Bone Healing/ Grafts

Question 1

Stress level and gap size below which primary healing will occur?

Answer 1

2%

<5Microm

Question 2

2 modes of bone healing?

Answer 2

1. Intramembranous

2. Enchondral

Question 3

Main stages of fracture repair 4

Answer 3

1. Hematoma and inflammation
2. Soft callus
3. Hard callus
4. Remodelling

Question 4

Cytokines released during inflammation? (7)

Answer 4

1. PDGF
2. TNF alpha
3. TGF beta
4. IL1,6,10,12

Question 5

Soft callus converted to hard callus via which ossification?

Answer 5

Enchondral

Question 6

Collagen type during early callus formation?

Answer 6

2

Question 7

Soft callus resorbed by?

Answer 7

Chondroblasts (MMP)

Question 8

Remodelling according to? 2

Answer 8

Wolff’s Law

Piezoelectric charges

Question 9

3 types material properties of bone grafts?

Answer 9

Osteoconductive
Osteoinductive
Osteogenic

Question 10

A bone graft with osteogenic properties contain what?

Answer 10

Live mesenchymal cells

Question 11

Osteoinductive bone grafts contain what?

Answer 11

Factors that stimulate bone growth/induction
BMPs
TGF-B

Question 12

2 processing methods for Allografts?

Answer 12

Frozen

Freeze dried

Question 13

Fresh frozen vs Freeze dried allograft?

Answer 13

Less Osteoinductive

Question 14

What is Demineralized Bone Matrix?

Answer 14

Highly processed allograft derivative - acidic extraction from bone matrix

Question 15

Demineralized bone matrix properties?

Answer 15

Osteoconductive

Osteoinductice

Question 16

3 types of bone grafts?

Answer 16

Autograft
Allograft
Substitute

Question 17

Fastest to slowest absorption bone substitutes?

Answer 17

1. Calcium Sulphate
2. Tricalcium phosphate
3. Ca hydroxyapetite

Question 18

Cancellous graft is incorporated via?

Answer 18

Creeping substitution

Question 19

Cortical grafts are incorporated via?

Answer 19

Cutting cones (Bone resorbed first before formation)

Question 20

Osteoinductive agents? 4

Answer 20

1. TGF B
2. BMPs
3. PDGF
4. FGF

Question 21

Changes with increased preparation of allografts (Fresh - Freeze dried)

Answer 21

Decreased immunogenicity Decreased strength

Decreased osteoinductive

Question 22

Autograft vs Allograft incorporation differences? 2

Answer 22

1. Allograft = increased inflammatory response

+- incomplete incorporateion

Question 23

What is necessary prior to an osteochondral graft?

Answer 23

Typing

cartilage induces immune response

Question 24

3 zones in a cutting cone and properties?

Answer 24

1. Cutting zone - OC
2. Reversal zone - Vascular bundle - forms haversian system
3. Closing zone - OB

Question 25

Cells involved in production of collagen matrix?

Answer 25

Fibroblasts

Question 26

Secondary bone healing occurs at what levels of stress?

Answer 26

2-10%

Question 27

What creates a negative piezoelectric charge?

Answer 27

Compression

Question 28

Which cell does a positive piezoelectrical charge induce? What type of stress is this side under?

Answer 28

OC

Tension

Question 29

Strain amount at which fibrous connective tissue predominates?

Answer 29

17%

Question 30

What factors are included in the ‘diamond concept’?

Answer 30

1. Mechanical stability
2. Growth factors
3. Osteoprogenitor cells
4. Adequate scaffold

Question 31

How to vascularised autografts heal?

Answer 31

Like normal fractures with no initial resorption

Question 32

3 Factors affecting incorporation of bone grafts?

Answer 32

1. Modification of inflammatory response
2. Mechanical stability
3. Quality of host bed

Question 33

Stages of graft healing? (5)

Answer 33

1. Inflammation
2. OB differentiation
3. Osteoinduction
4. Osteoconduction
5. Remodelling

Question 34

Synthetic graft associated with serous drainage>

Answer 34

Calcium Sulphate

Question 35

2 FDA approved osteoinductive synthetics?

Answer 35

rhBMP 2 and 7