11. Osteonecrosis Flashcards Preview

Tri 6 - Tumors > 11. Osteonecrosis > Flashcards

Flashcards in 11. Osteonecrosis Deck (91)
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1

Death of osseous cellular components and marrow

Osteonecrosis

2

mc location for trauma induced osteonecrosis?

intracapsular epiphyses

3

Osteonecrosis from Alcoholism mc affects the

femoral head

4

Osteonecrosis from Alcoholism possibly due to

fatty liver releasing fat
emboli, and increased marrow fat

5

most common theory for Osteonecrosis from Corticosteroids

fatty liver emboli

6

rapid removal from high pressure environment (diving) which forms nitrogen bubbles in blood vessels causing bone infarction

Caisson’s Disease

7

extensive epiphyseal and metaphyseal necrosis may occur bilaterally

Caisson’s Disease

8

mechanical infringement of marrow sinusoids by
lipid-laden histiocytes causing femoral head necrosis

Gaucher’s Disease

9

RA and SLE due to vasculitis of peripheral blood vessels
causes

vascular thromboses and tissue infarction

10

Corticosteroids increase incidence of

Osteonecrosis

11

sludging, thrombosis, and eventual infarction especially in epiphyses and metadiaphyseal regions

Sickle Cell Anemia:

12

how manuy rads are needed to produce osteonecrosis?

3000

13

how many rads in children are needed to affect epiphyseal
bone growth

300 - 400

14

very rarely causes bone infarcts due to fatty emboli

Pancreatitis

15

medullary and epiphyseal infarcts may occur in 30%
of pts with

gout

16

anatomically predisposed to osteonecrosis

Intraartcicular epiphyses

17

AVN usually takes how long to run its course?

2-8 yrs

18

obliteration of epiphyseal blood supply leading to
death of marrow cells and osteocytes, bone growth stops but the Adjacent articular cartilage continues to
grow

AVN: Avascular Phase

19

new vessels into necrotic bone causes deposition of new
bone onto necrotic bone, and resorption of dead bone, trabeculae thicken and bone density increases

AVN: Revascularization Phase

20

Avascular necrosis of the shoulder showing subchondral radiolucent line, aka

crescent sign

21

deformity occurs due to stress and forces applied during

revascularization and remodeling

22

"Mushroom" deformity

AVN femoral head

23

Infarcts heal with calcification

serpiginous configuration of healed infarcts

24

occurs at area of greatest mechanical stress of cortex indicating localized impaction fracture of weakened necrotic bone (step defect)

Collapse of Articular Cortex from Epiphyseal Infarction

25

thickened, irregular trabecular pattern causes increased bone density revascularization and repair phases

Mottled Trabecular Pattern:

26

very common in femoral capital epiphysis and subcortical in areas of greatest articular stress

Subchondral Cyst Formation

27

due to weakening of subchondral bone

Subchondral Fracture

28

separates articular cortex from underlying cancellous
bone (rim sign, crescent sign)

Subchondral Fracture

29

central high signal intensity surrounded by a serpentine, thin low signal margin

MRI of Metaphyseal - Diaphyseal Infarction

30

Bone scan of AVN: Initially a focal area of decreased activity appears, corresponding to the ________
Later increased activity corresponding to the phase of _________

local ischemia, hyperemia and osteoblastic repair