Intro to lameness

Question 1

What are the general parts of lameness invistigations?

Answer 1

• History
• Physical examination
  
  • observation from a distance
  • direct palpation
  • ancillary tests
• Lameness examination
  
  • basic examination
  • additional movements/surfaces
  • evocative tests

Question 2

what is the definition of lameness and what are the 5 types?

Answer 2

“A clinical sign [caused by] inflammation including pain or a mechanical defect that results in a gait abnormality”
Five “types” of lameness
* supporting limb (stance phase) lameness (when leg hits the ground)
* swinging limb lameness
* mixed lameness
* compensatory lameness
* induced/artefactual lameness

Question 3

fill in the blanks:
* typically …………… lameness is more common than ………………… lameness.
* forelimb lameness above the ……………… is extremely uncommon in all groups of horses

Answer 3

• typically forelimb lameness is more common than hindlimb lameness
• forelimb lameness above the carpus is extremely uncommon in all groups of horses

Question 4

Specific age groups often suffer from specific conditions.
What commmon conditions affect Foals, Young horses and older horses?

Answer 4

• foals: haematological septic arthritis, lateral luxation of the patella
• young, skeletally immature animals: developmental orthopaedic diseases including OCD, stress related injuries (esp TB horses)
• older horses: chronic progressive OA, navicular disease

Question 5

What history questions do you need to ask with lameness?

Answer 5

• When did the owner first notice the problem? Is there a history of trauma?
• Have any treatments been attempted?
• What is the nature of the lameness?
• Does it improve with exercise? Is it worse on different surfaces/with different tack?
• Have there been any recent changes in management/exercise level/paraprofessional involvement?
• Is there any previous history of lameness?

Question 6

Hock conformation has a very significant effect on the prognosis for of hind limb suspensory desmopathy, what is the prognosis of horses with primary PSD and normal hock conformation after surgery vs gorses with primary PSD and straight hock conformation after surgery?

Proximal suspensory desmitis (PSD)

Answer 6

• 77.8% (70/90) of horses with primary PSD and normal hock conformation returned to full soundness for >1yr following surgery
• 0% of horses with primary PSD and straight hock conformation and/or hyperextension of the MTPJ returned to exercise

Question 7

What points do you need to observe when looking at the horse’s posture from a distance?

Answer 7

• laminitis or severe skeletal injuries might be readily obvious
• pointing or reduced weight-bearing
• “dropped elbow” indicates failure of the triceps apparatus
• cervical pain (can’t move neck)
• upward fixation of the patella (locked out hind limb behind horse)
• (neurological conditions)

Question 8

Asymmetry is often very important in lameness evaluation, what do you need to look at?

Answer 8

• muscle atrophy (disuse or neurogenic)
• foot size (foot cna shrink with laemness)
• fetlock height/angle
• localised swelling (synovitis, cellulitis, exostosis/callus formation)
• bony asymmetry (e.g. scapular height, tuber coxae/sacrale)

Question 9

What steps do you need to take when palpating a horse for lameness?

Answer 9

• A good and systematic routine is vitally important
  
  • always use the same system every time
• examine limbs during weight-bearing and elevated from the ground
• ideally perform static examination before dynamic
  examination

This should include assessment of:
* asymmetry
* signs of inflammation
* pain (by both deep palpation and induced movement)
* loss of function e.g. range of movement
* crepitus
* peripheral pulses

Question 10

what do you need to examine in the cervical region regarding lameness?

Answer 10

• Examination of the poll including wings of the atlas
• Palpation of the para-spinal musculature
• Palpation of the brachiocephalicus muscle
• If indicated assessment of the range of cervical movement using food

Question 11

What are you doign to do to examine the forelimb in a lameness case?

Answer 11

• Shoulder and bicipital region
• Elbow and antebrachium
• Carpus
• Metacarpal region
• Fetlock
• Pastern
• Foot - include use of hoof testers

Question 12

How are you going to examine the throacolumbar spine in a lameness examination?

Answer 12

• Use digital pressure to assess dorsal contour
• Deep digital pressure of the epaxial muscles is resented by many horses and is not pathognomomic for back pain
  
  • pressure over the thoracic and cranial lumbar region usually results on lordosis (curve down)
  • pressure over the caudal lumbar and sacral region results in kyphosis (curve up)
  • often lack of these actions more indicative of back pain
• Often back pain is secondary to hindlimb lameness

Question 13

What is examined on the hindlimb during a lameness examination?

Answer 13

• Femoral region
• Stifle
• Tibia
• Tarsus
• Metatarsophalangeal region
• Fetlock
• Pastern
• Foot - includign foot testers

Question 15

What is examined in regards to the pelving in a lameness examination?

Answer 15

• Often externally palpable abnormalities of the pelvis appreciated during observation
  
  • include gentle rocking of the pelvis to detect crepitus
  • generally performed last due to inherent risks (horse kick)
  • include basic neurological assessment (tail tone, lower motor neurone function)

Question 16

how is lameness graded?

Answer 16

• Ten point grading system (more commonly adopted in Europe) (0 = sound, 10 = non-weight baring)
• Five point systems usually attempt to be more objective
  
  • care as different systems exist
  • especially in the UK clinicians will refer to a 5 point system without appreciating any objective nature

Question 17

How is lameness assessed at a walk? what is observed?

Answer 17

• The horse should be walked at a steady pace away from and towards the observer
  
  • observe horses carefully during the turn
• Careful attention should be placed upon
  
  • foot placement
  • gait abnormalities (e.g. “dishing”, “plaiting”)
• Include lateral observation to assess:
  
  • foot flight
  • “tracking up”
  • cranial and caudal phases of the stride

Question 18

what are 4 alternative/mechanical causes of lameness?

Answer 18

• “stringhalt” (hypermetria of the hindlimb)
• fibrotic myopathy (of the hamstrings)
• upward fixation of the patella
• “shivers” syndrome

Question 19

What are the key points of examination of thehorse at trot, during a lameness examination?

Answer 19

Horse should again be moved at a steady pace away from and towards the observer
* ensure that the handler does not constrain the horse’s natural movement
* pace can sometimes mask or complicate assessment so different speeds can be useful
* assessment now focuses less on the foot placement and more on other alterations in gait

Question 20

What is head nodding and how is it used in lamness examination?

Answer 20

“Head nodding” is the most useful method of forelimb lameness assessment
* head elevation begins just before the stance phase of the lamb limb
* results in reduced ground reaction force (GRF) due to upwards acceleration of the head and neck, and caudal movement of the centre of gravity
* consequently the horse appears to nod when the “good” leg is in contact with the ground

Question 21

What points can you use to assist in identify hindlimb lameness?

Answer 21

• Relative excursion of the tuber coxae is generally the accepted visual method of assessing hindlimb lameness
  
  • often given terms like hip or pelvic “hike”
  • the limb with the greater degree of movement is the lame limb
  • visual cues can be improved by placing tape on each hindlimb running between the tuber coxae and tuber sacrale
• Hind limb lameness is harder to appreciate than forelimb lameness

Question 22

Artefactual lamness - Hindlimb lameness can mimic forelimb lameness at trot (lame on hind but looks like forelimb)
why does this occur?

Answer 22

• when the lame limb hits the ground the horse moves it centre of gravity cranially to help unload the limb
• the two-beat gait means that there will be a head nod during the stance phase of the contralateral forelimb
• therefore the horse appears to be lame on the ipsilateral forelimb to the lame hindlimb

eg if RH lame then head will do down on the LF and therefore will appear that is lame on the RF

It should be noted that this is generally apparent only if moderate lameness is present

Question 23

what additional assessment can be used to help assist with lameness examination?

Answer 23

• Sound - excluding all visual clues and listening to syncopation can be extremely useful (remembering the beats of the four standard gaits)

Fetlock drop
* at trot because there is a higher GRF in the sound (less lame limb) the fetlock will drop further
* structural disruption of the suspensory apparatus and flexor tendons will typically result in over-extension of the affected limb at walk

Question 24

how cna duratino of the stance phase be used to asses lameness?

Answer 24

• Most lameness results from pain during limb loading
  
  • therefore horses will attempt to reduce the duration of the stance phase
  • can be especially useful in the assessment of hindlimb lameness during lunging exercise

Question 25

How can lunging exercise be used to assess lameness?

Answer 25

• Helpful in ascertaining there might be a bilateral component to lameness
• Lunging on different surfaces can also be extremely useful
• Beware of over interpretation
  
  • “soft tissue lameness is worse with the limb on the outside/when lunged on soft ground”
  • very tight circles on hard ground can evoke forelimb lameness of questionable significance, especially in heavier horses

lunging at canter:
not particularly helpfull, but willingness to go into canter can show pain, and horse might spontaneouly go into canter to relive pain with some lameness

Question 26

How is ridden exercise used in lameness assessment?

Answer 26

• The additional weight of the rider can elicit lameness in either the forelimbs or the hindlimbs
  
  • subtle changes in weight can also mask signs of lameness
  • having an experienced rider can be extremely useful especially when evaluating subtle poor performance issues

Question 27

How cna flexion and extension tests be used to assess lameness? And Wedge tests?

Answer 27

Flexion/extension:
* Important to remember that these are not specific to one particular structure
* Different clinicians will also apply different forces
* No clear guidelines as to how long flexion should be applied

Wedge tests
often overlooked
* limb should be placed on the block whilst the contralateral limb is held
* wedge can be placed to evoke lateromedial or dorsopalmar forces

Question 28

What are the benefits of using kinetics and kinematics for lameness assessment?

Answer 28

allow objective measurement
* allows assessment of single and multiple limb lameness
* not affected by psychological factors or bias
* allows repeatablenreliable and documentable data to be obtained

Question 29

How do kinetic systems work to assess lameness?

Answer 29

kinetics describes motion (e.g. examines the forces applied)
* Use three wireless sensors on poll and hips, which transmit data to a computer
* algorithms then identify the severity of the lameness and which limbs are involved

Question 30

what is the difference between kinetics and kinematics?

Answer 30

• kinetics describes motion (e.g. examines the forces applied)
• kinematics explains motion (e.g. a geometric description of motion without considering causal forces)