Ch.78 Bone Grafts and Bone Replacements Flashcards
How can bone grafts be treated to reduce antigenicity
Decellularization
Deproteinization
What is a xenograft
Tissue transferred between 2 members of same species
What is an orthotopic graft
Implantation site is similar to donor site
What is a heterotopic graft
Implant site dissimilar to donor site
Which confers better structural support a cancellous or a cortical bone graft
Cortical
Which provides more cells and promotes revascularization a cancellous or a cortical bone graft
Cancellous
Most common bone graft in horses
Autogenous cancellous
Locations for harvesting an autograft
Sternum
Tuber coxae
Proximal tibia
3 major functions of bone grafts
Osteoinduction
Osteocondction
Osteogenesis
Cellular components of a bone graft
- Osteoblasts
- Osteocytes
- Osteoclasts
- Supporting Stromal Cells
Acellular components of bone graft
Extracellular matrix
What is osteoinduction
Process of signalling new bone formation
Polypeptide family associated with bone grafts
BMPs Bone Morphogenetic Proteins
What is osteoconduction
Formtation of new bone from existing bone or periosteum on a matrix that acts as a scaffold
Cell adhesion of osteoproginator cells occur through what molecules
Fibrin
Fibronectin
Collagen
What is osteogenesis
Formation of osteoid by osteoblasts
What occurs during the first week of graft implantation
- Hematoma formation
- Cells within secrete chemotactic, mitogenuc and angiogenic growth factors.
- Capllaries present within days
- Proginator cell proliferation and differentiation
How long after implantation does the graft become vascularized
14-21 days
How long after graft implanation does remodeling begin
6th week
How long before the graft is 90% mature
6 months
Advantages of natural polymers as bone graft subsitutes
Biodegradable
Biocompatible
Bioactive
Unlimited
Disadvantages of natural polymers as bone graft subsitutes
Low mechanical strength
Rapid degradation
Variable properties
Advantages of synthetic polymers as bone graft subsitutes
Biodegradable
Biocompatible
Versatile
Disavantages of synthetic polymers as bone graft subsitutes
Low mechanical strength
Acidic degradation products
Advantages of ceramics as bone graft subsitutes
Biodegradable
Biocompatible
Bioactive
Osteoconductive
Osteoinductive
Disdvantages of ceramics as bone graft subsitutes
Brittle
Low fracture strength
Variable degradation rate
Advantages of cement (calcium phosphate based) as bone graft subsitutes
Osteoconductive
Osteoinductive
Moldable
Biocompatible
Disavantages of cements (calcium phosphate based) as bone graft subsitutes
Low mechanical strength
Variable initial stability
