Test 1: ex fix Flashcards
why use ex fix
easy to remove implants
can alter stability throughout healing process (start with a bunch of clamps very strong, then decrease as healing starts)
wound management/ open fracture
placed without a large incision
parts of an ex fix
transfixation pin (goes through bone)
external connector bar
linkage devices (clamps)
when to use smooth transfixation pin
young animals and simple fractures
exotics with small bones
cheaper but can loosen
negative profile transfixation pin
thread is smaller then shaft diameter= weak point
positive profile transfixation pins
thread bigger then shaft diameter
more expensive and can break cortical bone if inserted inproperly
half vs full pins
half= go through both layers of bone but only attached to one bar
full= go through both layers of bone and attached at two sides
what are connecting bars made of?
carbon fiber= light and less expensive
can be made of stainless steel, aluminum and graphite
what can you use instead of connecting bar
acrylic or PMMA
can be placed in weird positions and for very small fractures
type 1A- unilateral-uniplanar
single clamp
Type 1A- unilateral-uniplanar
2 connection bars, stiffer but uncommon to use
Type 1A- unilateral-uniplanar
double clamp
easier to place
very weak
not- commonly used
type 1B: unilateral-biplanar
2 type IA configurations
at a 90 °angle to each other
Very strong in cranial- caudal bending
type 2 bilateral- uniplanar
type 3 bilateral-biplanar
Type II and IA (montage)
Interconnected for strength
Stiffest configuration
tie in configuration
IM pin placed
Commonly used in the humerus and femur where large musculature and interference with thorax/abdomen prevent Types II and III
surgical placement of ex fix
leg hanging- helps align/ reduce
can use closed, open or mini approach
try to decrease soft tissue and blood supply damage
pins should not exceed — % of bone diameter
20
connection bar should be placed — from the skin
0.5cm allows for swelling
ex fix complications
pin lossening
infections
pin break
bone breaks at pin site
fracture nonunion
staged disassembly/ dynamization
slowly take apart exfix as bone starts to heal
increase load on bone vs exfix over time
Ilizarov
circular fixator
can lengthen bone by tightening bolts
circular fixator
K-wires under tension attached to ring
can be used to lengthen bone
hybrid fixator
combo of linear and ring fixator
used when distal fracture with a very small segment of bone or angular limb deformities
distraction osteogenesis
used for bone lengthening/ straightening
