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)