Bone healing and fracture Flashcards

1
Q

what does secondary (indirect bone healing involve)?

A
  1. hematoma
  2. fibrous tissue
  3. cartilage
  4. mineralized cartilage
  5. endochondral ossification
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2
Q

What does primary healing of bone involve?

A

spot welding

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3
Q

What does primary healing of bone require?

A

close contact and rigid stabilization of bone fragments

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4
Q

What does anatomic repair alow for?

A

early load bearing by repaired bone

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5
Q

How can anatomic repair slow fracture healing?

A

disruption of blood supply

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6
Q

How can biologic repair have faster healing?

A

because even though the apparatus is initially taking all the forces, the fracture may heal more rapidly since the blood supply has been minimally disrupted

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7
Q

How much can bone cells stand to be deformed?

A

2% of their length

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8
Q

How much can cartilage or fibrous tissue handle being stretched?

A

10-15% of their length

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9
Q

How much elongation can granulation tissue tolerate?

A

100% elongation

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10
Q

Fractures that have more than a mm gap heal by:

A

indirect healing

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11
Q

How does indirect healing occur?

A

Cells that can be stretched and squashed bridge the gap and produce matrix. the movement decreases, the next group of cells can come in and produce even stiffer matrix and so on

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12
Q

How does indirect healing occur?

A

Cells that can be stretched and squashed bridge the gap and produce matrix. the movement decreases, the next group of cells can come in and produce even stiffer matrix and so on. eventually bone cells can survive and endochondral ossification occurs

  1. fracture
  2. hematoma
  3. fibrin
  4. pluripotent eclls
  5. granulation tissue
  6. fibrous tissue
  7. fibocartilage
  8. mineralized cartilage
  9. bone
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13
Q

What are the two flavors of primary healing?

A
  1. contact healing

2. gap healing

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14
Q

What happens in contact healing?

A

osteoclasts make tunnels across fracture lines (cutting cones with bone multicellular units) and new bone laid down–cutting cone
==>spot welds

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15
Q

What is gap healing?

A

ther eis a thin gap. hematoma forms, followed by CT and blood vessels. Once the blood vessels are present the osteoblasts lay down lamellar bone in the gap, THEN cutting cones come through

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16
Q

What are conditions that favor secondary bone healing?

A
  1. external coaptation
  2. intramedullary pinning
  3. interlocking nail repairs with incomplete reduction of fragments
  4. elastic plating
  5. buttress plating
  6. external skeletal fixation w/ out perfect reduction
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17
Q

What are conditions favoring primary healing?

A
  1. compression plating
  2. rigid forms of external fixation, with close bone contact
  3. pin/tension band repairs
  4. screw repair of condylar fractures
18
Q

What are the three main roots for blood supply to come in?

A
  1. nutrient artery (cancellous bone, 2/3 of cortex)
  2. blood vessels at metaphysis
  3. periosteum–nourish outer 1/3 of cortex
  4. extraosseous supply of healing bone–arise from surrounding soft tissues to augment the damaged blood supply coming to the fracture fragments–

(more muscle attachment, better lbood supply)

19
Q

Why do bones heal faster with minimal disruption of soft tissue attachments to bone?

A

because there is extraosseous supply of healing bone that comes form surrounding soft tissue

20
Q

Why do bones heal faster with minimal disruption of soft tissue attachments to bone?

A

because there is extraosseous supply of healing bone that comes form surrounding soft tissue

21
Q

what are the two main strategies for fixing fractures?

A
  1. anatomic and biologic repair
22
Q

What is anatomic repair?

A

involves putting fractured bone back together again like a jigsaw puzzle and holding pieces together so some weight can be transferred through the bone right away–sometimes may allow direct healing

23
Q

What are the advantages of anatomic repair?

A
  1. minimal callus formation–good for joint

2. load sharing between bone and hardware–good if expect healing slow

24
Q

What are disadvantages of anatomic repair?

A
  1. often need a big approach, which disrupts blood supply

2. not all fractures can be put back together again and held that way

25
Q

When is anatomic repair most appropriate?

A
  1. near or involving joints

2. older animals–slow healing anyway

26
Q

What is biologic repair?

A

pulling bone out to length and spanning fracture with hardware. No attempts to put back together

27
Q

What are the advantages of biologic repair?

A
  1. minimally disruptive of blood supply–encourages rapid healing if blood supply ok to begin with
  2. faster than putting all the pieces together
28
Q

What is a disadvantage of biologic repair?

A

no load sharing between bone and hardware so the hardware is could fail before healing occurs

29
Q

When are biological repairs appropriate?

A
  1. dipahyseal fractures in young animals

2. highly comminuted fractures

30
Q

When are biological repairs appropriate?

A
  1. dipahyseal fractures in young animals

2. highly comminuted fractures

31
Q

fracture repair for mandible

A

tension band, interfragmentary wiring, splinting, plates, ESF

32
Q

skull fracture

A

interfragmentary wiring, suturing, maybe bone plate

33
Q

vertebrae fracture

A

bone plate, interfragmentary wiring, internal form of ESF

34
Q

pelvis fracture

A

scews, bone plates, maybe internal form of ESF

35
Q

What is humerus fracture repair

A

pins, cerclage wiring, interlocking nails, bone plates, IM pin-ESF tie in, fESF Ia, Ib

36
Q

radius

A

external coaptation, bone plates, ESF. NO NO NO IM, interlocking nails

37
Q

ulna

A

maybe nothing if radius stabilized or external coaptation, IM pin, bone plate

38
Q

carpal and tarsal bones

A

scews and pins

39
Q

metarcarpal and metatarsal bones

A

extenal coaptation, bone plates, IM pins–uncommon

40
Q

phalanges

A

external coaptation, scews, eenie weenie little plates

41
Q

femur

A

interlocking nails, IM pin/bone plate combo, IM pin ESF tie in, bone plate fixation. NOT just pin and wire

42
Q

tibia

A

external coapatation, IM pin ESF tie in, Im pin/cerclage wire, bone plate fixation ESF, interlocking nails