5 - Pediatric Fractures Flashcards
1
Q
Key learning points
A
- Describe the anatomy and mechanical principles of a physis and its relationship to injury patterns
- Memorize the Salter-Harris fracture classification
- Discuss the significance of the classification on fracture development and prognosis
- Review transitional fractures (Tillaux and tri-plane)
- Summarize the principles for treatment of physeal injuries
2
Q
Anatomic definitions
A
1 = diaphysis 2 = metaphysis 3 = physis (growth plate) 4 = epiphysis
3
Q
Histology of pediatric bone
A
- Woven bone predominates
- More porous than lamellar bone
- Same mineral content
- Thicker periosteum
- Highly vascular
- Heals rapidly
4
Q
Physis histology
A
- Five distinct zones in the growth plate
- Weakest spot is between the zones of hypertrophy and ossification
- 50% of physeal injuries cross multiple zones
- Blood supply is from three sources
5
Q
Vascular supply
A
- Epiphysis = Capsular soft tissues
- Metaphysis = Endosteal vessels
- Physis = Epiphyseal, metaphyseal and perichondral vessels
- Epiphysis and metaphysis blood supplies are separate
6
Q
Types of physes
A
- Pressure Physis = Secondary ossification center that forms a joint
- Traction physis (apophysis) = Secondary ossification center that serves as attachment for tendon
7
Q
Mechanical properties of pediatric bone
A
- Fails in compression and tension Compression is weaker
- Plastic deformation
- Rarely comminutes
8
Q
Mechanical properties of the physis
A
- Weaker than metaphyseal, epiphyseal and diaphysis bone
- Weaker than ligaments
- Most resistant to traction
- Least resistant to torsion
9
Q
Angular remodeling
A
- Unique to children
- Position improves over time secondary to growth and external forces
- Allows for less than perfect anatomic reduction in certain instances
- There are limitations to remodeling
10
Q
Unacceptable imperfect reduction
A
- Greater than 15 degrees angulated
- Angulation outside the plane of motion
- Intra-articular and displaced
- Significantly shortened
- Rotated
- Child has
11
Q
Salter-Harris Classification of Physeal Injuries (1963)
A
Based on: o Mechanism of injury o Relationship of the fracture line to the various layers of the physis o Prognosis for growth disturbance
12
Q
Types of SH physeal injuries
A
I = physis only (no fracture) II = fracture in metaphysis and along physeal line only (not in epiphysis) III = fracture in epiphysis only IV = fracture in metaphysis down through epiphysis V = crush injury of physis VI = lateral force injury of physis
13
Q
Salter-Harris II
A
- Type II = most common (75%)
- Growth disruption is unlikely
- With type II and type I, it is unlikely to disrupt growth
- The free fragment in a type II (Thirst and Holland sign)
- Seen in patients greater than 10 years old
- In general, we treat with closed reduction and casting most of the time
- Pinning if unstable in cast
- ORIF only if reduction cannot be obtained
- Transverse slip of the physis and fracture through the metaphysis
14
Q
General principles of physis fracture ORIF
A
- Gaps >2mm have increased incidence of growth disturbance
- Every effort should be made to limit growth center damage
o Limited dissection and gentle reduction
o Do not disturb the physeal periosteum - Only smooth pins should cross the physis
- Parallel pins are safer than crossed pins
o Crossing pins do not allow growth - Pins are removed early
- Screws and compression should be avoided when crossing physis
15
Q
Salter-Harris V
A
- Crush of the physis
- Axial load through the epiphysis
- No slip of the physis
- No visible fracture
- High risk for growth interruption
- Treated with protected WB and careful follow up to identify complications
16
Q
Rang’s type VI
A
- Follows blunt trauma
- Injury to the perichondral ring
- Osseous bridging of one side of the physis
- Leads to progressive angular deformity due to partial physeal closure
- Treatment can be complicated
17
Q
Rang (1969) added SH VI
A
- Result of damage to periosteum or perichondral ring with resultant bony bridge formation external to growth plate