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104 Cards in this Set
- Front
- Back
What is Kirby's rule of 20?
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a list of 20 parameters to evaluate daily in the critically ill animal.
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What are the 4 As of fracture repair?
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Alignment
Apposition Apparatus Activity |
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In fracture scoring, which is worse - low numbers or high numbers? What is the scale?
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0-3 = low = BAD
8-10 = high = GOOD |
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Low fracture scores are given to...
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...older dogs with non-reducible fractures and extensive soft tissue damage.
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High fracture scores are given to...
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...young dogs with good fracture load sharing.
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What are issues with epiphyseal fracture healing?
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cartilage does not heal
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What are issues with metaphyseal fracture healing?
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Not really any - good blood supply and softer bone.
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What are issues with diaphyseal fracture healing?
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Limited blood supply and very hard bone
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Strain greater than what value inhibits bone healing?
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>2% strain inhibits bone healing
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T or F:
With a properly apposed fracture under compression, there is no bone resorption at the fracture line. |
True!
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What are the advantages of compression in fracture repair?
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increases interfragmentary friction
neutralizes micromotion |
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What are the two types of primary bone healing? How are they different?
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Contact healing (gap <0.01mm, simultaneous healing and remodeling)
Gap healing (gap <1mm; gap fills with intramembranous bone then remodeled) |
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In secondary bone healing, how much strain do the following tissues tolerate?
Lamellar bone Membranous bone Fibrocartilage Granulation tissue |
Lamellar bone (2%)
Membranous bone (5%) Fibrocartilage (10%) Granulation tissue (100%) |
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What is the reaction of bone to movement?
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bone resorption
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What are the AO principles of fracture stabilization?
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1) Fracture reduction/fixation to restore normal anatomy
2) Stability/fixation as the fracture requires 3) preserve blood supply & gentle tissue handling 4) early and safe mobilization of the part and patient |
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Which implants counteract bending or angular forces?
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Plates
IM Pins Interlocking nails External fixation External copation |
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Which implants counteract rotational forces?
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Wires
Ex fix Plate and screw External copation |
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Which implants counteract shearing or compressive forces?
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Wires
Ex fix Plate and screw Interlocking nail |
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Force on body protuberances are known as...
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...distractions
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What are some indications for open reduction?
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Articular fracture
Simple displaced fractures Comminuted fractures (treated by segment alignment and allografts) |
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What are indications for closed fixation?
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Nondisplaced or incomplete fractures
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Which of the following is NOT a method of open fracture reduction?
a) tent pegging b) hanging leg traction c) instrument leverage d) pointed reduction forceps e) cornholing |
b) hanging leg traction
e) cornholing |
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What are the basic biomechanical principles that must be addressed in rigid fracture fixation? How many must be fulfilled?
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Interfragmentary compression
Rigid bone splinting (fulfill at least 1) |
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What are the two NEVERS associated with IM pin use?
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NEVER use IM pins alone!
NEVER use an IM pin on the radius |
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What are the two types of threaded Steinman pins? Which type is better?
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Negative profile (worse, prone to breakage)
Positive profile |
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How should a femoral head capital physeal fracture be fixed?
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Use 2-3 unthreaded Steinman pins, allowing fixation but continued growth
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What is a big fat NEVER DO THIS when fixing a fracture with pins?
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NEVER have pins cross at the fracture site
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An IM pin should fill ___________ % of the medullary canal diameter.
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60-70%
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What is the ONLY manner in which to pin the tibia?
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Normograde pinning
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What is the weakest point of cerclage wire?
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the knot
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What are the cerclage wire application rules?
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Place wire 0.5cm from fracture ends.
Place 1cm or a full bone diameter between wires. Place wire perpendicular to bone long axis Do NOT put wire in a fracture! |
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What are two ways to hold cerclage in place in conical bone?
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Notch the bone
Wrap around a place Kirchner wire |
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What are some rules for twisting cerclage wire?
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Pull and twist simultaneously
Equal tension on each loop arm Do not bend down after twisting (can bend down while twisting) Leave 3 wire wraps |
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T or F:
Cerclage should not be used in oblique fractures >2x the bone width. |
False!
This is when you use cerclage (with an IM pin, of course) |
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When is the pin and tension band technique of fixation used?
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With tuberosity/tendon and ligament attachment avulsion fractures.
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What are the 3 types of external fixators?
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Linear
Free-form Ring or Illizarov |
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What type of cerclage wire knot has the best strength?
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Double loop!!!
It's the devil knot... |
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What are the types of linear ex-fixes? Which is weakest? Strongest?
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Type 1a (uniplanar - weakest)
Type 1b (multiplanar) Type 2 (uniplanar) Type 3 (multiplanar - strongest) |
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The further away an implant is from a bone...
a) the higher the shear modulus b) the lower the shear modulus c) the higher the bending moment d) the lower the bending moment |
c) the higher the bending moment
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When placing an ex fix, what is the greatest number of pins that should be placed in a bone segment?
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no more than 4
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When placing an ex fix, how close can the pins be placed to the fracture ends? The joint?
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1/2 in (1cm) from each
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T or F:
Pins should be placed through both cortices and be no larger than 20-30% of the bone diameter. |
True!
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For pin insertion with ex fix you should use...
a) Jacob's Chuck b) Power drill c) Both are appropriate |
b) Power drill
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How far should the connecting bar be from the skin?
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1cm
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Where are safe tissue corridors in the humerus?
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Across the humeral condyles
Proximal-lateral aspect |
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Where on the femur is safe for tissue corridors?
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Only the lateral femur
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Where are safe tissue corridors for the radius for ex fix?
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Distal 2/3 of the medial aspect.
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T or F:
The cranial aspect of the tibia is the only safe route for an ex fix. |
False!
Cranial and medial are both safe! |
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What are important post-op considerations after placing external fixators?
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Pain meds!
Clean limb/pin sites w/antisceptic and triple abx Expect swelling; add padding under bar Bandage limb cage rest! |
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Choose the correct type of bone screw...
...greater pullout strength. |
cancellous
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Choose the correct type of bone screw...
...deep pitch and threads. |
cancellous
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Choose the correct type of bone screw...
...greater bending strength. |
cortical
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Choose the correct type of bone screw...
...shallow threads and pitch. |
cortical
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Screws MUST NOT be greater than ______% of bone diameter.
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40%
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Screws MUST NOT be placed any closer than _____ times the screws width from the fracture edge.
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2x
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Which of the following describe how should a lag screw be placed?
a) perpendicular to bone cortex b) parallel to fracture line c) through both cortices d) perpendicular to the fracture line |
c) through both cortices
d) perpendicular to the fracture line |
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Screws should not be placed in loaded position with which type of fracture?
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Oblique
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Removing part of the fixator to increase weight bearing is known as...
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...dynamization
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What are the 3 goals of plate and screw fixation?
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anatomical reduction
blood supply preservation stable internal fixation |
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What are the 4 functions of plates (or, the four manners in which they can be placed)? In which ones does the plate take the entire weight bearing load?
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Neutral
Bridging (wt bearing) Buttressing (weight bearing) Compressing |
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What are the rules to plate placement?
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Contour plate to bone surface
Screws engage near and far cortex AT LEAST 2 screws on either side of the fracture |
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Which side of the bone is the plate placed on and why?
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The tension band; this is because steel has more tensile strength than bone
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Where should plates be placed on the humerus? The femur?
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Humerus (cranial/lateral proximally and caudal/medial distal)
Femur (cranial and lateral) |
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Where should plates be placed on the tibia? The radius?
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Tibia (medial)
Radius (cranial and medial) |
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Which plate type improves blood flow?
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Limited contact DCP
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T or F:
When placing a threaded plate, the screws must be placed perpendicular to the plate. |
Dumb question.
Just know that threaded plates can accept screws with threaded heads (must be placed perpendicular) as well as normal screws (can be placed at an angle). |
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How large should the intermedullary nail be in an interlocking nail fixation?
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70-80% of medullary cavity
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What are the general pre-surgical steps before fracture repair?
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Stabilize patient
Neuro exam Treat soft tissue injuries first Imaging Place a splint |
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Why perform a neurological exam before surgery?
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Figure out if nerve issues exist before surgery
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How should fractures be stabilized prior to surgery?
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Splint or Robert-Jones Bandage
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How should the humerus be splinted? The femur?
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Humerus - Spika Splint
Femur - DO NOT SPLINT |
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What are factors impacting the clinical fracture assessment score?
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Client/patient compliance
Pain level Comfort level |
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What are some factors impacting the biologic fracture assessment score?
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Age
Health Bone type Injury type Approach type Soft tissue envelope (blood supply) |
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Post op fracture repair care should always include...
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E collar
Pain meds (10-14d) STRICT rest |
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What does pain at the site of a healed fracture indicate?
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Its probably really not healed...
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T or F:
Bone heals to 100% of its original strength |
True dat beeeeeeyooooooooochh
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When should bone allograft be used?
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Any fx w/open reduction, internal fixation
Dogs >5y Small/toy breeds Osteomyelitis Delayed/non-unions |
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What are indications for taping the muzzle in mandibular fracture repair?
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TMJ luxation
Vertical ramus fracture Minimally displaced, stable fracture Additional support for other fixes |
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Mandibular wiring should be used with...
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...symphyseal separations
...interfragmentary wiring |
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T or F:
Acrylic external stabilization can be used for any mandibular fracture type. |
True!
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When placing wires or pins in the mandible, what should be avoided?
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Salivary caruncle
Tooth roots Mandibular canal |
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What should be added to post-op care for mandibular fracture repair surgery in dogs? Cats?
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Dogs (canned food/gruel; flush w/dilute chlorhex)
Cat (probably feed tube; flush mouth w/saline) |
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Scapular fracture is commonly also associated with...
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...thoracic trauma (70% concurrence)
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How should a humeral IM pin be placed?
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NORMOGRADE!!!
Start pin lateral to greater tuberosity aim caudal and medial to seat pin in medial epicondylar area |
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T or F:
The medial humeral condyle is more frequently fractured than the lateral. |
False.
Lateral is smaller and more weight bearing and, thus, more prone to fracture |
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Which type of humeral fracture is like being dealt a big poop sandwich?
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Dicondylar fractures (Y or T) configuration
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When should you cast a radial fracture in a small dog?
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NEVER! It will cause a nonunion!
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T or F:
Fractures of the ulna don't need to be repaired in small to medium breed dogs. |
False!
There are special ulnar fractures requiring repair (styloid avulsion, semilunar notch fracture, olecranon fracture) |
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The most common cause of pelvic fracture is...
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...vehicular trauma
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T or F:
Most patients with pelvic fractures are in shock. |
True! 93%
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T or F:
Most patients with pelvic fractures have urinary tract ruptures. |
False! But 39% do so always suspect it...
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Which pelvic fractures must be repaired?
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Weight bearing axis bones (acetabulum, ileal body, SI joint)
Avulsed tuber ischii (racing dogs) Avulsed prepubic tendon |
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In SI luxation repair, how far across the sacrum should the lag screw be placed?
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At least 60%
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What is the shit sandwich in the pelvis when it comes to fracture repair?
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Acetabular fractures
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What radiographic view is helpful in diagnosing capital physeal fractures?
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Frogleg
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What anatomical feature can assist with femoral diaphyseal fracture alignment?
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Linea aspera (attachment of adductor magnus et brevus)
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What is a common complication/sequel to femoral fracture repair in puppies?
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Quadriceps fibrosis
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T or F:
The femur can be pinned normograde or retrograde |
Yup
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Where would an IM pin be placed in this tibia? How should you aim?
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Where the X is (between patellar ligament and MCL); aim slightly laterally
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When should retrograde IM pins be placed in the tibia?
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NEVER NEVER NEVER
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What are the weight bearing toes?
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3 and 4
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What are some antibiotics with good bone penetration?
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Clavamox
Enrofloxacin Clindamycin (mostly bacteriostatic) Chloramphenicol |
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T or F:
Infected bone will still heal as long as vascular supply and rigid stabilization are still present. |
True!
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T or F:
A nonunion will not heal without surgery. |
True
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