Nails, Pins, Wires Flashcards
Orthopedic wire
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)
Applications for orthopedic wire
Cerclage wire
Tension band
Interfragmentary wire
Ligament substitution
Cerclage wire
Wire placed circumferentially around bone column —> compression across fracture line
Either spooled or pre made eyed wire
Never used alone!!
Rules for use of Cerclage wire
- Only on long oblique or spiral fractures
- Place at least 2 Cerclage wires to stabilize
- Place at least 0.5 cm from fracture ends; 0.5-1.0x bone diameter apart
- Wire perpendicular to bone
- Cut wire leaving 2-3 twists of 5-10mm arm
Tension band wire
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
Placement of tension band wire
- Reduce fragment + drive 2 K-wires across fracture (perpendicular to fragment; parallel to each other; penetrate both near + far cortex
- Drill hole through both bone vortices distal to fracture line to pass wire (wire passed equidistant across each side of fracture)
- Pass wire through hole and around ends of pin + back to other end of wire —> figure 8
- Twist to tighten
- Bend K-wire and cut (maintain 2-3 twists)
Interfragmentary wire
Placed like “sutures” holding bone fragments together
Indications: simple fractures of flat, non-weight bearing bones with good interdigitation (i.e., mandibular/maxillary fractures)
Steinmann pins
Aka intramedularry pins
316L stainless steel cylindrical rods
Vary in diameter, length, end, threading
Kirschner wires
Very small Steinmann pins —> easily bent (i.e. do not withstanding bending forces)
Varying diameters, lengths, threading
Trochar point
Applications of Steinmann pins
Intramedullary placement
Cross pinning
Diverging pins
Skewer pin
Tension band constructs
Pros and cons of Steinmann pins
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
Intramedullary pins
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
Intramedullary pin placement
*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
Cross pinning
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
Diverging pin technique
Indication: Salter Harris 1 fractures of proximal humerus/femoral head
Must achieve anatomical reduction, not cross far cortex (because joint)
AT LEAST 3 pins
Interlocking nail
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
