Lameness Flashcards
(196 cards)
1
Q
Important aspects of the standing examination
A
- consistent complete; always performed and documented in same way
- NOT BIASED by Hx…..unless horse is non-weight bearing lame, follow routine
2
Q
Hoof conformation/angle problems
A
- sloping
- stumpy
- broken back
- broken forward
3
Q
areas of hoof palpation
A
- frog
- coronary band
- heel bulbs
4
Q
Lameness not perceptible under any circumstance
A
grade 0
5
Q
Lameness is difficult to observe and is not consistently apparent, regardless of circumstances
A
grade 1
6
Q
Lameness is difficult to observe at a walk or when trotting in a straight line but consistently apparent under certain circumstances
A
grade 2
7
Q
Lameness is consistently observable at a trot under all circumstances
A
grade 3
8
Q
Lameness is obvious at a walk
A
grade 4
9
Q
Lameness produces minimal weight bearing in motion and/or at rest or a complete inability to move
A
grade 5
10
Q
Flexion tests
A
- help localize source of lameness
- NOT factored into lameness score
- should not “block” off positive flexion test lameness alone
- perform and interpret consistently
- evaluate limb flexed AND opposite limb for increased lameness after weight-bearing
11
Q
Wedge test with heel elevated is done to evaluate ______________
A
suspensory ligament
12
Q
Wedge test elevating the toe is done to evaluate __________
A
- navicular structures
- DDFT
13
Q
A wedge test placed to elevate one side of the foot is evaluating __________
A
collateral ligaments
14
Q
Examples of mechanical gait abnormalities
A
- upward fixation of patella
- fibrotic myopathy
- stringhalt
- shivers
- ruptured peroneus tertius
15
Q
Types of diagnostic analgesia
A
- Perineural = “nerve block”
- Intra-articular = “joint block”
16
Q
Why are nuclear scintigraphy and thermography exceptions to the rule of performing blocks prior to imaging?
A
with these two modalities, any injection site will be “hot” regardless of pathology
17
Q
What is the lowest nerve block?
A
Palmar/plantar digital (PD)
18
Q
PD nerve block blocks:
A
- L & M palmar/plantar digital nerves; back of pastern below level of dorsal branches
(so heel, more than toe)
19
Q
Abaxial (basisesamoid) nerve block blocks:
A
- L & M palmar/plantar digital nerves at level of sesamoid bones
20
Q
Of the L&M artery, vein, and nerve, how do the structures go from lateral to medial?
A
L to M: VAN so nerves are most medial
21
Q
Low 4 point - nerves blocked
A
- L&M palmar/plantar metacarpal/tarsal nn
- L&M palmar/plantar nn
22
Q
Be cautious about what structure when doing low four point block?
A
digital flexor tendon sheath
23
Q
Blocking the deep branch of the lateral plantar nerve is done for what purpose?
A
suspecting proximal suspensory disease
24
Q
Local anesthetic considerations for blocks:
A
- Lidocaine: rapid onset but shortest duration (~1.5h)
- Mepivicaine: rapid onset and intermediate duration (~3h)
- Bupivicaine: intermediate onset but longest duration (6-8h)
25
Preparation of joint/tendon sheath blocks and nerve blocks close to joints
* sterile preparation (4-5 min contact)
* sterile gloves and technique
* new bottle of local anesthetic
26
Needle size for low blocks? What about higher blocks and joint blocks?
Low: 25g
Higher & joint: 20 or 21
27
Diagnostic imaging-anatomical only
* Radiography
* CT
* MRI
* Standard US
28
Anatomical and functional diagnostic imaging
* Nuclear scintigraphy
* MRI
* Advanced US
* Thermography
29
If you have a suspect stress fracture but normal rads, how long should you wait before re-imaging?
7-10 days (latent period)
30
How does MRI produce an image?
exciting hydrogen nuclei at a specific resonance frequency within magnetic fields then detecting the energy released as the nuclei relax
31
What is the only good way to image soft tissue structures within the hoof capsule?
MRI
32
Preferred modality for soft tissue imaging after lameness is localized to a specific region
MRI
33
What functional information does MRI give you?
fluid signal within tissues indicates edema & inflammation
34
Primary imaging modality for soft tissue structures outside of the hoof
ultrasound
35
Functional assessments-ultrasound
* doppler-blood flow
* elastography-tissue strain for tendons and ligaments; helps determine how functionally tendons are healing
36
What imaging modality may be indicated when you can't effectively diagnose lameness from a block?
nuclear scintigraphy
37
mechanism-nuclear scintigraphy
99mTc - diphosphonate thought to bind to exposed hydroxyapatite crystals in areas of bone remodeling or in soft tissues undergoing mineralization
38
Pool phase-nuclear scintigraphy
* less than 15 min
39
Thermography is touchy, but possible applications are:
detect inflammation or vascular damage in limbs
40
Origin of the majority of lameness in horses:
forelimb, within foot
41
Laminar corium
soft tissue attachment to the coffin bone
42
What structures are interdigitating in the hoof
epidermal lamina + laminar corium(dermal lamella)
43
abnormal foot angles predispose to:
* coffin joint OA
* navicular dz
44
With sheared heels, what side is generally longer?
medial longer than lateral
45
What abnormal hoof-pastern axis is most common?
broken back
46
angle of heels at least 5 degrees
underrun heels
47
Breed disposition to underrun heels
TB
48
Consequences of underrun heels
* subsolar abscesses
* bruised heels
* increased strain on DDFT
49
Underrun heels-corrective shoeing
heel support (wedge)
50
Etiology of contracted feet
* secondary to lameness
* induced through shoeing (too small)
* hereditary
51
Tx for contracted foot
* fix primary problem
* keep barefoot
* exercise-concussive forces encourage foot to grow
52
Single most common cause for **sudden onset of severe unilateral limb lameness**
subsolar foot abscess
53
Etiologies of subsolar abscess
* sole trauma
* laminitis
54
most important aspect of tx for subsolar abscess
debride to provide drainage
55
Dx for subsolar abscess
very reactive to hoof testers at the abscess site
56
Organism causing thrush
*Fusobacterium necrophorum*
57
Breeds with higher incidence of navicular than others
QH, TB, WB
58
Clinical signs of navicular syndrome
* insidious onset
* commonly bilateral & worse on hard surfaces and when circled
* often short strided
* may stumble/shuffle-trying to land on toe
* often point the forelimb that is most painful
59
Predisposing factors-navicular syndrome
* excessive weight
* small or narrow feet (e.g. QH)
* broken back conformation
* medial-lateral hoof imbalances
* work on hard surfaces
60
Structures involved in navicular syndrome
* navicular bone
* **flexor surface** of navicular bone
* DIP (coffin) joint
* DDFT
* navicular suspensory ligaments
* impar ligament
61
What is the origin of pain with navicular syndrome?
* intraosseous pressure
* damaged supporting soft tissue structures
* inflammation of bursa & coffin joint
62
Navicular syndrome-dx
CS, response to blocks, rads
* PD - also blocks coffin joint and navicular bursa
* rads: increase in #, size, shape of synovial invaginations. changes in navicular bone shape. flexor cortex (where DDFT glides over back of navicular bone) erosions, roughening. loss of corticomedullary distinction. medullary sclerosis. enthesopathy at collateral lig.
63
MRI findings - navicular syndrome
* bone edema
* adhesions
* flexor cortex adhesions
can change prognosis, see things rads can miss
64
Corrective trimming/shoeing for navicular syndrome
* enhance breakover w/ rocker or square toe
* raise and support heel (2-3 degrees)
can vary with indiv. horses. have to see how they respond.
65
What does Tildren do?
inhibit bone resorption
66
Mainstay of surgical treatment of navicular syndrome
**PD Neurectomy**
67
Potential complications with PD neurectomy
* neuroma
* re-innervation
* **DDFT rupture**-poor prognosis, maybe life ending
68
Laminitis CS
* classic stance to take weight of front feet
* reluctance to move/walk
* increased recumbency
* increased digital pulses
* sinking at or separation of coronary band
69
Etiologies-laminits
* mechanical-d/t overload from opposite leg lameness
* endotoxemia-vascular microthrombosis
* grain overload
* metabolic derangements
* black walnut shavings
70
A _______ can be done to stop P3 rotation
DDF tenotomy
71
Prognosis for a toe/quarter crack that starts at the bottom
good
72
Prognosis for coronary cracks
poor
73
Tx for toe cracks
patch, hoof resection, shoeing
74
chronic, hypertrophic, moist pododermatitis of the epidermal tissues of the foot
canker
75
Causes of canker
* *F. necrophorum*
* *Bacteroides* spp.
76
Main difference in canker vs. thrush
horn hypertorpy
77
Canker is most common in \_\_\_\_breeds
draft
78
Topical abx that would be suitable for canker
oxytetracycline, metronidazole
79
Treatment for a keratoma
remove affected hoof wall & debride all abnormal tissues
80
Sterile medical maggots are sometimes used when?
after debridement of a keratoma; they eat the necrotic tissue
81
White line disease can be caused by?
bacteria or fungi
82
Sidebones are caused by:
calcification of collateral cartilages
83
Necrosis of the collateral cartilages is called
Quittor
84
Quittor is most common in _____ breeds
draft
85
Chronic draining tracts above the coronary band is indicative of \_\_\_\_\_\_\_
quittor
86
Etiology of pedal osteitis
* concussion
* thin soles
87
Painting the soles of the hooves with iodine may be indicated in what condition?
pedal osteitis
88
**Structures at risk for sepsis when you have a sole puncture**
* **navicular bursa**
* **coffin joint**
* **tendon sheath**
89
Foal recovery vs. adult recovery with septic OA
61% in foals vs. 88% in adults
90
Normal synovial fluid
transluscent yellow/straw colored & highly viscous (string b/w fingers)
91
What do the following values indicate (synovial fluid analysis)?
* TP \<2.5
* WBC 500-20,000
* 10-20% neutrophils
* Inflammation
92
What do the following values indicate (synovial fluid analysis)?
* TP \>4.0
* WBC \> 30,000
* \>80% neutrophils
infection
93
Systemic abx choice for septic joint
**Penicillin** combined with **amikacin (foals)** or **gentamicin (adults)**
94
Mainstay of treatment for septic joints
IV regional limb perfusion
95
Arthrotomy pro/con
* eliminates infection more rapdily than arthroscopy
* increased risk of ascending infection
96
Arthroscopy pro/con
* better exam; debridement if bony lesion
* increased $
97
Know adult vs. foal septic OA & study septic OA slides
98
50% of equine lameness is due to \_\_\_\_\_
joint disease and injury
99
Synovial fluid functions
* nutrients
* lubrication
100
Synoviocytes that make synovial fluid
type B
101
Type A synoviocytes
macrophage like: cytokines, phagocytosis of bacteria
102
Subchondral bone fxn
absorbs shock of forces acting on cartilage
103
Is articular cartilage good at intrinsic repair?
NO
104
primary collagen type in cartilage
type II
105
**Anabolic** cytokines
* IGF-1
* BMP
* TGF-B
106
**Catabolic** cytokines
* IL-1B
* TNF-alpha
* NO
107
Abnormal cartilage with normal forces
OC, OCD
108
Normal cartilage with abnormal forces
poor conformation, articular fx
109
Pain in OA is due to:
* damaged subchondral bone
* joint capsule; pressure from fluid distension, thickened capsule reducing joint mobility
110
What are radiographic findings associated with OA?
* periarticular osteophytosis
* joint space narrowing
* subchondral sclerosis
* subchondral lysis
* osteochondral bodies
* ankylosis-distal hocks, pasterns
111
The distal hock joints are a classic site of what?
OA
112
Failure of endochondral ossification and therefore abnormal cartilage and bone =
Osteochondrosis (OC)
113
3 major scenarios for retained cartilage
1. healing occurs
2. break out and form flaps --\> OCD
3. necrosis and development of subchondral cystic lesions
114
OC-heritable?
yes
115
Low copper, excess zinc or energy is linked to \_\_\_\_\_\_\_
OC
116
**OC common locations**
* Stifle (femoropatellar joint)
* trochlear redge of femur; L\>M
* patella
* Hock (tarsocrural joint)
* DIRT
* trochlear ridges of talus; \>M
* medial malleolus - also a common site for fx
117
Most common Tx of OCD lesions:
* arthroscopic fragment removal and debridement
118
When might an OCD lesion heal spontaneously?
LTR femur OCD in a very young horse
119
Tx of MFC cysts
* corticosteroid injections can be tried as first treatment
* debridement +/- grafting
120
Advantages of intra-articular corticosteroids
* decrease MMPs, IL-1, TNF-alpha
* decrease fibrin deposition
* pain relief
* economical
121
Intra-articular corticosteroids
* chondrocyte necrosis
* decrease ECM production (up to 4 months)
* laminitis
* decreased resistance to infection
122
Long acting intra-articular corticosteroid
methylprednisolone acetate
123
Intermediate to long acting intraarticular corticosteroid
Triamcinolone
124
short acting intraarticular corticosteroid
betamethasone
125
What corticosteroid should be used in distal tarsal joints ("low motion")
Methylprednisolone acetate
126
Triamcinolone advantage?
has some protective properties
127
HA-direct anti-inflammatory effects?
Y/N?
YES
128
Functional mechanisms directly of HA depends on?
molecular weight
129
Polysulfated glycosaminoglycans MOA
* inhibit MMPs
* stimulate matrix synthesis
* promote HA synthesis
* anti-inflammatory: inhibit PGE2 & free-radicals
130
Interleukin-1 receptor antagonist
IRAP
131
Used for facilitated ankylosis
* IA corticosteroids
* monoiodoacetic acid
* ethanol
* exercise
132
"simple" fractures
not major long bone fractures
133
examples of simple fractures
* splint bone fractures
* metacarpal stress fractrues
* intra-articular fractures
* proximal sesamoid bone fractures
* condylar fractures
* coffin bone fractures
134
Splint bone fractures
* more common in **distal 1/3**
* **forelimbs** \>\>\>\>hindlimbs
135
Surgical treatment if distal 1/3 of splint bones fractured
remove fragment
136
Surgical treatment if splint bone fx in mid and proximal 1/3
secure fx to MC/MTII
137
Which splint bone is substantially load-bearing?
MCII
138
Prone to metacarpal stress fractures
young TB-race training
139
What is the preferred tx for metacarpal stress fx?
Surgery: osteostixis + unicortical lag screw is optimal
140
Sequelae to intra-articular fragments
recurrent synovitis & OA--\>shortened athletic career
141
"nutcracker" fractures are fractures of what?
palmar carpus; crush accessory carpal bone
142
Locations of intra-articular fragments in race horses
* Carpal OC or "chip" fx
* proximal P1 chip fx
* apical sesamoid fx
143
What is the most commonly diagnosed IA fracture?
Carpal OC fx
144
Hyperextension of the carpus is the underlying cause of\_\_\_\_\_\_\_\_\_
carpal OC fragments
145
Most common sites of carpal OC fragments
* radiocarpal bone
* intermediate carpal bone
* proximal 3rd carpal
146
effusion and lameness after cooling out that subsides with rest and supportive care is consistent with \_\_\_\_\_\_\_\_\_\_\_?
carpal OC fragments
147
Hyperextension of fetlock joint is underlying etiology of _________ fractures
dorsal proximal P1
148
What type of proximal sesamoid fracture is a catastrophic breakdown?
biaxial mid-body
149
Type of tendons more affected by tendonitis
flexors
150
Resolution of tendonitis?
* slow to heal
* healed tendon inferior in strength and elasticity
* high incidence of recurrence
151
which specific tendon is more commonly affected by tendonitis?
SDFT \>DDFT
152
Factors that predispose SDFT to tendonitis
* smallest cross sectional area
* most external=greatest strain, trauma
* less vascular in metacarpal region where lesions occur
153
Tendonitis phases
Sub-clinical
* degradation of ECM
* weakened tendon
Clinical
* acute inflammation
Reparative (at 3 wks)
* tenocyte migratoin
* fibroplasia
* angiogenesis
* higher collagen III/I ratio
Remodeling (up to months post injury)
* replace type III collagen with type I
* formation of x-links
* re-orientation of fibers with max tension
154
When are tendonitis lesions usually the worst?
2 weeks
155
Treatment of tendonitis-acute phase
* stall confinement
* control inflammation
* NSAIDs
* Ice boots, cold hosing, game ready
* bandaging
156
What is a critical treatment of tendonitis in repair phase?
controlled exercise
157
Idea behind proximal check ligament desmotomy
increases elastic ligament of muscle tendon unit
158
Do flexor or extensor tendons heal better?
extensor
159
Hyperextension of fetlock is seen when \_\_\_\_\_\_\_is lacerated
SDFT
160
Laceration of DDFT=you see what?
toe up
161
Loss of fetlock support occurs when what structures are lacerated?
SDFT, DDFT, suspensory ligament
162
Other structures that can be affected with suspensory ligament desmitis?
* splint bones
* proximal sesamoid bones
163
Suspensory ligament desmitis-can do neurectomy of \_\_\_\_\_
deep branch of lateral plantar n.
164
**Degenerative suspensory ligament disease**
* Peruvian Paso, arabian, saddlebreds
* **no treatment**
* **painful**
* **poor prognosis**
165
**Muscles most common affected by fibrotic myopathy**
* **semitendinosus**
* **semimembranosus**
* also biceps femoris, gracilis
166
CS of fibrotic myopathy
acquired non-painful "slapping" gait
167
Australian dandelions can cause\_\_\_\_\_\_\_\_\_
stringhalt
168
Fibrotic myopathy-treatment
possibly tenotomy or myotenectomy
best thing is prevention if muscle tear is recognized
169
Lateral digital extensor myotenectomy is useful for treating \_\_\_\_\_\_\_
stringhalt
170
Most common congenital flexural deformities
fetlock (SDFT, DDFT)
carpal (combination & carpal fascia)
171
**Congenital flexural deformities-Tx**
* increase exercise
* oxytetracycline
* NSAIDs
* toe extension shoes
* surgery (severe cases)
* **must assist to stand and nurse**
* splints-12h on 12h off
172
Acquired flexural deformitis: most common joints affected
coffin or fetlock joints; unilateral or bilateral
173
What tendon is affected if fetlock joint is affected by flexural deformity?
SDFT
174
Timeframe of development of acquired fetlock joint flexural deformity
9 months to 2 years
175
Timeframe of development of acquired coffin joint flexural deformity
4 weeks to 4 months
176
What complication of PD neurectomy (performed for navicular syndrome) is catastrophic?
DDFT rupture
177
**Do sidebones cause lameness?**
**no**
178
**OC lesions are very often bilateral so you should \_\_\_\_\_\_\_\_\_\_\_\_**
**always check/radiograph both limbs**
179
**Arthrodesis is usually only performed in which joints?**
**distal hock joints, pastern joints**
(low motion!)
180
**Carpal OC fragments are often bilateral so you need to\_\_\_\_\_\_\_\_\_\_\_\_**
**radiograph both carpi**
181
**increasing evidence that the pathogenesis of tendon injury is what?**
**degenerative**
182
**Valgus**
**lateral** deviation of a limb below a joint
183
**Most common angular limb deformities**
**carpal valgus, fetlock varus**
184
Periostial transection
-to **stimulate** growth; perform on **concave** side, proximal to the physis
185
Transphyseal bridging
performed to **slow** growth; on **convex** side of deformity. place screws proximal and distal to physis and figure of 8 wires around screws
186
Inflammation and degradation of articular cartilage is initiated by _______ and propagate by \_\_\_\_\_\_\_\_
initiated: bacteria
propagated: synoviocytes, chondrocytes
187
Septic OA in foals:
Hematogenous
* patent urachus/umbilical infections often seen concurrently
* common for **multiple joints** to be infected
* common for **larger joints** to be infected
* septic **osteomyelitis & physitis** common; may cause irreversible damage
* complicaitons from septicemia & hematogenous spread: kidey, myocardial involvement. invection of vertebral bodies, scapula, etc.
188
How long are the transphyseal vessels present?
7-10 days old
189
With septic OA in foals, where do bacteria preferentially lodge?
synovial membrane, subchondral bone
190
Classifications of septic OA in foals
* **S**ynovium
* **E**piphysis
* **P**hysis
* **T**arsal bones
191
T-type septic OA in foals is most common in \_\_\_\_\_\_\_
premature foals
192
Septic OA in adults is due to:
1. wounds/penetrating injury to synovial structures
2. intra-articular/intra-thecal injection or sx
193
potential complications with IV regional limb perfusion
* injection site morbidity
* thrombosis
* cellulitis
194
Three components of drug therapy for septic OA
NSAIDs, sodium hyaluronate, doxycycline or minocycline
195
Functions of sodium hyaluronate
* decreases cell infiltration, granulation tissue, and total GAG loss
* in tendon sheaths, it helps reduce adhesions
196
