Lecture 5: Equine Navicular Disease and corrective shoeing

chronicm, bilateral, progressive degernation of navicular bone and apperatus

what is the pathogenesis of navicular disease

7-9 years

what age is navicular syndrome usually found in

quarter horses

what breed is navicular diseease most common in

distal zesmoidean bone

what is the other name for the navicular bone

decreases strain on DDFT and decreases work onto P3 itself

main functions of the navicular bone

navicular apperatus anatomy

navicular apperatus anatomy

navicular apperatus in color

navicular apperatus in color

small feet, big body (quarter horses) underrun heels, contracted heels

what conformation of a horse can lead to navicular syndome

uni or bilateral (most common) forelimb lameness, short-choppy stride, toe lands first, looks like a shoulder problem

what are the main clincial signs of navicular syndome

underrun heels

what is this

+/- heels on hoof tester, +/- coffin joint hyperextension, BLOCKS TO PD NERVE BLOCK

how do you diagnose navicular syndrome

navicular syndrome, heel pain

if they block to PD nerve block they have ___ ___ or ___ __

shifts to the other side

when you block a PD in navicular syndrome the lameness often ____ ___ ___ ___ ___

soft tissues are often the primary problem

why are x-rays not good for navicular syndrome dx

clean foot, PACK IT with multiple peices of play doh, position correctly

how to radiograph for the navicualr bone

flexor cortex, medullary cavity, insertion of impar lig, insertions of navicular suspensory, hoof balance

what do you evaluate in a lateral

P2 and P3

where is the NB superimposed on a DP

hoof balance, lateral/medial aspect (wings) of NB

what do you evaluate on a DP for NB

60-65 degrees DP

what angle is this where the NB is superimpsoed on P2

insertions of navicular apparatus on lateral and medial aspects, distal and proximal borders of NB, shape of NB

what does 60-65 DP evaluate

skyline, flexor cortex

the ____ view evaulates the ___ ____ ****

enthesophyte on insertion of impar ligament and sclerosis of medullary cavity

what are the two most major radiographic lesions found in NB disease******

enthesophyte on inserttion of impar ligament (the bright dot)

what is happening here

flatteened palamasr angle (it is starting to slip down)

what Is happening here

yellow = cyst in navicular bone

red = synovial invaginations or lollipop leisons

what is seen in red and yellow

navicular cysts

what is seen here

know this

know this

yellow = enthesiophyte where apparatus attaches

red = mineralization in the DDF tendon

what is seen here

yellow = enthesiophyte at suspensory apperatus insertion

red = roughing of the abaxial surfaec of navicualr bone

what is being seen here

severe sclerosis and loss of corticomedullary junction

what is happening here

lolipop lesions

what is happening here

caudal heel pain

what is it if radiographs are normal and you thought it was NB disease

DDF tendon, impar ligament, suspensory ligament, CL of DIP joint, navicular bursa

what soft tissue structures may indicate NB disease but can't be seen on radiographs

MRI

for definitive dx if nothing is seen on radipgraphs, what must you do

shoeing (elevate heel and roll toe)

what is the first step of navicular syndrome and how is it achieved ****

NSAIDs, coriticosteroid injection (triamcinolone), osteoclast inhibitors, palmar digital neurectomy

what are the 4 major options for also treat navicular disease

coffin (for navicular bursa) and navicular bursa directly (radio guided)

what joints are injected for NB disease

if there is cystic bone lesions

when do you used osteoclast inhibitors for NB syndrome

ease breakdown, supports palmar structures, and address coffin bone palmar angle

what are the goals for shoeing for NB disease

why increasing breakover helps

why increasing breakover helps

2-3 degrees

when shoeing for NB syndrome what degree wedge do you use

it can cause contracted heels

what do you need to be careful of when using bar shoes to help with NB syndrome

shoe in active months and barefoot in less active months

optimal use pattern of bar shoes

coffin joint

which joint is most commonly used to inject first for NB syndrome

tiludronate

what osteoclast inhibitor is used to help with bony cyst lesions in NB syndrome

summary

summary

no, just slows progression

does NB syndrome ever fully heal

based on treatment response and soft tissue involvement

what is prognosis of NB syndrome

NOT first line treatment, used to improve lameness

when do you use palmar digital neurectomy

helps pain, but DOES NOT help treat the problem

what does neurectomy actually achieve

DONT use if there is soft tissue injury, nerve can regrow

things to remember about palmar digital neurectomy

lamness must improve alot with PD nerve block, no DDF ossification, no DJD in coffin, no roughing on flexor surface of NB, owner compliance

5 conditions you do a palmar digital neurectomy

standing, general anesthesia

palmar digital neurectomy can be performed ____ or under ___ ___

DDF tendon rupture and coffin joint subluxation

what are the major complication risks of a palmar digital neurectomy

coffin joint subluxation

what complication is this after a neurectomy

DDF tendon rupture

what complication is this after a neurectomy

3 years

palmar digital reinnervation almost always occurs within _____

leave toe haning over shoe (set shoe back), squaring toe, rockering/rolling toe

3 shoeing techniques to influence breakover

hock pain

what can happen due to a horse hoof being turned sideway in a trailer

supporting the side of the hoof that is turned

how do you manipulate trailer hoof pain

NB syndrome, suspensory apparatus demitis

when is shoeing in order to support palmar structures needed

increased risk of horse pulling shoe

what can leaving a long heel on a shoe cause

bar shoes, reverse shoe, egg bar, straight bar

what are the three types of shoeing that are used to help support palmar structures

reverse shoe

what kind of shoe is this

egg bar

what kind of shoe is this

straight bar

what kind of shoe is this

transfer forces from hoof wall to sole

what is the goal of shoeing to support the bony column

P3 fractures, NB fractures

in which instances would you have to shoe to help stabilize the hoof capsule

rim shoes (work like makeshift cast)

what kind of shoes do you use to stabilize the hoof capsule

critical

positioning and even weight bearing is ____ to shoeing

laminitis, NB syndrome, severe hoof imbalance

which instances must you radiograph to ensure proper shoe placement

elevate the heel and roll toe

what shoeing would you recommend for low or neg. palmar angle