Orthopedics Flashcards

1
Q

What 4 factors make rabbit bones more brittle with a higher predisposition for fractures compared to dogs and cats?

A
  1. A smaller contribution of bony weight to whole body mass
  2. Thinner cortices
  3. Lower density/higher mineral composition
  4. Large muscle mass
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2
Q

What surgical fracture repair technique is generally preferred to other methods in rabbits due to versatility, minimal disruption of vasculature and low cost of equipment?

A

External skeletal fixation

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3
Q

Which bone is most commonly contaminated with fractures in rabbits?

A

The tibia

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4
Q

What are 3 indications for external coaptation?

A
  1. Fixation of closed fractures distal to elbow/stifle joints
  2. Temporary treatment pre-op to provide hemostasis, avoid further trauma, and keep the patient comfortable
  3. In combination with internal fixations such as IM pins to prevent rotational movement
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5
Q

What forces do IM pins not counter?

A

Rotational and shear forces

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6
Q

What are 5 potential risks of IM pin insertion?

A

Causing further fractures, cracking of affected bone, pin loosening, arthritis if placed through a joint, and interfering with the medullary blood supply

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7
Q

What makes up a ‘tie-in’ or hybrid external fixator?

A

An IM pin combined with an external skeletal fixator

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8
Q

What forces does ESF eliminate?

A

Bending, rotational and shear

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9
Q

What are potential complications of ESF?

A

Damage to the fixator, premature pin loosening, bending/breaking pins, pin-tract infections

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10
Q

When placing an ESF, why should distance between the limb and connecting materials be minimized?

A

To increase biomechanical stiffness and decrease fixator weight

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11
Q

What limitations prevent bone plating from being practical in ECM?

A

Small size of bones, thin cortices, technical difficulty & extra equipment, potential for disruption of periosteal blood supply, increase in risk of infection and prolonged surgical time

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12
Q

What complication can be seen in short-legged species such as guinea pigs and hedgehogs post amputation?

A

Decubitus and/or moist dermatitis of amputated lesions

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13
Q

In what circumstances will direct/primary fracture healing occur?

A

Only when fracture fragments are reduced anatomically and stabilized under interfragmentary compression with less than 2% interfragmentary strain

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14
Q

What does direct fracture healing mean?

A

Cortical bone is directly formed across fracture line with no evidence of callus formation

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15
Q

When does secondary/indirect bone healing occur?

A

When the interfragmentary strain is between 2 and 10%

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16
Q

What are the 3 phases of bone healing?

A

Reactive, reparative and remodeling

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17
Q

The phases of rehabilitation closely match the stages of ___. The 3 stages are:

A

Healing;
1. Inflammatory stage
2. Reparative (fibroblastic) stage
3. Remodeling (maturation) stage

18
Q

What are the four main interventions in a rehabilitation program?

A
  1. Ergonomics
  2. Manual therapy
  3. Therapeutic exercise
  4. Electrophysical (therapeutic) modalities
19
Q

How does cryotherapy work on injured tissue?

A

Reducing or delaying infiltration of white blood cells and subsequent inflammatory cytokines in injured tissue

20
Q

What are the three phases of rehabilitation?

A

Inflammatory, transition and strength/function

21
Q

What does the functional evaluation consist of in a rehabilitation assessment?

A

Passive and active assessments

22
Q

Give examples of passive assessments in physical rehab (7)

A

Passive range of motion, end-feel, goniometry, joint play, flexibility, muscle girth, myofascial exam

23
Q

Give examples of active assessments in physical rehab (4)

A

Posture, Gait/mobility, Transfer, Strength (muscle) test

24
Q

What are the basic goals in the inflammatory stage of rehabilitation?

A

Protect healing tissues, relieve pain, reduce inflammation, maintain joint ROM

25
What are the goals in the reparative stage of healing/subacute/transition stage of rehab?
Promote weight bearing/joint function, reeducation of muscle, regain ROM, regain flexibility/strength
26
What are the goals in the remodeling stage of healing/ chronic or strength/function stage of rehab?
Restore full ROM/flexibility, improve muscle mass/strength, improve proprioception, regain endurance, return functional activity
27
Which is typically the longest phase of the rehabilitation process? How long does it typically last?
The chronic or strength/function phase; For bone - 12 wks+; for tendon/ligament - 1 yr+
28
How does pulse electromagnetic field (PEMF) energy work?
A flow of electricity runs through a coil or antenna, which in turn generates a magnetic field that can be directed at tissues for therapeutic effects
29
When is PEMF particularly helpful?
Nonunion fractures and neurologic injury
30
What are the four main skeletal tissues found in vertebrates?
Cartilage, bone, enamel, dentine
31
What is the approximate composition of skeletal bone?
75% inorganic (water and minerals) and 25% organic (extracellular matrix and cells)
32
What are the most common complications in fracture healing?
Infection, sequestration, delayed union, nonunion, malunion
33
When can periosteal proliferation be detected on radiographs after infection of a fracture?
7-10 days
34
What are potential reasons for delayed union of a fracture?
Disuse, instability, poor fracture reduction, poor vascular irrigation, poor nutrition, MBD, old age, infection, sequestrum, or underlying pathology s/a neoplasia
35
When should nonunion be considered?
After 12 weeks, especially if no evidence of radiographic healing in sequential radiographs
36
What is the most frequently fractured bone in the ferret and guinea pig?
The femur
37
What is the most common traumatic fracture in chinchillas? What type of fracture usually occurs?
Tibia; short spiral or transverse
38
Where is the most common site for vertebral fractures in rabbits?
LS junction (L7)
39
How much bone loss must occur before being radiographically evident?
30-60%
40
What area do osteosarcomas in rabbits more commonly affect?
The skull
41
What is the most common spinal curvature malformation in small mammals?
Scoliosis