Final Exam - Intro To Fractures Part II Flashcards
what are the 3 basic principles for fracture healing?
- fracture fixation & healing is a race
- most failures are caused by surgeon error
- goal is to assess healing potential in that patient and plan accordingly
what factors are evaluated when determining a patient’s fracture assessment score?
mechanical, biological, & clinical factors
for the fracture assessment score, from 1-10, what does a low score mean? high score?
low score - HIGH RISK, highly comminuted
high score - little risk, simple two piece fractures
what are some examples of mechanical factors in FAS?
fracture configuration, breed (size)/BCS, activity, direct vs. indirect reduction, health of remaining limbs
what are some examples of biologic factors in FAS?
patient age, open vs. closed fractures, amount & health of supporting soft tissues, location of the bone, open vs. closed approach, & concurrent diseases
blood supply of healing bone depends on what?
surrounding soft tissue
what are some examples of primary bone healing?
contact & gap
what is an example of indirect bone healing?
callus formation
what is the difference between contact healing & gap healing?
gap healing can have a gap up to 1mm
contact is 0.01mm
T/F: direct bone healing only occurs with absolute stability
true
T/F: indirect bone healing occurs with relative stability
true
what is anatomical direct reduction?
all fracture fragments are put back into their original position - bone shares load with the implants
what is anatomical alignment (indirect reduction)?
re-establishing the original axis of the bone
the implant must be strong enough to support the entire load until the fracture heals
what is the reduction type shown here?
anatomical alignment - indirect reduction
how is direct reduction of fracture fragments performed?
fracture site is exposed
instruments are used to directly manipulate fracture fragments
reduction achieved is directly visible
how is indirect reduction performed?
fracture site is not exposed
reduction is achieved by applying forces at a distance from the fracture
reduction is checked using imaging
of the fractures shown here, which are amenable to direct reduction?
3rd from the left & the last 3
which of the following is correct regarding the fracture pictured?
a. it should be directly reduced
b. it should be indirectly reduced
c. it will heal by direct bone healing
d. the blood supply remains intact
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when considering tissue tolerance to deformation, how do granulation tissue, cartilaginous/fibrous tissue, & bone resist changes?
granulation tissue - 100%
cartilage & fibrous tissue - 10%
bone - 2%
what does direct fracture reduction require?
rigid stability
what can happen if you use flexible fixation with a small fracture gap?
may lead to delayed or non-union of bone
when is direct fracture reduction typically indicated?
in fractures with 2-3 large segments
when is indirect reduction typically indicated?
non-reconstructable fractures or when direct reduction leads to excessive interfragmentary strain
what support does an intramedullary pin provide?
excellent bending support, poor axial support, & poor rotational support
what support does cerclage wire provide?
good axial support, good rotational support, & poor bending support
what is the mechanism of support provided by cerclage wire?
compression
when is cerclage wire properly used?
used for stabilization (compression) only with direct reduction of fracture
what does full cerclage wire mean?
wire completely encircles the bone
what does hemi-cerclage mean?
wire penetrates bone through a pre-drilled hole
what type of cerclage wire is shown here?
hemi-cerclage
how does cerclage wire work?
wire squeezes fracture fragments together & interdigitation prevents rotation & collapse
what is necessary to use along with cerclage wire?
IM pin used to resist bending
what are the guidelines for using full cerclage wire?
- 2-3 piece, long oblique fractures, 2 time the bone diameter (y should be at least 2 times x)
- direct reduction & full reconstruction of the fracture required
- elevate periosteum & soft tissues only where you are placing the wire
T/F: cerclage wire can be used with some indirect reduction
false - it should never be used with indirect reduction
what kind of support does an external fixator provide?
excellent axial support, good to excellent bending & rotational support
what are the advantages of using external skeletal fixators?
nice for type 2 & 3 open fractures
can manage wound around implants
implants are easily removed after the wound heals
femur & humerus ESF
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what kind of support is provided by bone plates & screws?
excellent bending & axial support, good rotational support
in some cases, the shape of a bone plate hole allows for what?
compression of fracture in some cases
what are some of the functions of a dynamic compression plate?
compression, neutralization, bridging
when is compression plating used? what are the benefits of its use?
transverse fractures
provides rigid stability & allows the bone to share the load with plate
when is neutralization plating used? what are the benefits of its use?
when the fracture is anatomically reconstructed
plate protects the repair from weight-bearing forces & the plate shares the load with bone
what kind of bone plate is shown here?
compression plating
what kind of bone plate is shown here?
neutralization plating
what kind of bone plating is shown here?
bridge plating
what are the benefits of using bridge plating with bone plates?
implant takes the entire load, must be much stronger, limb length & alignment is key, & emphasis is placed on implant selection & respect for soft tissues
what method of fracture fixation is shown here?
bone plate-pin (rod)
what is the purpose of using bone plate-pin as a fracture fixation method?
IM pin is very strong in bending forces - protects the plate from breaking where there is no bone to support it
pin makes it trickier to apply screws - but not all screws have to penetrate both cortices of the bone
why use a lag screw for fixing a fracture?
creates compression between fragments & can be used when the screw crosses a fracture line
inserted perpendicular to the fracture line to maximize compression
what kind of support does a interlocking nail provide?
excellent bending & axial support, good rotational support
screws go through the holes inside the large IM pin
what is a critical size defect?
roughly double the diameter of the bone at the level of the defect
what is the rule of thumb when assessing a critical size defect?
50% cortical contact in 2 planes
why must a critical size defect be considered in fracture fixation?
bone must be in relatively close proximity to heal
