Description

Pediatric bone consists of four segments: The diaphysis or shaft, the metaphysis (the widest region, where bone growth occurs), the physis or growth place, the epiphysis (distal to the growth plate, site of secondary ossification)

Fractures through the physis account for approximately a 3rd of pediatric fractures; 30% of confirmed physeal fractures are complicated by growth disturbance:

• Most frequently seen in the distal radius and ulna, distal tibia and fibula, and the phalanges
• In children, more common than ligamentous injuries:
  • Tensile strength of pediatric bone is less than adjacent ligaments
  • Physis is weakest part of pediatric bone
  • Similar mechanism of injury in an adult usually results in a sprain
• Most common during peak linear growth:
  • Females: Age 9–12
  • Males: Age 12–15
  • Much less common in infancy and early childhood because epiphysis is not yet ossified and acts as a shock absorber
• Twice as common in males because female bones mature earlier
• Salter–Harris (SH) classification: Simplest and most commonly used classification system:
  • The grade of the SH fracture correlates with the likelihood of subsequent growth disturbance, with a higher SH grade corresponding to a worse prognosis
  • A helpful mnemonic for remembering the types is SALTER:
    • Straight: Type I
    • Above: Type II
    • Lower Type III
    • Through: Type IV
    • ERasure (cRush, or Ram): Type V
  • SH type I:
    • Transverse fracture line confined to physis
    • Complete epiphyseal separation from metaphysis through the physis
    • If periosteum remains intact, epiphysis will not displace
    • Clinical diagnosis made with focal tenderness over the physis
    • Usually radiographically occult. Radiographically can see widening at the growth plate
    • Most classic example is SCFE
    • Growth disturbance is rare
  • SH type II:
    • Most common type; accounts for ∼80% of physeal fractures
    • Fracture propagates along physis, and fragment from metaphysis accompanies the displaced epiphysis
    • Growth is rarely disturbed
  • SH type III:
    • Rare
    • Fracture through a portion of physis extending through the epiphysis
    • Distal tibia most commonly affected
    • If displaced, requires reduction to maintain anatomic alignment
    • Growth disturbance may occur despite anatomic reduction because blood supply can be affected
  • SH type IV:
    • Fracture originates at articular surface
    • Extends through physis and involves both the metaphysis and epiphysis
    • Distal humerus most commonly affected
    • Also has Thurston Holland fragment
    • Anatomic reduction essential and displaced fractures require ORIF
    • Growth arrest is common even with optimal treatment
  • SH type V:
    • Results from severe crush injury to physis
    • No immediately visible radiographic alteration so almost impossible to diagnose initially
    • Often found in retrospect
    • Compression forces lead to physeal injury and inevitable growth disturbances
  • There are other scoring systems such as the Ogden and Peterson classifications that describe additional epiphyseal fracture patterns

Etiology

• Competitive and recreational sports
• Traumatic injuries
• Child abuse