The document summarizes bone grafting procedures. It discusses the properties of bone grafts including osteoinduction, osteoconduction and osteogenesis. It describes different types of grafts such as autografts, allografts, xenografts and alternatives like calcium phosphate ceramics. Autografts are ideal but have morbidity risks. Allografts have limitations due to processing but are commonly used. Demineralized bone matrix and mesenchymal stem cells are discussed as promising alternatives.

1. DR MOHSIN ANSARI
DEPARTMENT OF ORTHOPAEDICS ,
KATURI MEDICAL COLLEGE ,GUNTUR

2. • Bone grafting is a surgical procedure that
replaces missing bone ,that are lost either due
to trauma ,or defects formed by curettage of
tumours,cysts, or fractures that fail to heal
properly.
Introduction

3. Properties of bone Graft
• OSTEOGENESIS : Itis the ability of cellular
elements within a graft that survive
transplantation to synthesize new bone
• OSTEOINDUCTION: It is the ability of a graft to
recruit host mesenchymal stem cells into the
graft that differentiate into osteoblasts.
• OSTEOCONDUCTION : It is the ability of a graft to
facilitate blood vessel ingrowth and bone
formation into a scaffold structure.

4. Types of Graft
• AUTOGRAFT :When the bone grafts come from the
patient.
-cancellous
-cortical
-Bone marrow aspirate
• ALLOGRAFT :is one that is obtained from an individual
other than the patient.
– Freeze
• ISOGRAFT
• XENOGRAFT
• ORTHOTOPIC
• HETEROTOPIC

5. • Autogenous bone grafting provides consistent
results with regard to healing and integration .
– however, the morbidity associated with graft
harvesting, such as
– donor site pain,
– nerve or arterial injury,
– and infection rates of between 8% and 10%

6. INDICATIONS
1. To fill cavities or defects resulting from cysts,
tumors, or other causes .
2. To bridge joints and provide arthrodesis.
3. To bridge major defects or establish the
continuity of a long bone.
4. To provide bone blocks to limit joint motion
(arthroereisis) .

7. 5. To establish union in a pseudarthrosis.
6. To promote union or fill defects in delayed
union, malunion, fresh fractures, or
osteotomies .

8. AUTOLOGOUS BONE
• It provides the ideal graft requirements in
terms of osteoinductivity, osteoconductivity,
and osteogenicity.
• Sources of autologous bone include
– Pelvis
– Distal radius
– Fibula
– Proximal tibia, and the ribs.

9. Advantages
– graft-versus-host reaction is eliminated,
– the risk of disease transmission .
Disadvantages
- donor site pain,
- nerve or arterial injury,
- and infection rates of between 8% and
10%

10. Autologous Cancellous Bone Graft
• Cancellous bone is an effective graft material
for specific types of fractures, particularly
those that do not require immediate structural
support from the graft.
• Its main function is to act as a scaffold for the
attachment of host cells and to provide the
osteoconductive and osteoinductive functions
required for the laying down of new bone.
• The process by which the graft is replaced by
new bone is known as “Creeping substitution”
• It is usually complete within 1 year

11. • Commonly used sources of cancellous graft
– Iliac crest
– Distal radius,
– Greater trochanter
– Proximal tibial
– Distal femoral metaphyses

12. • Cancellous graft does not provide structural
support by itself, it can be impacted into
skeletal defects and, in conjunction with
internal fixation devices, support areas of bone
loss.
• Examples : depressed fractures of the tibial
plateau and in revision hip and knee
arthroplasty where there is bone loss.

13. Autologous Cortical Bone Graft
• Cortical bone can provide structural
support as well as osteoconductive and
osteoinductive properties.
• Cortical bone grafts are usually
harvested from the ribs, fibula, or crest
of the ilium and can be transplanted
with or without a vascular pedicle.

14. Vascularized & Nonvascularized bone
graft
• Nonvascularized grafts are mostly
osteoconductive and possibly provide
some osteoinductive properties but
possess little or no osteogenic properties
because they contain very few
osteoblasts or osteoprogenitor cells .

15. • Vascularized bone graft :
–Most of these grafts are harvested from
• the iliac crest with the deep circumflex artery
• fibula with peroneal artery branches
• Medial femoral condyle with descending
genicular artery branches
• distal radius with supraretinacular artery branches
• the ribswith the posterior intercostal artery
– Once implanted with its viable vascular
pedicle, there is the provision of an
immediate blood supply that is independent
of the surrounding bone.

16. • In the treatment of bone defects that will
not heal without grafting, also known as
critical-sized defects, both vascularized and
nonvascularized grafts are indicated.
• For defects up to 6 cm in length
nonvascularized grafts can be used.
• while defects greater than 12 cm are good
candidates for vascularized grafting
procedures.

17. • Vascularized grafts are also indicated for
reconstruction of defects where the
microenvironment of the host is inadequate to
initiate an effective biological response .
• Examples :
– Acute traumatic injuries with extensive soft tissue
damage and impairment of blood supply
– Atrophic nonunions
– irradiated or severely scarred tissue.

18. Mesenchymal Stem Cells
• Progenitor cells are totipotent, in which
case they have the ability to form any cell
type in the body,
• then they progress toward more
committed, or monopotent cells.
• In contrast, multipotent cells, such as
mesenchymal stem cells (MSCs), can be
directed toward cells of a specific germ
layer only

19. • In the elderly, the pool of available
progenitor cells may be diminished, leading
to delayed or possibly impaired fracture
healing .
• Adult MSCs obtained from bone marrow
have been shown to be a source of
autologous graft material.
• (CFU-APs), a marker of osteoblast
progenitors, was 55 per 1 million nucleated
cells .

20. • As the aspirate volume increases, so does the
number of CFU-APs.
• Contamination of the sample by peripheral
blood
• MSCs could also be isolated, cryopreserved,
without the loss of osteogenic potential.
• In addition to adult stem cells, it has been
hypothesized that embryonic stem cells are
deposited during embryogenesis in various
organs, including bone marrow, and may persist
in these locations into adulthood as pluripotent
stem cells.

21. • These cells have the capability to both respond
to a normal repair process in the body and
participate in the repair of soft tissue and bone.
• Examples :
– Very small embryonic like (VSEL) cells,
– Multipotent adult progenitor cells (MAPCs)
– Marrow-isolated adult multilineage inducible
(MIAMI) cells.

22. Allogeneic Bone Graft
• Allografts are frequently used in spinal
surgery and in joint arthroplasty .
• Limitations attributed to its storage and
sterilization procedures such as Freeze-
drying, or lyophilization(involves removal
of water and vacuum packing of the
tissue )

23. • It reduce immunogenicity, including the
expression of the major histocompatibility
complex (MHC) class I antigen in
osteoblasts.
• It reduces its mechanical integrity,
thereby diminishing its loadbearing
properties.
• It reduces the osteoinductive potential .

24. • Allogeneic bone is available in many
preparations including
– Morselized and cancellous chips
–Corticocancellous and cortical grafts
–Osteochondral segments
–Demineralized bone matrix

25. • Lack of vascularization may account for
the high incidence of fractures seen with
these grafts, which has been reported to
occur in between 16% and 50% of cases.
• Histologically, mononuclear cells invade
the graft and surround newly developing
blood vessels.

26. • Necrotic graft bone remains in the host
tissue much longer compared with autograft
bone and may be seen for many years after
implantation depending on the size of the
graft and its anatomic location.
• During the first 2 years, new vessel
penetration rarely exceeded a depth of 5
mm, and new bone apposition occupied no
more than 20% of the graft

27. • The depth of penetration after 2 years was
typically less than 10 mm, although 80% of the
surface area of the graft was found to be
attached to the local soft tissues.
• Overall, necrotic tissue remained in the central
aspects of the allograft, and these areas
appeared to be isolated from the remodeling
process.
• The biological nature of the recipient host bed
is a critical factor in facilitating allograft
incorporation.

28. • A well-vascularized bed aids in the
incorporation of the allograft through a
combination of revascularization,
osteoconduction, and remodeling.
• Cortical allografts are harvested from a number
of sites including
– Pelvis
– Ribs
– Fibula

29. • They are available as
– Whole bone segments for limb salvage procedures
– Or they may be cut longitudinally to yield struts that can
be used to fill bone defects or periprosthetic fractures
• To achieve graft-host union - autogenous graft
harvested from the iliac crest can be placed at the
allograft-host bone interface.
• This technique was described by Wang and Weng
in the treatment of distal femoral nonunions.

30. Demineralized Bone Matrix
• DBM is produced by acid extraction of
allograft bone.
• It contains type I collagen, noncollagenous
proteins, and osteoinductive growth factors .
• They are available as a freezedried powder,
granules, gel, putty, or strips.

31. BONE GRAFT SUBSTITUTES
• The ideal bone graft substitute would provide
three elements:
– Scaffolding for osteoconduction,
– Growth factors for osteoinduction,
– Progenitor cells for osteogenesis.

32. • Substitutes
–Calcium phosphate ceramics
– Calcium sulfate
– Bioactive glass
–Biodegradable polymers
–Autologous bone marrow cells

33. • Calcium Phosphate Ceramics
–Calcium phosphate ceramics are
osteoconductive materials produced by a
sintering process in which mineral salts are
heated to over 1000°C.
– Sintering reduces the amount of carbonated
apatite, an unstable and weakly soluble form
of HA.
–Despite this, their brittleness and poor tensile
strength limit their use as bone graft materials.

34. • HYDROXYAPATITE
–HA is a slow resorbing compound that is
derived from several sources, both animal
and synthetic.
–Interpore HA. - is a coralline hydroxyapatite
and was the first calcium phosphate-based
bone graft substitute approved by the FDA.
– A simple hydrothermal treatment process
converts it from its native coral state to the
more stable HA form with pore diameters of
between 200 and 500 µm, a structure very
similar to human trabecular bone.

35. • TRICALCIUM PHOSPHATE :
–Undergoes partial resorption and some of it
may be converted to HA once implanted in
the body.
–The composition of TCP is very similar to
the calcium and phosphate phase of human
bone.
– Incorporation by 24 months.

36. • CALCIUM PHOSPHATE – COLLAGEN
COMPOSITE :
– Collagen is the most abundant protein in the
extracellular matrix of bone and promotes
mineral deposition by providing binding sites
for matrix proteins.
–Types I and III collagen have been combined
with HA, TCP, and autologous bone marrow to
form a graft material devoid of structural
support but able to function as an effective
bone graft substitute or bone graft expander
to augment fracture healing.

37. • CALCIUM SULFATE OR PLASTER OF PARIS :
–It acts as an osteoconductive material,
which completely resorbs as newly formed
bone remodels and restores anatomic
features and structural properties.

38. • CALCIUM PHOSPHATE CEMENTS
–used in the treatment of bony defects
associated with acute fractures.
– Inorganic calcium and phosphate are
combined to form an injectable paste that can
be delivered into the fracture site.
–commercially available CPC, Norian SRS , in the
treatment of distal radius fractures.
– Under physiologic conditions, this material
begins to harden within minutes, forming a
mineral known as dahllite.

39. • By 12 hours, dahllite formation is nearly
complete, providing the cement with an
ultimate compressive strength of 55
megapascals (MPa).

40. GROWTH FACTORS AND RELATED
MOLECULES
• BMP (Bone Morphogenetic Proteins)
• OTHER PEPTIDE SIGNALING MOLECULES
o TGF-β
o VEGF
o FGF
o PDGF

41. Bone Morphogenetic Proteins
• BMPs are a group of noncollagenous
glycoproteins that belong to the transforming
growth factor beta (TGF-β) superfamily.
• They are synthesized locally and
predominantly exert their effects by autocrine
and paracrine mechanisms.

42. • Fifteen different human BMPs have been
identified and their genes cloned.
• For clinical applications, the most extensively
studied among these are BMP-2 and BMP-7
(also called OP-1).
• (rh)BMP-7.

43. • The subcutaneous anteromedial aspect of the
tibia is an excellent source for AUTOGENOUS
grafts .
• Disadvantages to the use of the tibia as a
donor area include the following:
– A normal limb is jeopardized
– removal of the graft adds to the duration and
magnitude of the procedure;
– Convalescence is prolonged, and ambulation must
be delayed until the defect in the tibia has
partially healed

44. – The tibia must be protected for 6 to 12 months to
prevent fractures.
• The entire proximal two thirds of the fibula
can be removed without disabling the leg.
• Advantages :
• The proximal end has a rounded
prominence that is partially covered by
hyaline cartilage and forms a satisfactory
transplant to replace the distal third of the
radius or the distal third of the fibula

45. – After transplantation, the hyaline cartilage
probably degenerates rapidly into a
fibrocartilaginous surface; even so, this surface is
preferable to raw bone.
– The middle one third of the fibula also can be used
as a vascularized free autograft based on the
peroneal artery and vein pedicle using
microvascular technique.
– this graft is used for the treatment of large defects
in congenital pseudarthrosis of the tibia.

46. Techniques of bone grafting
• Single Onlay Cortical Grafts
• Dual Onlay Grafts
• Inlay Grafts
• Peg Grafts
• Medullary Grafts
• Osteoperiosteal Grafts
• Multiple Cancellous Chip Grafts
• Hemicylindrical Grafts
• Whole Bone Transplant

47. • Single Onlay Cortical Grafts :
– simplest and most effective treatment for most ununited
diaphyseal fractures.
– Usually the cortical graft was supplemented by
cancellous bone for osteogenesis.
– The onlay graft is still applicable to a limited group of
fresh, malunited, and ununited fractures as well as after
osteotomies.
– used bridging joints to produce arthrodesis .
– Fixation as a rule is best furnished by internal or external
metallic devices.

48. • Dual Onlay Grafts
– Two cortical onlay grafts are placed opposite
each other on the host bone across the
nonunion and are fixed with the same set of
screws; they grip the fragments.
– Any intervening space at the bone ends is filled
with cancellous chips.
–for bridging massive defects .
–Nonunion of shaft fractures in elderly
patients whose bones are osteoporotic also
should be treated with dual grafts.

49. Advantages Dual Onlay Grafts
–Mechanical fixation is better than fixation by
a single onlay bone graft;
–The two grafts add strength and stability
–The grafts form a trough into which
cancellous bone may be packed

50. • During healing, the dual grafts, in
contrast to a single graft, prevent
contracting fibrous tissue from
compromising transplanted cancellous
bone.
• Non wt bearing for long time .

51. • Disadvantages Dual Onlay Grafts
–They are not as strong as metallic
fixation devices;
–An extremity usually must serve as a
donor site if autogenous grafts are used
– They are not as osteogenic as
autogenous iliac grafts, and the surgery
necessary to obtain them has more
risk.

52. Inlay Grafts
• A slot or rectangular defect is created in
the cortex of the host bone usually with
a power saw.
• A graft the same size or slightly smaller is
fitted into the defect.
• Used in arthrodesis, particularly at the
ankle

53. Peg Grafts
• Peg grafts usually are considered an
innocuous means of internal fixation rather
than a means of osteogenesis.
• Because they are weaker than metal, their
use is limited to conditions such as
nonunions of the medial malleolus and some
of the small bones of the hand, wrist, or
foot.

54. Medullary Grafts
• nonunion of diaphyseal fractures.
• Fixation was insecure, and healing was
rarely satisfactory.
• This graft interferes with endosteal
circulation and consequently can
interfere with healing.
• Medullary grafts are rarely used except in
the metatarsals, the metacarpals, and
the distal end of the radius.

55. TIBIAL GRAFT

56. FIBULAR GRAFT

57. • Three points should be considered in the
removal of a fibular graft:
– The peroneal nerve must not be damaged.
– Tthe distal fourth of the bone must be left to
maintain a stable ankle.
– The peroneal muscles should not be cut.

58. Wolfe-Kawamoto technique

61. • Large cancellous and corticocancellous
grafts may be obtained from the anterior
superior iliac crest and the posterior iliac
crest.
– Small cancellous grafts may be ob-tained from
• The greater trochanter of the femur
• Femoral condyle

62. • proximal tibial metaphysis,
• medial malleolus of the tibia,
• olecranon, and distal radius.
• At least 2 cm of subchondral bone must remain
to avoid collapse of the articular surface.

63. Whole Fibular Transplants
• A whole fibular transplant may be useful for
bridging defects in the radius or ulna.
• Because it is tubular, it is stronger than a tibial
graft with the same amount of cortical bone
and need not be as large;
• the tissues of the forearm are not unduly
crowded by it, and closing the wound is easier.

65. THANK U