Bone Healing and Bone Grafting Flashcards Preview

Mechanisms of Disease > Bone Healing and Bone Grafting > Flashcards

Flashcards in Bone Healing and Bone Grafting Deck (109)
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0
Q

What are 2 sources of long bone blood supply seen in immature animals?

A
  • Epiphyseal arteries

- Metaphyseal arteries

1
Q

What are 3 sources of long bone blood supply in mature animals?

A
  • Principle nutrient artery
  • Metaphyseal arteries
  • Periosteal arteries
2
Q

What is a source of long bone blood supply seen with fractured bones?

A

Development of extraosseous blood supply.

3
Q

What are 2 types of bone healing?

A
  • Indirect healing

- Direct healing

4
Q

What are 3 steps seen in indirect healing (healing by intermediate callus formation)?

A
  • Inflammation
  • Repair
  • Remodeling
5
Q

Healing by intermediate callus formation is known as what?

A

Indirect healing

6
Q

Primary osteonal reconstruction is known as what?

A

Direct healing

7
Q

What are 2 kinds of direct healing?

A
  • Contact healing

- Gap healing

8
Q

What type of bone healing occurs with unstable mechanical environment and motion between fracture fragments?

A

Indirect bone healing

9
Q

Indirect bone healing can be seen when the gap between the fracture fragments are what distance apart?

A

> 1mm

10
Q

You will see what type of bone healing with impaired blood supply or impaired revascularization?

A

Indirect bone healing

11
Q

Transient extraosseous blood supply develops with what type of bone healing?

A

Indirect bone healing

12
Q

When does the inflammatory stage of indirect bone healing begin?

A

Immediately after the fracture.

13
Q

How long does the inflammatory stage of indirect bone healing last?

A

3-4 days

14
Q

What develops at the site of fracture?

A

Clot

15
Q

Release of osteoinductive growth factors at the fracture site can cause what 2 things to happen?

A
  • Stimulates angiogenesis

- Bone formation

16
Q

Abundant mast cells at the site of fracture can cause what?

A

Vasoactive substances leading to new vessel formation.

17
Q

Extraosseous blood supply to the site of fracture occurs when?

A

Within hours.

18
Q

During which stage of indirect bone healing does the clot change into granulation tissue by action of mononuclear cells and fibroblasts?

A

Repair stage

19
Q

During the indirect bone healing repair stage, slight gain in mechanical strength is achieved with the formation of what?

A

Formation of a soft callus.

20
Q

During the indirect bone healing repair stage, mesenchymal cells become what which form what?

A
  • Osteoblasts

- A medullary and external callus (fibrocartilage).

21
Q

Resorption and mineralization of the fibrocartilage in the repair stage of indirect bone healing forms what?

A

A hard callus.

22
Q

Bony union is achieved during what stage of indirect bone healing?

A

Repair stage

23
Q

How long does the repair stage of indirect bone healing last?

A

Approximately 2 months

24
Q

How long can the remodeling stage of indirect bone healing last in humans?

A

6-9 years

25
Q

70% of total healing time seen with indirect bone healing takes place during what stage?

A

Remodeling stage

26
Q

Which stage of indirect bone healing functions to provide optimal function and strength?

A

Remodeling stage

27
Q

The balance of osteoclast resorption and osteoblast deposition takes place during what stage of indirect bone healing?

A

Remodeling stage

28
Q

The remodeling stage of indirect bone healing is governed by what?
What are 2 aspects of this?

A
  • Wolfe’s Law

- Compression (osteoblasts) and Tension (osteoclasts)

29
Q

Which type of bone healing refers to direct filling of fracture site with bone without callus formation?

A

Direct Bone Healing

30
Q

Direct bone healing occurs by what?

A

Direct osteonal proliferation

31
Q

Which type of bone healing requires precise reduction and rigid fixation that minimizes osteoprogenitor cells?

A

Direct bone healing

32
Q

How long can direct bone healing take?

A

6-12 months for appropriate mechanical strength.

33
Q

Contact healing of direct bone healing will be seen when the defect between the fracture site is what distance?

A

< 0.01mm

34
Q

What type of healing will be seen with an interfragmentary strain < 2%?

A

Contact healing

35
Q

Contact healing results in lamellar bone oriented in what direction?

A

Normal axial direction.

36
Q

Bony union and remodeling occur simultaneously with what type of healing?

A

Contact healing

37
Q

What type of bone healing is initiated by cutting cones of osteoclast directly followed by osteoblasts?

A

Direct bone contact healing

38
Q

How far do cones of osteoclasts travel in a day?

A

50-100 micrometers/day

39
Q

How big is a fracture gap?

A

< 1mm

40
Q

How big is an interfragmentary strain?

A

<2

41
Q

With direct bone gap healing, are bony union and remodeling separate steps or the same step?

A

Separate steps

42
Q

Osteoblasts deposit what in the fracture gap in what orientation?

A

Laminar bones in fracture gap perpendicular to long axis.

43
Q

With gap direct bone gap healing, the bone is mechanically weak where?

A

At the fracture ends.

44
Q

In what time frame do osteoclasts form cutting comes allowing osteoblast to lay longitudinally oriented lamellar bone with direct bone gap healing?

A

3-8 weeks

45
Q

T/F: Cancellous bone is more stable than cortical bone (fractures).

A

True

46
Q

What is woven bone deposited on during the healing of cancellous bone?

A

Trabeculae

47
Q

What occurs before the union of cortical shell in the healing of cancellous bone?

A

Bridging of fracture site.

48
Q

Why does a physeal fracture occur?

A

Because the area is weaker than the surrounding bone.

49
Q

How will a fracture of zone of hypertrophy will heal?

A

By continued growth of physeal cartilage.

50
Q

How will a fracture of the zone of proliferation heal?

A

By endochondrial ossification.

51
Q

What do physeal fractures prevent?

A

Normal physeal function.

52
Q

Physeal fractures can lead to what?

A

Premature physeal closure.

53
Q

An absolutely stable fracture is seen with what hype of bone healing?

A

Direct bone healing

54
Q

An unstable fracture is seen with what type of bone healing?

A

Indirect bone healing

55
Q

What are 6 factors affecting fracture healing?

A
  • Location of fracture
  • Stability
  • Method of fixation
  • Biological environment
  • Blood supply
  • Biomechanical vs biological osteosynthesis
56
Q

What are 3 aspects of the biomechanical approach of fracture healing?

A
  • Anatomical reduction
  • Rigid fixation
  • Will compromise soft tissue to achieve
57
Q

T/F: Biological osteosynthesis emphasizes the role of soft tissue integrity.

A

True

58
Q

What 2 things are restored with biological synthesis in fracture healing?

A
  • Overall length

- Overall alignment

59
Q

What 2 things should be limited with biological osteosynthesis with fracture healing?

A
  • Surgical approach

- Soft tissue disruption

60
Q

T/F: Biological osteosynthesis of fracture healing does not emphasize the use of bone grafts.

A

False - It does emphasize the use of bone grafts.

61
Q

How do plates and ESF affect bone healing?

A

May result in direct (contact or gap) healing.

62
Q

How do pins with wires, ESF and interlocking nails affect the type of bone healing?

A

Direct and/or indirect healing

63
Q

How do casts and splints affect the type of bone healing?

A

Indirect healing

64
Q

What type of bone healing is seen with no fixation?

A

Indirect healing

65
Q

What 2 types of implants can disrupt endosteal blood supply and block medullary flow when in contact with endosteal surface?

A

Intramedullary pins and nails

66
Q

Do cerclage wires and external fixator pins significantly impair vascularity?

A

No

67
Q

Where do bone plates impair blood supply to?

A

The outer layer of cortical bone.

68
Q

What results in increased stability of the fracture and allows early reformation of medullary blood supply?

A

Bone plate stabilization

69
Q

Loose implants may significantly damage what?

A

Blood supply

70
Q

Open reduction and fixation may result in what?

A

Damage to blood supply.

71
Q

Bone grafts will enhance what but will not compensate for what?

A

Enhance healing but will not compensate for unstable mechanical environment.

72
Q

What are 3 indications of bone grafts?

A
  • At initial fracture repair
  • Delayed or non-union fractures
  • Arthrodeses
73
Q

A bone graft from the patient’s own bone is known as what?

A

Autograft

74
Q

Bone grafts using bone from another individual of the same species as the patient is known as what?

A

Allograft

75
Q

Bone grafts using bone from an individual of another species are known as what?

A

Xenograft

76
Q

What are 3 types of bone grafts?

A
  • Cancellous
  • Cortical
  • Cortical-cancellous
77
Q

Laying down new bone by osteoblasts is known as what?

A

Osteogenesis

78
Q

Recruitment of host mesenchymal cells to form new bone or osteogenesis is known as what?

A

Osteoinduction

79
Q

Providing a scaffold for the growth of new bone is known as what?

A

Osteoconduction

80
Q

What is the gold standard of cancellous bone grafts?

A

Autogenous

81
Q

What type of cancellous bone graft is readily available?

A

Autogenous

82
Q

What type of cancellous bone graft helps to avoid immune reactions?

A

Autogenous

83
Q

What are 5 disadvantages of autogenous cancellous bone grafts?

A
  • Mechanically weak
  • Increased surgical time
  • Limited storage time
  • Pain at donor site
  • Intraoperative blood loss
84
Q

Which type of cancellous bone graft wis available as frozen chips or powder?

A

Allograph

85
Q

What are 3 pros of allograph cancellous bone grafts?

A
  • Decreased surgical time
  • Readily available
  • No donor site problems
86
Q

What are 2 problems with allograph cancellous bone grafts?

A
  • Expensive

- Lack osteogenic properties

87
Q

Allograph cancellous bone grafts can be mixed with what other type of bone graft to increase volume?

A

Autograft

88
Q

What are the 4 phases of cancellous bone graft effect?

A
  • 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)
89
Q

What do cortical bone grafts provide?

A

Structural support

90
Q

Do cortical bone grafts have osteoconductive properties?

A

Yes

91
Q

What type of bone grafts are used with highly comminuted fractures/bone tumors?

A

Cortical bone grafts

92
Q

What are 4 bones where cortical autographs can be used?

A
  • Ribs
  • Ulna
  • Fibula
  • Ilial wing
93
Q

What are 3 forms you can find allographs in?

A
  • Harvested
  • Processed
  • Frozen
94
Q

What type of bone graft can be incorporated in the fracture site with surgical with surgical implants?

A

Cortical bone grafts

95
Q

Osteoclasts move into the graft and do what?

A

Resorb bone

96
Q

Osteoblasts follow osteoclasts and do what?

A

Lay down new bone.

97
Q

The phases of cortical bone graft effect are termed as what?

A

“Creeping substitution”

98
Q

What does a cortical-cancellous bone graft contain?

A

Both cortical and cancellous bone

99
Q

What type of bone graft provides immediate mechanical support?

A

Cortical-cancellous bone grafts

100
Q

Do cortical-cancellous bone grafts promote osteogenesis?

A

Yes

101
Q

Are cortical-cancellous bone grafts both osteoinductive and osteoconductive?

A

Yes

102
Q

What is the most commonly used type of bone graft?

A

Cancellous autograft

103
Q

Are cancellous autografts readily available?

A

Yes

104
Q

What type of bone grafts are highly cellular and mechanically weak?

A

Cancellous autografts

105
Q

Which form of bone graft has less osteoconductive properties?

A

Cancellous autografts

106
Q

Which type of bone graft has excellent mechanical support?

A

Cortical bone grafts

107
Q

Which type of bone graft is more osteoconductive?

A

Cortical bone grafts

108
Q

Which type of bone graft is acellular with no osteogenic properties?

A

Cortical bone grafts