Lameness/physiotherapy Flashcards
what are the parts of a horses frog?
collateral sulci
central sulcus
frog apex
what directions do hoof cracks usually run?
proximo-distal direction
what are some possible risk factors for hoof cracks?
poor foot balance/care
poor horn quality
trauma/environment
what are transverse hoof cracks associated with?
coronary band injury
how can hoof cracks be described?
complete/incomplete
deep/superficial
what does a superficial hoof crack involve?
just stratum externa involved
what needs to be done when examining hoof cracks before a nerve block is done?
determine how deep it is - whether sensitive/insensitive parts effected
how can hoof cracks be treated by a farrier?
deride necrotic tissue
filler to stabilise crack (plate/wire)
shoes to stabilise
what are some possible causes of coronary band/hoof wall injuries?
laceration/trapped foot
overreach injury (back foot hitting the front)
why is there usually a lot of haemorrhage when the hoof wall or coronary band is injured?
digital cushion is highly vascularised (good blood supply to foot)
what other structures may be involved with hoof wall/coronary band injuries?
distal/proximal interphalangeal joint
navicular bursa
digital flexor tendon sheath
tendons/ligaments
where does the DDFT attach to distally?
distal phalanx
is coronary band/hoof wall injuries usually treated with primary or secondary intention?
aim for primary but are often very contaminated so use secondary intention
what is essential to do when treating coronary band/hoof wall injuries?
preserve the coronary band as best as possible (allows hoof to grow back)
what is often the best way to stabilise the distal limb when there has been a coronary band or hoof wall injury?
with a cast
how can possible sepsis of the joints be prevented when treating coronary band or hoof wall injuries?
flushing synovial structures if they are involved in the injury
what is nail bind?
when shoeing a horse the nail is close to sensitive structures and puts pressure on this
what is shoeing prick?
when shoeing a horse a nail is placed into the sensitive structures causing immediate pain/bleeding
what can form if a shoeing prick is left?
subsolar abscess
what are the clinical signs of a sub solar abscess?
acute lameness
increased digital pulse
increased hoof temperature
sensitivity to hoof testers
why do sub solar abscesses cause pain?
put pressure of sensitive hoof lamina
what is the key to treating sub solar abscesses?
drainage - remove shoe/nail and all tracts/necrotic tissue
what can be done to try soften the foot to remove a sub solar abscess?
poultice
epson salts
what structures would be at risk of injury in foot penetrations?
navicular bone/bursa
DDFT
distal sesamoidean impar ligament
DIP joint
DFT sheath
what are some possible clinical signs of a foot penetration involving a synovial structure?
moderate/severe lameness
presence of foreign body or wound
distal limb swelling
increased digital pulse
sensitive to hooftesters
what should synovial fluid look like?
clear straw coloured
how are foot penetrations involving synovial structures treated?
remove necrotic horn/tendons
flush synovial structures
what is the prognosis for foot penetration injuries involving synovial structures?
fairly well but guarded for returning to athletic function if flexor tendons damaged
what could be some causes of chronic hoof abscessation?
immunocompromise
teratoma
laminitis
bone sequestrum
infective osteitis
what is quittor?
infection of the collateral cartilage
what are keratomas?
benign tumours of the hoof/solar horn
how do keratomas appear?
circular area of abnormal keratinisation with a discharging tract
what is canker?
chronic condition associated with hypertrophy of the germinal layer of the epithelium of the frog
what pathogen is canker related to?
Fusobacterium spp.
what can be done to treat early/mild canker cases?
improve environment (remove wet bedding…)
deride abnormal areas
dilute formalin
what can predispose to white line disease?
warm, wet weather
biotin/zinc/selenium deficiency
bacterial infections
what are the clinical signs of white line disease?
lameness
separation of hoof wall
grey/black crumbly horn
what is white line disease?
a progressive, crumbling, poor quality hoof wall with separation at the white line
how is white line disease treated?
remove abnormal horn
support remaining horn (acrylic, bar shoe…)
prevent progression (environment, feed, topical iodine…)
how do local anaesthetics work?
blocking sodium channels so preventing depolarisiation
what are the two commonly used local anaesthetics in equine diagnostics?
mepivicaine and bupivicaine
what are the contraindications for using diagnostic analgesia?
suspected fractures
cellulitis (gets more infected, and don’t work well in inflamed tissue)
uncooperative horse
why might there be a poor response to local anaesthetic?
sever pain
poor technique
inadequate volume
nerve variation
subchondral bone pain
pain originating more proximally (neck…)
neurological pain
what are the most common nerve blocks used in the forelimb? (to block feet)
palmar digital nerve block
abaxial sesamoid nerve block
distal interphalangeal joint
navicular bursa
what are the most common nerve blocks used in the hindlimb? (to block feet)
abaxial sesamoid nerve block
distal interphalangeal joint
navicular bursa
what is the site for a palmar digital nerve block?
just proximal to collateral cartilage
abaxial to the edge of DDFT
over and distal to neuromuscular bundle
what volume is used for a palmar digital nerve block?
1.5-2ml
what structures are desensitised by the palmar digital nerve block?
navicular bone/bursa
collateral suspensory ligaments
distal sesamoidean impar ligament
DDFT/sheath
digital cushion
palmar third of lamellae
palmar pedal bone
collateral cartilage
what is the site for the abaxial sesamoid nerve block?
immediately palmar to neurovascular bundle at the abaxial surface of the base of the proximal sesamoid bone
what volume is used for the abaxial sesamoid nerve block?
2ml
what structures are blocked by the abaxial sesamoid nerve block?
(all of palmar digital nerve block)
P2/P3 and palmar P1
collateral ligaments of DIP/PIP joints and joints itself
distal sesamoidean ligaments
lamellar corium and coronary band
distal digital extensor tendons
what is the site used for a distal interphalangeal joint block?
depression proximal to coronary band and then place needle vertically through skin and extensor tendon
what volume is needed for a distal interphalangeal joint block?
6ml
what structures are desensitised by the distal interphalangeal joint block?
DIP joint
collateral ligaments of DIPJ
navicular bone/bursa
what structures are desensitised by the navicular bursa block?
quite specific to navicular bursa
what is laminitis?
(inflammation of the lamellae)
lameness arising from damage to the laminae of the hoof
where is the majority of the weight bearing done in the horses hoof?
through lamellae, frog and hoof walls (not the sole)
what do lamellae need a constant supply of?
glucose
if glucose fails to be supplied to the foot, what happens?
basement membrane structures break down meaning the lamellae breaks down
is glucose uptake in the foot insulin mediated?
no
what is the most common aetiology of laminitis?
endocrinopathic laminitis
what are some of the less common aetiologies of laminitis?
endotoxins/inflammatory laminitis
mechanical laminitis
supporting limb laminitis
glucocorticosteroud induced laminitis
carbohydrate overload
what is the vascular theory for laminitis?
laminitis is partly caused by altered blood flow leading to ischaemia and necrosis (hence the use of blood modifying agents and anti-inflammatories
what is the supporting limb laminitis theory?
horses which are non-weight bearing on one-leg often develop laminitis in the contralateral limb because the passive blood pump in the foot is no longer in action
what is mechanical laminitis?
a force which physically tears the hoof from the laminae - can be a chronic force or one off incident
what drugs can cause laminitis?
steroids (glucocorticoids)
how does carbohydrate overload lead to laminitis?
excessive intake overwhelms the small intestine and overspills into the large bowel this causes bacterial proliferation and handgun acidosis releasing laments-inducing substances
what are the sugars in grass that can cause laminitis?
fructans
what is fructans associated with?
pasture-induced laminitis
what influences the amount of fructans present in grass?
type of plant, part of plant, growing season, temperature, sunlight, stress…
what are the endocrinopathic causes of laminitis?
equine metabolic syndrome (EMS) or pituitary pars intermedia dysfunction (PPID)
why does insulin dysregulation cause laminitis?
high insulin levels damages the cytoskeleton of laminar cells and alters the blood flow to the foot
what forces can act to separate the pedal bone from hoof wall in laminitis cases?
weight of horse driving downwards
DDFT pulling P3 around
force of toe on the floor
what are the two types of rotation that can be seen with laminitis?
capsular rotation - P3 remains in line with P2
bony rotation (associated with severe laminitis)
what is a sinker?
vertical displacement of P3 downwards (with/without rotations) causing a very thin sole
why does infection/abscesses often occur with cases of laminitis in which the pedal bone has moved?
movement of the bone causes a gap to for which becomes a heamatoma/necrotic which can often get infected
the stretched wall also allows easier access for bacteria
why does laminitis often result in abnormal growth of the hoof?
if pedal bone drops down it drags the coronary band with it, leading to compromised (crushed) blood supply to the band
the toe will grow slower than the heel so diverging hoof rings can be seen
which feet is laminitis most commonly seen in?
both front feet
why would you want to find out the age of a horse with suspected laminitis?
too see if he has PPID (>15 years of age - definitely consider)
what score using the neck of a horse was developed to aid laminitis?
cresty neck score - lower the score the less likely the horse is to have hyperinsulinaemia
what is the typical stance seen in a horse with laminitis of the front feet?
rocking back onto hindlimbs to take weight off forelimbs
(or shifting weight between limbs)
what is the stance and gait of a laminitic horse?
reluctant to move
short steps
worse on hard and stoney surfaces
exacerbated by turning
(high stepping in hindlimb laminitis)
what is a grade 1 laminitis?
lameness not noted at a walk but short stilted gait is noted
what is a grade 2 laminitis?
stilted gait at walk but moves willingly
what is a grade 3 laminitis?
reluctant to move and resists attempt to lift feet
what is grade 4 laminitis?
horse refuses to move
what are the clinical signs regarding the hoof of a horse with laminitis?
increased digital pulse
sinking of coronary band
heat in hoof
pain on hoof testers
where is pain usually worse when using hoof testers on a laminitis horse?
over the edge of the pedal bone
what ways can aid diagnosis of whether a horse has laminitis or just a sore foot?
give them time (bruise improves, abscess worsens, laminitis stays the same)
laminitis often has bilateral focal pain
(often very difficult to say for sure)
what are the phases of laminitis?
prodromal
acute
stabilisation
chronic
relapse or soundness
what is the best way to prevent laminitis in the prodromal phase?
cryotherapy (often no clinical signs)
what happens in the acute phase of laminitis?
P3 begins to move and pain becomes apparent
what actions should be taken during the acute phase of laminitis?
limit damage with analgesia, rest and supporting P3
what are the basic aims of treating laminitis?
remove the cause
provide analgesia
provide circulatory changing drugs
support the foot
investigate the cause
rehabilitate the foot (trim/shoe)
how can we remove the cause of laminitis?
remove them from pasture (can control diet better)
look for endocrinopathies (PPID and EMS)
box rest (control walking)
what is the usual analgesia used for laminitis?
phenylbutazone
what types of analgesics can be used for laminitis?
NSAIDs
paracetamol
(can try others)
why are nerve blocks contraindicated for laminitis?
horse moves around to much which will cause more damage and needs regularly administration (good if horse needs to be moved)
what nerve block is used to move painful laminitic cases?
abaxial sesamoid nerve block
what circulation changing drugs can be used for laminitis cases?
acepromazine
aspirin (rarely used)
how does acepromazine effect blood flow to the feet?
vasodilator - decreases blood pressure to digit
what phase of laminitis is cryotherapy most commonly used in?
acute phase (needs to be done early) - very time consuming
where does weight need to be transferred to to support the laminitis foot?
heel, frog and hoof wall (take pressure off sole and pedal bone tip)
how can you support the foot in laminitis cases?
deep bedding and shift weight onto heel, frog and hoof wall
what diet is fed to EMS horses?
1.5-2% of body weight in soaked hay with balanced protein and minerals
(no treats)
when is trimming of laminitic feet considered?
once foot is stabilised and pedal bone has stopped moving
how is the foot trimmed in laminitis cases?
shorten toe and remove excess heel (little and often is best)
what is the most common shoe used to rehabilitate a laminitic foot?
heartbar
when should the horse start walking/exercise again after laminitis?
depends on horse and level of pain
introduce gentle work when stable
what can be done regarding the DDFT in cases of laminitis?
severe case can have the DDFT cut to stop pedal rotation
what should the perfect hoof capsule look like from the front?
medial/laterally symmetrical
coronary band perpendicular to ground
what is the T square used for?
to assess symmetry at the heel of the hoof (on the long axis)
where should the centre of the foot be when looking at the solar view?
just back from the apex of the frog
what does the white line of the hoof represent?
the true shape that the hoof capsule/foot should be
how does the angulation of the hindfoot compare to the forefoot?
hind foot usually has a steeper angulation
what shape of the feet does a horse standing underneath itself correlate to?
forefeet - long heel, short toe
hind feet - short heel, long toe
what is assessed on a dynamic assessment of a lame horse at walk?
soundness (lame or not)
stride length/symmetry
footfall (landing on toe/heel/lateral and rotation/twisting)
what is broken back hoof pastern axis?
long toe and short heel
when raising a heel, what features does the shoe need to have?
longer than usual to support
packing to weight is evenly distributed
what can be done to correct medio-lateral imbalances in the hoof?
put a shoe on that loads the effected side and then trim the hoof capsule so it doesn’t touch the shoe (floating)
how should a shoe be fitted if the horse has a crack in its hoof?
with the crack open so when the horse puts weight on it again it doesn’t split open
what are the first things to do when treating acute laminitis?
remove cause
box rest
mild pain relief
improve frog pressure
(keep feeding)
what is the function of a lilypad?
provide instant frog pressure to improve the blood supply
what is the function of a styrofoam support?
provide instant from pressure and support the hoof
what is true rotation of P3?
when P3 is no longer in alignment with P1 and P2
what is not true rotation of P3?
when P3 is still in line with P1 and P2 (due to horse having a long toe)
what is done to fix the rotation of P3?
trim the frog out and then X-ray to see how much heel to remove then fit a heart bar shoe
what are the clinical signs of a founder/sinker?
coronary band depression
serum exudate
separation of hoof capsule
what is the founder distance?
distance from coronary band to extensor process of P3
what is the rough technique for a dorsal wall resection?
trim hoof capsule and apply heart bar shoe
mark area to be removed and dremmel out
don’t use a nerve block - want to know when sensitive tissue has been reached (just sedate)
what are the disadvantages of using plastic glue ons for chronic laminitis?
expensive
poor grip (especially white)
don’t get sufficient frog pressure
when performing a clinical exam on a horse with foot pain, what should be noted?
resting stance (weight shifting…)
foot balance/conformation
wound/injury
effusions/swellings
heat/pulses
pain (hoof testers)
what is the location of a palmar digital nerve block?
proximal to collateral cartilage and abaxial to the edge of DDFT
what is the most common imaging modality for the foot?
radiography
what are the five main radiographic views of the foot?
dorsopalmar
lateromedial
dorsoproximal-palmarodistal oblique
palmaroproximal-palmarodistal oblique
how is the horse positioned for a lateromedial radiograph of the foot?
weightbearing on the foot but on a raised block
where is the beam of the radiograph centred to for a lateromedial of the foot?
1-2 cm below coronary band halfway between dorsal hoof wall and heel
perpendicular to foot
what should the solar angle be?
very slightly downwards towards the toe and the sole
what should be distinct on the radiograph of the navicular bone?
corticomedullary definition
if a horse has sidebone, what has happened?
collateral cartilages of P3 have mineralised
how is the horse positioned for a horizontal dorsopalmar radiograph of the foot?
stood on a block and weight-bearing
where is the beam centred for a horizontal dorsopalmar of the foot?
2cm below coronary band perpendicular to limb
what are the two versions of a dorsoproximal-palmarodistal oblique radiograph of the foot?
upright pedal
high coronary
what is the difference between an upright pedal and high coronary radiograph?
upright pedal has the horses toe on a Hickman block so the beam is perpendicular to the plate
high coronary has beam angled through the coronary band with cassette underneath horse
how is the image of a high coronary radiograph distorted?
slightly elongated foot
what is the palmaroproximal-palmarodistal oblique radiographic view also known as?
skyline
how is the horse positioned for a palmaroproximal-palmarodistal oblique radiograph?
foot on casette
leg back/fetlock extended
what could cause primary pain of the distal interphalangeal joint and associated structures?
synovitis
osteoarthritis
osteochondral fragmentation
joint trauma
collateral ligament desmitis
osseous-cyst like lesions
what is done to treat synovitis or osteoarthritis of the distal interphalangeal joint?
intra-articular medication (hyaluranon…)
NSAIDs
remove fragments (if present)
how is joint trauma of the distal interphalangeal joint treated?
rest and NSAIDs
what can cause a pedal bone fracture?
kicking a wall (blunt trauma) or penetrating injury
what are the clinical signs of pedal bone fractures?
acute foot pain
increased digital pulse
positive response to hoof testers
how are pedal bone fractures managed?
immobile and rest using a bar shoe of foot cast
surgery
what are the options for surgical management of pedal bone fractures?
removal of fragments
internal fixation
PD neurectomy
what reduced the prognosis of a pedal bone fracture?
if it is articular
what is non-septic pedal osteitis?
vague term covering radiographic changes in the pedal bone in horses with chronic foot soreness due to foot imbalances
what is the typical history/presentation of a horse with navicular disease?
chronic bilateral forelimb lameness
lameness worse on hard surfaces and when walked in a circle
low heel, long toe conformation
unwilling to walk forward
what pathology is associated with navicular disease?
age - thinning of fibrocartilage
defects in palmar surface cartilage
DDFT damage
defects in palmar cortical bone
new bone formation along collateral sesamoidean ligament
degenerative changes
how will horses with navicular disease move in dynamic evaluation?
lame - worse on hard surface and in circles
land toe first
what nerve blocks should a horse with navicular disease respond to?
palmar digital
distal interphalangeal
navicular bursa
what radiographic abnormalities will be seen with navicular disease?
medullary cyst
flexor cortex erosion
loss of corticomedullary definition
distal border fragmentation
what is the most important aspect to preventing progression of navicular disease?
farriery - correcting foot balance
what medical treatments are available for the management of navicular disease?
NSAIDs
intra-articular medication (hyaluranon…)
bisphosphonates (modulate bone change)
what structures stabilise the proximal interphalangeal joint?
collateral ligaments
distal sesamoidean ligaments
insertion of SDFT
how is the motion and loading of the proximal interphalangeal joint described?
low motion and high loading
where does the SDFT insert?
palmar/plantar scutum of P2
what bones make up the fetlock?
P1, third metacarpal/tarsal, proximal sesamoid bones
is the fetlock a high or low motion joint?
high
what are the radiographic views used for the pastern region?
lateromedial
dorsopalmar
dorsolateral palmaromedial oblique
dorsomedial palmarolateral oblique
what is osteoarthritis of the pastern known as?
articular ringbone
why is osteoarthritis of the pastern commonly seen?
high loading, low motion joint
what is osteoarthritis?
progressive destruction of articular cartilage with subchondral bone thickening and osteophyte production
what are the two main clinical signs of pastern osteoarthritis?
mild/moderate lameness
bony thickening over dorsal pastern
how commonly is osteochondrosis seen in the pastern?
relatively uncommon
what are the manifestations of osteochondrosis of the pastern region?
osseous cysts
palmar/plantar osteochondral fragmentation
what is the prognosis for osteochondrosis of the pastern region?
guarded
what soft tissue injuries occur in the pastern area?
SDFT branch injury
distal sesamoidean ligament injury
what are the possible outcomes/treatments for pastern fractures?
conservative management
surgery
euthanasia
what type of pastern fractures does euthanasia need to be considered for?
comminuted, open, unstable fractures
what is pastern subluxation?
soft tissue structures of pastern are disrupted causing displacement/instability
what are the main clinical findings of a horse with pastern subluxation?
acute lameness/instability
marked soft tissue swelling
what are the locations that describe a proximal sesamoid bone fracture?
apical (top third)
mid-body
basilar (bottom)
axial (inside)
how can proximal sesamoid bone fractures be managed?
conservative - foals
surgical - fragment removal
euthanasia - biaxial/comminuted
what is sesamoiditis?
inflammation around the soft tissue of the palmar fetlock
what horses is sesamoiditis seen in?
young performance horses
how is sesamoiditis managed?
rest/NSAIDs
cold therapy
shockwave therapy
how clinically significant are osteochondral fragments of P1?
can be not clinically relevant - block the joint and see if any improvement is seen
what are the manifestations of osteochondrosis of the fetlock?
osteochodritis desicans of the sagittal ridge
osseous cysts of distal third metacarpal
how is osteochondritis desicans of the fetlock seen on radiographs?
flattening of sagittal ridge
fragmentation/flaps
what is osteoarthritis of the fetlock region?
degenerative joint disease resulting in joint effusion, cartilage loss, osteophyte production of loss of joint function
why is osteoarthritis a problem in the fetlock joint?
it is a high motion joint - don’t cope very well
what horses is palmar/plantar osteochondral disease seen in?
young racehorses
what is palmar/plantar osteochondral disease?
degenerative condition of the distal condyles
what causes palmar/plantar osteochondral disease in young racehorses?
repetitive high strain on the bone and articular tissue leading to cartilage loss and collapse of the articular surface
how can palmar/plantar osteochondral disease be treated in the early stages?
often altering the exercise routine of the horse is enough
what causes chronic proliferative synovitis?
chronic repetitive trauma to the dorsal aspect of the fetlock due to hyperextension
what are the radiographic findings of chronic proliferative synovitis?
crescent shaped bone loss of distal third metacarpal
soft tissue swelling
what is the third metacarpal/tarsal bone called?
cannon bone
what is the proper name of the inferior check ligament?
accessory ligament of the DDFT
where does the medial and lateral suspensory ligament insert onto?
proximal sesamoid bones
what do the tendons enter when they pass through the fetlock canal?
digital flexor tendon sheath
when radiographing fractures of the third metacarpus/tarsus why should you be careful not too over collimate?
lateral condylar fractures tend to exit laterally above the physical scar and medial condylar fractures spiral proximally
what are the remnants of the second and fourth metacarpal/tarsal bone called?
splint bone
is the second or fourth metacarpal/tarsal bone more medial?
second - medial splint bone
fourth - lateral splint bone
what is the digital extensor called in the forelimb and hindlimb?
forelimb - common digital extensor
hindlimb - long digital extensor
what is the main reason for condylar fractures?
repetitive strain injuries (usually have underlying pathology)
