Lecture 2: Equine Lameness Exam

what is the order of events for a lameness exam?

1. history

2. PE

3. motion exam

4. flexion tests

5. hoof testers

6. localize lameness

7. diagnostic imaging

history for lameness exam

• signalment

• use of the horse

• duration of lameness

• worsened or improved

• history of trauma

• management changes

• medications administered

• which leg owner thinks is affected

• last farrier visit

PE for lameness exam

• quick TPR

• observation → conformation, swellings, how horse is standing, hoof care, muscle symmetry

• limb palpation → joints, tendons/ligaments, digital pulses

is this poor or good quality hoof trimming/shoeing?

poor

is this poor or good quality hoof trimming/shoeing?

good

which side of this horse is hollow and abnormal?

the right

limb palpation is to check for

effusion, edema, bony proliferation

what joint is being palpated?

coffin joint

what joint is being palpated?

carpus

what joint is being palpated?

fetlock joint of all 4 limbs

what joint is being palpated?

tibiotarsal joint

what joint is being palpated?

femoropatellar

what is the most common site of joint palpation in horses?

medial femorotibial joint

what is circled?

medial femorotibial joint

what is this?

pastern OA

what is this?

bone spavin, distal tarsal joint OA

what is this?

carpal OA

what are you looking for during tendon and ligament palpation?

enlargement, thickening, pain

digital pulses

• every horse should have them → faint in normal horse

• increases in ability to palpate are significant

• should not be hot

what is the most appropriate conclusion to make from palpating increased digital pulses?

the horse has inflammation in the foot

back pain is often secondary to

hock pain/hind limb lameness

hoof testers should be used before

blocking the horse

basic motion exam

• walking in straight line

• trotting in straight line

• trotting in a circle → hard and soft surface

advanced motion exam

canter and under saddle

walking gait evaluation

• 4 beat gait

• evaluating stride length

• tracking up

trot gait evaluation

• 2 beat gait

• limbs move in diagonal pairs

• best gait for seeing lameness

what is the best gait for seeing lameness?

trot

AAEP lameness grade 0

lameness is not present under any circumstances

AAEP lameness grade 1

lameness is difficult to observe and is not consistently apparent

AAEP lameness grade 2

lameness is difficult to observe at a walk or when trotting in a straight line but consistently apparent under certain circumstances

AAEP lameness grade 3

lameness is consistently observable at a trot under all circumstances

AAEP lameness grade 4

lameness is obvious at a walk

AAEP lameness grade 5

lameness produces minimal weight bearing in motion and/or a rest

sound

the “not” lame leg/legs

head bob

refers to movement of the horse’s head and neck when lame in the front limb → down on sound

hip hike

lame limb has increased motion in the pelvis as the horse tries to bear less weight on the lame hind limb

fetlock drop

sound limb fetlock drops further with increased weight bearing to compensate for lame limb

tracking up

hind limb lands in or beyond front limb hoof print

stride length

comparable between sound and lame limbs

lameness detection

evaluating for asymmetry in the gait

sound limb lameness detection

• drops fetlock

• head nod → head moves down when horse bears more weight

lame limb lameness detection

• head bob → head moves up when lame leg hits the ground

• hip hike → hind limb lameness, increased pelvic movement

• asymmetric movement → shorter stride

flexion tests

• put stress on a joint to see if it changes the horse’s lameness

• pretty subjective

• learn to do these ergonomically

• variation in medical records

forelimb flexion tests

• distal limb → coffin, pastern, fetlock

• carpus → will flex elbow some

• upper limb → shoulder and elbow

• coffin joint hyperextension → stress on navicular apparatus

hindlimb flexion tests

• challenge of the reciprocal apparatus

• distal limb → same as forelimb, will flex hock some

• upper limb → hock, stifle, hip, will flex fetlock some

• caudal extension → mostly stifle

distal limb flexion test

typically hold for 30s

carpus/tarsus flexion test

hold for 45 seconds

nerve blocks

• local anesthetic injected SQ over nerves

• numbs the area distal to the injection site

principles of nerve blocks

• start distal and work proximal

• typically skip the palmar digital in the hind limb

principles of joint blocks

• local anesthetic within a joint to numb the joint

• order of joints is not as important as nerves

local anesthetic migrates so

• time → wait 5 mins

• volume → least possible

• location → accurate

mepivicaine

• most commonly used

• less tissue irritation

• fast acting

• duration is 2-3 hours

lidocaine

• stings

• fastest acting

• duration is 1.5-3 hours

bupivicaine

• intermediate onset of action

• duration is 3-6 hours

palmar digital nerve block

• called PD

• insert needle over neurovascular bundle proximal to the collateral cartilages

• 1-2ml carbocaine per site

• usually 25g needle

what structures are blocked with a PD nerve block?

caudal 1/3 of the foot, sole, navicular apparatus

what nerve block is this?

PD

abaxial sesamoid block

• commonly called abaxial

• insert needle SQ over the neurovascular bundle at the abaxial surface of the sesamoid bones

• 1-3ml carbocaine at each site

what structures are blocked with an abaxial sesamoid block?

all structures below the fetlock, ± the fetlock itself

what block is this?

abaxial sesamoid

low 4 point block

• inject under the button of the splint bone (medial and lateral)

• inject over the neurovascular bundle between the DDF and the suspensory ligament

• deposit 2-3ml per site

what structures are blocked with the low 4 point block?

fetlock joint and distal → inconsistent loss of skin sensation dorsally on the hind limb

what block is this?

low 4 point block