Recognizing Lameness Flashcards
what are the goals of gait assessment of lame horse
- identify lame limb(s)
- quantify severity of lameness (grade it)
- differentiate primary and compensatory lameness
how is the lame limb identified
- physical examination –> inspection, palpation (heat/pain/swelling, digital pulse strength, muscle atrophy, asymmetry)
- joint manipulation (flexion & extension)
- hoof tester application
- gait assessment
how is the gait assessed at the trot
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)
what is ipsilateral, contralateral,
ipsilateral = same side
contralateral = opposite side
how does the head move during one complete forelimb stride cycle (L&R)
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)
what is one complete hindlimb stride cylcle (L&R)
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
what is tubera coxae movement
asymmetric verticle movement on contralateral/ipsilateral hindlimbs during stride cycle (results in pelvic rotation)
what is contralateral tubera coxae movement
greater movement than for ipsilateral TC
minimum height during ipsilateral limb stance
maximum height following ipsilateral limb push off
what is ipsilateral TC movement
minimum height during stance
maximum height following push off
what is hindlimb protraction
observe distance between ipsilateral fore and hind foot prints
greatest hindlimb weight bearing first half of stance phase
decrease indicates hindlimb lameness
what is joint angle change
extension of fetlock joint reflects weight bearing on the limb (ground reaction force)
what else can be observed in a lameness exam
total stride length, foot placement, tripping or toe drag less reliable indicators of lameness
how is forelimb lameness identified
the head will drop when the sound foot lands and will rise when weight is placed on the unsound foot or limb
what does a downward head movement indicate
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
when does upward head movement occur
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
what are patterns of forelimb head movement with impact pain
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)
what are the patterns of forelimb head movement with severe pain on weight bearing such as a fracture
head moves upwards during the lame limb stance
what is the pattern of forelimb head movement with pain on full weight-bearing like suspensory ligament injury
less downward movement on lame limb stance (minimum head height: lame > non-lame)
what patterns of forelimb head movement with second-half of stance pain such as deep digital flexor tendon injury within foot
more upward movement after stance phase of lame limb (maximum head height: lame > non-lame)
how do we identify hindlimb lameness
hip hike and hip drop
what is hip hike and drop
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
what is downward pelvic movement
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
what is upward pelvic movement
less upward movement after stance phase (push-off) of lame limb –> hip-drop
how does pelvic movement indicate hindlimb lameness
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
what is pelvic rotation
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)
what is compensatory lameness
due to redistribution of load, not pain
forelimb lameness –> contralateral hindlimb lameness (RF, LH)
hindlimb lameness –> ipsilateral forelimb lameness (RH, RF)
what is the numerical rating system
semi-quantitative assessment
scale of 0-5 or 0-10
what is the AAEP system
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
what are the limitations of rating systems
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
what are visual lameness assessment tips
- identify changes in both min and max head/pelvic height to accurately identify limb
- adopt a single scale for scoring severity (AAEP)
- maintain accurate records of assessment
