2. Outline
• Introduction
• Classifications
• Properties of bone graft
• Indications
• Graft incorporation
• Principles
• Bone graft substitute
• Complications
• Conclusion
3. Introduction
• Bone graft/substitute can be defined as
any material that alone or in combination
with other materials promotes bone
healing by providing osteogenic,
osteoinduction and osteoconductive
activity to the local site
• BG is among the most commonly
transplanted tissue in the body
4. Based on vascularity
◦ Vascularised
Theoretically the ideal graft
Microsurgical skills needed
Sources;
Iliac crest with one of the circumference a. e.g PCIA
Fibula with peroneal artery
Ribs with posterior intercoastal artery
◦ Non-vascularised
Fibular strut
5. Classification
• Based on source
– Autograft (gold standard)
– Allograft
– Isograft
– Xenograft
– BG substitute
6. Autograft
◦ No immunogenicity
◦ No disease transmission
◦ Cheap
◦ Limited availability
◦ Donor site morbidity
◦ Increased op and anaesthetic time
7. Allograft
◦ No donor site morbidity
◦ Large amounts available
◦ Disease transmission
◦ Immunogenic
◦ Slow incorporation
◦ Bone banking
8. Based on composition
◦ Cancellous
– More rapidly incorporated
– Sources – iliac crest, GT, metaphysis of proximal
tibia, distal femur, distal tibia, distal radius,
proximal humerus
◦ Cortical
– Less biologically active
– Less surface area
– Less cellular matrix
– Prolong time to revascularize
– They may need fixation
– Sources – iliac crest, fibula, ribs, anterior-medial
surface of tibia
9. ◦ Corticocancellous
– Dual function of providing healing and
support
– Sources – iliac crest and tibia plateau
◦ Osteochondral
◦ Bone marrow aspirate
10. Richer and more
growth factors
Up to 50cc of bone
graft can be
harvested
11. Based on state of graft
◦ Fresh
Highly antigenic
Limited time to check antigenicity
◦ Preserved using
Ethylene oxide
Ionizing radiation
Freezing (-70 degree)
Freeze drying
Demineralization
12. Osteoconduction
◦ Provide scaffold/matrix for which new bone will be
laid down
Osteoinduction
◦ Provide growth factors that encourage
differentiation of messenchymal cells into
osteoblast
Osteogenic
◦ Presence of cells that related to bone formation
such as primitive messenchymal cells, osteoblast
and osteocytes
13. Augment fracture healing e.g non union
Fill defect e.g following cyst or tumour
excision
Arthrodesis
To replace a bone/disc
Establish continuity of long bone e.g fibula
strut
14. Aid screw fixation in osteoporotic bone
Help establish union in pseudoarthrosis
Provide joint block to limit joint motion
(arthroereisis)
Treatment of bone gap e.g Masquelet
technique
16. Autograft undergo necrosis
Viable surface cells on the graft stimulate
inflammatory response
Fibrovascular stroma formed
Blood vessels and osteoprogenitor cells pass
from recipient bone to graft
Remaining viable cells stimulate
osteoprogenitor cells which differentiate to
osteoblast (osteoinduction)
17. Graft also provide scaffold for new bone
(osteoconduction)
New bone formed replaced graft (creeping
substitution)
Cancellous bone incorporate more quickly
and complete
Vascularised graft remain viable
18. Cancellous
◦ Faster
◦ Analogous to fracture healing
◦ Creeping substitution
Cortical
◦ Slower inflammatory process
◦ Osteoclastic activity precede osteoblastic bone
formation
◦ Loss of mechanical strength first 3-6 months,
returns over 1-2 years
20. Inflammation; chemotaxis stimulated by
necrotic debris
Osteoblast differentiation from precursors
Osteoinduction; osteoblast and osteoclast
Osteoconduction
Remodelling process continues for years
21. Local (+v)
◦ Large surface area
◦ Good vascular supply
◦ Growth factors; BMP, VEGF, PDGF
◦ Mechanical loading
◦ Mechanical stability
22. Local (-ve)
◦ Denervation
◦ Infection
◦ Radiation
◦ Local bone disease
◦ Foreign body
◦ Mechanical instabilty
23. Systemic (+ve)
◦ Growth hormone
◦ Insulin
◦ PTH
◦ Thyroid hormone
◦ Vitamins A and D
25. Pre op
◦ Indications met
◦ Remove/reduce –ve factors
◦ Informed consent
26. Intra op
◦ GA/SAB, positioning, exposure
◦ Fresh instruments/gloves for op and donor site
◦ Cortical window
◦ Stay posterior to ASIS
◦ Don’t go beyond 8cm lateral to PSIS
In children posterior iliac crest is a good donor site
◦ Dissect directly down to the bone
27. ◦ Expose only area needed
◦ Take only amount needed
◦ Cancellous BG; morselisation increases the surface
area of the graft and also exposes the bone cells
◦ Harvested bone graft should be kept moist
◦ Achieve haemostasis
28. Post op
◦ Monitor post op bleeding
◦ Analgesia
◦ Protect donor site
◦ Change dressing as frequent as necessary
29. Dispensable?
◦ Dispose and harvest another graft
Indispensable?
◦ Rinse with normal saline
◦ Place in antibiotics for 10-15 minutes
◦ Make use of the graft
◦ Inform patient post op
31. BMP
◦ Originally extracted from allogenic BG
◦ BMP 2 and 7 are commercially produced
◦ Need carriers
Allograft
Demineralized bone matrix
Collagen
Bone cement
32. Calcium based
Calcium phosphate
Calcium hydroxyapetite
Calcium sulphate
◦ Primarily osteoconductive
◦ Calcium hydroxyapetite and phosphate are used to
fill metaphyseal defects
Tibial plateau
Calcaneum
Radial fracture
◦ No sufficient strength
33. ◦ Absorbed
Calcium sulphate 6-9 weeks
Calcium phosphate 6-9 months
Calcium hydroxyapetite several years
34. Bone graft and bone graft substitute play
important role in orthopaedics; arthroplasty,
limb reconstruction, spine etc
