Exam 1 - Equine Limb Deformities

Question 1

what are the most common angular limb deformities seen in horses? what plane are they in?

Answer 1

varus & valgus - frontal plane

valgus - in frontal plane, legs move out laterally
varus, in frontal plane, legs go towards midline

Question 2

what are the most common flexural deformities seen in horses? what plane are they in?

Answer 2

joint laxity or contracture - sagittal plane

Question 3

T/F: it is common for most foals to be born with mild valgus which should correct itself naturally over time

Answer 3

true

Question 4

what 2 components are suggested to contribute to the development of angular limb deformities in neonatal horses?

Answer 4

periarticular laxity from lack of movement in utero & incomplete ossification

Question 5

what should you do for a foal that presents like this to you?

Answer 5

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

Question 6

are these proper splints for a foal with severe valgus from periarticular laxity?

Answer 6

yes - doesn’t splint the fetlock

Question 7

what should you do for a foal that presents like this to you? what is this known as?

Answer 7

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

Question 8

what bones do we commonly see incomplete ossification in & why?

Answer 8

cuboidal bones - last bones to ossify late in gestation or early after birth

Question 9

what are some factors that may result in incomplete ossification of cuboidal bones in neonatal foals?

Answer 9

premature, twins, or dysmature foals

Question 10

how is incomplete ossification of cuboidal bones managed?

Answer 10

confinement with daily walks, +/- axial support, +/- foot plates

used to encourage ossification

Question 11

what is the major consequence of incomplete ossification of cuboidal bones?

Answer 11

malformation & end stage DJD

Question 12

where do we commonly see acquired varus deformities in perinatal-weanling foals?

Answer 12

fetlock

Question 13

where do we commonly see acquired valgus deformities in perinatal-weanling foals?

Answer 13

knees/hock

Question 14

why do we commonly see acquired limb deformities in perinatal-weanling foals?

Answer 14

asynchronous physeal growth

Question 15

what things contribute to compressive forces causing asynchronous physeal growth?

Answer 15

severity of force, size of the foal, & activity of the foal

very severe deformity = growth inhibited on side of compression

Question 16

T/F: there is a physiologic range that is self correcting for limb deformities in horses

Answer 16

true - each growth plate has its own time frames in which we can affect them

Question 17

T/F: compression of the growth plates both stimulates growth or inhibits

Answer 17

true - too much can exceed physiological limit & stop growth

but the right amount encourages growth

Question 18

why do most foals with mild valgus self-correct?

Answer 18

as they grow & their chest thickens, this rotates their elbows out which corrects the valgus

Question 19

when evaluating limb deformities what are you paying special attention to on your physical exam?

Answer 19

look for the toe being pointed out, the alignment of mc/mt 3/digits, & axial alignment

also assess lameness & ROM

Question 20

what are you looking for on rads of a horse with angular limb deformities?

Answer 20

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

Question 21

what is the conservative management for limb deformities caused by asynchronous metaphyseal growth?

Answer 21

confinement/foot plates for mild deformities or moderate deformities with early growth

careful monitoring - put foal & mare in a pasture alone

Question 22

when is periosteal transection/elevation used for a foal with limb deformities caused by asynchronous metaphyseal growth?

Answer 22

foal that is early in a moderate deformity

Question 23

when is growth plate retardation used for a foal with limb deformities caused by asynchronous metaphyseal growth?

Answer 23

mid to late in a moderate deformity or early/mid with a severe deformity

Question 24

when is a corrective osteotomy used for a foal with limb deformities caused by asynchronous metaphyseal growth?

Answer 24

foal with post-physeal closure

Question 25

what are the main considerations in deciding which surgical procedure to use for a foal with limb deformities caused by asynchronous metaphyseal growth?

Answer 25

type of surgery & the timing of it

Question 26

why do you need to intervene early for a foal with limb deformities caused by asynchronous metaphyseal growth in the fetlock?

Answer 26

growth is gone by 3-4 months of age

Question 27

what are the disadvantages of using growth plate retardation for correcting limb deformities caused by asynchronous metaphyseal growth?

Answer 27

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

Question 28

what surgery is commonly done for moderate/severe fetlock varus? what time is the surgery done? when do you take the screw out?

Answer 28

growth plate retardation

3-6 weeks of age

take screw out when almost corrected to avoid over correction

Question 29

what surgery is commonly done for moderate/severe tarsal valgus? what time is the surgery done? when do you take the screw out?

Answer 29

GPR/TPS

less than 60 days old - risk of malformation

Question 30

what surgery is commonly done for moderate/severe carpus valgus? what time is the surgery done? when do you take the screw out?

Answer 30

GPR/TPB-SW

done later - risk of malformation

Question 31

what is the normal conformation of a weanling horse?

Answer 31

carpus valgus at 4-5 degrees & toes out, external rotation

mc/mt 3 & digit aligned

Question 32

what is the normal conformation of a yearling horse?

Answer 32

carpus alignment - growth at 8-10 months

toes forward due to chest expansion

Question 33

what flexural problem does this foal have?

Answer 33

excessive laxity

Question 34

what clinical signs are associated with a foal that presents like this?

Answer 34

dropped fetlock

toe is elevated

palmi-plantigrade stance

Question 35

what management should you do for a foal with excessive laxity?

Answer 35

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

Question 36

T/F: you can use support bandages in a foal with excessive joint laxity

Answer 36

false - contraindicated, will make the problems worse

Question 37

what is the common name for this?

Answer 37

ballerina foal - flexural limb deformity with excessive flexion

Question 38

what is the common clinical presentation of a ballerina foal?

Answer 38

contracted flexors, upright digit, toe touch/heel elevation

Question 39

how do you treat excessive flexion in ballerina foals?

Answer 39

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

Question 40

what are some things that may be causing the clinical presentation of this foal?

Answer 40

carpal contracture

flexor contracture

ruptured common digital extensor

arthrogryposis

Question 41

how do you manage a foal with carpal contracture?

Answer 41

harder to manage than ballerina foals & can look like varus foals - they can’t stand long

treat with oxytet, bandages, splints, tenotomy UL/FCU

Question 42

what causes this?

Answer 42

contracture of the DDF at the DIP joint - causes club foot

look for overgrown heels, uproght dorsal wall, & toe broken off

NORMAL FETLOCK ANGLE

Question 43

why do rads for a horse with club foot?

Answer 43

look for damage - need to evaluate degree of contracture, & look at the coffin bone for laminar separation & remodeling

Question 44

if you catch club foot early, how do you manage it?

Answer 44

trim the feet aggressively, protect the toe, use toe extensions, but be careful because you can cause laminitis

Question 45

T/F: if you have a foal with club foot that isn’t responding to corrective farriery, you should keep trying more aggressively

Answer 45

false, don’t persist because you will cause laminar separation & mechanical founder!!!!!

seek surgical correction

Question 46

what treatment is indicated for older foals/non-responsive to treatment foals with contracted DDF?

Answer 46

need surgery - distal check desmotomy with farriery

Question 47

when may you need to do a distal check desmotomy & deep flexor tenotomy for a horse with contracted DDF?

Answer 47

salvage procedure to save the horse for breeding purposes only

Question 48

what clinical signs are seen in foals with contracted SDF?

Answer 48

yearling foals with contracture at the fetlock, most commonly fetlock - upright digit & knuckle forward

hoof capsule is normal

Question 49

what management may be done for mild cases of contracted SDF?

Answer 49

conservative management - heel elevation, bandages/splints, NSAIDS, limit exercise

DON’T PERSIST

Question 50

what treatment is indicated for a horse with non-responsive/moderate-severe contracted SDF?

Answer 50

proximal +/- distal check desmotomy

Question 51

what problem is seen here?

Answer 51

contracture of the SDF at the fetlock joint

Question 52

T/F: in club foot, the angle of the fetlock is normal

Answer 52

true