This document discusses bone grafts and bone morphogenic proteins. It defines bone grafts as the transfer of bone tissue from one site to another. There are several types of bone grafts including autografts, allografts, and synthetic grafts. Autografts are obtained from the patient and provide osteoinduction, osteoconduction and osteogenesis. Allografts are obtained from donors and provide osteoconduction and variable osteoinduction depending on processing. Synthetic grafts like calcium phosphate and hydroxyapatite are osteoconductive. Bone morphogenic proteins can be produced recombinantly and are osteoinductive. The document compares the properties and uses of different graft types.

1. Bone graft/substitute and
BMP (bone morphogenic
protein)
Ahmad Syahmi Bin Che Sulaiman

2. Overview
 Definition
 Properties of bone graft
 Indication of bone graft
 Type of bone graft
◦ Autograft
◦ Allograft
◦ Synthetic bone graft
 Graft incorporation

3. Definition
 Graft – tissue transfer from one site to
another
 Bone graft – transfer of bone from one
site to another

4. Properties of bone graft
 Osteoconductive
◦ Provide integrated porous structure through
which new cell can migrate and new vessel
form
– acts as a framework/scaffold for bone growth
 Osteoinductive
– stimulate and support mitogenesis of
undifferentiated cells to osteoblastic cell
 Osteogenic
– presence of progenitor cell for bone
formation (osteoblast/osteoblast precursor)

5. Indication of bone graft
 To promote union
 Bridging of joint and provide
arthrodesis
 To fill defect in
◦ Fracture
◦ Osteotomies
◦ Cavities resulting from cyst/tumours

6. Type of bone graft
 Autograft
◦ Cancellous bone
◦ Cortical bone
◦ Bone marrow aspiration
 Allograft
◦ Demineralized bone matrix
 Synthethic bone graft
◦ Calcium based bone graft
◦ Bone morphogenetic protein

7. Autograft
 Bone transfer from one site to another
in the same individual
◦ Cortical bone
◦ Cancellous bone
◦ Bone marrow aspirate
 Autograft have osteoinductive,
osteoconductive and osteogenesis
properties

8. Site of harvest
Cortical bone Cancellous bone
 Iliac crest
 Fibula
 Rib
 Iliac crest
 Proximal tibia(Tibial
Plateau)
 Greater Trochanter

9. Advantage Disadvantage
 No antigenicity
 No potential for disease
transmission
 Provides
osteoconduction,
osteoinduction and
osteogenic cells.
 Limited quantity
 Requires additional
surgery
 Donor site morbidity
◦ Risk of infection
◦ Pain over surgical site

10. Bone marrow aspirate
 Osteogenic property
◦ Provides mesenchymal stem cells
(osteoprogenitor cells)
◦ Can be used in combination with an
osteoconductive matrix

11. Allograft
 Bone transferred from one person to
another
◦ Fresh – highly immunogenic
◦ Fresh frozen – less immunogenic, BMP
preserved
◦ Freeze dried – least immunogenic, loses
BMP
 Allograft have osteoinductive and
osteoconductive properties

12. Advantages Disadvantages
 Eliminate donor site
morbidity
 Abundant supply
 Immune reaction
(antigenicity)
 Risk of infection
 Disease transmission
 Reduce osteoinduction
and osteogenicity
 Variable osteoinduction
based on processing

13. Demineralised bone matrix
 Acid extractraction of allograft bone
leaving
◦ Collagen
◦ Noncollagenous proteins
◦ Bone growth factors
 Offer some osteoinductive potential,
mainly act as an osteoconductive
agents

14. Synthetic bone graft
 Calcium based synthetic bone graft
are primarily osteoconductive
◦ Calcium phosphate
◦ Calcium hydroxyapatite
◦ Calcium sulphate

15. Calcium phosphate
 Osteoconductive
 Highest compressive strength of any
graft
 Biodegrade slowly (6-9 months)

16. Calcium hydroxyapatite
 Osteoconductive
 Combination of ceramic hydroxiapatite
granules, tricalcium phosphate
granules and collagen
 Very slow resorption

17. Calcium suphate
 Osteoconductive
 Low compressive strength
 Rapid resorption (6-9 weeks)
 Can be used as autogenous graft
expander
 Usually used in conjunction with
gentamicin to provide local antibiotic
delivery in treatment of cavities in
osteomyelitis

19. Bone Morphogenetic Protein
 Osteoinductive – targets the
perivascular messenchymal cells
 Originally extracted from allograft
bone
 Recent advance in technology allow
manufacturing of BMP using
recombinant technology
 rhBMP-2 and rhBMP-7

20. Graft Osteoconductiv
e
Osteoinductive Osteogenic
cells
Structural
integrity
Others
Cancellous
bone
Excellent Good Excellent Good Rapid
incorporation
Cortical bone Good Good Good Excellent Slow
incorporation
Bone marrow
aspirate
Poor Poor Excellent Poor
Allograft Good Fair None Good Variable
osteoinduction
based on
preparation
Demineralize
d bone matrix
Good Fair None Poor
Calcium
based
synthetic
bone graft
Good None None Good
BMP Poor Good None Poor
Differences between bone
graft/substitutes

21. Incorporation of graft
 Inflammation
◦ At graft site, hematoma develop, which
provides heamatopoetic cells that secrete
growth factor
 Reparative
◦ Autograft undergo necrosis, which stimulate
inflammatory respons with fibrovascular
stroma, and stimulus for bone growth
◦ The dead autograft provide passive scaffold
for new bone formation (creeping
substitution)
 Bone remodelling

22. Reference
 Miller’s review of orthopaedics 7th
edition
 Apley’s system of orthopaedic and
fractures 9th edition
 Campbell operative orthopaedics 11th
edition

23. Thank You