Lame - Equine acute foot problems Flashcards
What does bruising of the hoof look like?
Reddening of the hoof wall or sole
What are two types of cracks in hooves? What are they?
Grass cracks - up wall
Sand cracks - grow down from coronary band after injury
Where do swellings/depressions in the hoof occur?
At the coronary band
What causes depressions at the coronary band?
Laminitis - sinking of the extensor process of P3
What is thrush?
Destructive lesion of the hoof - fusebacterium
What can cause thickening of the white line in horses?
Laminitis
What is divergence in the equine hoof?
Growth lines on the hoof wall as they grow from the coronary band
Should be parallel
May be rasped off at the bottom by farrier
What can you palpate the coronary band for?
Depression - sinking of P3
Effusion of DIP joint
Hoof abcess tracking up - painful area
What is a grass crack?
Crack that is going up from the solar edge (like a blade of grass growing out the ground)
What is a sand crack?
Crack going down from the coronary band
What can you do to stop a grass crack moving up the wall of the hoof?
Avoid horseshoe clips put in that area
Rasp a horizontal line across it to interrupt the crack
What can you do to treat a sand crack coming down from the coronary band?
Reduce load on that area by shortening, shoeing
What are the 3 synovial structures in the equine hoof?
Navicular bursa
Distal interphalangeal joint (coffin)
Digital flexor tendon sheath
What are the key nerve blocks for the hoof?
Palmar/plantar digital
Abaxial sesamoid
What is the key joint block that you need to know how to do?
DIP joint
Where is the navicular bursa located?
Distal to the navicular bone
What other structures can cross react with a navicular bursa block?
Communicates with the DIP joint
What is a common cause of sepsis in the navicular bursa?
Solar puncture wound
Is the navicular bursa injection easy?
No, it is difficult - but can be done with experience, ultrasound or radiographic guided
Also can treat via DIP joint if both affected
What should you do to prepare equine hooves for radiograph?
Remove mud, shoes, and flaky sole
Pack frog with playdoh
Why do you pack frog with playdoh for radiographs?
Because it gives an artefact over the radiograph otherwise - flattens the surface to all one colour
Where do you apply markers on hooves for radiographs?
Dorsal hoof wall
Coronary band
Point of frog
What position do you use for P3 lateromedial radiograph?
Hoof weight bearing on block
Cassette against medial aspect of limb on the ground
Beam on mid coronary band
What do you use hoof wall markers for?
Evaluating rotation or sinking of the hoof on radiograph
What should all be parallel on lateromedial radiograph of the hoof?
Dorsal hoof wall
Dorsal P3
Heel
Pastern
Where should the centre of the ark of the distal interphalangeal joint be on radiograph?
Vertically over middle of hoof and point of frog
What does broken forward mean?
Dorsal hoof wall angle is pointing further forward than the angle of the pastern
What angle should the solar surface of P3 be from the the sole of the hoof?
5-10 degrees
What shape should the tip of P3 be?
A point, not a ski slope - this would suggest chronic P3 pathology
What is the positioning for dorsopalmar radiograph of a hoof?
Weight bearing on block - square to beam
Cassette on palmar aspect of limb
Beam parallel to the ground centred at coronary band
What features can you look at on dorsopalmar radiograph of a hoof?
Mediolateral imbalance - difference between P3 and sole
Hoof wall flare
What structures can often be mistaken for abnormal pathology?
Vascular channels - normal
What is the dorsoproximal palmaro-distal oblique view radiograph of a hoof used to look at?
Solar margin of P3
Dorsal navicular bone
What positioning do you use for the dorsoproximal palmaro-distal oblique view radiograph of a hoof?
Weight bearing with foot stood on tunnel that you slide the cassette into
Beam 2cm above coronary band at 60 degree angle from cassette
What do you change when you want to focus on P3 or navicular bone?
Increase exposure
Reduce collimation
Decrease angle by 5 degrees
What is the crena?
Midline P3 margin - variable appearance
What is the dorsolateral-palmaromedial oblique radiograph of a hoof?
Same as the dorsoproximal palmaro-distal oblique view radiograph of a hoof but moved 45 degrees lateral to medial
What is the dorsolateral-palmaromedial oblique radiograph of a hoof useful for?
Assessing pedal wings, DIP joint and symmetry
What is the palmaroproximal-palmarodistal oblique radiograph of the hoof?
Navicular skyline:
Limb extended caudally while weight bearing on cassette in tunnel
Beam into divot at back of pastern avoiding the fetlock
What structures does the palmaroproximal-palmarodistal oblique radiograph of the hoof show?
Navicular bone
P3 - particularly wings
What does transcutaneous view ultrasound show? What can you see?
MRI used more now
Collateral ligament of DIP
DIP joint effusion
DDFT can be seen between heel bulbs
How do you do a solar view ultrasound through the frog of a hoof?
Difficult, not really done much now
Lots of preparation, soak hoof for hours
What can you see on solar view ultrasound through frog of hoof?
DDFT
Navicular bone/bursa
P3
What is gold standard imaging of the horses hoof? Why?
MRI - due to superior contrast details
What types of MRI are there?
Low field MRI - distal limb (25 in country)
High field MRI - head and neck, limbs (2 in country)
What is a pricked hoof/nail bind?
a nail placed in or axial to the white line during farriery
What does a pricked hoof present as?
Acute severe lameness a few days after the farrier has been
How do you diagnose a hoof prick?
Hoof testers and paring
How do you treat a pricked hoof?
Remove nail/shoe
Poultice - dressing
Week of rest
When do you get hoof bruising?
Unshod hooves walking on rough ground
How do you treat bruising in hooves?
Rest
Unshoe and poultice dressing
Reshoe after pairing
What are corns? What are they caused by?
Specific type of bruising at heel caused by a collapsed bar or too long shoeing interval
How do you diagnose corns?
Pain on hoof testers, usually specifically at the heel
What causes a hoof subsolar abscess?
Penetrating injury to solar surface
Bacteria tracking up the white line
What are the clinical signs of a hoof abcess?
Acute non weight bearing lameness
Increased digital pulses
Pain on hoof testers
How do you diagnose a hoof abcess?
Pus released during paring
How do you treat a hoof abcess?
Poultice - hoof dressing/bandage
Tubbing
Rest
What is tubbing?
Hoof in a bucket of salt water for 20 mins
Where do most hoof abcesses drain?
At the white line
What are some other hoof abcess draining sites than at the white line?
Coronary band
Frog
At the penetration site
What animals get very deep foot abcesses?
Donkeys
Small horses
What should you do in deep puncture wound cases?
Leave the foreign body in situ
Use wooden blocks for weight bearing
What structures must you assess in deep puncture wounds?
DIP joint
Navicular bursa
Digital flexor tendon sheaths
What should you do if the puncture wound affected any of the synovial structures of the hoof?
Arthroscopic lavage
Or euthanasia
Or poultice and rest
Analgesia
What is pedal osteitis?
Septic focus in P3 often following a puncture or pus in the foot
What are the clinical signs presentation of pedal osteitis?
Acute severe lameness which persists
Increased digital pulses
Pain on hoof testers
How is pedal osteitis diagnosed?
Imaging
How is pedal osteitis treated?
Curettage back to healthy bone - remove disease bone
Manage open wound - hospital plate, bandaging
How long will pedal osteitis surgical treatment take to heal?
Several months
Need to wait for granulation tissue to form and hoof to grow in to hole
What is a common cause of P3 fractures?
Trauma
Kicking brick walls - especially hind limbs
What is a type 1 P3 fracture?
Involve the palmar/plantar process
Dont enter DIP joint
Wing fracture
What is a type 2 P3 fracture?
Oblique or parasagittal fracture
Articular but not on the midline
Wing fracture
What is a type 3 P3 fracture?
Midline articular fracture
Bisect pedal bone into 2 equal halves
What is a type 4 P3 fracture?
Involve the extensor process of the pedal bone (top bit)
What is a type 5 P3 fracture?
P3 split into multiple fragments
What is a type 6 P3 fracture?
Solar margin fracture - chip out the bottom
What is a type 7 P3 fracture?
Exclusive to foals
Fracture of solar margin
What are the two treatment options for P3 fractures?
Depends on configuration
Surgical lag screw across fracture
Or conservative management - bar shoe and rest
What radiographic view is best for navicular bone fracture?
Palmaroproximal-palmarodistal oblique view
What does a parasaggital fracture mean?
Close to midline but not on it
What is the configuration of navicular bone fractures?
Usually parasagittal and slightly oblique
What is a fracture associated with ossification in the hoof?
Fracture of ossified ungual cartilages - ossification usually asymptomatic but are predisposed to trauma
How do fractured ossified ungual cartilages present?
Acute severe lameness
Increased digital pulses
Pain on palpation of heel bulbs
How are fractured ossified ungual cartilages treated?
Bar shoes and rest
What are the 4 phases/types of laminitis?
Developmental stage
Acute
Sub-acute
Chronic
What is the developmental stage of laminitis?
Causal event up until the clinical signs - need to act before clinical signs start if you can
What is acute laminitis?
From onset of signs to 72 hours
What is subacute laminitis?
Repair over 2-3 months
What is chronic laminitis?
Structural failure developing over an indefinite period
What is the main primary cause of laminitis?
Endocrinopathies - PPID, EMS, corticosteroids given to uncontrolled endocrinopathy horses
What causes of laminitis are there other than endocrinopaties?
Excess carb intake
Toxaemia
Contralateral limb lameness
What is the pathogenesis of laminitis?
Dermal epidermal separation of lamellae
Basement membrane lysis
What is the recurrence rate of laminitis?
30% recurrence rate
What breeds/types of horses are predisposed to laminitis?
Ponies
Heavy horses
Obese
Crest neck
What are the clinical signs of acute laminitis?
Weight on heels stance
Reluctant to move
Increased digital pulses
Pain on hoof testers
flatter solar surface
Coronary band depression
Solar bruising
What are the clinical signs of chronic laminitis?
Divergent growth rings
Change in hoof shape - boxy
What hoof changes can you see on radiograph in laminitis cases?
Rotation
Sinking
Gas
Remodelling/lysis
What degree rotation is non consistent with survival in laminitis?
More than 20 degrees
What can you use to alter laminar perfusion in the developmental phase of laminitis? Why?
Cold - ice feet
Vasoconstriction - prevent endotoxins reaching foot
What can you do to alter laminar perfusion in the acute phase? Why?
ACP
Vasodilation - increase perfusion, more oxygen
How can you prevent inflammation in laminitis treatment?
NSAIDs - also some analgesia
What mechanical support can you give laminitis cases?
Rest on deep bed
Styrofoam pads for frog support
Remove length of toe
Elevate heel
How do you trim hooves in subacute or chronic phases of laminitis?
Shorten toe
Remove heel height
Heart bar shoes
What is the prognosis for laminitis cases?
Very difficutl to predict - can go either way
How do you treat navicular bone fractures?
Surgical - lag screw (tricky)
Conservative - bar shoe and rest