Long Bone Fractures 1: Cannon Bone And Ulnar Fractures Flashcards
What is one of the biggest difference between orthopedic surgery in small animals and large animals (horse)?
A horse must be ambulatory and fully weight-bearing in the immdedate post op period after plating
-most fixation devices were not designed for horses
What are the challenges of Large animal fracture fixation?
1) large animals require large plates which need space —> Skin closure is challenging
2) implant failure—>cyclic fatigue
3) Post operative lameness
- contralateral limb lameness
4)orthopedic implants are not large animal specific
What are some post operative complications that can affect the contralateral lim?
1) Contralateral limb laminitis
2) angular limb/flexural limb deformities (due to consistent overloading of the limb)
What are the 5 types of Physeal fractures?
-what is important to know about these?
Salter Harris type 1-5
-decreased prognosis with articulate involvement
What does prognosis decrease with articulate involvement of Physeal fractures?
DJD subsequent to fracture.
Where do condylar fractures most often happen?
Metatarsus/metacarpus 3
Cannon bones
Condylar fractures can be lateral or medial, Which do we see most often?
Lateral
What special view needs to be taken to identify fractures in the articulate surface?
Tangential DP view
- bend the horses fetlock
- highlights palmer aspect of bone to fully evaluate the joint
Why is it important to see/assess comminution at the joint surface in an image (tangential view)
-Condylar fractures
To evaluate prognosis
What is the difference between TB and SB horses with condylar fractures?
TB: RACE HORSES
-forelimb (MC3) >2x more common than hind limb (MT3)
SB:
-Fore and hind limb Cannon bones are equally affected
What is the etiology of Lateral condylar fractures?
- high compressive load
- leads to Osseous adaption/sclerosis
- Microtrauma/ microfracture
= Condylar fracture
What is the CS of a non displaced incomplete condylar fracture
History of lameness with acute exacerbation
What are the CS of an Acute displaced fracture?
1) Acute onset of severe lameness after intense exercise
2) effusion of MCP/MTP joint (FETLOCK)
3) Pain on palpation
What will you do (in the field) if you suspect a lateral condylar fracture?
First aid:
1) compression bandage (stabilize, possible Robert Jones)
2) NSAIDs And SEDATIVE (xylazine) and OPIOID (butorphanol)
3)ABSOLUTE stall rest until definitive treatment undertaken
Possible Kimsey Splint
When would you use Phenylbutazone over flunixin Meglumine?
Bute:
-orthopedic pain
Banamine:
- visceral pain
- ocular pain
How would you surgically treat Lateral Condylar Fractures?
Internal Fixation with transcortical screws in LAG fashion
-compress across the joint
What does LAG screw repair involve?
- 4.5mm or 5.5mm cortical bone screws
- Place in lag fashion
- 2cm apart
- most only require 2 screws
Where do you place the first LAG screw during lateral condylar fracture fixation?
- CLOSE to the joint
- in the Epicondylar fossa of the cannon bone
When performing surgery for condylar fractures, What diagnostic tool should be used to aid placement of LAG screws?
- Fluoroscopy
- Radiographs
- arthroscopy
intraoperatively
Dont forget your bone reduction forceps! Know what these look like
How can you make sure you have realigned the articulations surface properly during internal fixation of a condylar fracture?
Arthroscopy
articulate alignment = no cartilage gap
What is the prognosis for RETURN to RACE for :
A) Non displaced and incomplete condylar fracture
B) Displaced condylar fracture
C) Joint comminution
A) 70-80%
B) 50%
C) <50% Not looking good bro
How are lateral condylar fractures different from Diaphyseal fractures of the Cannon bone?
??????
What is the MOST common LONG Bone fracture in horses?
Diaphyseal fractures of MC3 and MT3
Cannon bone
What is the prognosis of Diaphyseal fractures of MC3 and MT3?
Depends on:
- immediate 1st aid
- external coaptation
What is the optimal treatment for Cannon bone fracture repair?
- Double plate fixation
- *plates on the tension side of the bone**
- Staggered
- span entire length of long bone
Forelimb: dorsomedial and dorsolateral
Hindlimb:
How would you treat a comminuted Cannon bone fracture?
-Transform into 2 fragments
WHy is interfragmentary compression IMPORTANT?
- compress across fracture line
- Minimize the amount the body has to heal
What is the Maximum compression that can be applied using plate holes?
4mm
-using a load drill guide to compress a fracture with a broad DCP/LC-DCP
What is the difference between DCP and LC-DCP?
LC-DCP has:
- Continuity of bending stiffness
- Improved blood supply under plate
Limited contact-Dynamic compression Plate
What is the LCP?
Locking compression plate**
-5.5mm LCP specifically designed for equine fracture repair
Known for Strength and rigidity we can achieve
What are the 4 main plate functions?
1) compression
2) Neutralization
3) Tension band
4) Buttressing
When would you use a plate in Butress?
Buttressing—> placed to bridge area of bone defect (even after reconstruction)
NOT a VIABLE option in HORSES/Large animal
When would you use compression?
Maximum 2 screws on either side of FX are placed under load**
-4mm max compression when using plates and screws
What does a tension band do?
Transforms tensile forces into compressive forces
When do you use neutralization?
Already reconstructed the site, we just need it to stay ridgidly immobilized
T/F: LC-DCP can use locking screw and cortex screw
True
- combo-holes permit the combination of conventional or locking screw
- treaded and smooth
Locking goes in threaded holes
T/F: locking compression plates ((LCP) can be placed using standard screws or locking screws
True
-locking screws increase the stability and the fixation strength of the plate screw construct
Are ulnar fractures common?
Yes
“They are not uncommon”-Dr. Little
What muscle inserts on the olecranon/Apophysis?
Triceps
What are the causes if Ulnar fractures?
1) direct trauma
- external trauma
- injury during halter training (rearing up)
How do ulnar fractures usually present?
*usually closed fracture
- Dropped elbow with carpus in flexion
- no weight bearing
- unable to fix carpus in extension
Why are horses with ulnar fractures unable to keep the elbow in extension ?
Because they have disrupted the triceps apparatus!
What are the differential diagnosis for a horses with a DROPPED elbow and Non weight bearing?
1) numeral fracture
2) Radial nerve paralysis
3) olecranon fracture
4) Neuro Disease (rare)
How would you stabilize a horse with an Ulnar fracture ?
-i.e: non weight bearing, unable to fix carpus in extension
Splint to fix carpus in extension
-splint PALMARLY extending from the fetlock to the level of the elbow
ADEQUATE padding is a MUST!!!!!
What is the exception to the rule of
“A joint above, a joint below”
Splinting an Ulnar fracture
What is the mainstay of treatment for elbow fractures?
Open Reduction and Internal Fixation (ORIF)
Why does Stall rest not work for elbow fractures in horses?
Even if it is not displaced the triceps apparatus will displace the fracture
How do you surgically treat an Olecranon fracture ?
1) ORIF** treatment of choice!!!!
2) Use tension-band principle
3) plate applied to the caudal ulna
- or tension band wire/cable fixation
4) Narrow DCP, LC-DCP, LCP
What is the treatment of choice for an olecranon fracture repair?
ORIF
More often than not to fix a an olecranon fracture, surgeons will do what?
Bone plate contoured to fit of the the top of the olecranon tuberosity
T/F: All olecranon fractures are articulate
FALSE
Not all olecranon fractures are articular
You have a <250 Kg foal with a Salter Harris type 1 minimally displaced olecranon fracture….How would you repair it?
Tension band technique (screws and wires)
You have a Heavy >250 Kg foal with a Salter Harris type 1 minimally displaced olecranon fracture….How would you repair it?
Must apply a plate!!!!!
Over what weight must a olecranon fracture be corrected with a plate?
> 250kgs
Why do we not want to engage the RADIUS in foals (<1year) corrected with olecranon fractures?
Engagement of the radius can cause elbow dysplasia
-elbow subluxation
If it has to be done, then it has to be removed
What is the prognosis for Ulnar fracture repair?
GOOD (68-87%)
With ORIF!!!!!
