Exam 1 - Equine Limb Deformities Flashcards
what are the most common angular limb deformities seen in horses? what plane are they in?
varus & valgus - frontal plane
valgus - in frontal plane, legs move out laterally
varus, in frontal plane, legs go towards midline
what are the most common flexural deformities seen in horses? what plane are they in?
joint laxity or contracture - sagittal plane
T/F: it is common for most foals to be born with mild valgus which should correct itself naturally over time
true
what 2 components are suggested to contribute to the development of angular limb deformities in neonatal horses?
periarticular laxity from lack of movement in utero & incomplete ossification
what should you do for a foal that presents like this to you?
for severe, non-responsive, or worsening valgus, you want to apply a splint in axial alignment from the fetlock proximally where you leave it on for 24 hours & take it off for 12 & keep the foal confined
being careful for managing pressure sores - keep them in the hospital with you to manage
are these proper splints for a foal with severe valgus from periarticular laxity?
yes - doesn’t splint the fetlock
what should you do for a foal that presents like this to you? what is this known as?
windswept foal - want them to bear weight on the sole of their hoof, so you apply a foot plate to extend the sole laterally & leave it on for a few weeks
what bones do we commonly see incomplete ossification in & why?
cuboidal bones - last bones to ossify late in gestation or early after birth
what are some factors that may result in incomplete ossification of cuboidal bones in neonatal foals?
premature, twins, or dysmature foals
how is incomplete ossification of cuboidal bones managed?
confinement with daily walks, +/- axial support, +/- foot plates
used to encourage ossification
what is the major consequence of incomplete ossification of cuboidal bones?
malformation & end stage DJD
where do we commonly see acquired varus deformities in perinatal-weanling foals?
fetlock
where do we commonly see acquired valgus deformities in perinatal-weanling foals?
knees/hock
why do we commonly see acquired limb deformities in perinatal-weanling foals?
asynchronous physeal growth
what things contribute to compressive forces causing asynchronous physeal growth?
severity of force, size of the foal, & activity of the foal
very severe deformity = growth inhibited on side of compression
T/F: there is a physiologic range that is self correcting for limb deformities in horses
true - each growth plate has its own time frames in which we can affect them
T/F: compression of the growth plates both stimulates growth or inhibits
true - too much can exceed physiological limit & stop growth
but the right amount encourages growth
why do most foals with mild valgus self-correct?
as they grow & their chest thickens, this rotates their elbows out which corrects the valgus
when evaluating limb deformities what are you paying special attention to on your physical exam?
look for the toe being pointed out, the alignment of mc/mt 3/digits, & axial alignment
also assess lameness & ROM
what are you looking for on rads of a horse with angular limb deformities?
alignment of bones involved & malformation
look at the hock & stifle for baseline
at the carpus - collapse of the intermediate & 3rd carpal bone & displacement of 3rd mc bone distally
hock - bone extrudes dorsally
what is the conservative management for limb deformities caused by asynchronous metaphyseal growth?
confinement/foot plates for mild deformities or moderate deformities with early growth
careful monitoring - put foal & mare in a pasture alone
when is periosteal transection/elevation used for a foal with limb deformities caused by asynchronous metaphyseal growth?
foal that is early in a moderate deformity
when is growth plate retardation used for a foal with limb deformities caused by asynchronous metaphyseal growth?
mid to late in a moderate deformity or early/mid with a severe deformity
when is a corrective osteotomy used for a foal with limb deformities caused by asynchronous metaphyseal growth?
foal with post-physeal closure
what are the main considerations in deciding which surgical procedure to use for a foal with limb deformities caused by asynchronous metaphyseal growth?
type of surgery & the timing of it
why do you need to intervene early for a foal with limb deformities caused by asynchronous metaphyseal growth in the fetlock?
growth is gone by 3-4 months of age
what are the disadvantages of using growth plate retardation for correcting limb deformities caused by asynchronous metaphyseal growth?
implants can lead to infection or cosmetic issues
may overcorrect - there is a need for a 2nd surgery to remove the pin placed across the plate
what surgery is commonly done for moderate/severe fetlock varus? what time is the surgery done? when do you take the screw out?
growth plate retardation
3-6 weeks of age
take screw out when almost corrected to avoid over correction
what surgery is commonly done for moderate/severe tarsal valgus? what time is the surgery done? when do you take the screw out?
GPR/TPS
less than 60 days old - risk of malformation
what surgery is commonly done for moderate/severe carpus valgus? what time is the surgery done? when do you take the screw out?
GPR/TPB-SW
done later - risk of malformation
what is the normal conformation of a weanling horse?
carpus valgus at 4-5 degrees & toes out, external rotation
mc/mt 3 & digit aligned
what is the normal conformation of a yearling horse?
carpus alignment - growth at 8-10 months
toes forward due to chest expansion
what flexural problem does this foal have?
excessive laxity
what clinical signs are associated with a foal that presents like this?
dropped fetlock
toe is elevated
palmi-plantigrade stance
what management should you do for a foal with excessive laxity?
self-limiting usually, but check the feet for epinichium & rasp the heel
may use heel extensions - goal is to get them weight bearing
controlled exercise
T/F: you can use support bandages in a foal with excessive joint laxity
false - contraindicated, will make the problems worse
what is the common name for this?
ballerina foal - flexural limb deformity with excessive flexion
what is the common clinical presentation of a ballerina foal?
contracted flexors, upright digit, toe touch/heel elevation
how do you treat excessive flexion in ballerina foals?
goal is to induce laxity - large doses of oxytetracycline for foals <72 hours of age, very diluted & given slowly
monitor the kidneys!!! may dose up to 3 times
stretch the flexors using support bandages/splints/toe extensions constantly monitoring for pressure necrosis
what are some things that may be causing the clinical presentation of this foal?
carpal contracture
flexor contracture
ruptured common digital extensor
arthrogryposis
how do you manage a foal with carpal contracture?
harder to manage than ballerina foals & can look like varus foals - they can’t stand long
treat with oxytet, bandages, splints, tenotomy UL/FCU
what causes this?
contracture of the DDF at the DIP joint - causes club foot
look for overgrown heels, uproght dorsal wall, & toe broken off
NORMAL FETLOCK ANGLE
why do rads for a horse with club foot?
look for damage - need to evaluate degree of contracture, & look at the coffin bone for laminar separation & remodeling
if you catch club foot early, how do you manage it?
trim the feet aggressively, protect the toe, use toe extensions, but be careful because you can cause laminitis
T/F: if you have a foal with club foot that isn’t responding to corrective farriery, you should keep trying more aggressively
false, don’t persist because you will cause laminar separation & mechanical founder!!!!!
seek surgical correction
what treatment is indicated for older foals/non-responsive to treatment foals with contracted DDF?
need surgery - distal check desmotomy with farriery
when may you need to do a distal check desmotomy & deep flexor tenotomy for a horse with contracted DDF?
salvage procedure to save the horse for breeding purposes only
what clinical signs are seen in foals with contracted SDF?
yearling foals with contracture at the fetlock, most commonly fetlock - upright digit & knuckle forward
hoof capsule is normal
what management may be done for mild cases of contracted SDF?
conservative management - heel elevation, bandages/splints, NSAIDS, limit exercise
DON’T PERSIST
what treatment is indicated for a horse with non-responsive/moderate-severe contracted SDF?
proximal +/- distal check desmotomy
what problem is seen here?
contracture of the SDF at the fetlock joint
T/F: in club foot, the angle of the fetlock is normal
true
