Bone Healing/Grafting Flashcards Preview

Surgery Lab Quiz > Bone Healing/Grafting > Flashcards

Flashcards in Bone Healing/Grafting Deck (39):
1

What are the three long bone blood supply sources in mature animals?

Principle nutrient artery
Metaphyseal arteries
Periosteal arteries

2

What are the long bone blood supply sources in immature animals?

Epiphyseal and metaphyseal arteries

3

What occurs in terms of blood supply with fractured bone?

Development of extraosseous blood supply

4

What are the two types of bone healing?

Direct- primary osteonal reconstruction
Indirect- callus formation

5

When does indirect bone healing (callus formation) occur?

Unstable mechanical environment and motion between fracture fragments
- >1mm gap between fragments
- impaired blood supply or revascularization

6

What are the three stages of indirect bone healing?

Inflammation
Repair
Remodeling

7

When does the inflammation stage of indirect bone healing occur?

IMMEDIATELY after fracture, lasts 3-4 days

8

What occurs in the inflammation stage of indirect bone healing?

Clot at fracture site
-Osteoinductive growth: angiogenesis, bone formation
-Abundant mast cells: vasoactive substances (new vessel formation)

9

When does the remodeling phase of indirect bone healing occur?

Around 2 months

10

What occurs during the remodeling phase of indirect bone healing?

Clot differentiates into granulation tissue, gain strength, soft callus, mesenchymal cells become osteoblasts (lay down fibrocartilage)

11

What is the governing law of remodeling?

Wolfe's law
Compression- osteoblasts
Tension- osteoclasts

12

What is the difference of direct and indirect bone healing?

Direct bone healing fills fracture sites with no callus formation

13

How long does it take to gain mechanical strength?

6-12 months

14

What size are the fracture gaps with direct gap healing?

< 1 mm

15

What size are fracture gaps with direct contact healing?

< 0.01 mm

16

What is contact healing initiated by?

Cutting cones of osteclasts directly followed by osteoblasts

17

How far do cones travel per day? (micrometers/day)

50-100

18

What are characteristics of cancellous bone healing?

More stable than cortical bone
No callus formation
Fracture gap filled then cortical shell

19

Fractured zone of hypertorphy will heal how?

Continued growth of physeal cartilage

20

Fractured zone of proliferation will heal how?

Endochondral ossification

21

What is a disadvantage to physeal fractures?

Premature physeal closure (stunted growth)

22

What are factors that affect fracture healing?

Location of fracture
Stability
Method of fixation
Biological environment
Blood supply
Biomechanical vs. Biological Osteosynthesis

23

What is biological osteosynthesis?

Restores overall length and alignment
Limits soft tissue disruption

24

What are the different types of repairs used on fractures?

Intermedullary pins with wire
Cast/splints/no fixation
Bone plates
External skeletal fixator

25

Which repairs utilize indirect healing?

IM pins/wires
Casts/splints/no fixation
External skeletal fixator

26

What repair heals by direct healing?

bone plates

27

What effect does IM pins/nails have on the blood supply?

Disrupts endosteal blood supply and medullary blood flow

28

What effect does bone plates have on the blood supply?

Disrupt perioseal bone supply

29

What does improper bone implants do to blood supply?

damage blood supply

30

When are bone grafts used?

Bone loss
Arthrodesis
Delayed/non-union fractures
Old age

31

What are the three bone graft origins?

Autograft
Allograft
Xenograft

32

What are the three functions of bone grafts?

Osteogenesis (osteoblasts)
Osteoinduction (mesenchymal cells)
Osteoconduction

33

What are the three bone graft types?

Cancellous
Cortical
Combination

34

What is the gold standard of bone grafts?

Autogenous cancellous bone graft

35

What does Autogenous cancellous bone graft promote?

Osteogenesis

36

What are the four phases of cancellous graft?

Inflammatino (hours)
Revascularization (1-2 weeks)
Osteoconduction (2-4 weeks)
Mechanical support (up to 12 weeks)

37

Where are autograft cortical bone grafts used?

Ribs
ulna
Fibula
Ilial wing

38

What patients are cortical bone grafts indicated in?

Devascularized comminuted fractures
OSA patients and limb sparing procedures where dz is caught early and hasn't metastasized

39

What are the phases of cortical bone graft effects?

Osteoclasts move into graft and resorb bone
Osteoblasts follow and lay down new bone
Mechanical strength of graft maintained
Termed "creeping substitution"