Bone Healing and Bone Grafting Flashcards
What are 2 sources of long bone blood supply seen in immature animals?
- Epiphyseal arteries
- Metaphyseal arteries
What are 3 sources of long bone blood supply in mature animals?
- Principle nutrient artery
- Metaphyseal arteries
- Periosteal arteries
What is a source of long bone blood supply seen with fractured bones?
Development of extraosseous blood supply.
What are 2 types of bone healing?
- Indirect healing
- Direct healing
What are 3 steps seen in indirect healing (healing by intermediate callus formation)?
- Inflammation
- Repair
- Remodeling
Healing by intermediate callus formation is known as what?
Indirect healing
Primary osteonal reconstruction is known as what?
Direct healing
What are 2 kinds of direct healing?
- Contact healing
- Gap healing
What type of bone healing occurs with unstable mechanical environment and motion between fracture fragments?
Indirect bone healing
Indirect bone healing can be seen when the gap between the fracture fragments are what distance apart?
> 1mm
You will see what type of bone healing with impaired blood supply or impaired revascularization?
Indirect bone healing
Transient extraosseous blood supply develops with what type of bone healing?
Indirect bone healing
When does the inflammatory stage of indirect bone healing begin?
Immediately after the fracture.
How long does the inflammatory stage of indirect bone healing last?
3-4 days
What develops at the site of fracture?
Clot
Release of osteoinductive growth factors at the fracture site can cause what 2 things to happen?
- Stimulates angiogenesis
- Bone formation
Abundant mast cells at the site of fracture can cause what?
Vasoactive substances leading to new vessel formation.
Extraosseous blood supply to the site of fracture occurs when?
Within hours.
During which stage of indirect bone healing does the clot change into granulation tissue by action of mononuclear cells and fibroblasts?
Repair stage
During the indirect bone healing repair stage, slight gain in mechanical strength is achieved with the formation of what?
Formation of a soft callus.
During the indirect bone healing repair stage, mesenchymal cells become what which form what?
- Osteoblasts
- A medullary and external callus (fibrocartilage).
Resorption and mineralization of the fibrocartilage in the repair stage of indirect bone healing forms what?
A hard callus.
Bony union is achieved during what stage of indirect bone healing?
Repair stage
How long does the repair stage of indirect bone healing last?
Approximately 2 months
How long can the remodeling stage of indirect bone healing last in humans?
6-9 years
70% of total healing time seen with indirect bone healing takes place during what stage?
Remodeling stage
Which stage of indirect bone healing functions to provide optimal function and strength?
Remodeling stage
The balance of osteoclast resorption and osteoblast deposition takes place during what stage of indirect bone healing?
Remodeling stage
The remodeling stage of indirect bone healing is governed by what?
What are 2 aspects of this?
- Wolfe’s Law
- Compression (osteoblasts) and Tension (osteoclasts)
Which type of bone healing refers to direct filling of fracture site with bone without callus formation?
Direct Bone Healing
Direct bone healing occurs by what?
Direct osteonal proliferation
Which type of bone healing requires precise reduction and rigid fixation that minimizes osteoprogenitor cells?
Direct bone healing
How long can direct bone healing take?
6-12 months for appropriate mechanical strength.
Contact healing of direct bone healing will be seen when the defect between the fracture site is what distance?
< 0.01mm
What type of healing will be seen with an interfragmentary strain < 2%?
Contact healing
Contact healing results in lamellar bone oriented in what direction?
Normal axial direction.
Bony union and remodeling occur simultaneously with what type of healing?
Contact healing
What type of bone healing is initiated by cutting cones of osteoclast directly followed by osteoblasts?
Direct bone contact healing
How far do cones of osteoclasts travel in a day?
50-100 micrometers/day
How big is a fracture gap?
< 1mm
How big is an interfragmentary strain?
<2
With direct bone gap healing, are bony union and remodeling separate steps or the same step?
Separate steps
Osteoblasts deposit what in the fracture gap in what orientation?
Laminar bones in fracture gap perpendicular to long axis.
With gap direct bone gap healing, the bone is mechanically weak where?
At the fracture ends.
In what time frame do osteoclasts form cutting comes allowing osteoblast to lay longitudinally oriented lamellar bone with direct bone gap healing?
3-8 weeks
T/F: Cancellous bone is more stable than cortical bone (fractures).
True
What is woven bone deposited on during the healing of cancellous bone?
Trabeculae
What occurs before the union of cortical shell in the healing of cancellous bone?
Bridging of fracture site.
Why does a physeal fracture occur?
Because the area is weaker than the surrounding bone.
How will a fracture of zone of hypertrophy will heal?
By continued growth of physeal cartilage.
How will a fracture of the zone of proliferation heal?
By endochondrial ossification.
What do physeal fractures prevent?
Normal physeal function.
Physeal fractures can lead to what?
Premature physeal closure.
An absolutely stable fracture is seen with what hype of bone healing?
Direct bone healing
An unstable fracture is seen with what type of bone healing?
Indirect bone healing
What are 6 factors affecting fracture healing?
- Location of fracture
- Stability
- Method of fixation
- Biological environment
- Blood supply
- Biomechanical vs biological osteosynthesis
What are 3 aspects of the biomechanical approach of fracture healing?
- Anatomical reduction
- Rigid fixation
- Will compromise soft tissue to achieve
T/F: Biological osteosynthesis emphasizes the role of soft tissue integrity.
True
What 2 things are restored with biological synthesis in fracture healing?
- Overall length
- Overall alignment
What 2 things should be limited with biological osteosynthesis with fracture healing?
- Surgical approach
- Soft tissue disruption
T/F: Biological osteosynthesis of fracture healing does not emphasize the use of bone grafts.
False - It does emphasize the use of bone grafts.
How do plates and ESF affect bone healing?
May result in direct (contact or gap) healing.
How do pins with wires, ESF and interlocking nails affect the type of bone healing?
Direct and/or indirect healing
How do casts and splints affect the type of bone healing?
Indirect healing
What type of bone healing is seen with no fixation?
Indirect healing
What 2 types of implants can disrupt endosteal blood supply and block medullary flow when in contact with endosteal surface?
Intramedullary pins and nails
Do cerclage wires and external fixator pins significantly impair vascularity?
No
Where do bone plates impair blood supply to?
The outer layer of cortical bone.
What results in increased stability of the fracture and allows early reformation of medullary blood supply?
Bone plate stabilization
Loose implants may significantly damage what?
Blood supply
Open reduction and fixation may result in what?
Damage to blood supply.
Bone grafts will enhance what but will not compensate for what?
Enhance healing but will not compensate for unstable mechanical environment.
What are 3 indications of bone grafts?
- At initial fracture repair
- Delayed or non-union fractures
- Arthrodeses
A bone graft from the patient’s own bone is known as what?
Autograft
Bone grafts using bone from another individual of the same species as the patient is known as what?
Allograft
Bone grafts using bone from an individual of another species are known as what?
Xenograft
What are 3 types of bone grafts?
- Cancellous
- Cortical
- Cortical-cancellous
Laying down new bone by osteoblasts is known as what?
Osteogenesis
Recruitment of host mesenchymal cells to form new bone or osteogenesis is known as what?
Osteoinduction
Providing a scaffold for the growth of new bone is known as what?
Osteoconduction
What is the gold standard of cancellous bone grafts?
Autogenous
What type of cancellous bone graft is readily available?
Autogenous
What type of cancellous bone graft helps to avoid immune reactions?
Autogenous
What are 5 disadvantages of autogenous cancellous bone grafts?
- Mechanically weak
- Increased surgical time
- Limited storage time
- Pain at donor site
- Intraoperative blood loss
Which type of cancellous bone graft wis available as frozen chips or powder?
Allograph
What are 3 pros of allograph cancellous bone grafts?
- Decreased surgical time
- Readily available
- No donor site problems
What are 2 problems with allograph cancellous bone grafts?
- Expensive
- Lack osteogenic properties
Allograph cancellous bone grafts can be mixed with what other type of bone graft to increase volume?
Autograft
What are the 4 phases of cancellous bone graft effect?
- Phase I: inflammation (within hours)
- Phase II: revascularization and Osteoinduction (2 weeks)
- Phase III: Osteoconduction (3-4 weeks)
- Phase IV: mechanical support (up to 12 weeks)
What do cortical bone grafts provide?
Structural support
Do cortical bone grafts have osteoconductive properties?
Yes
What type of bone grafts are used with highly comminuted fractures/bone tumors?
Cortical bone grafts
What are 4 bones where cortical autographs can be used?
- Ribs
- Ulna
- Fibula
- Ilial wing
What are 3 forms you can find allographs in?
- Harvested
- Processed
- Frozen
What type of bone graft can be incorporated in the fracture site with surgical with surgical implants?
Cortical bone grafts
Osteoclasts move into the graft and do what?
Resorb bone
Osteoblasts follow osteoclasts and do what?
Lay down new bone.
The phases of cortical bone graft effect are termed as what?
“Creeping substitution”
What does a cortical-cancellous bone graft contain?
Both cortical and cancellous bone
What type of bone graft provides immediate mechanical support?
Cortical-cancellous bone grafts
Do cortical-cancellous bone grafts promote osteogenesis?
Yes
Are cortical-cancellous bone grafts both osteoinductive and osteoconductive?
Yes
What is the most commonly used type of bone graft?
Cancellous autograft
Are cancellous autografts readily available?
Yes
What type of bone grafts are highly cellular and mechanically weak?
Cancellous autografts
Which form of bone graft has less osteoconductive properties?
Cancellous autografts
Which type of bone graft has excellent mechanical support?
Cortical bone grafts
Which type of bone graft is more osteoconductive?
Cortical bone grafts
Which type of bone graft is acellular with no osteogenic properties?
Cortical bone grafts