Internal fixation #1

Question 1

Big advantage of internal fixation is?

Answer 1

attached directly to bone and so provides more rigid stabilization than external coaptation

Question 2

Fractures for which internal fixation is better than than external coaptation (5)

Answer 2

open fracture
fractures of the femur humerus and pelvis
articular fractures
obliqueor comminuted fractures
fractures with tension

Question 3

intramedullary pins control what force well?

Answer 3

bending

Question 4

Are IM pins often used alone?

Answer 4

No

Question 5

4 advantages of IM pins

Answer 5

Availability
Axial alignment
Bending control
minimal blood supply disruption

Question 6

What is cyclic fatigue?

Answer 6

Think of how you break a paper clip

Question 7

4 disadvantages of IM pins

Answer 7

only control bending
anatomic repair required
Potential injury to surrounding structures
Not good in any flat or curvy bones

Question 8

Which bone should never ever ever ever be pinned?

Answer 8

Radius

Question 9

How does an IM pin cause potential injury to surrounding tissues?

Answer 9

Usually atleast one end is sticking out to some extent into the soft tissue

Question 10

2 ways to place an IM pin?

Answer 10

Normograde

Retrograde

Question 11

Describe normograde placement of an IM pin?

Answer 11

Line up fracture fragments and then run the pin down from one end to the other
tibial fractures

Question 12

Describe retrograde placement

Answer 12

Start by placing the pin the proximal fragment via the fracture site, put it all the way until just the tip is in the fracture site then reduce and alignt he fracture and push it down intot he distal fragment

Question 13

Advantage to retrograde placement?

Answer 13

Cant miss medullary cavity

Question 14

Disadvantages to retrograde placement?

Answer 14

Surgical approach at fracture site needed

In the tibia the proximal side of the pin will come out into a joint so it is not an option

Question 15

Disadvantages to retrograde placement?

Answer 15

Surgical approach at fracture site needed

In the tibia the proximal side of the pin will come out into a joint so it is not an option

Question 16

How big should the diameter of the pin be? What about when combined with a bone plate?

Answer 16

60%of the medullary canal

50% of medullary canal

Question 17

Should the IM pin penetrate the diatal fragment cortex?

Answer 17

NO there is invariable a joint there

Question 18

Cross pinning crosses what?

Answer 18

two cortices as well as the fracture line

Question 19

When is cross pinning approriate

Answer 19

Repairing physeal or very distal/proximal fractures

Question 20

What forces does cross pinning neutralize?

Answer 20

bending, torsion and compression

Question 21

When can wiring techniques be useful? (4)

Answer 21

Prevent propogation of fissures
reconstruct fragments to aid in reduction
hold things in place temporarily
Help an IM pin control torsional or compressive forces

Question 22

When should full cerclage be used?

Answer 22

Long oblique fractures

Question 23

What constitutes a long oblique fracture?

Answer 23

length of fracture is > than 2 times the diameter of the bone

Question 24

Why do we always place cerclage wires in groups of 2

Answer 24

because one acts a fulcrum to concentrate forces on the fracture line

Question 25

What is interfragmentary wiring

Answer 25

Placing wires between 2 fragments to connect them

Question 26

What are 3 wiring techniques

Answer 26

Full cerclage
interfragmentary wiring
tension band wiring

Question 27

Tension band wiring is done to counteract what forces/

Answer 27

Tension

Question 28

Describe tension band wirring?

Answer 28

2 small pins perpendicular tot he fracture line
a figure 8 of wire is then passed through a hole distal to the fracture and the apparatus is looped over those 2 pins and tightend to turn the bad tension into good tension

Question 29

What is an interlocking nail

Answer 29

Psecially designed rod that is fixed in place with bolts that pass through the rod itself and back through the cortex of the bone

Question 30

forces controlled by interlocking nails

Answer 30

bending
compression
torsion
aaaand prevents the nail from migrating like in IM pinning

Question 31

BIg advantage of interlocking nails?

Answer 31

Do not have to remove

Can fix comminuted fractures without anatomic reconstruction of the bone

Question 32

What is the limitation of an interlocking nail?

Answer 32

need a bone protrusion proximally or distally to avoid going therough a joint

Question 33

What is the limitation of an interlocking nail?

Answer 33

need a bone protrusion proximally or distally to avoid going therough a joint

Question 34

Advantage of pin plate combination?

Answer 34

Drop diameter of the pin also only the most distal and most proximal screws for the plate have to do both cortices the rest can do 1