- Bone grafting/substitution/transplantation = replacing bone with something (called a bone graft)
- As the native bone grows it will generally replace the graft material with normal bone
- Needed in
- Alignment correction
- A wedge of bone graft may be inserted into a gap made by an osteotomy to correct alignment
- Tumour surgery
- Significant amounts of bone are removed and should be replaced
- Tumour in diaphysis -> part of the diaphysis is removed and must be replaced
- Revision joint replacement (replacing the previously implanted prosthesis with a new one)
- Bone cyst removal
- Congenital bone defects
- Post-traumatic bone defects
- Properties of an ideal bone graft
- Sterility
- Good mechanical properties
- Loadability
- Fixation – must be fixable by plate or screw
- Good healing properties
- Osteoconduction – the grafts ability to connect the resected bone surfaces of host bone
- Osteoinduction – the grafts ability to induce host osteogenesis
- Osteogenesis – the grafts ability to produce bone by itself
- Some grafts contain living osteoblasts, or a protein called BMP which stimulates host osteoblasts
- Good availability
- The choice of graft depends on the patient
- A modern orthopaedic department should have all different types of bone graft available
- There is no single “best” graft or material
- Types of grafts according to material
- Bone grafts
- Solid (tubular) bone grafts
- To replace bone after tumour removal, etc.
- Morselized bone (= bone chips)
- To replace bone inside a bone cyst
- Artificial grafts
- Metal grafts
- Bone cement grafts
- Types of grafts according to origin
- Autologous (from the patient)
- Best graft
- Osteogenesis + osteoinduction + osteoconduction
- Patient needs an extra surgery to acquire the bone graft
- Limited amount
- Allogenic
- From a human donor
- Cadaver
- Brain dead
- From another patient who had bone removed as part of joint replacement, etc.
- Osteoinduction + osteoconduction
- Contains BMP
- May contain transmittable diseases (hepatitis, HIV)
- Expensive
- Xenogenic (from another species)
- Only used after deprotonation, so only the inorganic bone remains
- No BMP or transmittable diseases
- No osteoinduction or osteogenesis, only osteoconduction
- Grafts from sea corrals
- Sea corrals are comprised of hydroxyapatite with similar properties as human bone