Cerclage wires (Lewis) Flashcards
1
Q
Cerclage wires
Definition
A
- Heavy gauge stainless steel wire placed circumferentially around bone
- provides fragment apposition and adjunctive fixation
2
Q
Cerclage wires:
Function
A
- Provide fragment apposition
- Inadequate stability to resist forces of weight-bearing alone
3
Q
Ability of various implants to neutralize fracture forces
- Forces
- Rotational
- Bending
- Shearing
- Fragment apposition
- Implant
- Single IM pin
- Multiple IM pin
- Screws and Plates
- External Fixator
- Cerclage wires
A
4
Q
First rule of cerclage wire application
A
- Need to have 360 degree anatomic reconstruction of cylinder of bone at the level wires are places
5
Q
Fractures heal from:
A
End to end
-not side to side
6
Q
Cerclage wires
Application
A
- Resistance to axial, rotational, bending and shear forces dependent on
- frictional forces generated when interdigitating intricacies of fracture surfaces are statically compressed
- Complete 360 degree anatomic reconstruction is mandatory
-
Wire must be of sufficient diameter
- 18, 20, 22 gauge wire
- Fracture must be oblique
- twice or 2.5 times in length as diameter of bone at level of fracture
- Use multiple wires to distribute the forces along the entire length of the fracture
- 1 cm apart
- placed 5 mm from end of fracture segments
- Place wire perpendicular to long axis of bone
- Must be tight
7
Q
Cerclage wire
DON’Ts
A
- Don’t use on short, oblique fracture
- Don’t ever use a single cerclage wire
- One wire is like a teeter totter
- Do not allow soft tissue to be interposed between the wire and the bones
- but don’t strip soft tissue
8
Q
Dead piece of bone not conjoined
A
Sequestrum
9
Q
Preventing cerclage wire slippage
A
- Hemicerclage wire
- K wire perpindicular to fracture line
- Then cerclage wire around it
- proximal end proximal to k wire
- distal end distal to k wire
- Then cerclage wire around it
10
Q
Loose implant will cause
A
infection
11
Q
Layer of new bone growth outside existing bone seen in pyogenic osteomyelitis
A
Involucrum
12
Q
Cerclage wires
Twist knot
A
- Both phases of application occur simultaneously
- Limits wire tension because wire is bent before it is tight
- Wire is pulled & deformed through multiple planes during application
- Usually use heavy needle holders
- Pull against wire, use elevator to make sure wire perpindicular to bone
*both sides need to be twisted around one another (not like a fireman on a pole)
13
Q
Cerclage wires
Loop knot
A
- Wire is tightened and subsequently secured by bending
- Wire pulled through a single plane during application
*Can get much greater tension than with a twist knot
14
Q
Cerclage wires
Biomechanics
A
- Loop knots produced greater tension than twist knots
- before and after bending
- Twist knot cerclage wires lost significant tension
- if bend over
- Twisted knots provide greater resistance to distractive forces
- Knot resistance to distractive forces increased with increasing wire diameter
15
Q
Twist Cerclage wires
Advantages
A
- More resistant to distractive forces
- Simpler to apply
- Wires can be re-tightened
- More economical than loop wires
