Screws and bone plates

Question 1

What is the principle behind bone plate weightbering

Answer 1

increases friction between the bone and the plate

Question 2

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

Answer 2

Plate

Question 3

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

Answer 3

No not as much cause friction comes from screws

Question 4

Downside to screwplacement with locking plates?

Answer 4

Screws cannot be placed at an angle

Question 5

What forces are neutralized by plates?

Answer 5

All forces

Question 6

By themselves screws mostly control?

Answer 6

Torsion, compression, and tension

Question 7

When do we often use screws?

Answer 7

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

Question 8

3 advantages to plate fixation?

Answer 8

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

Question 9

3 disadvantages to plate fixation

Answer 9

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

Question 10

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

Answer 10

Make reduction for plate placement almost done

Question 11

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

Answer 11

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

Question 12

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

Answer 12

3

Question 13

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

Answer 13

Outer diameter

Inner diameter

Question 14

What is an interfragmentary screw?

Answer 14

Holds things together while you place the plate on

Question 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?

Answer 15

6

Question 16

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

Answer 16

Squeeze them together with a clamp or they will push apart

Question 17

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

Answer 17

Squeeze them together with a clamp or they will push apart

Question 18

Describe what is meant by lagging a screw?

Answer 18

near cortex is overdrill and far cortex is normally drilled

Screw is tightened and it sucks them together

Question 19

What is screw pitch?

Answer 19

Distance between threads

Question 20

Variable pitch screws have what effect?

Answer 20

Behaves just like a lag screw

Question 21

Bone plates are named by?

Answer 21

The size of the screws their holes can accomodate

Question 22

3 forms of screw accommodation?

Answer 22

Locking
Round hole
Oval holes

Question 23

3 forms of screw accommodation?

Answer 23

Locking
Round hole
Oval holes

Question 24

Describe neutralization plate

Answer 24

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

Question 25

Describe a compression plate

Answer 25

fragments are actually squeezed together

Question 26

Describe a tension band?

Answer 26

If plate is there to counter mostly tensile forces

Question 27

What is a buttress plate?

Answer 27

weightbering for almost all of the forces

Question 28

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

Answer 28

6

Question 29

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

Answer 29

Compressed

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

Question 30

3 fractures that are good to plate?

Answer 30

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

Question 31

Fractures that are not good to plate

Answer 31

short proximal or distal fragments

involving growth plates