Bone grafting

burdwan medical college and hospital

1. BONE GRAFTING By :- SANJOY MONDAL 2 nd year PGT Department of Orthopaedics BMCH

2. Bone grafting is defined as a meterial that is intended to fill, augment or reconstruct the bony defects . It may be either by new bone or replacement material. Bone grafts may be :- 1) AUTOGRAFT :- Bone harvested from patients own body. 2) ALLOGRAFT :- Usually obtained from cadaveric bone. 3) SYNTHETIC :- Often made of hydroxyapatite or other naturally occurring and biocompatible substances with similar mechanical properties to bone 4) DEMINERALISED BONE MATRIX :- Acidic extraction of bone matrix from allograft removes the minerals and leaves the collagenous and non collagenous structural protiens .

3. 5) BONE MORPHOGENETIC PROTEIN :- rhBMP-2 and rhBMP-7 are currently approved by FDA for application in long bones and spine. It stimulates undifferentiated perivascular mesenchymal cells to differentiated osteoblasts through serine-threonine kinase pathway. It has various complications like under or overproduction of bone , early bone resorption and carcinomatous changes. 6) REAMER ASPIRATOR IRRIGATOR :- Provides large volume of bone graft from intramedullary source . Most commonly taken from femur and tibia. Debris harvested during RIA and bone graft harvested from illiac crest have similar RNA transcriptional profiles for genes that act in bone repair and formation. Hence RIA is a viable alternative to iliac crest autogenous cancellous graft. 7) MESENCHYMAL STEM CELLS

4. INDICATIONS FOR BONE GRAFTING :- Fill cavities or defects resulting from cysts, tumors , or other causes Bridge joints and provide arthodesis . Bridge major defects or establish the continuity of a long bone Provide bone blocks to limit joint motion ( arthroereisis ) Establish union in a pseudoarthrosis Promote union or fill defects in delayed union, malunion , fresh fractures or osteotomies.

5. ESSENTIAL PROPERTIES OF BONE GRAFT :- GRAFT OSTEOGENESIS :- is the ability of cellular elements within a graft that survive transplantation to synthesise new bone. GRAFT OSTEOINDUCTION :- is the ability of a graft to recruit host mesenchymal stem cells into the graft that differentiate into osteoblasts. Bone morphogenic protien and other growth factors in the graft facilitate this process. GRAFT OSTEOCONDUCTION :- is the ability of a graft to facilitate blood vessel ingrowth and bone formation into a scaffold structure.

6. AUTOGRAFT Bone is transferred from one site to other in the same individual. Graft posses all essential characteristics i.e , osteoconductivity , osteoinductivity and osteogenicity . It includes:- 1) cortical bone graft 2) cancellous bone graft 3) vascularised bone graft 4) autologus bone marrow graft Advantage :- a) no immune reaction b) all essential characteristics present Disadvantage:- a) additional surgery b) donor site morbidity c) limited amount of graft can be obtained.

7. CORTICAL GRAFT Used primarily for structural support. Obtained from :- 1) fibula 2) tibia 3) illiac crest 4) rarely from recected rib. Disadvantage of using Tibia as bone graft donor:- A normal limb is jeopardized The duration and magnitude of the procedure is increased Ambulation has to be delayed Tibia has to be protected for 6 to 12 months to prevent fractures.

8. CANCELLOUS GRAFT Used primarily for osteogenesis but provides less structural support than cortical graft. They are more rapidly incorporated into host bone than cortical grafts. Obtained from:- 1) thicker portion of illium 2) proximal metaphysis of tibia 3) lower radius 4) olecranon In case of a segmental bone loss a two stage technique with methyl methacrylate spacer and cancellous bone graft is used. The spacer is placed into the defect to induce the formation of bioactive membrane . 4-8 weeks later the spacer is removed and cancellous autograft is placed in the now membrane surrounded defect. The membrane prevent graft resorption and promote revascularisation.

9. FREE VASCULARISED GRAFT Bone is transferred with its blood supply which is anastomosed to vessel at recipient site. Available donor sites are:- 1) free fibula strut graft ( peroneal artery) 2) free iliac crest graft ( deep circumflex illiac artery) Advantage :- 1) quicker union 2) lesser chance of graft rejection Disadvantage :- 1) technically challenging 2) donor site morbidity.

10. ALLOGRAFTS Graft is obtained from an individual other than the patient. INDICATION :- 1) in small children where sufficient graft is not available from donor site. 2) in elderly people where large defects have to be filled like periprosthetic long bone fracture or reconstruction after tumor excision Advantage :- 1) no donor site morbidity 2) large amounts can be used Disadvantage :- 1) risk of infection 2) immune reaction 3) reduced osteoinductivity and osteogenicity .

11. TYPES OF ALLOGRAFT :- FRESH :- Highest risk of immunogenicity Highest risk of disease transmission BMP is preserved and therefore osteoinductive . B) FRESH FROZEN :- Less immunogenicity than fresh allograft BMP is preserved and therefore osteoinductive C) FREEZE DRIED :- Least immunogenic L owest likelihood of viral transmission Least structural integrity. BMP depleted hence purely osteoconductive

12. BONE BANK To provide safe and useful allograft material efficiently, a bone banking system is required. Bones with ligaments and tendons may be preserved. Even nowadays articular cartilage and menisci can be cryopreserved. PROCEDURE :- 1)Bones can be harvested in a clean and nonsterile environment 2) Sterilized by irradiation, strong acid or ethylene oxide 3) Freeze dried for storage. Bones under sterile condition can be deep frozen to -70 to -80 degree celsius for storage. DONORS ARE SCREENED FOR :- 1)Any bacterial, viral( including hepatitis and HIV) or fungal infection 2)Malignancy ( except basal cell carcinoma of skin) 3)Collagen vascular disease 4) Metabolic bone disease 5) Presence of toxins.

13. BONE GRAFT SUBSTITUTES Bone graft substitutes can replace autologous or allogenic grafts or expand an existing amount of available graft material. Autologous cancellous and cortical grafts are still “gold standard” against which all other graft forms are judged. LAURENCIN CLASSIFICATION OF BONE GRAFT SUBSTITUTE :- Natural bone based Growth factor based Cell based Ceramic based Polymer based Miscellaneous

14. VARIOUS BONE GRAFT TECHNIQUES ONLAY CORTICAL GRAFT :- Graft is placed subperiosteally across the fragments without mobilizing the fragments. Cortical graft is supplemented with cancellous bone for osteogenesis . Fixation is achieved by internal or external metallic device. USES :-1) Malunited or nonunited fracture of shaft of long bone 2)Bridging joints to produce arthrodesis B) DUAL ONLAY GRAFT :- Two cortical onlay grafts are placed opposite to each other on the host bone across the nonunion and are fixed with the same set of screws. They grip the fragments like a forceps USES :- to fix nonunited short osteoporotic fracture near a joint. ADVANTAGE OF DUAL ONLAY GRAFT :- 1) Mechanical fixation is better than fixation by a single onlay bone graft. 2)Two grafts add strength and stability.

15. 3) Grafts form a trough into which cancellous bone may be packed. 4) During healing the dual graft prevent contracting fibrous tissue from compromising transplanted cancellous bone. DISADVANTAGE OF DUAL ONLAY GRAFT :- 1) Not as strong as metallic fixator devices. 2) Extremity usually must serve as a donor site if autogenous grafts are used. 3) Not as osteogenic as autogenous iliac grafts. 4) The surgery necessary to obtain them has more risk. C) INLAY GRAFTS :- a slot or rectangular defect is created in the cortex of host bone then a graft of the same size or slightly smaller is fitted into the defect. USES :- Occationally used in arthrodesis,particularly at ankle.

16. D) MULTIPLE CANCELLOUS CHIP GRAFTS :- Multiple chips of cancellous bone are the best osteogenic material available USES :- 1) Filling defects or cavities resulting from cysts or tumor 2) for establishing bone blocks and wedging in osteotomies. E) HEMICYLINDRICAL GRAFT :- A massive hemicylindrical cortical graft from the affected bone is placed across the defectand supplemented by cancellous iliac bone. USES :- 1) Suitable for obliterating large defects of tibia and femur. 2)Applicable for resection of bone tumor when amputation is to be avoided. F) WHOLE BONE TRANSPLANT :- Fibular graft is most commonly used. USE:- 1) Useful for filling large defects in the diaphyseal portion of bones of upper extremity. 2) In children , the fibula can be used to span a long gap in the tibia.

17. VARIOUS GRAFTING TECHNIQUES ONLAY GRAFT INLAY GRAFT HEMICYLINDRICAL GRAFT

18. LOCAL AND SYSTEMIC FACTORS INFLUENCING GRAFT INCORPORATION

19. REMOVAL OF TIBIAL GRAFT Tourniquet is applied to avoid excessive blood loss Slightly curved longitudinal incision over the anteromedial surface of tibia is made. Because of the shape of tibia the graft is usually wider at the proximal end than the distal end Periosteum over the tibia is relatively thick in children and is sutured as a separate layer In adults periosteum is thin and is sutured along with the subcutaneous tissue.

20. REMOVAL OF FIBULAR GRAFT PRECAUTIONS TO BE TAKEN :- 1) The peroneal nerve must not be damaged. 2) The distal fourth of the bone must be left to maintain a stable ankle 3) The peroneal muscles should not be cut PROCEDURE :- 1) Dissect along the anterior surface of the septum between the peroneus longus and soleus muscle. 2) protect the peroneal nerve by tracing it from the posteromedial aspect of the distal end of biceps femoris tendon. 3) Protect the anterior tibial vessels that pass between the neck of fibula and tibia by subperiosteal dissection 4) After the resection is complete , suture the biceps tendon and the fibular collateral ligament to the adjacent soft tissue.

21. SITE OF INCISION OF FIBULAR GRAFT

22. METHOD OF PRESERVATION OF COMMON PERONEAL NERVE IN FIBULAR GRAFT

23. REMOVAL OF ILIAC BONE GRAFT Iliac crest is an ideal source of bone graft because :- It is relatively subcutaneous Has ample cancellous bone Has cortical bone of varying thickness Removal of bone carries minimum risk Usually there is no significant residual disability INCISION :- along the subcutaneous border of the iliac crest at the point of contact of the periosteum with the origins of the gluteal and trunk muscles Large cancellous and cortico cancellous grafts may be obtained from the anterosuperior iliac crest and the posterior iliac crest In children the physis of the iliac crest is preserved together with the attached muscles

24. Generally only one cortex and the cancellous bone are removed for grafts. The fractured crest along with the apophysis is replaced in contact with the remnant of the ilium by non absorbable suture. When the crest of the ilium is not required as a part of the graft , then we split off the lateral side or both sides of the crest in continuity with the periosteum . COMPLICATIONS :- 1) Hernia develops if full thickness massive grafts are taken 2) The superior cluneal nerves are at risk if dissection is carried farther than 8 cm lateral to the posterior superior iliac spine. 3) Removal of large full thickness grafts from the anterior ilium can result in cosmetic deformity.

25. WOLFE-KAWAMOTO TECHNIQUE OF TAKING ILIAC BONE GRAFT

26. FULL THICKNESS CORONAL SEGMENT OF ILIUM SUPERIOR CLUNEAL NERVES PASSING 8 cm LATERAL TO POSTERIOR SUPERIOR ILIAC SPINE

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