Nails, Pins, Wires

Question 1

Orthopedic wire

Answer 1

316L stainless steel

Thicker wire ~ increased tensile strength ~ lower gauge

Should never be used as the sole method of fracture fixation (except some mandibular fractures, flat bone)

Question 2

Applications for orthopedic wire

Answer 2

Cerclage wire
Tension band
Interfragmentary wire
Ligament substitution

Question 3

Cerclage wire

Answer 3

Wire placed circumferentially around bone column —> compression across fracture line

Either spooled or pre made eyed wire

Never used alone!!

Question 4

Rules for use of Cerclage wire

Answer 4

1. Only on long oblique or spiral fractures
2. Place at least 2 Cerclage wires to stabilize
3. Place at least 0.5 cm from fracture ends; 0.5-1.0x bone diameter apart
4. Wire perpendicular to bone
5. Cut wire leaving 2-3 twists of 5-10mm arm

Question 5

Tension band wire

Answer 5

Fixation used to neutralize pull of muscles/tendons on fracture fragment —> distractive forces of tendon/ligament converted to compressive forces

Indicated for avulsion fractures and some osteotomies

Question 6

Placement of tension band wire

Answer 6

1. Reduce fragment + drive 2 K-wires across fracture (perpendicular to fragment; parallel to each other; penetrate both near + far cortex
2. Drill hole through both bone vortices distal to fracture line to pass wire (wire passed equidistant across each side of fracture)
3. Pass wire through hole and around ends of pin + back to other end of wire —> figure 8
4. Twist to tighten
5. Bend K-wire and cut (maintain 2-3 twists)

Question 7

Interfragmentary wire

Answer 7

Placed like “sutures” holding bone fragments together

Indications: simple fractures of flat, non-weight bearing bones with good interdigitation (i.e., mandibular/maxillary fractures)

Question 8

Steinmann pins

Answer 8

Aka intramedularry pins

316L stainless steel cylindrical rods

Vary in diameter, length, end, threading

Question 9

Kirschner wires

Answer 9

Very small Steinmann pins —> easily bent (i.e. do not withstanding bending forces)

Varying diameters, lengths, threading

Trochar point

Question 10

Applications of Steinmann pins

Answer 10

Intramedullary placement
Cross pinning
Diverging pins
Skewer pin
Tension band constructs

Question 11

Pros and cons of Steinmann pins

Answer 11

Pros: less expensive than plates/screws, less inventory required, potential smaller surgical approach, potential shorter surgery, easy to remove if needed, ideal for fractures with less rigid fixation

Cons: only resist bending forces, pin migration; limited application as primary implant

Question 12

Intramedullary pins

Answer 12

Placed in medullary cavity of bone —> restore length / maintain alignment

Resist bending force only —> need fortification with other fixation methods

Indications: humerus, femur, tibia, ulna, metatarsals, metacarpals

Contraindicated in radius

Question 13

Intramedullary pin placement

Answer 13

*Must not penetrate joint surface

Normograde (proximal to distal) or retrograde placement (distal to proximal)

Pin diameter:
For pin as primary (with Cerclage) - 70% canal filled
Pin as secondary (with plate) - 35-40% canal filled

Question 14

Cross pinning

Answer 14

Small diameter Steinmann pins / wires across simple transverse fracture close to joint forming a cross

Engagement to far + near cortex is important
Ensure pins cross ABOVE fracture line

Question 15

Diverging pin technique

Answer 15

Indication: Salter Harris 1 fractures of proximal humerus/femoral head

Must achieve anatomical reduction, not cross far cortex (because joint)

AT LEAST 3 pins

Question 16

Interlocking nail

Answer 16

Internal fixation combing benefits of inter medullary pin + plate (counters bending, rotation, tension, compression)

Removable jig to guide placement

Treat diaphyseal comminuted fractures —> plate as sole bearer of forces

Contraindications - radial fracture