Internal Fracture Fixation (2 of 4) Flashcards
What is orthopedic wire made of?
Stainless steel
What is the benefit of thicker wire (lower gauge)?
Increased tensile strength
What is orthopedic wire never used for?
The sole method of fx fixation
NOTE: Exception is some mandibular fractures
What 3 things is orthopedic wire typically used with?
IM pins
External skeletal fixators
Plates
What are 3 applications for orthopedic wire?
Cerclage wire (+/- skewer pins) Tension bands (avulsion fractures) Interfragmentary wire
What is cerclage wire?
Wire places circumferentially around the bone column to cause compression across the fracture line (oblique fx)
What are the 5 major rules for cerclage wire placement?
Only use on long oblique or spiral fx
Place at least 2 cerclage wires
Place 0.5cm from fx ends, spaced ~0.5-1x bone diameter apart
Place the wire perpendicular to the bone
Cut the wire leaving 2-3 twists or a 5-10mm arm
When considering cerclage for long oblique or spiral fx, what 2 conditions must exist?
Fracture line >2x bone diameter
Must be able to reconstruct the bone column (so it can bear weight)
Why should you not bend over the twist in the cerclage wire?
It loosens the wire
What situation would you use cerclage and skewer pins?
Short oblique fractures
How is a cerclage and skewer pin applied?
K-wire placed through fracture segments perpendicular to the fracture and cerclage wire is placed around the bone to hold pieces together
What is the purpose of a tension band wire?
To neutralize the pull of muscle/tendons on the fracture fragment
When is a tension band wire indicated?
Avulsion fractures and some osteotomies
What are 6 clinical applications for a tension band wire?
Acromion Olecranon Greater trochanter Patella Greater tuberosity Lateral malleolus
What are the general 4 steps to applying a tension band wire?
- Reduce the fragment and drive 2 K-wires across the fx
- Drill hole through both bone cortices distal to the fx line to pass orthopedic wire
- Pass wire through the hole and figure-eight around the ends of the pins and back to other end of wire
- Tighten wire via twist
What is an interfragmentary wire?
Used like sutures to hold bone fragments together
What is the indication for an interfragmentary wire?
Simple fx of flat, non-weight bearing bones that interdigitate well
What is the most common use for an interfragmentary wire?
Mandibular and maxillary fx
What are Steinmann pins often referred to as?
Intramedullary pins
What are Steinmann pins made of?
Stainless steel
What are Kirschner wires?
Small Steinmann pins
NOTE: Can be easily bent
What type of points can you find on a Steinmann pin?
Trochar vs. chisel
Smooth vs. threaded
What type of points can you find on a Kirschner wire?
Trochar point
Smooth vs. threaded
What are the 6 different Steinmann pin applications?
Intramedullary placement Cross pinning Rush pinning Diverging pins Skewer pin Tension band constructs
What are two types of intramedullary placement of Steinmann pins?
Single pin
Stack pinning
What is Cross pinning most commonly used for?
Salter-Harris fx
What are 3 advantages of Steinmann pins?
Less expensive than plates/screws
Smaller surgical approach with less surgical time
Easy to remove if necessary
What are 2 disadvantages of Steinmann pins?
Only resists bending (bone can still rotate and distract)
Pin migration
How do you place an Intramedullary pin?
In medullary cavity of bone
Why would you place an intramedullary pin?
To help restore length and maintain alignment
What is an IM pin almost never indicated as the sole form of fixation?
Because only resists bending forces, needs to be fortified with other fixation methods
What 6 bones can IM pins be used in?
Humerus Femur Tibia Ulna Metatarsals Metacarpals
What bone is an IM pin contraindicated for?
Radius because of the shape, you will end up passing the pin through the articular surface
What must IM pins NEVER do?
penetrate the joint surface
What are 2 methods of placing and IM pin?
Normograde
Retrograde
If you’re using an IM pin and cerclage, what diameter pin do you want?
70% canal fill
If you’re using an IN pin and a place, what diameter pin do you want?
35-40% canal fill
NOTE: This smaller diameter is because you don’t want the pin to be in the way of the screws
What is stack pinning?
Using 2 or more smaller diameter pins
What are 3 reasons stack pinning is not really practiced anymore?
No mechanical advantage
Higher incidence of migration
Increased damage to medullary blood supply
What is cross pinning?
Use of small diameter Steinmann pins or K-wiresto engage the near and far cotex
NOTE: Pins will cross above the fx line
When is cross pinning indicated?
Simple, transverse fractures that are close to the joint, especially Salter-Harris type 1 and 2 fxs
What is Rush pinning?
Uses 2 IM pins that are forced to curve and have 3 points of contact
When is Rush pinning indicated?
Some Salter-Harris fxsx and supracondylar fxs
What is a diverging pin technique used for?
To stabilize Salter-harris type 1 fxs of proximal humerus or femoral head
What must a diverging pin technique do?
Achieve anatomical reduction to promote normal physeal anatomy and bone growth
