A2: Fracture repair and implants

Question 1

Which fractures are suitable for cage rest?

Answer 1

Cancellous, non load-bearing bones which are minimally displaced e.g. pelvis, mandible, spine, scapula

Question 2

What is external co-aptation?

Answer 2

Splint, bandage, cast etc

Question 3

Which fractures are suitable for external coaptation?

Answer 3

Below elbow or stifle, young, minimal displacement, stable fracture, only one bone if a two-bone area

Question 4

When are IM pins usually used?

Answer 4

Auxiliary - not alone

Question 5

How much do IM pins cost?

Answer 5

Cheap

Question 6

What are two methods of inserting IM pins?

Answer 6

Normograde or retrograde

Question 7

Which method of IM pin insertion is preferred?

Answer 7

Normograde, as disturbs fracture site less

Question 8

How much stability does an IM pin provide?

Answer 8

Not much - minimal torsion or axial support

Question 9

When is IM pin contra-indicated?

Answer 9

In radius, as no entry point that doesn’t damage the joint

Question 10

What three methods do you usually use IM pins in combination with?

Answer 10

With a unilateral ESF, or along with a bone plate, or along with an interlocking nail

Question 11

How can you tell how far you have inserted a pin?

Answer 11

Compare another pin of the same size to the outside

Question 12

What’s the advantage of using an interlocking nail?

Answer 12

Prevents rotation and axial collapse (better torsional and axial stability)

Question 13

What’s another name for an IM pin below 2mm?

Answer 13

K wire

Question 14

What is a long oblique fracture?

Answer 14

fracture 2.5x diameter of bone

Question 15

When applying cerclage wire to a long oblique fracture, how many cerclages should you apply?

Answer 15

2

Question 16

What is the principle of the tension band wire?

Answer 16

Active distracting forces are counteracted and converted into compressive forces

Question 17

What can bone screws be combined with?

Answer 17

Plate, interlocking nail, ESF or IM pin

Question 18

Which bone type can you use plates on?

Answer 18

Cancellous

Question 19

When should you never use bone screws in isolation?

Answer 19

Diaphyseal fractures

Question 20

What is the pitch of a screw?

Answer 20

The angle of the threads

Question 21

Where can you use cortical screws?

Answer 21

Diaphyseal bone

Question 22

What does a cortical screw look like?

Answer 22

Fully threaded, shallow threads, flat pitch

Question 23

Why are cortical screws strong?

Answer 23

Wide core diameter

Question 24

Where can you use cancellous screws?

Answer 24

Epiphyseal or metaphyseal fracture

Question 25

What do cancellous screws look like?

Answer 25

Partially or fully threaded, fewer threads per unit length, deep threads

Question 26

Why are cancellous screws weak?

Answer 26

Narrow core diameter

Question 27

When do you use locking screws?

Answer 27

With locking plates

Question 28

What does a locking screws look like?

Answer 28

Threaded head, narrowest pitch

Question 29

What do lag screws do?

Answer 29

Join and compress two pieces of bone e.g. in articular fractures

Question 30

What are three functions bone plates can perform?

Answer 30

Compression, neutralisation, bridging

Question 31

Which plate can perform which function?

Answer 31

Any can do any

Question 32

Which fractures would you put a compressive plate on?

Answer 32

Transverse, short oblique below 45 degrees, or osteotomies

Question 33

What are three advantages gained by using a compressive plate?

Answer 33

Friction increases stability, primary bone healing, load sharing between bone and implant

Question 34

How do plates compress?

Answer 34

By closing fracture gap as screws are tightened

Question 35

Which is the tension side of the femur?

Answer 35

Lateral

Question 36

Which is the tension side of the tibia?

Answer 36

Cranial or medial

Question 37

Which is the tension side of the humerus?

Answer 37

Cranial or lateral

Question 38

Which is the tension side of the radius

Answer 38

Craniomedial or cranial

Question 39

Which force side do you apply the plate to?

Answer 39

The tension side to convert this into compression (dynamic compression)

Question 40

What is neutralisation?

Answer 40

Reconstructing a bone to anatomical shape by lag screws or wire

Question 41

What is "bridging"?

Answer 41

Joining up the fragments of an unreconstructable fracture

Question 42

Which forces can IM pins withstand?

Answer 42

Bending a little

Question 43

Which forces can an IN nail withstand?

Answer 43

All, mainly torsion and compression

Question 44

Which forces can ESF withstand?

Answer 44

All, mainly bending

Question 45

Which forces can plate withstand?

Answer 45

All, but bending least

Question 46

What is a DCP?

Answer 46

Dynamic compression plate

Question 47

What kind of compression can you do with a DCP?

Answer 47

Static

Question 48

What is an LCP?

Answer 48

Locking compression plate

Question 49

What do you use an LCP with standard screws for?

Answer 49

Interfragmental or axial compression

Question 50

What do you use an LCP with locking screws for?

Answer 50

stable plate-screw connection without loss of | reduction, regardless of plate modelling

Question 51

What do you use reconstruction plates for?

Answer 51

To contour in three planes e.g. pelvic or mandibular fracture

Question 52

What's the disadvantage of reconstruction plates?

Answer 52

Weak

Question 53

What are veterinary cuttable plates for?

Answer 53

Long bones of cats, MTs, MCs

Question 54

What are cuttable plates NOT for?

Answer 54

Compression of fracture