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Week 45: Joint Fracture > MSK Imaging of Fractures > Flashcards

Flashcards in MSK Imaging of Fractures Deck (15)
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1

2 best modalities for
1. Bone injury
2. Soft tissue injury

1. X ray, CT
2. MRI, US

2

Cortical bone osteon formation

Osteoclasts carve Haversian canal through damaged or disorganized bone
Osteoblast follow and deposit concentric layers of osteoid that mineralize into new bone
Osteoblasts trapped in the matrix differentiate into osteocytes

3

Callus

New bone formed around a fracture site
Initially cartilaginous, hardens as mineralization takes place (endochondral ossification)

4

Repair process in stable vs unstable fractures

Stable: primary bone healing (no callus)
Unstable: secondary bone healing (callus forms to bridge the fracture gap) - most common

5

3 phases of secondary bone healing

Inflammation (5-14 days)
Repair (weeks to months)
Remodelling (months to years)

6

Inflammation stage

Hematoma formation
Inflammatory cells migrate to site
Necrotic tissue resorbed
Angiogenesis
Cell differentiation (chondrocytes to osteoblasts)

7

Repair stage

Synthesis of reparative matrix
Soft callus formation
Hard callus formation (mineralized)
Woven bone (strong but disorganized bone structure)

8

Remodelling stage

Replacement of woven bone with lamellar bone by osteon formation
Process influenced by Wolff's Law

9

4 types of healing disruption

Delayed union
Non-union (6-9 mon)
Mal-union
Re-fracturing

10

What views to get?

2 views (orthogonal)
2 joints (above and below)

11

Salter-Harris classification

S: straight across
A: above growth plate
L: lower or below
T: two or through growth plate
ER: erasure of the growth plate or crush

12

8 fracture patterns

Transverse
Oblique
Spiral
Comminuated (multiple pieces)
Avulsion
Impacted
Fissure
Greenstick

13

FOOSH injury

Falling on an out-stretched hand

14

Skeletal survey

Performed in the evaluation of children with suspected NAI <2 years old
21 views of the skeleton
Repeat in 2 weeks if suspicion is high

15

High specificity fractures for NAI

Classic metaphyseal lesions (most specific)
Rib fractures (posterior more suspicious)
Scapular fractures
Spinous process fractures
Sternal fractures