Principles of internal fixation: wiring technique (Lewis)

Question 1

What is a cerclage wire

Answer 1

Heavy gauge stainless steel wire placed circumstantially around bone

Question 2

How does a cerclage wire function

Answer 2

Neutralize rotational, bending, shearing forces, and fragment apposition

Question 3

10 rules for proper cerclage wire application

Answer 3

1. Sufficient diameter
2. 260 anatomic reconstruction
3. Multiple wires
4. Fx should be long and oblique
5. Placed 1 cm apart
6. Placed .5cm from tip of fx
7. Perpendicular to long axis of bone
8. Prevent wire from migrating
9. Do not entrap
10. Tight

Question 4

Why is a loose cerclage wire so detrimental

Answer 4

reduce fx healing
increase risk of infection
Rub against blood supply

Question 5

Advantage of twist knot

Answer 5

can re-tighten

Greater resistance to the cyclic forces of weight bearing

Question 6

Disadvantages of twist knot

Answer 6

decrease final wire tension
wires protrude
do not alight perpendicular to long axis during tightening

Question 7

Loop wire advantages

Answer 7

Greater final wire tension

Question 8

Disadvantage of loop wire

Answer 8

cannot re-tighten wires

more cumbersome

Question 9

3 ways to prevent cerclage wire slipping

Answer 9

hemicerclage wire
Notch bone
Place wire adjacent to or straddling an inter-fragmentary K wire

Question 10

What is a hemicerclage wire

Answer 10

drill a hole into the bone and run cerclage wire through it

Question 11

purpose of Tension band principle

Answer 11

Converts distractive (tension) forces to compressive forces