Screws and bone plates Flashcards Preview

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Flashcards in Screws and bone plates Deck (31):
1

What is the principle behind bone plate weightbering

increases friction between the bone and the plate

2

Locking plates don't only screw into the bone but into the?

Plate

3

Do locking plates need to be closely contoured tot he bone?

No not as much cause friction comes from screws

4

Downside to screwplacement with locking plates?

Screws cannot be placed at an angle

5

What forces are neutralized by plates?

All forces

6

By themselves screws mostly control?

Torsion, compression, and tension

7

When do we often use screws?

Half a condyle has broken off, times when bending is not an issue

8

3 advantages to plate fixation?

Anatomic reconstruction is not necessary
do not require removal
fragments can be conmpressed

9

3 disadvantages to plate fixation

PLacement requires very large entry
Cant capture small proximal or distal chunks
If infection sets in you need another surgery

10

Not only are pins great for helping out with bending forces but?

Make reduction for plate placement almost done

11

If plate pin combo do all the screws need to double cortices?

No only the most proxinmal and distal screws then need to be within bo0th cortices

12

The minimum number of cortices that must be engaged by a screw in each major fragment with IM pin plate combo is?

3

13

Screws, size is named based on? the hole you drill for the screw is based on?

Outer diameter
Inner diameter

14

What is an interfragmentary screw?

Holds things together while you place the plate on

15

In order for a fracture repair to be stabilised adequately by a non locking plate screws going through the plate must engage how many cortices per majore fragment?

6

16

How can you still drill a screw across a fracture line in a neutral fashion?

Squeeze them together with a clamp or they will push apart

17

How can you still drill a screw across a fracture line in a neutral fashion?

Squeeze them together with a clamp or they will push apart

18

Describe what is meant by lagging a screw?

near cortex is overdrill and far cortex is normally drilled
Screw is tightened and it sucks them together

19

What is screw pitch?

Distance between threads

20

Variable pitch screws have what effect?

Behaves just like a lag screw

21

Bone plates are named by?

The size of the screws their holes can accomodate

22

3 forms of screw accommodation?

Locking
Round hole
Oval holes

23

3 forms of screw accommodation?

Locking
Round hole
Oval holes

24

Describe neutralization plate

Holds the fracture fragments in close formation so some axial forces can be borne

25

Describe a compression plate

fragments are actually squeezed together

26

Describe a tension band?

If plate is there to counter mostly tensile forces

27

What is a buttress plate?

weightbering for almost all of the forces

28

Number of cortices that need to be engaged for a non locking plate in each main fragment?

6

29

Plates bend far mor easily when they are? Meaning you should do what?

Compressed
If putting them on a bending bone or bone where bending is a concern put them on the side that will stretch

30

3 fractures that are good to plate?

Diaphyseal fractures that take long to heal
proximal areashard to use ESF on
Animals that wont return

31

Fractures that are not good to plate

short proximal or distal fragments
involving growth plates