Bone Grafts And Orthobiologics Flashcards
What are some benefits of bone grafts
- important in treatment of nonunion
- Fill large defects
- Structural integrity
- Increase vascularity
What is the gold standard for bone grafts
Authogenous grafts
Describe the properties of Autogenous grafts
- osteogenic
- osteoconductive
- osteoinductive
What are some common sites for harvesting Autogenous bone grafts
Calcaneus
Tibia
Fibula
Iliac crest
What is the importance of the cortical portion of the corticocancellous bone grafts
Structure and length
What is the importance of the cancellous portion of corticocancellous bone in a bone graft
BMP mediates osteoprogenitor/MSCs, necessary for incorporation
What is the trephine technique
- percutaneous
- largely cancellous,
- good for small defects
- can be mixed with other products
What is the maximum free graft that can be interposed/implanted
2.5cm
If greater than 2.5cm of bone graft is needed, what can be done
- onlay/inlay graft
- bone transport
- vascularized graft
What are the properties of allogenic grafts
- osteoinductive
- osteoconductive
What is the advantages of allogenic grafts
- no donor sire morbidity
- decreased OR time
The success of orthobiologics depends on what
- vascularity
- surgical intervention with adequate preparation
- proper alignment
- application of stable fixation
What is he make of of osteoinductive orthobiologics
- PRP
- BMP
- Growth factors
Wha is the make up os osteoconductive orthobiologics
- DBM
- Bioceramics
- Bioglass
What is the make up osteogenic orthobiologics
- Mesenchymal stem cells
Describe the osteoinductive PRPs
Platelet Rich Plasma
- used for bone, ligament and tendon healing
- centrifuging the patient’s blood to separate out and obtain a gel-like concentration of growth facts
- PRP injected in and around the surgical site
How many BMPs are recognized and how play a role in bone healing
- 20 recognized
- 7 play a role in bone healing
The BMPs that play a role in bone healing belong with which family
TGF-beta superfamily
Describe osteoinductive growth factors
- naturally occurring and are prominent at various phases of the healing process
What happens when PDGF is combined with tricalcium phosphate
An osteoinductive and conductive substrate is produced
What is osteoconductive DBM
Processed allograft - lacks mineralization but retains growth factors and collagen
Describe how DBM is prepared
- combinations of acids or detergents/solvents
- antibiotics and freeze dryin
Is DBM osteoconductive or osteoinductive
Can be both osteoconductive and osteoinductive
What is the disadvantage of sterilizing DBM with gamma irradiation, formaldehyde and/or ethylene oxide prep?
It will strip the osteoinductive properties of DBM
What is one benefit of DBM
It comes in many forms: gel, putty, sheets and chips, different strengths and pliability
What are the most common materials for osteoconductive Calcium based bioceramics
- hydroxyapatite **
- tricalcium phosphate **
- ceramics
- fibrillation collagen
- and/or coralline hydroxyapatite
What are the two important considerations for osteoconductive calcium based bioceramics
- calcium-phosphate ratio
- Pore size of the graft
Why is the calcium-phosphate ratio of calcium based bioceramics important
- it dictates the rate of absorption
- when filling a bone void, the rate of resorption cannot exceed the rate of bone deposition because that will destroy our scaffolding
What is the ideal and most widely accepted resorption to bone deposition ratio
1.5 - 1.67
Why is pore size of the calcium based bioceramics graft important
- pore size is critical to allow influx of appropriate cells and growth factors and subsequent osteogenesis
What is the idea pore size of calcium based bioceramics graft that have yielded better angiogenesis and healing
300 micrometers or greater
What is one benefit of using calcium sulfate and calcium phosphate in combination as a bone graft
Greater compressive strength
Which bone graft may be combined with antibiotics to treat infections while serving as a filler?
What does that mean for Autogenous graft?
Bioceramics
Decreases the need for Autogenous graft
What is the advantage of using bioceramics combined with antibiotics over polymethylmethacrylate beads
Bioceremics are absorbable and does not need removal
What is osteoconductive bioglass made of
Calcium
Phosphorous
Silicon dioxide
Which graft has osteoconductive and osteointegrative properties
Bioglass
What is the importance of the osteoconductive and osteointegrative properties of the bioglass
Binding with hydroxyapatite forming a scaffold for healing, which is subsequently resorbed
What is the importance of the calcium phosphate deposition from bioglass
Attracts osteoblasts which results in electrical bone growth stimulation
Which bone graft has intrinsic antomicrobial activity due to the additional bactericidal activity from its components
Bioglass - possible enhance bone tissue regeneration
What is a key feature of Osteogenic MSCs
Can differentiate into osteoblasts and chondroblasts
What is a common source of osteogenic MSCs
bone marrow aspirate (BMA)
- tibia using jamshidi or syringe
What is BMA containing MSCs typically combined with
DBM or calcium-based bioceramics - to get all three components we’re looking for
What is the risk associated with allogenic MSCs
Cross-reactivity
Is the chance of cross-reactivity in allogenic MSCs high
Studies show low potential for rejection as well as high content of viable cells at time of implantation with resultant osteogenesis
