Equine Lameness - Overview

Question 1

what are some common presentations of a lame horse?

Answer 1

subtle changes in weight-distribution during gait, non-weight bearing lameness that causes severe distress, & severe mechanical lameness without pain

Question 2

what are some differentials for traumatic causes of lameness in horses?

Answer 2

fracture, soft tissue injury, laminitis, foreign body, bruised sole/heel, muscle strain, hygroma, & OA

Question 3

what are some differentials for congenital causes of lameness in horses?

Answer 3

OCD & angluar limb deformity

Question 4

what are some differentials for infectious causes of lameness in horses?

Answer 4

foot abscess, septic joint/tendon sheath/bursa, cellulitis, white line disease/thrush/quittor/canker, & lyme disease

Question 5

what are some differentials for metabolic causes of lameness in horses?

Answer 5

laminitis & myopathy

Question 6

what are some differentials for mechanical causes of lameness in horses?

Answer 6

stringhalt, fibrotic myopathy, & intermittent upward fixation of patella/delayed patellar release

Question 7

what are some differentials for circulatory/other causes of lameness in horses?

Answer 7

laminitis, navicular syndrome, improper hoof balance/shoeing (especially on top of poor confirmation), silicosis, OA, & keratoma

Question 8

what are the very important questions you need to ask when taking a history on a lame horse?

Answer 8

duration, onset (sudden vs gradual), any previous lameness or recent illness, treatments/management of lameness & results, level of work the horse does, last shoeing/trim, & what exacerbates the lameness

Question 9

what are the different grades of the AAEP lameness scale?

Answer 9

grade 1: only perceptible under certain conditions, grade 2: consistently perceptible under certain circumstances, grade 3: consistently perceptible in a straight line & circle at a trot, grade 4: consistently perceptible at a walk, & grade 5: non-weight bearing

Question 10

how do you need to exam a lame horse to assign a lameness score?

Answer 10

observe the horse moving from the front/side/behind at a walk, trot, & canter both on a straight line +/- lunge line, on a hard & soft surface, in hand or under saddle

Question 11

what are some signs seen on physical exam of a horse that is lame on its forelimbs?

Answer 11

down on sound - head bobs up when lame limb hits the ground & goes down when the sound leg hits the ground

Question 12

what are some signs seen on physical exam of a horse that is lame on its hindlimbs?

Answer 12

more difficult to assess - sacrum/pelvis hikes up or moves more when the lame limb hits the ground - can get contralateral head bob with severe hind limb lameness

Question 13

what should you palpate on a lame horse during your physical exam?

Answer 13

limbs, joints, soft tissues, neck, back, & musculature - look for heat, pain, swelling, effusion - compare with contralateral limb

Question 14

what should you look to observe on a lame horse during your physical exam?

Answer 14

muscular asymmetries, stride length (often shorter in lame limb), wounds/scars, stance at rest, & wear on hooves.shoes & hoof confirmation

Question 15

what is the purpose of doing flexions on a lame horse? where do you perform them on the horse?

Answer 15

localize source of lameness - distal forelimbs, carpus, +/- shoulder, distal hindlimbs, hock/entire limb, stifle - make sure to use consistent pressure & duration

Question 16

what is the purpose of using hoof testers on a lame horse? where do you check the foot with the hoof testers?

Answer 16

help localize any foot soreness - toes, quarters, & across heel/frog

Question 17

when should you use extreme caution & not force a lame horse to move/exercise during a lameness exam?

Answer 17

lamesness is severe or a fracture is suspected - do not use regional blocks, making them walk on the limb can worsen the injury, & a closed fracture can become an open fracture

Question 18

how long does lidocaine work for regional anesthesia for a lameness exam? what about mepivacaine? bupivacaine?

Answer 18

lidocaine: 30-45 minutes, mepivacaine: 90-120 minutes, & bupivacaine: 4-6 hours

Question 19

if a lameness disappears after a nerve block, what does that indicate?

Answer 19

the problem causing the lameness is at or distal to the location of that injection

Question 20

you always should start local blocks distally & move proximally when working up a lame horse except in the case of what?

Answer 20

if you suspect a specific joint based on the exam!!!

Question 21

90% of all equine lameness is localized to what?

Answer 21

the foot!!!!!

Question 22

when are rads the best diagnostic option for a lame horse? what is required for good images?

Answer 22

best for bone lesions, & can be performed in clinic or in the field - good images require proper positioning and at least 2 views in 2 planes - can use contralateral limb to compare if needed

Question 23

when is ultrasound the best diagnostic tool for a lame horse?

Answer 23

best for soft tissue, some bone lesions, & wound evaluation - can perform in the field or in a clinic, diagnostic utility correlates with user experience, & can compare contralateral limb if needed

Question 24

when is nuclear scintigraphy the best diagnostic for a lame horse?

Answer 24

best for bone lesions - useful when lameness can’t be localized or there are multiple lame limbs - requires referral & a hospital stay

Question 25

when is an MRI the best diagnostic for a lame horse?

Answer 25

best for soft tissue but also used for bone - requires referral & sedation/general anesthesia

Question 26

when is a CT the best diagnostic option for a lame horse?

Answer 26

best for bone lesions, but contrast can be used to enhance soft tissue lesions - requires referral & sedation/general anesthesia

Question 27

what are some medications used for joint injections?

Answer 27

steroids, hyaluronic acids, & autolgous therapies such as platelet-rich plasma, stem cells, sarapin, & interleukin-1 receptor antagonist protein

Question 28

what NSAIDS are often used to treat lame horses?

Answer 28

phenylbutazone, flunixin meglumine, & firocoxib

Question 29

what is the purpose of using methocarbamol for a lame horse?

Answer 29

muscle relaxer

Question 30

what is the benefit of using shock wave therapy for a lame horse?

Answer 30

increases healing, decreases pain & inflammation, increases neovascularization, & increases osteogenesis

Question 31

what are some adjunctive therapies used for lame horses?

Answer 31

massage, chiropractics, & acupuncture

Question 32

if a lame horse presents with multifocal neuro signs & asymmetric muscle atrophy- what do you suspect?

Answer 32

EPM