Diagnosing Lameness in the Horse

Question 1

Why perform a lameness exam?

Answer 1

Pre-purchase exam, neurologic disorder, etc

Question 2

What is lameness? What are some common causes?

Answer 2

An abnormality due to pain

- Caused by neurologic, metabolic, or mechanical problems

Question 3

What are the 7 classic steps of a lameness exam?

Answer 3

1. History
2. PE
3. Palpation of weight bearing/ non-weight bearing limbs
4. Exercise observations
5. Flexion tests
6. Diagnostic Nerve blocks
7. Diagnostics imaging

Question 4

What is the primary goal of a lameness exam?

Answer 4

To localize and diagnose the lameness

Question 5

What are you feeling for on a PH/ palpation?

Answer 5

• Weight bearing vs. non-weight bearing
• Symmetry
• Hoof testers

Question 6

What is the importance of trotting during an exercise observation?

Answer 6

• It is where the gait lameness is graded from

Question 7

What is the best surface for a lameness exam?

Answer 7

Blacktop/ tarmac

Question 8

What is a “ down sound” in a forelimb lameness exam?

Answer 8

• Head rises when the LAME limb is weight bearing and drops when SOUND limb is weight bearing

Question 9

What abnormal motions do you see with a hindlimb lameness exam?

Answer 9

• Head goes down when lame limb is weight bearing

- Gluteal excursion increases in lame limb –> Hip hikes and hip drops

Question 10

When can a hindlimb lameness be confused with a forelimb lameness?

Answer 10

• When a head and neck nod is present

Question 11

What parts of the hoof are you testing with hoof testers?

Answer 11

Wall, sole, frog, heels, coronary band

Question 12

What is a Grade 1 Lameness?

Answer 12

• Difficult to observe, inconsistent

Question 13

What is a Grade 2 Lameness?

Answer 13

• Difficult to observe in a straight line but consistently apparent under certain circumstances (circling, hard surface, incline)

Question 14

What is a Grade 3 Lameness?

Answer 14

• Consistently observable at a trot under all circumstances

Question 15

What is a Grade 4 Lameness?

Answer 15

• Obvious lameness with marked head nod, hitching, shortened stride

Question 16

What is a Grade 5 Lameness?

Answer 16

• Minimal weight bearing/non weight bearing and inability to move

Question 17

What are 5 pathognomonic lamensses that can be diagnosed at the walk?

Answer 17

• Peroneus tertius rupture
• Upward fixation of patella (Locking patella)
• Stringhalt
• Fibrotic myopathy
• Sweeney

Question 18

What is fibrotic myopathy?

Answer 18

Damage to the semimembranosus and semitendinosus resulting in fibrosis of these muscles and inability to contract those muscles

Question 19

What is stringhalt?

Answer 19

Overexagerrated gait

Question 20

What sign do you see in a positive flexion test?

Answer 20

Exacerbated lameness

Question 21

How do you perform a forelimb flexion test?

Answer 21

DISTAL: hold for 30 sec
can give false positives in normal young horses
PROXIMAL LIMB FLEXION: flex carpus for 60 secs

Question 22

How do you perform a hindlimb flexion test?

Answer 22

DISTAL LIMB: same as forelimb

PROXIMAL LIMB: Spavin test –> 90 sec (not hock specific)

Question 23

In what direction should you give local anesthesia?

Answer 23

Begin distally and work proximally –> direct needle distally

Question 24

What diagnostic tool allows you to look soft tissue and some bone real time?

Answer 24

Ultrasound

Question 25

When is nuclear scintigraphy/ bone scan indicated?

Answer 25

• Can’t determine site of lameness
• Lameness not detected with US or radiographs
• Multiple limb lameness
• Intermittent lameness
• Upper limb/ pelvic lameness
• Possible fracture not seen on rads

– Gives poor anatomic detail

don’t use in young horses –> active physis

Question 26

What is a side-effect of nuclear scintigraphy?

Answer 26

• Horse will be radioactive

Question 27

What diagnostic tool is great for soft tissue unable to be seen with US?

Answer 27

MRI

• Better for soft tissue and fluid contrast
• Used for lameness diagnosis that can’t be made with other diagnostics

Question 28

What is an Equinosis Q/ Lameness Locator

Answer 28

• Uses wireless, body-mounted sensors to detect lameness