilization in a splint or bivalved cast
  • Univalving, especially with a fiberglass cast, does not provide adequate cast flexibility necessary to accommodate extremity swelling
• In children, casts or splints should encompass the joint proximal and distal to the site of injury
  • Post-immobilisation stiffness is not a common problem for children
  • Short arm or short leg casts are only used as opposed to longer immobilization techniques in rare cases such as stable torus fracture of distal radius
• All fractures should be elevated at above heart level, iced and frequently monitored with attention to extremity warmth, capillary refill and sensation. Admit for observation if necessary
• Fractures in which reduction cannot be achieved or maintained should be splinted and the child put under general anesthesia with which complete relaxation may be achieved
• Intraarticular fractures and Salter-Harris types III and IV require anatomic reduction
  • This involves <1-2mm of displacement both vertically and horizontally
  • Serves to restore articular congruity and minimize physeal bar formation
• Indications for open reduction:
  • Most open fractures
  • Displaced intra-articular fractures (Salter-Harris types III and IV)
  • Fractures with vascular compromise
  • Fractures with associated compartment syndrome
  • Unstable fractures requiring abnormal positioning to maintain closed reduction

Complications

• Complete growth arrest
  • May occur with physeal injuries in Salter-Harris fractures
  • May result in limb length discrepancies necessitating
    • use of orthotics
    • use of prosthetics
    • operative interventions for correction e.g. osteotomy
• Overgrowth
  • May be seen in certain pediatric fractures, e.g. of the femoral diaphysis
• Progressive angular or rotational deformities
  • May result from physeal injuries with partial growth arrest, or malunion
  • May also occur in some metaphyseal fractures, e.g. of proximal tibia
  • May require operative interventions for correction e.g. osteotomy, in case of significant functional disability or cosmetic deformity
• Osteonecrosis
  • May result from disruption of tenuous blood supply in skeletally immature patients in whom vascular development is incomplete, e.g. osteonecrosis of femoral head in slipped capital femoral epiphysis