IM pin

Question 1

Other name for IM pin?

Answer 1

Steinman pin, even K-wires can be used

Question 2

can it be used alone?

Answer 2

NO

Question 3

Which bones can we place an IM pin?

Answer 3

Humerus
Ulna
Femur
Tibia
Metacarpal
Metatarsal

Question 4

What force does IM pin counteract?

Answer 4

Bending - very resistant!

Question 5

Appropriate pin size?

Answer 5

60-70% of diameter of the intramedullary canal at the narrowest point
30% if combined with plate

• always start with smaller diameter

Question 6

What increases the IM pins resistance to bending?

Answer 6

increase in diameter

Question 7

What increases the stiffness of the IM pin?

Answer 7

shorter pin

Question 8

How is the surface of the IM pin?

Answer 8

can be smooth, threaded or partially threaded

Smooth is strongest

Question 9

IM placement in the femur?
Direction?

Answer 9

Normograde (retro ok)
Trochanteric fossa

Retrograde - risk of sciatic nerve injury

Question 10

IM placement in the humerus?

Answer 10

Normograde
Lateral slope of ridge of greater tubercle

Retrograde ok

Question 11

IM placement of the Ulna?

Answer 11

Retrograde

Normograde difficult

Question 12

IM placement in the TIbia?

Answer 12

Normograde
From medial side of proximal tibia between tibial tuberosity and medial collateral ligament

Question 13

IM pin placement metacarpal/metatarsal?

Answer 13

Retrograde
K-wires, Steinman, rush pins

Question 14

What can decrease risk of pin migration?

Answer 14

avoiding opening distal cortex

Question 15

Why must you leave 5mm of the pin when cutting?

Answer 15

reduce risk of seroma
reduces damage to nearby structures
reduces post-op pain
keeps pin more stable

Question 16

Cross pinning - indication?

Answer 16

Simple Salter Harris fractures or metaphyseal fractures

Question 17

How can you increase stability by cross pinning?

Answer 17

• do not cross at fracture site
• pins gaining purchase by penetrating transcortex
• rush pinning