Chapter 42 ESF

Question 1

Negative profile pin

Answer 1

Threads cut into pin so outer diameter of threaded portion is same as shaft and threaded portion is smaller diameter

Question 2

Positive profile pin

Answer 2

Outer diameter of threaded portion wider than diameter of shaft

Question 3

What type of ESF is unilateral and uniplanar?

Answer 3

Ia

Question 4

What type of ESF is unilateral and biplanar?

Answer 4

Type Ib

Question 5

What type of ESF is bilateral and uniplanar?

Answer 5

Type II

Question 6

What type of ESF is bilateral and biplanar?

Answer 6

Type III

Question 7

What are three augmentation techniques that increase stiffness and strength?

Answer 7

1. Articulations
2. Diagnoals
3. Combined frames (+/- tie-in)

Question 8

When combining an IM pin with an ESF, what % of medullary cavity should the pin fill?

Answer 8

No more than 40%

Question 9

Acrylic ESF strength is equivalent to stainless steel when placed under load TRUE or FALSE

Answer 9

True

Question 10

What type of wire can be used to prevent bone fragments from sliding along wire?

Answer 10

Olive wire (stopper on mid-shaft)

Question 11

What happens to wires in a circular ESF when load increases?

Answer 11

Wires exponentially increase in stiffness until it levels off and becomes linear on stress-strain curve -> beyond this point wires have similar stiffness to large diameter pin

Question 12

How quickly are bone ends drawn apart for distraction osteogenesis?

Answer 12

1mm per day

Question 13

How many pins should be placed per bone segment?

Answer 13

3-4 per segment

Question 14

Where should pins be placed in relation to the joint and fracture lines?

Answer 14

3/4 of bone diameter away from adjacent joints
1/2 bone diameter away from fractures

Question 15

What size pins should you use for a linear ESF?

Answer 15

20-30% bone diameter

Question 16

What insertion speed is recommended for pin placement?

Answer 16

<300 rpm

Question 17

How far should a clamp be from the surgace of the skin?

Answer 17

1cm

Question 18

In what order are pins placed in relation to the fracture?

Answer 18

Far-near-near-far placement