Random Flashcards
Clinical Assessement for fracture assessment score
Mechanical fracture assessment
Biological fracture assessment scoring
Primary objective of fracture management
Promote an early &
complete return to
function
alignment vs. reduction
a= spacial arrange of joint above and below the fracture
reduction= process of re-
apposing the fracture
fragments &/or
segments
The combination of the fixation device and the fracture segments is called
osteosynthesis
Steps of secondary bone healing
Endochondral Ossification:
inflammatory phase- hematoma
granulation tissue
fibrous tissue
fibrocartilage
cartilage
woven bone
lamellar bone
Requirements for primary bone healing
rigid fixation & anatomic reduction
What two types of healing occur w/ primary bone healing?
contact healing
gap healing <1mm gaps
When should a callus be present?
2-4wks
What are the 4 main fxns of bone grafts?
osteogenic (fresh autogenous graft)
osteoconduction (scaffold- for ingrowth of capillaries & mesenchymal cells)
osteoinduction (induces bone synthesis; BMP)
structural support (cortical grafts)
Harvest sites for cancellous bone graft?
Greater tubercle of the humerus • Iliac crest • Proximal tibia
Biological vs. mechanical fixation
The underlying concept is protection of the surrounding soft tissues and blood supply to the fracture fragments. This is achieved by spanning the fracture with implants which do not substantially disrupt the fracture site. This is often referred as bridging osteosynthesis. In all fracture repairs there must be a balance between the biology and the mechanics of the repair. An excess of either may result in nonunion and or loss of function.
When do you pad the protuberances vs. the depressions?
Rigid pre-formed
splints: pad
depression
Malleable splints:
pad protuberances
With a rigid lateral splint, what do you pad extra?
depressions
What does the figure 8 sling do for coxofemoral luxations?
abducts
flexes
internally rotates
What forces does ESF overcome?
axial (compression)
bending
rotational
What are the three types of external fixators?
Which of the ESF is the strongest? Weakest?
III > II > I
What should the core diameter of the pilot hole for ESF pins be compared to the pin’s diameter?
0.1mm less than actual pin diameter
What are the fixation pins locations for the various bones?
what speed & torque should be used when placing fixation pins for ESF?
slow speed
high torque drill
Fixation pin diameter should not exceed % of diameter of bone
30%
With application of ESF, how many pins should be placed in each fracture segment?
3-4 pins
What forces are intramedullary fixation devices resistant to? Which ones are they not?
bending
little resistance to shear forces
not compression, tensile, or torsional
What force does using an interlocking nail in IM fixation prevent against?
axial collapse
What type of fracture is sole use of IM pins not enough?
comminuted fractures
When is it common to use rush pins?
young animals w/ salter harris fractures
If you use interlocking nails w/ the IM pin, what forces can be overcome?
bending
rotational
axial
How can an IM pin be inserted in the humerus? What is the direction the pin should take?
retrograde
cranio-lateral to caudo-medial (avoid olecranon fossa)
expected time for union
3-6 months old: ~ 4-6 weeks
> 1 year old: ~ 12 weeks
normal fracture healing requires &
vascularity
stability
What are the classifications of non-unions?
Tx for non-unions
Requirements for osteomyelitis to occur?
bacterial contamination & vascular compromise
Rad findings for osteomyelitis
Soft tissue swelling • Irregular periosteal
reaction far from fracture • lysis/bone resorption
What three structures are shown here?
Sequestrum: necrotic bone
fragment
• Involucrum: periosteal
reaction surrounding the
sequestrum
• Cloaca: opening in
involucrum, resulting in
drainage
TX for osteomyelitis
Causes of quadriceps contracture
prolonged immobilization
quadriceps m. trauma
For the different implants, what fracture forces are neutralized?
What is the requirement of the fracture to use cerclage wires?
oblique
2-21/2 length the diameter of bone
Rules about applying cerclage wires
• Wires should be
1 cm apart
•The wire must be
placed 5 mm from
the end of the
fracture segments
3+ wires (never use just one)
twist vs. loop cerclage wires
10 commandments of cerclage wires
fxn of pin & tension band
Converts
distractive/tensile forces
to compressive
forces
