Ch.78 Bone Grafts and Bone Replacements

Question 1

How can bone grafts be treated to reduce antigenicity

Answer 1

Decellularization
Deproteinization

Question 2

What is a xenograft

Answer 2

Tissue transferred between 2 members of same species

Question 3

What is an orthotopic graft

Answer 3

Implantation site is similar to donor site

Question 4

What is a heterotopic graft

Answer 4

Implant site dissimilar to donor site

Question 5

Which confers better structural support a cancellous or a cortical bone graft

Answer 5

Cortical

Question 6

Which provides more cells and promotes revascularization a cancellous or a cortical bone graft

Answer 6

Cancellous

Question 7

Most common bone graft in horses

Answer 7

Autogenous cancellous

Question 8

Locations for harvesting an autograft

Answer 8

Sternum
Tuber coxae
Proximal tibia

Question 9

3 major functions of bone grafts

Answer 9

Osteoinduction
Osteocondction
Osteogenesis

Question 10

Cellular components of a bone graft

Answer 10

1. Osteoblasts
2. Osteocytes
3. Osteoclasts
4. Supporting Stromal Cells

Question 11

Acellular components of bone graft

Answer 11

Extracellular matrix

Question 12

What is osteoinduction

Answer 12

Process of signalling new bone formation

Question 13

Polypeptide family associated with bone grafts

Answer 13

BMPs Bone Morphogenetic Proteins

Question 14

What is osteoconduction

Answer 14

Formtation of new bone from existing bone or periosteum on a matrix that acts as a scaffold

Question 15

Cell adhesion of osteoproginator cells occur through what molecules

Answer 15

Fibrin
Fibronectin
Collagen

Question 16

What is osteogenesis

Answer 16

Formation of osteoid by osteoblasts

Question 17

What occurs during the first week of graft implantation

Answer 17

1. Hematoma formation
2. Cells within secrete chemotactic, mitogenuc and angiogenic growth factors.
3. Capllaries present within days
4. Proginator cell proliferation and differentiation

Question 18

How long after implantation does the graft become vascularized

Answer 18

14-21 days

Question 19

How long after graft implanation does remodeling begin

Answer 19

6th week

Question 20

How long before the graft is 90% mature

Answer 20

6 months

Question 21

Advantages of natural polymers as bone graft subsitutes

Answer 21

Biodegradable
Biocompatible
Bioactive
Unlimited

Question 22

Disadvantages of natural polymers as bone graft subsitutes

Answer 22

Low mechanical strength
Rapid degradation
Variable properties

Question 23

Advantages of synthetic polymers as bone graft subsitutes

Answer 23

Biodegradable
Biocompatible
Versatile

Question 24

Disavantages of synthetic polymers as bone graft subsitutes

Answer 24

Low mechanical strength
Acidic degradation products

Question 25

Advantages of ceramics as bone graft subsitutes

Answer 25

Biodegradable
Biocompatible
Bioactive
Osteoconductive
Osteoinductive

Question 26

Disdvantages of ceramics as bone graft subsitutes

Answer 26

Brittle
Low fracture strength
Variable degradation rate

Question 27

Advantages of cement (calcium phosphate based) as bone graft subsitutes

Answer 27

Osteoconductive
Osteoinductive
Moldable
Biocompatible

Question 28

Disavantages of cements (calcium phosphate based) as bone graft subsitutes

Answer 28

Low mechanical strength
Variable initial stability