Exam 2 - Goh Material Flashcards
what is direct healing
intramembranous ossification
what is indirect healing?
what are the steps?
endochondral ossification
1. hematoma
2. fibrocartilaginous callus
3. bony callus
4. bone remodeling
what dictates the type of healing?
fracture gap width and stability
fracture gap strain formula
how much can lamellar bone have
change in gap width / original gap width
< 2% strain
which healing has a faster speed of bone healing?
indirect/secondary is faster
how can you reduce strain?
wider original fracture gap width
increase stability - bone callus diameter (because stabilizing influence is a factor of radius^4)
majority of fractures are non-reconstructable or reconstructable?
non-reconstructable
what initial stabilization do you use for an injury distal to the stifle or elbow?
robert jones bandage
what initial stabilization do you use for an injury proximal to the stifle or elbow?
crate rest
analgesia
nursing support
what injuries are good for a cast?
transverse fractures
fracture with internal support - metacarpals or paired bones
partial fractures
what forces are cast good for
bending
rotation
when can you use a cast relative to joints
fractures below the elbow or stifle
must immobilize the joint above and below the fracture
what can you add to a cast to prevent digits from contacting the ground with fractures distal to carpus or tarsus
walking bars
what is unique about toy breeds
poor blood supply to distal radius and ulna
slow bone healing
avoid coaptation
when can you use a splint instead of a cast
soft tissue injury - strain or sprain
what are half pins?
end threaded
dont go through both sides of bone
what are full pins?
centrally threaded
go through both sides of bone
pros of an ESF
affordable, reusable
closed, minimally invasive
improved access to wound
can adjust stability for phases of healing
minor procedure to remove
cons of an ESF
pins can cause soft tissue irritation or infection
not good for all bones or patients
eccentric position of connecting bar is weak
weekly post op care
what forces does an ESF combat
all forces
indications for ESF
ALD correction
limb lengthening
tib/fib & radius/ulna
mandible
birds
open fx
list ESF configurations
unilateral
bilateral (must have > 1 full pin)
uniplanar
biplanar
other ESF classifications
linear
circular
hybrid (both)
freeform (acrylic)
describe staged disassembly of ESF
Frame gradually dismantled to allow increased loading by the healing fracture
Remove pins causing morbidity
Downgrade frame configuration
pros of IM pin + cerclage wire
affordable
somewhat simple
cons on IM pin + cerclage wire
limited fx scenarios
required rapid healing
limited stability
prone to complications
what fractures can you use an IM pin + wire
long oblique
oblique butterfly
long spiral
for an IM pin + wire the fracture line length must be at least _____
2x the diameter of the bone
can you use an IM pin and wire on a comminuted fx?
NO requires complete/perfect reconstruction
what spacing is required for cerclage wire
at least 2 wires
spaced 1/2 bone diameter apart
differentiate between an ILN and IM pin
ILN - IM pin + bolts that lock into the IM pin
an IM pin should fill what % of the canal
60-70%
do tight or loose cerclage wire impede blood supply
loose wires devascularize & disrupt callus formation
pros of bone plate + screws
suitable for reconstruction or bridging
highly stable/durable
early return to limb use
low post-op maintenance
cons of bone plate + screws
expensive
extensive inventory
challenging
compression plating technique
ideal load sharing
reconstructable
simple transverse fx
dynamic compression plates (DCP)
how do dynamic compression plates work
tighten eccentrically placed screw
slides plate along bone = compressing the fx
neutralization plating technique
partial load sharing
reconstructable
butterfly fx
doesn’t compress or distract, just holds everything in place
buttress/bridge plating technique
non-load sharing
non-reconstructable
comminuted fx
plate prevents collapse of fx
all weight-bearing forces are transmitted through plate/screws
how does a lag screw work
compress fragments (interfragmentary compression)
screw threads don’t engage side of bone closest to head
what forces do bone plates + screws combat
all - bending, rotation, compression, tension
what are unique features about a locking screw/plate system
rigid link
fixed screw angle
bone plate functions as an internal fixator
delayed union and non-union treatment
prevention
delayed union and non-union prognosis is based on
neuro exam
muscle contracture
types of malunions
varus
valgus
procurvatum
recurvatum
pronation
supination
bone shortening
torsional
malunion prognosis
procurvatum/recurvatum well tolerated
varus better than vargus
torsional NOT well tolerated
short hind limb better than forelimb
