Overview Flashcards
1
Q
Components of a physical exam
A
- observation from a distance
- direct palpation
- ancillary tests
2
Q
Components of a lameness exam
A
- basic examination
- additional movements/surfaces
- evocative tests
3
Q
What is lameness?
A
= a clinical sign, [manifesting] signs of inflammation including pain, or a mechanical defect that results in a gait abnormality
4
Q
5 ‘types’ of lameness
A
- supporting limb (stance phase) lameness
- swinging limb lameness
- mixed lameness
- compensatory lameness
- induced/artefactual lameness
5
Q
Hind limb lameness
A
- limb with greatest movement when trotting
6
Q
Is forelimb or hindlimb lameness more common?
A
- forelimb
7
Q
Are forelimb lamenesses above the carpus common?
A
- no, extremely uncommon in all groups of horses
8
Q
History - signalment: age
A
Specific age groups often suffer from specific conditions:
* 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
but these are not necessarily exclusive
9
Q
History - signalment: sex
A
- There are very few sex related conditions; however, breeding potential may be important for treatment
- may also see behavioural changes associated with oestrus
- RER has been shown to be more common in female TB and
event horses - anecdotally lameness has been implicated in cryptorchid animals
10
Q
History - signalment: discipline
A
- certain disciplines will place unique strains on animals
- some manifestations of lameness are seen in all groups of animals
11
Q
Top 3 causes of lameness in a flat-racing TB
A
- foot-related lameness
- suspensory desmitis
- middle carpal joint dz
12
Q
Top 3 causes of lameness in a National hunt TB
A
- SDFT injury
- suspensory desmitis
- carpal dz
13
Q
Top 3 causes of lameness in a show jumper
A
- palmar foot pain
- distal tarsal pain
- DIPJ OA
14
Q
Top 3 causes of lameness in an event horse
A
- back.neck pain
- foot related lameness
- traumatic OA
15
Q
Top 3 causes of lameness in a dressage horse
A
- PSD
- suspensory branch injury
- DIPJ OA
16
Q
Top 3 causes of lameness in a draft horse
A
- foot-related lameness
- tarsal lameness
- ‘splints’
17
Q
Top 3 causes of lameness in a pony
A
- laminitis
- distal tarsal pain
- ALDDFT desmitis
18
Q
What is the most common cause of lameness in the horse?
A
- hoof abscess
19
Q
History
A
- 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?
20
Q
Conformation
A
- severe conformational abnormalities are easy to appreciate
- asymmetry of conformation is often particularly important
- there may be important breed characteristics that lead to lameness e.g.
long toe/low heeled TBs
21
Q
Hock conformation
A
- Hock conformation has a very significant effect on the prognosis for hind limb suspensory desmopathy (Dyson and Murray, 2011)
– 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
22
Q
Posture
A
- Careful observation from a distance is extremely important
- laminitis or severe skeletal injuries might be readily obvious
- pointing or reduced weight-bearing
- “dropped elbow” indicates failure of the triceps apparatus
- cervical pain
- upward fixation of the patella
- (neurological conditions)
23
Q
Symmetry
A
- Asymmetry is often very important in lameness evaluation
- muscle atrophy (disuse or neurogenic)
- foot size
- fetlock height/angle
- localised swelling (synovitis, cellulitis, exostosis/callus formation)
- bony asymmetry (e.g. scapular height, tuber coxae/sacrale)
24
Q
Palpation
A
- examine limbs during
weight-bearing and
elevated from the ground - ideally perform static examination before dynamic examination
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
25
Cervical region examination
* 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
26
Forelimb examination
* Shoulder and bicipital region
* Elbow and antebrachium
* Carpus
* Metacarpal region
* Fetlock
* Pastern
* Foot
-- should include use of hoof testers
27
Thoracolumbar spine examination
* 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
-- pressure over the caudal lumbar and sacral region results in kyphosis
-- often lack of these actions more indicative of back pain
* Often back pain is secondary to hindlimb lameness
28
Hindlimb examination
* Femoral region
* Stifle
* Tibia
* Tarsus
-- capped hock, bog spavin, bone spavin, curb and thoroughpin
* Metatarsophalangeal region
* Fetlock
* Pastern
* Foot
29
Pelvic exam
* 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
* include basic neurological assessment (tail tone, lower motor neurone function)
30
General physical examination
* This should not be overlooked
-- pyrexia may be concurrent with septic arthritis especially in
the foal
* Lameness and gait abnormalities may also result from other conditions
-- peritonitis/pleuritis, abscessation, genito-urinary disease
31
Dynamic examination
* Select an appropriate environment and surface
* safety of the horse and handler are paramount
* select an even, straight, firm surface free from distractions; however, alternate surfaces can be useful
* explain to inexperienced handlers exactly what you require
32
Lameness characteristics - examination should attempt to assess
* baseline lameness (i.e. before provocative tests) or
lamenesses
-- attempt to identify multiple limb lameness, and also establish whether these are primary or secondary problems, or if they are artefactual
* any lameness identified should be graded and immediately recorded to attempt to create a degree of objectivity
33
Lameness grading - AAEP Grade 1
- Lameness difficult to observe and not consistently apparent regardless of circumstances (such as weight carrying, circling, inclines, hard surfaces)
34
Lameness grading - AAEP Grade 2
- Lameness difficult to observe at a walk or trotting a straight line but is consistently apparent under certain circumstances (such as weight carrying, circling, inclines, hard surfaces)
35
Lameness grading - AAEP Grade 3
- Lameness consistently observable at a trot under all circumstances
36
Lameness grading - AAEP Grade 4
- Obvious lameness with marked nodding, hitching, or shortened stride
37
Lameness grading - AAEP Grade 5
- Lameness characterized by minimal weight bearing in motion or at rest and the inability to move
38
Assessment at walk
* 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
39
Alternative/mechanical causes of lameness
* “stringhalt”
* fibrotic myopathy
* upward fixation of the patella
* “shivers” syndrome
40
Which age of horse is it important to assess neurological function when it comes to lameness?
- young horses
41
Examination at trot
* 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
42
Head nodding
* head elevation begins just before the stance phase of the lame 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
43
Hindlimb lameness
* 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
44
Artefactual lameness
* Hindlimb lameness can mimic forelimb lameness at trot
-- 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
* This is generally apparent only if moderate lameness is present
45
Additional assessments - sound
- * excluding all visual clues and listening to syncopation can be extremely useful (remembering the beats of the four standard gaits)
46
Additional assessments - fetlock drop
* at trot because there is a higher GRF (ground reaction force) 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
47
Duration of stance phase
* 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
48
Lunging exercise
* 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
49
Lunging at canter
* Three beat gait
* L lead: LF, RF and LH, RH
-- although RH contacts the ground on its own, stance phase, GRF and degree of flexion in the proximal joints is greater in the LH
-- therefore a horse with a RH lameness may possibly prefer to canter on a left lead
* R lead: RF, LF and RH, LH
50
Ridden exercise
* 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
51
Flexion tests
* Important to remember that these are not specific to one particular structure
* Different clinicians will also apply different forces
-- consequently you need to be familiar with the normal
-- it is possible to induce lameness
-- studies show that 100-150N is optimal (????)
-- aim to flex the limb to a point slightly before a withdrawal response is elicited
* No clear guidelines as to how long flexion should be applied
-- most clinicians use 60 seconds
-- however, it has been shown that 5 seconds of flexion generally produces similar results to 60 seconds in many cases
52
Evocative tests
* Extension tests
* Direct palpation and pressure
* 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
53
Horse temperament
* Safety of the horse and handler should be the first consideration
* acepromazine can be useful in calming fractious horses without providing analgesia
* some clinicians advocate low doses of xylazine; however, this will be analgesic and may result in ataxia
* more frequently xylazine is used to facilitate local anaesthesia in which case it is important to allow sufficient time for the effects to wear off
54
Kinetics vs kinematics
* kinetics describes motion (e.g. examines the forces applied)
* kinematics explains motion (e.g. a geometric description of motion without considering causal forces)
55
Objective lameness recording
Equinosis, took 20 years of development
* Use three wireless sensors which transmit data to a computer
* algorithms then identify the severity of the lameness and which limbs are involved
* Other systems now available some with up to 8 sensors
