Recognizing Lameness

Question 1

what are the goals of gait assessment of lame horse

Answer 1

1. identify lame limb(s)
2. quantify severity of lameness (grade it)
3. differentiate primary and compensatory lameness

Question 2

how is the lame limb identified

Answer 2

1. physical examination –> inspection, palpation (heat/pain/swelling, digital pulse strength, muscle atrophy, asymmetry)
2. joint manipulation (flexion & extension)
3. hoof tester application
4. gait assessment

Question 3

how is the gait assessed at the trot

Answer 3

most useful gait for lameness identification

symmetric two beat diagonal gait (RH-LF, suspension, LH-RF, suspension)

severeal possible variations (collected, medium/extended/flying trot, piaffe, passage)

Question 4

what is ipsilateral, contralateral,

Answer 4

ipsilateral = same side

contralateral = opposite side

Question 5

how does the head move during one complete forelimb stride cycle (L&R)

Answer 5

head moves down and up twice

minimum head height occurs at mid stance

maximum head height occurs after stance phase, just prior to weight bearing of contralateral forelimb (contralateral limb stance phase)

Question 6

what is one complete hindlimb stride cylcle (L&R)

Answer 6

pelvis moves down and up twice

minimum pelvic height at mid stance

maximum pelvic height after stance phase, just prior to wieght bearing of contralateral hindlimb

Question 7

what is tubera coxae movement

Answer 7

asymmetric verticle movement on contralateral/ipsilateral hindlimbs during stride cycle (results in pelvic rotation)

Question 8

what is contralateral tubera coxae movement

Answer 8

greater movement than for ipsilateral TC

minimum height during ipsilateral limb stance

maximum height following ipsilateral limb push off

Question 9

what is ipsilateral TC movement

Answer 9

minimum height during stance

maximum height following push off

Question 10

what is hindlimb protraction

Answer 10

observe distance between ipsilateral fore and hind foot prints

greatest hindlimb weight bearing first half of stance phase

decrease indicates hindlimb lameness

Question 11

what is joint angle change

Answer 11

extension of fetlock joint reflects weight bearing on the limb (ground reaction force)

Question 12

what else can be observed in a lameness exam

Answer 12

total stride length, foot placement, tripping or toe drag less reliable indicators of lameness

Question 13

how is forelimb lameness identified

Answer 13

the head will drop when the sound foot lands and will rise when weight is placed on the unsound foot or limb

Question 14

what does a downward head movement indicate

Answer 14

less on lame limb stance phase

reduced weight bearing by lame limb

significant difference in minimum head height between non-lame and lame limbs (greater on lame limb stance) –> down on sound

Question 15

when does upward head movement occur

Answer 15

upward head movement occurs after stance phase

less after lame limb stance phase

significant difference in maximum head height in majority of lame horses –> less after stance phase of lame limb

*head may move upwards during the lame limb stance phase when lameness is very severe

Question 16

what are patterns of forelimb head movement with impact pain

Answer 16

less downward movement on limb stance (minimum head height: lame > non-lame

less upward movement after lame limb stance (maximum head height: non-lame > lame)

Question 17

what are the patterns of forelimb head movement with severe pain on weight bearing such as a fracture

Answer 17

head moves upwards during the lame limb stance

Question 18

what is the pattern of forelimb head movement with pain on full weight-bearing like suspensory ligament injury

Answer 18

less downward movement on lame limb stance (minimum head height: lame > non-lame)

Question 19

what patterns of forelimb head movement with second-half of stance pain such as deep digital flexor tendon injury within foot

Answer 19

more upward movement after stance phase of lame limb (maximum head height: lame > non-lame)

Question 20

how do we identify hindlimb lameness

Answer 20

hip hike and hip drop

Question 21

what is hip hike and drop

Answer 21

rapid elevation of the hip and gluteals recognized as hip hike

gluteal muscle contraction is shortened –> shortened duration of gluteal rise –> subsequent hip roll or drop off

Question 22

what is downward pelvic movement

Answer 22

less during stance phase of lame limb

difference in minimum pelvic height between non-lame and lame limbs

greater pelvic height on lame limb –> hip hike

Question 23

what is upward pelvic movement

Answer 23

less upward movement after stance phase (push-off) of lame limb –> hip-drop

Question 24

how does pelvic movement indicate hindlimb lameness

Answer 24

asymmetry between limbs may be predominately due to differences in upward or downward –> depends on cause of lameness

most sensitive indicator of hindlimb lameness is asymmetric movement of entire pelvis during and after stance phase

Question 25

what is pelvic rotation

Answer 25

asymmetric movement of tubera coxae over whole stride cycle

greater verticle movement on side of lame limb

not reliable as using movement of entire pelvis (and difficult to reconcile the two methods)

Question 26

what is compensatory lameness

Answer 26

due to redistribution of load, not pain

forelimb lameness –> contralateral hindlimb lameness (RF, LH)

hindlimb lameness –> ipsilateral forelimb lameness (RH, RF)

Question 27

what is the numerical rating system

Answer 27

semi-quantitative assessment

scale of 0-5 or 0-10

Question 28

what is the AAEP system

Answer 28

0: no lameness
1: difficult to observe, not consistently apparent regardless of circumstances
2: difficult to observe at the walk or trotting in straight line, consistently apparent under certain circumstance (lunging)
3: consistently observable at a trot under all circumstances
4: obvious lameness with marked nodding, hitching or shortened stride
5: minimal weight bearing in motion and/or rest, inability to move

Question 29

what are the limitations of rating systems

Answer 29

differences in severity at walk, trot, lunge, ridden –> can grade these independently

limited granularity –> can use 1/2 grades

but the more points on a scale, the less reliable it will be

grading systems should not be used interchangeably

Question 30

what are visual lameness assessment tips

Answer 30

1. identify changes in both min and max head/pelvic height to accurately identify limb
2. adopt a single scale for scoring severity (AAEP)
3. maintain accurate records of assessment