Long Bone Fractures 1 Flashcards
When must horses be ambulatory and fully weight-bearing post-internal plating of a bone fracture for a more favorable prognosis?
Immediately
How is prognosis affected by articular involvement?
Decreases
Where does a lateral condylar fracture of MC3 usually originate and which direction does it propagate?
Distal end, propagates abaxially up the bone
What radiographic view is required to evaluate joint involvement of a lateral condylar MC3 fractures
Tangential view
Which aspect of the bone does a tangential view highlight and what can it show you?
Palmar aspect highlights comminution at joint surface
What % of condylar fractures in young racehorses are lateral?
85%
Is MC3 or MT3 more commonly fractured in thoroughbreds?
MC3 2x more common than MT3
Is MC3 or MT3 more commonly fractured in standardbreds?
They’re about equal
What contributes to a cannon bone condylar fracture?
High compressive load = osseous sclerosis
Microtrauma = microfracture
History of lameness w/acute exacerbation
Non-displaced incomplete fracture
Acute onset of severe lameness after intense exercise, effusion, pain of fetlock
Acute displaced fracture
What first aid measurements can you do for a cannon bone condylar fracture?
Compression bandage, NSAIDs, absolute stall rest til sx
How big are the lag screws used to stabilize a cannon bone condylar fracture, how many are used, and how far apart are they placed?
Two 4.5mm/5.5mm screws placed 20mm apart
Why is the first screw placed close to the joint?
Align joint surface first
What is the px for repair of a non-displaced/incomplete cannon bone condylar fracture?
Favorable (70-80%)
What is the px for repair of a displaced cannon bone condylar fracture?
50%
What is the most common long bone fracture in horses?
Cannon bone diaphyseal fracture
What does the px of a diaphyseal cannon bone fracture depend on?
First aid
How do you surgically repair a diaphyseal cannon bone fracture?
Double plate fixation on tension side of bone
How do you repair a comminuted diaphyseal cannon bone fracture?
Transform the fracture into 2 segments
What is the max amount of fracture compression you can do for a comminuted diaphyseal cannon bone fracture?
4mm (2mm on either side of fracture)
Continuity of bending stiffness and improved blood supply under this plate
Limited contact - dynamic compression plate (LC-DCP)
A 5.5mm one of this kind of plate has been specifically designed for equine fracture repair
Locking compression plate (LCP)
What are functions of a plate?
Compression, neutralization
What plate technique is used to bridge area of bone defect, but unlikely to work if used in horses?
Buttressing
Transforms tensile forces into compressive forces
Tension band
Adaptable plate for different fixation needs, grooved undersurface, uniform stiffness
LC-DCP
How do locking screws have to be placed to work correctly?
Orthogonally
What plate has combi-holes to permit conventional or locking screw placement?
LCP
Which screws increase stability and the fixation strength of the plate screw construct?
Locking screws
Where do the triceps muscles insert?
Olecranon
What is the most common cause of ulnar fractures?
Direct trauma
How will a fractured ulna present?
Dropped elbow w/carpus flexion
How do you splint an ulnar fracture and why?
Fix carpus in extension to maintain stay apparatus
Which side of the limb do you place a splint on for an ulnar fracture?
Palmar
What is the treatment of choice for an olecranon fracture?
ORIF
Bone plate contoured to fit over the top of the oleranon tuberosity
ORIF
Why should your ORIF repair not engage the radius in young animals?
Could risk damage and subluxation of elbow
How can you repair a SH type 1 fracture of the olectranon in a <250kg patient? >250kg?
<250kg = tension band (screws and wires) >250kg = must apply plate
What is the px for an ulnar fracture repaired with ORIF?
Good (68-87%)
