Chapter 93 - part 1 condylar fx Flashcards
What is the function of the MCII and MTII bones in horses?
They serve major weight-bearing functions
How does the cross-section of MCIII change in horses?
It dramatically changes in response to increased loading as the horse ages and trains
What makes the great metatarsal (dorsal MTIII) artery particularly vulnerable in horses?
Its location between MTIII and MTIV
Where is the most common site of major fracture in MCIII/MTIII bones in athletic horses?
In the distal articulation
In the forelimb the major neurovascular structures course along the length of MCIII both medially and laterally dorsal to the flexor tendons but in the hindlimb the artery courses
laterally between MTIII and MTIV
Repetitive loading during intensive exercise leads to focal accumulated injury in the in a specific part of the MC III, where?
parasagittal groove region that can eventually result in complete fracture
Vertical fractures in the sagittal plane occur in the
distal condyle of MCIII/MTIII
In which group of horses are lateral condylar fractures most common?
Young racehorses
Which limb is more likely to be affected by lateral condylar fractures in Thoroughbreds?
Forelimb
What is a typical clinical sign of a lateral condylar fracture in horses?
Acute onset of severe lameness after intense exercise
What percentage of condylar fractures involve the lateral condyle?
Around 85%
In complete displaced fractures of the third MC/MT are displaced by the MCP/MTP joint flexion and reduced extension what is contraindicated in the immobilization?
All immobilization
techniques should therefore include extension; any
that involve flexion are contraindicated.
How do lateral condylar fractures typically propagate?
In a sagittal plane then spiral to oblique/frontal planes
What advanced imaging techniques are increasingly diagnosing unicortical condylar fractures?
CT and MRI
Figure 7.7 Digital pressure applied dorsoproximally frequently
elicits a painful response in horses with non-or
minimally
displaced sagittal/parasagittal fractures of the proximal phalanx.
Complete fractures disarm the_____________ _______________
ligament of the MCP/MTP joint leading to instability and
potential creation of an open fracture or disruption of the
proximal scutum
Complete fractures disarm the lateral collateral
ligament of the MCP/MTP joint leading to instability and
potential creation of an open fracture or disruption of the
proximal scutum
What are the immobilization that should be considered for MC/MT condylar fractures?
Compression boot in the FORELIMBS
Robert Jones bandage for incomplete, with medially and laterally splinted up to the level of thirc carpal or third/fourth tarsal bones
Robert Jones bandages, or a bandage cast for complete fractures.
In the absence of a compression boot, these techniques are also appropriate for forelimbs
What is the main difference of the medial condylar fracture in the immobilization comparing to LAT?
First aid and coaptation for medial condylar fractures does not differ much from lateral fractures with one major exception: horses with medial condylar fractures in the hindlimb should be crosstied until surgery is performed.
Figure 7.18 Construction of a splinted Robert Jones bandage for the distal hindlimb. (a) Splints should be positioned medially and
laterally in contact with the widest point of the hoof from the bearing surface to the level of the third (medially) and fourth (laterally) tarsal bones. The lateral splint is often longer in consequence. Sufficient cotton wool is added to fill the space between limb and splints. Minimal bandage material is applied at the level of the hoof to maintain the hoof/splint interaction. (b) Splint alignment is maintained by application of inelastic tape to prevent twisting or rotation while enclosing elasticated tape is applied. (c and d) The completed splinted bandage.
what is this?
Figure 7.20 Newmarket Compression Boot. Readily applied, radiolucent and rigid construct. The design enables the horse to load the limb in a normal position.
What if it is a diaphyseal fracture of the third metacarpal/metatarsal bone?
marked bending forces, and complete fractures are inherently
unstable even if not displaced. Casts provide the only
contributory support.
The medial condyle is ______in both mediolateral and dorsopalmar/plantar (DP) planes.
The medial condyle is larger in both mediolateral and dorsopalmar/plantar
(DP) planes.
Growth plate closure in MCIII and MTIII is…
Complete closure of the growth plate occurs between 10 and 18 months with radiographic, which is generally thought to
represent functional, closure between six and eight
months
Fractures are generally classified from radiographic features
(Figure 21.1). They may be unicortical (although
this usually involves pa/pl subchondral compacta rather
than cortical bone) or** bicortical. Fractures are classified
as complete if the fractures in dorsal and pa/pl cortices conjoin to exit through the periosteal surface of the metaphysis
or diaphysis of the bone and incomplete if this has
not occurred. Displacement has been variously and
inconsistently defined. The author’s favoured definition
is that displacement involves a change in the anatomic
axis of one fragment with respect to another. In distraction,
orientation is maintained and fragments simply
separate. Displacement can involve abaxial, proximodistal,
DP or rotational movement; frequently, there is a
combination of these. In some fractures, this can only be
determined arthroscopical. Incomplete fractures can distract at the articular surface but cannot displace. Fractures that extend into the diaphysis are described as propagating. These are of
two types. The first remain in a sagittal or parasagittal**
plane, and the second begin in this plane and then change
orientation to oblique or frontal planes; the latter are
generally referred to as** spiral**