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Flashcards in 5 - Pediatric Fractures Deck (43):
1

Key learning points

- 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

Anatomic definitions

1 = diaphysis
2 = metaphysis
3 = physis (growth plate)
4 = epiphysis

3

Histology of pediatric bone

- Woven bone predominates
- More porous than lamellar bone
- Same mineral content
- Thicker periosteum
- Highly vascular
- Heals rapidly

4

Physis histology

- 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

Vascular supply

- Epiphysis = Capsular soft tissues
- Metaphysis = Endosteal vessels
- Physis = Epiphyseal, metaphyseal and perichondral vessels
- Epiphysis and metaphysis blood supplies are separate

6

Types of physes

- Pressure Physis = Secondary ossification center that forms a joint
- Traction physis (apophysis) = Secondary ossification center that serves as attachment for tendon

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Mechanical properties of pediatric bone

- Fails in compression and tension ***Compression is weaker***
- Plastic deformation
- Rarely comminutes

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Mechanical properties of the physis

- Weaker than metaphyseal, epiphyseal and diaphysis bone
- Weaker than ligaments
- Most resistant to traction
- Least resistant to torsion

9

Angular remodeling

- 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

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***Unacceptable imperfect reduction***

- Greater than 15 degrees angulated
- Angulation outside the plane of motion
- Intra-articular and displaced
- Significantly shortened
- Rotated
- Child has

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Salter-Harris Classification of Physeal Injuries (1963)

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

Types of SH physeal injuries

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

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***Salter-Harris II***

- 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

General principles of physis fracture ORIF

- 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

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***Salter-Harris V***

- 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

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Rang’s type VI

- 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

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Rang (1969) added SH VI

- Result of damage to periosteum or perichondral ring with resultant bony bridge formation external to growth plate

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Others – Questionable utility

- SH VII (Ogden): damage to epiphysis and not to physis
- SH VIII: damage to metaphysis and not to physis
- SH IX: injury to diaphyseal periosteum that may result in disruption of normal diaphyseal growth and remodeling

19

Pediatric ankle fractures – Dias-Tachdjian Classification

- Eight classes
- Based on foot position and direction of rotation of the talus
- Combination of the Salter-Harris and the Lauge-Hansen classifications
- Treatment and risk of growth interruption is based on the Salter-Harris injury

20

Transitional fractures

- Juvenile Tillaux Fracture
- Tri-plane Fracture

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Transitional period – BE PREPARED TO DEFINE AND DESCRIBE

- The juvenile Tillaux and triplane fractures are classified as transitional fractures because of their occurrence in the period between adolescence and skeletal maturity, at which time the physis undergoes final closure
- This transitional period is an approximately 18-month window when the distal tibia physis closes, and it usually starts at ages 12 to 14 years
- The pattern of physeal closure proceeds from central, toanteromedial, to posteromedial, and finally to lateral
- The process of medial physeal closure preceding lateral closure directly lends itself to the injury pattern observed during triplane and juvenile Tillaux fractures

22

Which portion of the distal tibial physis closes first

o Central is first, then anteromedial
o Fuses medially before laterally
o This is why the fracture is not full thickness in a juvenile Tillaux fracture

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Tillaux

o Most common ORIF is a screw in the epiphysis
o Screw should not enter or cross the physis

24

Tri-plane fracture

- External rotation force produces the injury
- Results due to relative weakness of antero-lateral tibial physis
- There are multiple configurations to this fracture
- Always has fracture in each of the three body planes
and in the epiphysis, metaphysis and physis
- Tri-plane means a fracture in all three planes
- Treatment decision is based on the fact that it is intra-articular

25

Management of triplane fracture

- Screws above and below the physis
- Never through the physis

26

General fracture patterns

- A:
- B: transverse fracture (stable)
- C: oblique fracture (least stable)
- D: spiral fracture (least stable)
- E: diaphyseal fracture (at metaphyseal-diaphyseal junction)
- F: comminuted fracture (multiple fragments – unstable and displaced)
- G: plastic deformation of woven bone
- H: greenstick fracture (fracture on the tension side, not compression side)
- I:

27

Complications of pediatric fractures

- Growth arrest
- Articular degeneration
- Mal-union
- Non-union

28

***Causes of growth arrest ***

- Bridging of metaphyseal and epiphyseal cortex across the physis (Bone-Bridge)
- Physeal fracture gap filling due to poor reduction
- Physeal cellular necrosis
- Physeal blood supply damage

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***Result of growth arrest***

- Angular deformity results from partial interruption of physeal growth
- Bone length deformity results from total physeal interruption
- Deformity may be progressive with growth

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Mal-union

- Results from inadequate reduction
- Frontal, sagittal or transverse plane
- May improve with growth related remodeling
- Can be corrected by osteotomy or fusion

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Non-union

- Very uncommon in children
- Standard management

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Conclusion

- Consider the unique qualities of the pediatric patient and the pediatric musculoskeletal system prior to treatment
- Understanding the common and not so common fractures and fracture patterns along with their mechanisms will prevent misdiagnosis and aid in proper treatment

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CASE STUDY - Salter-Harris II

Definition
o Transverse slip of the physis and fracture through the metaphysis
o Type II = most common (75%)
o The free fragment in a type II (Thirst and Holland sign)
o Seen in patients greater than 10 years old

Growth
o Growth disruption is unlikely
o With type II and type I, it is unlikely to disrupt growth

Treatment
o In general, we treat with closed reduction and casting most of the time
o Pinning if unstable in cast
o ORIF only if reduction cannot be obtained
o In general they are treated with closed reduction and casting
o But pinning or external fixation is needed for a lot of displased metatarsal and toe fractures

34

When to sesamoids appear?

10 years

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Periosteum in pediatrics

- Intact and robust posterior periosteum allows easy closed reduction and maintenance in cast
- Traction on heel and dorsiflexion of the foot
- Physis is weaker than bone, ligament and periosteum

36

Type II with ankle dislocation

- SH-II with ankle dislocation
- ORIF needed due to instability of mortise and instability to hold in case
- Did I follow the principles of pediatric ORIF?
o The screws do not cross the physis so it
o The wire can allow the growth to slide, no compression
o Damage physis

37

Type I

- Slip through the physis only
- Tends to occur in younger children
- Intact periosteal hinge preventing displacement
- Treatment
o Protect with casting to maintain position and allow healing
o Weight bearing is based on clinical presentation – clinical judgement

38

Type I

- We do not see a fracture line, it is just a slip of the physis
- Closed reduction is an attempt to get it back into position
- The question is whether or not you can reduce it and hold it there
- It is a wrist, not an ankle

39

SH III

- Transverse physeal slip with vertical fracture through the epiphysis
- Intraarticular = unique
- Growth interruption is LIKELY
- Needs to be fixed because it needs to be perfect

40

How do we most accurately determine the amount of intraarticular displacement?

- CT scan
- This will clarify

41

Type IV

- Growth interruption is a lot more likely
- Treat with open reduction
- A type IV is unstable, so it is more appropriate to pin it rather than closed reduce it
- Need a CT because it is intraarticular

42

Harris line

- Parallel to physeal is less of a problem
- Memorize dias tach eventually = not asking on this test

43

Vascular supply

- Separation of blood supply leads to osteomyelitis in pediatric patients