Long Bone Fractures I (Cannon Bone and Ulnar) Flashcards
What are the two most common locations of condylar fractures?
- Metacarpus 3
- Metatarsus 3
Do condylar fractures occur in the lateral condyle, medial condyle or both?
Both
What type of view is necessary to highlight the palmar aspect of bone and fully evaluate the joint?
Tangential view
If there is a comminution at the joint surface of a condylar feature, what should be done?
The fragment should be removed.
Condylar fractures are seen predominantly in what type of horses?
Young racehorses
Are the majority of condylar fractures lateral or medial?
What percentage?
- Lateral
- 85%
What do medial fractures tend to do?
Spiral up the leg.
Which are more common in TBs, MC3 or MT3 condylar fractures?
MC3
Which are more common in SBs, MC3 or MT3 condylar fractures?
Both are about equal.
What are 3 possible causes of condylar fractures?
- High compressive load
- Asynchronous longitudinal rotation of the cannon bone
- Young racehorses during fast work or race
A history of lameness with acute exacerbation can be seen with what type of condylar fracture?
Non-displaced incomplete condylar fractures
An acute onset of severe lameness after intense exercise can be seen with what type of condylar fracture?
Acute displaced condylar fracture
Effusion of the MCP/MTP joint can be seen with what type of condylar fracture?
Acute displaced condylar fracture
Can on palpation can be seen with what type of condylar fracture?
Acute displaced condylar fracture
What is the most common treatment used for the majority of condylar fractures?
Internal fixation with transcortical screws in lag fashion
What are 3 first aid components involved with a lateral condylar fracture of the cannon bone?
- Compression bandage
- NSAIDs
- Absolute stall rest until definitive tX is undertaken
What should be placed on patient with a fracture if trailering is necessary?
Kimzey splint
What type of alignment is important with condylar fracture repair?
What should there not be?
- Articular alignment
- No cartilage gap
What should be used during surgery in order to evaluate the reduction and alignment of the articular surface?
Arthroscope
Where should the first screw be placed with a condylar fracture?
What is a good target for this?
- Close to the joint
- Epicondylar fossa
What kind of screws should be used with lag screw repair?
4.5 or 5.5 mm cortical bone screws
Placing screws in a lag fashion across a fracture causes what?
Compression of the fragment together.
How far apart should lag screws be placed when used for condylar fracture repair?
20 mm apart
Most condylar fractures only require how many lag screws?
2 screws
What type of condylar fractures have a 70-80% favorable prognosis?
Non-displaced and incomplete
Prognosis for condylar fractures is not as good if what 2 conditions occur?
- Displaced
- Joint communication
What are the most common long bone fractures in horses?
Diaphysial fractures of MC3 and MT3
What does the prognosis depend on with diaphysial fractures of MC3 and MT3 in horses?
Dependent on immediate management of fracture - how fracture was treated in the field.
What type of compression is important with diaphysial fracture repair?
What is the goal of this?
- Inter-fragmentary compression
- Transform comminuted fracture into 2 fragments
How should be plates be placed for a diaphysial fracture of the cannon bone?
Why?
- Plates should be staggered
- Allows screws to intersect each other and not hit
What needs to be done to a diaphysial fracture before plates can be put on?
Fracture needs to be reduced.
What is the optimal treatment for a simple transverse fracture of the diaphysis of a cannon bone?
Double plate fixation
Which side of a bone is a plate usually placed on?
Tension side
What is a tool that can be used to compress a fracture with a broad DCP plate?
Load drill guide
What are 4 types of plates that can be used for fracture repair?
- Dynamic compression (DCP)
- Limited contact-dynamic compression (LC-DCP)
- Locking compression (LCP)
- Anatomic/specialty
What does DCP stand for?
Dynamic compression plate
What does LC-DCP stand for?
Limited contact-dynamic compression plate
What does LCP stand for?
Locking compression plate
What is a type of plate that has continuity of bending stiffness and improved blood supply under the plate?
Limited contact-dynamic compression plate (LC-DCP)
What are 4 types of plate functions?
- Compression
- Neutralization
- Tension band
- Buttressing
2 screws on either side of a fracture are placed under load with what type of plate function?
Compression
What type of functioning plate is placed after anatomic reconstruction with screws inserted in a neutral position?
Neutralization
What type of functioning plate transforms tensile forces into compressive forces?
Tension band
What type of functioning plate is placed to bridge the area of bone defect?
Buttressing
A self-compressing plate where screws can be angled in many directions and can be adapted to different internal fixation needs is what?
Dynamic compression plate (DCP)
Screws used in a dynamic compression plate (DCP) can be placed up to what angle?
25 degree angle
Does a dynamic compression plate (DCP) have uniforms bending stiffness?
No
What is a type of plate that is adaptable for different internal fixation needs with limited contact due to a grooved undersurface?
Limited contact-dynamic compression plate (LC-DCP)
What type of plate has uniform bending stiffness?
Limited contact-dynamic compression plate (LC-DCP)
Screws used in a limited contact-dynamic compression plate (LC-DCP) can be placed up to what angle?
40 degree angle
What type of plate provides dynamic compression with atraumatic and minimally invasive application and has limited contact with a grooved undersurface?
Locking compression plate (LCP)
“Combi Holes” found in locking compression plates (LCP) can permit what?
Permit combined use of conventional and locking screws.
Locking screws used with locking compression plates are what size?
Cortex screws are what size?
- 4.0/5.0 mm
- 4.5/5.5 mm
What type of plate can be placed using standard screws or locking screws?
Locking compression plates (LCP)
What do locking screws increase?
Stability and fixation strength of the plate/screw construct.
T/F: The goal for horses is to be ambulatory and fully weight-bearing in the immediate post-op period after plating for diaphysial fracture repair.
True
What is the major problem with using fixation devices in large animals?
Most fixation devices were not designed for horses so may have implant failure.
Since large plates occupy more space, this makes what more difficult?
Skin closure
Most fractures of the ulna involve which part?
Olecranon
What group of muscles inserts on the olecranon?
Triceps
What is a common etiology of ulnar fractures?
What are 2 examples of this?
- Direct trauma
- Kick, injury during halter training of weanlings
What is a common presentation of an olecranon ulnar fracture?
Dropped elbow with carpus in flexion
What are 4 differentials for a horse with a dropped elbow with the carpus held in flexion?
- Humeral fracture
- Radial nerve paralysis
- Olecranon fracture
- Neuro disease
Ulnar fractures can result in disruption of what?
Disruption of the stay apparatus.
Ulnar fractures require what type of external coaptation?
Splint to fix carpus in extension
Where should a splint be placed when being used for an ulnar fracture?
Apply splint palmarly extending from the fetlock to the level of the elbow.
What is an important consideration when placing a splint for an ulnar fracture?
Use adequate padding
What is a good material to use for a splint when doing a full limb bandage?
Schedule 40 PVC
A Salter-Harris type 1 fracture with minimal displacement needs what type of fixation?
Needs internal fixation
If a foal weighing less than 250 kg has a Salter-Harris type 1 with minimal displacement, what is a fixation option?
If the horse is larger, what must be used?
- Tension band technique using screws and wires.
- Must use a plate
With a displaced Salter-Harris type 1b fracture with comminution of the anneal process, what is an important thing to remember to do?
Why?
- Remove fragments
- If fragments were left, more likely to develop OA
What is the treatment of choice for an olecranon fracture?
ORIF
What is a special type of plate that can be used for a foal less than 250 kg?
Hook plate
What has to be done with the bone plate for an olecranon fracture?
Contoured to fit over the top of the olecranon tuberosity.
Where can screws be added with an adult horse to help ensure rigidity of the fixation?
Distal screws can be inserted int eh caudal cortex of the radius.
What should not be done with screws used in ulnar fracture repair in horses less than a year old?
Why?
- Distal screws should not engage the radius.
- May lead to subluxation of the elbow.
What is the prognosis for ulnar fractures when internal fixation is used?
Good (68-87%)
