SL1 - Bone Healing Flashcards Preview

RUSVM Small Animal Surgery > SL1 - Bone Healing > Flashcards

Flashcards in SL1 - Bone Healing Deck (28):
1

bone is composed of 

minerals - Ca, P, Mg

Organic Matrix - type I collagen, proteoglycans, glycosaminoglycans

2

T/F there is separate venous drainage for cortex and medullary canal 

true

3

osteoblasts 

produce osteoid (unnmineralized bone matrix) on bone surface

4

osteocytes

osteoblasts that have been encased in mineral matrix 

maintain bone matrix

5

osteoclasts 

active in areas of bone remodeling 

reside near bone surface

6

what are the 3 phases of bone healing 

inflammation phase

repairative phase

remodeling phase

7

inflammatory phase

 

lasts about 2-3 weeks

death of osteocytes results in release of lysosomal enzymes

necrotic material at site of the fracture is source of inflammatory respose 

8

repair phase 

migration of osteoprogenitor cells - forms periosteal callus

angiogenesis - transient blood supply from surrounding soft tissue

deposition of Ca hydroxyapatite in matrix - callus mineralization 

cartilage replaced by bone via endochondral ossification 

9

remodeling phase

begins when fracture is bridged by callus 

woven bone remodeled into lamellar bone via osteoclasts and osteoblasts 

 

10

remodeling phase is directed by ______

stresses of weight bearing 

11

types of bone healing 

primary/direct 

secondary/indirect 

12

contact healing 

primary bone healing 

occurs with compression of bone ends under rigid fixation 

no cartilaginous callus formed 

13

gap healing 

gap between fracture ends is < 1mm 

granulation tissue at gap followed by transversely oriented lamellar bone 

haversian remodeling occurs at ~ 3 weeks post stabilization 

14

T/F primary bone healing outmoded in favor of secondary bone healing 

 

True

exceptions: articular fractures and simple, stable fractures 

15

secondary bone healing 

fracture ends dont touch 

micromotion at fracture promotes formation of callus 

bone heals via mineralization of fibrocartilagenous callus into boney callus 

16

biological osteosynthesis 

secondary bone healing 

fracture ends not compressed - protect surrounding soft tissue, protect blood supply 

plates in bridging mode, external skeletal fixaition, interlocking nails 

17

average fracture healing time 

6-8 weeks

18

factors that affect bone healing 

fracture configuration/severity 

soft tissue damge

stability of repair 

presence of infection 

patient factors (age, weight, disposition, comorbities) 

complience 

19

what is required to assess bone healing 

orthogonal radiographs 

 

20

4 A's of evaluation 

alignment 

apposition 

apparatus 

activity 

21

when does clinical union occur

when bone is strong enough that fixation is no longer necessary 

22

what is a delayed union 

healing is prolonged beyond normal expected time course 

fracture lines remains evident with feathery/wooly ends 

callus is visible but lacks appropriate mineralization 

no sclerosis of bone ends

 

23

malunion 

failure to re-establish normal function in face of healing 

 

24

which malunions are the lease tolerated 

roatation and lateral translation 

25

viable nonunion 

biologically active fracture with cartilage and fibrous tissue between fracture ends 

26

nonviable nonunion 

fracture ends are sclerotic with rounded bone edges and visible fracture gap (bone have blood supply) 

dystrophic, necrotic, defect, atrophic 

27

treatment options for delayed union 

 

pre-emptive treatment is ideal - bone grafts, increased mechanical stiffness of implants, bone morphogenic protein 

if delayed untion is anticipated -  rechecks q 3-4 weeks 

28

treatment options for non-union 

rigid stabilization 

removal of loose implants

encourage biologically active environment - graft, marrow, demineralized bone matrix, bone morphogenic proteins 

remove non-viable bone

+/- amputation