Equine Musculoskeletal Flashcards
1
Q
What are the 3 structural steps to examining the lame horse?
A
- History
- Clinical examination
- Trot up
2
Q
What do you aim to identify upon palpation of the limbs of a lame horse?
A
Abnormalities
Asymmetry between limbs
Range of movement
Painful response
3
Q
Why is the spine palpated in the lame horse?
A
Given the appendicular skeleton is linked to the spine. Lameness may manifest as back pain, and back pain as lameness
4
Q
What is assessed upon palpation of the spine in the lame horse?
A
- Palpate the DSPs and the epaxial musculature
- Assess movement away from pressure points
5
Q
How are hoof testers used in the examination of a lame horse?
A
- Use systematically serially around circumference, then frog and inside/outside heels then across both heels
- Look for reaction – withdrawal of limb, ears back, turn to bite you
6
Q
What is looked for in gait evaluation of the lame horse?
A
- Head nod
- Hip hike
- Change in phase of stride length
- Flight arc (height above ground)
- Flight path (medial/lateral) – plaiting if bilateral
- Foot placement should be flat. Usually, lame leg pushes under body
7
Q
How can lameness be exacerbated for detection?
A
- Walk and trot away and back on firm level surface
- Tight turns
- Backing up (reversing)
- Uphill/downhill
- Lunging on both reins
- Provocation tests - flexion tests, local pressure response tests
8
Q
How are horses lunged for exacerbation of lameness?
A
- Soft surface before hard if available
- Lunging loads the limbs differently to travelling in a straight line
- May exacerbate lameness on inside or outside leg
- Compare the way the horse moves between the 2 reins
9
Q
How are flexion tests done in the lame horse?
A
- Flex the appropriate part of the limb
- Alternate between left and right limbs for same amount of time
- Allow horse to maintain its’ balance by maintaining normal vertical alignment and not over lifting the limb
10
Q
What are local pressure response provocation tests?
A
- Local pressure on tendons or ligaments, or swellings may elicit a painful response
- Apply pressure for a period of time and then ask for trot
11
Q
How is twitching used for restraint for things like nerve blocks instead of sedation?
A
Rope or rope attached to some wood wrapped around the nose, pinch ear or handful of neck makes them stand still for restraint
12
Q
Why must nerve blocks be interpreted with care?
A
- Not all conditions will block out completely
- Local can diffuse up between tissue planes so may extend more proximal that you might realise
- Local can diffuse/leak from joints to block nerves as they pass the joint
13
Q
Name 4 appropriate agents for nerve blocks.
A
Mepivacaine
Prilocaine
Lidocaine
Bupivacaine
14
Q
How are nerve blocks reviewed?
A
- Synovial fluid confirms correct intraarticular or intrathecal placement
- Trot up from 5mins from injection
- Some blocks may require longer than this but beware unwanted diffusion
- Some distal blocks have areas of skin desensitisation “dermatomes”
15
Q
When is synoviocentesis used in equine lameness cases?
A
Rarely provides benefit in inflammatory conditions – just demonstrates inflammation, not done generally in lameness cases
Use for wounds/cases with severe acute lameness
16
Q
What is the normal gross appearance and properties of synovial fluid?
A
- Pale yellow, clear, translucent
- Viscosity – will string between fingers
- Total and differential cell count - <1 x 10^9 cells/L, predominantly mononuclear cells
- Total protein <20g/L
17
Q
What is nuclear scintigraphy in the lame horse?
A
Bone scan. IV taken up into bone mineral lattice
18
Q
When is nuclear scintigraphy used in the lame horse?
A
Non-weight bearing, fracture, non-compliant
19
Q
What is the use of CT scanning in the lame horse?
A
- Excellent image quality and 3D reconstruction options
- Advanced fracture repair
20
Q
What is the use of arthroscopy/tenoscopy in the lame horse?
A
Allows visualisation of some (not all) of joint surface – cartilage, synovium, ligaments, menisci
21
Q
Name the commonly performed nerve and joint blocks.
A
Nerve blocks
- Palmar digital abaxial sesamoid
- Low 4 point
Joint blocks
- Distal inter phalangeal joint (DIP)
- Tarsometatarsal joint (TMT)
22
Q
Where are the palmar digital nerves located?
A
- Abaxial – running down from the fetlock, pass over the annular ligament (safe to inject here) then over the SDFT sheath and then to ungual cartilage
- Are palpable from the fetlock to the pastern region, run withe PD artery and vein aim to block under the ungual cartilage at the most distal point
- If you can feel neurovascular bundle, go most palmar
23
Q
How are palmar digital nerve blocks done?
A
- 1-2ml mepivaciane
- Limb up or down
- Insert needle palmar to medial NVB axial to collateral cartilage, aiming distally
- Repeat on lateral aspect
24
Q
What area should the palmar digital nerve block desensitise?
A
Distally, hoof capsule and slightly misses the dorsal aspect of this
25
How is an abaxial nerve block done?
- 1-2ml mepivacaine
- Palmar/plantar digital nerve
- Limb up or down
- Palpate digital neurovascular bundle on palmarolateral and palmaromedial fetlock over annular ligament
- Insert needle palmar to medial NVB aiming distally
- Repeat on lateral aspect
26
What is the name of the coffin joint?
Distal interphalangeal joint
27
What approach is used for the distal interphalangeal joint block?
4 commonly used approaches. Dorsal is used - others are useful when the dorsal area is injured and we need to assess joint involvement
28
How is a dorsal approach to distal interphalangeal joint block done?
- Full sterile prep
- Limb loaded
- 0.5-1cm above hoof wall
- Aim vertically or slightly caudodistal
- 2-3cm deep
- Check viscosity
29
How are distal interphalangeal joint blocks interpreted?
If block abolishes lameness = likely DIP joint pain
30
Where might also be densensitised by a distal interphalangeal joint block?
The navicular bone, palmar digital nerves and solar surface by local diffusion
31
What are the 4 joints of the hock?
Tibiotarsal = Tarsocrural
Proximal intertarsal = Talocalcaneocentral
Distal intertarsal = Centrodistal
Tarsometatarsal
32
How much do the joints of the hock communicate and why is this important for joint blocks?
For diffusion of LA:
- Distal intertarsal – tarsometatarsal = 25%
- Proximal intertarsal – distal intertarsal – and tarsometatarsal = 10%
- Proximal intertarsal – tarsocrural all
33
How is a tarsometatarsal joint block done?
- Horse weight bearing
- Lateral approach
- Palpate the top of the lateral splint, divot just above is site for needle entry
- 2ml intraepicaine
- Aiming from caudolateral slightly distal to perpendicular
- 1-2cm deep
34
What confirms the location of the tarsometatarsal joint block? What is done next?
Outflow of synovial fluid but not always
- If not present may try to inject, if high pressure you are not intraarticular so need to reorientate
- If present, check viscosity
35
Where else might tarsometatarsal joint desensitise?
The deep branch of the lateral plantar nerve which supplies the plantar metatarsal nerves, which innervate suspensory ligaments, and potentially metatarsal nerves
36
How is the interpretation of the tarsometatarsal joint block ensured to be correct?
Perform cross over blocks with the deep branch of the suspensory ligament
37
What is seen when a horse becomes forelimb lame?
Starts to move the head up and down asymmetrically to help unload the painful limb. The head’s minimum position during stance of the left and right front foot hence looks asymmetrical
38
How do we determine which leg a horse is forelimb lame on?
The horse will look as if its nods down during stance of the sound limb. The reason for this is that the horse can carry more weight with the normal limb and the increased downward movement of the head during stance of the normal limb allows the lame leg to do less work to support the body.
39
What can be seen when a horse is hindlimb lame?
Hops onto the lame limb. The reason for this is that the horse pushes off a lot from the normal limb so that the lamb limb has to do less work to support the body. The foot making ground contact is the lame limb.
40
How do we determine which leg a horse is hindlimb lame on?
If lameness is present, we also need to determine the lamb limb. The hip that shows the greater movement amplitude is on the side of the lame limb, so you do not have to look at limb movement to establish the side of lameness.
41
What is the presentation of asymptomatic synovitis?
- Effusion of joint or sheath
- No pain/lameness
- No radiological changes
42
What is the aetiology of asymptomatic synovitis?
Uncertain - conformation, minor trauma?
43
How is asymptomatic synovitis treated?
No treatment necessary, often resolve
44
What is the presentation of reactive joint flare synovitis?
Acute onset 24h after joint injection
Lameness
Effusion
Heat
Resents palpation/flexion
45
What is the differential diagnosis for reactive joint flare synovitis?
Septic arthritis.
Test with synoviocentesis - TNCC <30 x 10^9 cells/L, minimal increase in TP, resolves in 1-3 days
46
What is the aetiology of reactive joint flare synovitis?
Injection induces inflammation
Chemical reaction
Steroid induced arthropathy (MPA)
Hyaluron flares
47
How is synovitis treated?
Oral NSAIDs
48
What are the clinical signs of traumatic synovitis?
Effusion, pain on flexion, lameness? Heat?
49
What is the clinical pathology of traumatic synovitis?
- TNCC is normal at < 10x 10^9 cells/L
- Possible haemarthrosis is painful (distinguish from iatrogenic if whole sample is pink/red)
- Synovitis, capsulitis
- Cartilage damage, articular fracture, ligament injury, luxation
50
What is the progression of traumatic synovitis?
Chronic thickening, beginning of osteoarthritis
51
How is traumatic synovitis investigated?
Radiographs
Ultrasonography
Synoviocentesis
Arthroscopy
52
What is the treatment for traumatic synovitis?
- Box rest whilst acute – NSAIDs, cold
- Rehabilitation
- Specific surgery?
- HA/PSGAGs
53
What is the signalment of septic arthritis?
- Foals with bacteraemia – check umbilicus
- Any horse with a penetrating injury
54
What are the clinical signs of septic arthritis?
- Lameness – progressive to NWB
- Resents palpation/flexion
- Effusion and heat
55
What are the local responses to bacterial inoculation in septic arthritis?
- Synovial hypertrophy
- Fibrin formation
- Cartilage breakdown
- Synovial membrane permeability increases
- PMN influx, phagocytosis then apoptosis
56
How is septic arthritis diagnosed from synoviocentesis?
Gross appearance – dark yellow/brown/red, less viscous
Cytology – TNCC> 10 x 109 cells/L most >30, >80% neutrophils, TP>40g/L
57
How is septic arthritis treated?
- Arthroscopic lavage
- Needle flush – reasonable option in acute case
- Intraarticular antimicrobials – last ditch if reason to avoid surgery, very poor success rate
58
When is arthroscopic lavage highly indicative of infection for septic arthritis?
TNCC >30 x 109 cells/L
Differential count >80% PMN
TP>40 g/L
Bacterial on gram stain
59
What is the pre-operative management for arthroscopic lavage for septic arthritis?
Systemic antimicrobials, analgesia
60
What is the intra-operative management for arthroscopic lavage for septic arthritis?
Arthroscopic lavage with copious (>5L) polyionic fluids
Remove fibrin clots
Synvectomy
61
What is the post-operative management for arthroscopic lavage for septic arthritis?
- Prolonged systemic course antimicrobials – penicillin and gentamycin IV
- Plus regional antimicrobials – intraarticular and/or intravenous regional perfusion (IVRP), amikacin/gentamycin
- Analgesia – NSAIDs
62
What is the presentation of osteochondrosis, OCD and bone cysts?
Young horse
Lameness
Effusion
63
How are osteochondrosis, OCD and bone cysts investigated?
Lameness examination
Positive flexion
Responds to joint block
64
How is osteochondritis dissecans/OCD treated?
Surgical removal of fragments, arthroscopic
65
What is the prognosis for osteochondritis dissecans/OCD treatment?
Good for hocks, guarded for shoulder
Predisposes later OA
66
How are subchondral bone cysts treated?
Surgical debridement
Trans lesional screw
Intra lesional corticosteroids
Current favoured treatment is transcondylar lag screw to favour more normal bone growth
67
What is the prognosis for subchondral bone cyst treatment?
Age related better in 3y for stifle
68
What is the classic site for subchondral bone cysts?
Medial condyle
69
What happens in osteoarthritis?
Disturbed balance between synthesis and degradation in joint tissues and characterised by focal loss of cartilage, subchondral bone sclerosis and marginal osteophyte formation.
70
What is stage 1 osteoarthritis?
At this stage, there is synovitis in the affected joint, but no morphologic changes in the articular cartilage
71
What is stage 2 osteoarthritis?
The synovitis is less acute at this stage, and the articular cartilage is starting to suffer damage
72
What is stage 3 osteoarthritis?
The synovitis has become chronic in this stage, and cartilage damage has become severe
73
What is stage 4 osteoarthritis?
The horse suffers from chronic synovitis and full thickness loss of articular cartilage
74
What is the cause of primary osteoarthritis?
Chronic repetitive trauma
75
What is the causes of secondary osteoarthritis?
Following traumatic arthritis, articular fracture, osteochondrosis or septic arthritis
76
Can you list the joints of the hock? Which communicate with each other? What joint(s) are affected by OA in this case?
Tibiotarsal/tarsocrural – always. Proximal intertarsal – sometimes. Distal intertarsal – often (40%). Tarsometatarsal. Here the distal intertarsal joins are completely fused and the TMT joint has advanced changes too
77
What are the clinical signs of osteoarthritis?
Lameness/poor performance
Pain on manipulation
78
How is osteoarthritis investigated?
Lameness workup
Reduced range of motion?
Thickened joint?
Crepitus?
Positive to flexion
Positive response to IA block
79
How is osteoarthritis identified from radiography?
Periarticular new bone
Subchondral bone sclerosis
Narrow joint space
80
How is osteoarthritis identified from scintigraphy?
Increased radiopharmaceutical uptake periarticularly
81
What are the treatment options for osteoarthritis?
- Possible to limit synovitis
- Limited ability to reverse cartilaginous/bony pathology
- Salvage – arthrodesis of low motion joints
82
What does the prognosis of osteoarthritis depend on?
Location
Severity
Treatment
Rehabilitation program
Previous attempts
83
How is management adapted for osteoarthritis related lameness?
- Exercise routine – ideally regular controlled, warm up and cool down, water treadmills show benefit
- Confinement/Box rest – ideally space to move freely. Manage with stretching exercises
- Cold weather – may warrant stabling/bandaging
- Bodyweight – avoid obesity
- Farriery – regular shoeing with optimal balance
84
When can surgery be used to change joint structure?
OCD – remove fragments
Fracture cases – restore congruity and stability
OA cases – salvage arthrodesis
Benefit of lavage
85
What are the long term NSAIDs that can be used for treatment of mature horses and ponies with joint disease?
Phenylbutazone
Suxibuzone
Flunixin
Meloxicam
86
What are the side effects of long term NSAID use for joint disease?
GI ulcers
RD colitis
Hypoproteinaemia
87
Name the 2 intraarticular corticosteroids used for local treatment of joint disease?
- Triamcinolone acetonide “Adcortyl”
- Methyl prednisolone acetate “Depo medrone”
- Often given concurrently with hyaluronic acid
88
Why are intraarticular corticosteroids used to treat joint disease?
- PPL A2 inhibitors reduce Arachidonic acid production, reducing inflammation mediators from synovium
- Cumulative
89
Why is triamcinolone thought to be safer for local joint disease treatment?
More chondroprotective so predominantly used in high motion joints
90
What are the possible complications of intraarticular corticosteroid treatment of joint disease?
Risk of joint sepsis (sterile prep) but masks symptoms
Laminitis – only if EMS/PPID not controlled/history of laminitis
91
What is the effect of intra-articular hyaluronate?
Lubricant
Anti-inflammatory
Modest analgesia
Disease modifying anti0osteoarthritic drug effects
Cumulative
92
What are the possible complications of intraarticular hyaluronate?
Joint flare
Sepsis risk
93
What is IRAP for local treatment of joint disease?
- Intraarticular interleukin-1 receptor antagonist protein
- Present in autologous conditioned serum
- Blocks IL-1
- Collect blood, incubate to enhance IRAP production, centrifuged to collect serum
- 3 doses at 7-10day intervals
94
What are the risks of IRAP local treatment of joint disease?
Joint sepsis so strict asepsis required
95
How is pentosan given for joint disease treatment?
4 intramuscular injections at 5-7d intervals
Prophylactically
96
What is the effect of pentosan treatment of joint disease?
- Supports cartilage recovery
- No primary analgesic effect
- Improves joint function by improving cartilage
97
How are polysulphated glycosaminoglycans given for joint disease treatment?
Every 4 days for 7 treatments IM injection
98
What is the effect of polysulphated glycosaminoglycans for joint disease?
Inhibits catabolic enzymes (MMPs) – reduce inflammation, restore lubrication, repair cartilage
99
What is the side effect of polysulphated glycosaminoglycans for joint disease?
Haemorrhage (heparinoid)
100
What are the effects of bisphosphates for joint disease?
- Reduce osteoblast activity
- Used when excessive bone development
- Slow effect – takes 2m
101
What are the side effects of bisphosphates for joint disease?
Binding of circulating calcium at time of injection may cause GI dysfunction and colic signs
Give concurrent NSAIDs, drip over 1hour and monitor signs
102
What is the effect of intraatricular polyacrylamide gel for local treatment of joint disease?
- Non-absorbable so long duration
- Shock absorption
- Increases elasticity of joint capsule
- Improves synovial fluid quality
103
What are the complications of intraatricular polyacrylamide gel for local treatment of joint disease?
Soreness and oedema at 1-2w post injection during integration
104
How can platelet rich plasma be used to treat joint disease?
- Blood derived autologous product containing growth factors cells and cytokines
- In joints
- Improves lameness scores
- May overcome negative affects of corticosteroid administration
105
What is the effect of mesenchymal stem cells to treat joint disease?
Improved lameness
Improved synovial fluid
Improved cartilage appearance
Improved cartilage composition
106
How are shock waves used to treat joint disease?
- Used on soft tissue injuries
- 1500-2000 pulses per joint
- 1 to 3 treatments at weekly intervals
- Usually well tolerated
- Used in lower motion joints
- Used for enthesopathies
- Reduces pain
- Benefits last approximately 1m
107
What are the visible lesions of equine hoof examination?
Bruising
Cracks - grass cracks come up from the bottom, sand cracks from the top
Swelling
Discharge
Widening of white line
Divergence (growth lines should be parallel)
108
How do you stop grass cracks perpetuating up the hoof?
- Avoid pressure up centre of hoof so avoid toe clip and use quarter clip instead to use the hoof as a singel structure
- We can interrupt the line by rasping a horizontal line at the top of its current level
- Can round off the top of the crack
109
How do you stop sand cracks perpetuating up the hoof?
Support the hoof from the base, may be by reducing the load on a small area so it floats slightly above the show/ground and this does not move, allowing better new growth of the following horn
110
What can you identify by palpating dorsal of the coronary band?
- Sinking of the extensor process of P3 in laminitic cases and
- Effusion of the DIP joint
111
What can you identify by palpating circumferentially at coronary band?
- If a foot abscess has tracked up under the dorsal hoof wall and is about to burst at the coronary band
- Chronic founder cases
112
Name the 3 synovial structures of the equine hoof.
Distal interphalangeal joint/DIP/coffin joint
Navicular bursa
Digital flexor tendon sheath
113
Where does the navicular bursa sit?
Small structure in the hoof which sits distal to the navicular bone
114
Describe navicular bursa injection.
- May cross react with DIP joint blocks
- Entry is difficult but may be ultrasound or radiographically guided
- Sepsis is common here following solar puncture wounds
115
What is the frog packed with and why for radiography of the hoof?
Pack frog with play doh – so shadows of frog not seen to assess bones
116
What are foot blocks/tunnels for?
To elevate and angulate the hoof
117
What is the positioning of the hoof for the lateromedial view of P3?
Weight bearing on blocks
Markers - dorsal hoof wall and point of frog
118
What is the positioning of the machine for the lateromedial view of P3?
Cassette - medial aspect of limb
Beam - centre 1/3 palmar from dorsal coronary band, 1cm below coronary band, aim horizontally, with heel bulbs superimposed
119
Which condition may be commonly assessed by a single lateromedial view of the affected limbs?
Laminitis
120
What are the features that we assess when we look at lateromedial views of P3?
- Centre of arc of DIP vertically down round line up with frog marker
- Pastern parallel with front of P3, back of heel and front of hoof
- Coronary band – extensor process of P3 height
- Extensor process can have separate centre of ossification which can look like free bone
- Solar thickness and solar surface wants to be inclined by 5-10 degrees
- Wall thickness relative to P3 length – wants to be a third of the length
- Tip of P3 should not be a lip but a fine point
121
What is the position of the hoof and machine for dorsoplantar view of P3?
Hoof - weight bearing on blocks, heel close to back
Cassette - on palmar aspect of limb
Beam - mid way between sole and coronary band
122
What is the convention for markers on a standard DP view where should the left/right marker be placed?
Laterally
123
What are the features we assess on dorsopalmar view of P3?
- Difference between P3 and sole
- Joint spaces should look symmetrical
- Hoof wall flare
124
How is the hoof and machine positioned for a dorsoproximal palmarodistal oblique view of P3?
- Toe on block, sole vertical (P3) or dorsal hoof wall vertical (nav)
- This can also be done with the horse stood on a tunnel housing the cassette using a 55-65˚ angled beam
- We can then rotate generator to add a lateral or medial 45˚ obliques too
125
How is the dorsoproximal palmarodistal oblique view of P3 altered to view for navicular bone?
- Increase exposure
- Reduce collimation
- Centre 1cm more proximal – to reduce angle by 5˚
126
What are the features used to assess DPrL-PaDiMO and DPrM-PaDiLO view?
- Dorso 60° proximal 45° lateral-palmarodistomedial
- Assess symmetry between M and L sides and L and R feet
- Useful for pedal wings and abaxial navicular fractures
- DIP joint
127
What is the position of the hoof and machine for palmaroproximal-palmarodistal oblique/skyline view of P3?
Weight bearing on tunnel, heel close to back and extended caudally ad/or lift heel
Beam – centre axially between heel bulbs angling 45-55˚ distally
128
What other modality is most commonly used in practice for investigation of foot lameness?
MRI
129
What are the aetiological causes of acute foot lameness?
Infection – nail prick, foot abscesses, penetration, foreign body
Trauma – bruising, corns
Laminitis
130
How is nail bind/picked hoof diagnosed and treated?
Diagnosis – hoof testers and paring
Treatment – remove nail/shoe, poultice, rest about a week
131
What is the aetiology of solar bruising?
Rough ground, unshod, laminitis
132
How is solar bruising diagnosed?
Pain on hoof testers
Visible bruising after paring
133
How is solar bruising treated?
- Rest – unshod or poultice?
- Reshoe after paring?
- Avoid stony ground
134
What is the aetiology of corns of the hoof?
Collapsed bars
Too long shoeing interval
135
How are hoof corns diagnosed?
Pain on hoof testers
Visible
136
How are hoof corns treated?
- Rest – unshod or poultice?
- Reshoe after paring
137
What is the aetiology of hoof subsolar abscesses?
- Penetrating injury to solar surface
- Bacteria tracking up white line
- May follow nail bind/solar bruising/corns
138
What are the clinical signs of hoof subsolar abscesses?
- Acute NWB lameness
- Increased digital pulses
- Pain on hoof testers
- May burst spontaneously
139
How are hoof subsolar abscesses diagnosed and treated?
Diagnosis – pus released during paring
Treatment – poultice/tubbing and rest
140
How do hoof subsolar abscesses progress?
Most abscesses drain at the white line
Occasionally elsewhere
141
Describe donkey hoof abscesses.
Donkeys have very deep and hard hoofs so abscesses are frequently very deep
142
What is the presentation of deep puncture wounds?
Acute lameness NWB
143
How are deep puncture wounds investigated?
- Hoof testers and paring
- Radiographs with/without contrast
- MRI
144
What must be assessed with deep puncture wounds and what action is taken?
Must assess DIP, NB and DFTS
- If affected – arthroscopic lavage or euthanasia
- If not affected – poultice and rest, analgesia, antimicrobials
145
What is the aetiology of pedal oesteitis?
Septic focus in P3, often following PIF/puncture
146
How does hoof osteitis present?
- Acute severe lameness which persists
- Increased digital pulses
- Pain on hoof testers
147
How is pedal osteitis treated?
- Curettage back to healthy bone, remove any sequestrate which have formed
- Management open wound – hospital plate or bandaging?
148
When might you consider initial radiographs shod?
Hoof fractures to avoid instability
149
What is the aetiology of P3 fractures?
Trauma
Wall kick - especially hindlimb
150
What is the presentation of P3 fractures?
Acute onset severe lameness
151
What is type 1 P3 fracture?
Involve the palmar/plantar process and do not enter the distal interphalangeal (DIP) (coffin) joint
152
What is a type 2 P3 fracture?
Fractures are oblique or parasagittal fractures that are articular but are not on the midline
153
What is a type 3 P3 fracture?
Are midline articular fractures that bisect the pedal bone into 2 equal halves
154
What is a type 4 P3 fracture?
Involve the extensor (pyramidal) process of the pedal bone
155
What is a type 5 P3 fracture?
Comminuted fragments and split the pedal bone into multiple fragments
156
What is a type 6 P3 fracture?
Solar margin fractures
157
What is a type 7 P3 fracture?
Fractures are exclusive to foals and are also fractures of the solar margin
158
What might be over diagnosed as a P3 fracture?
Can get evulsion fractures of extensor process – do not over diagnose from its own ossification
159
What are the 2 treatment options for P3 fractures?
Surgical lag screw
Conservative bar shoe and rest
160
What should assessment for treatment options be based on for P3 fractures?
Based on soundness, not radiography – heal by fibrosis so don’t know how old a fracture may be as it will look fractured forever as it does not heal by remodelling
161
How do navicular bone fractures present?
Acute severe lameness
Increased digital pulses
162
What radiographic view is done to investigate navicular bone fractures?
PaPr-PaDiO
163
What is the configuration of navicular bone fractures?
Usually parasagittal and slightly oblique
164
How are navicular bone fractures treated?
Surgical lag screw
Conservative – bar shoe with quarter clips, rest
165
What is the aetiology of fractures of the ossified ungal cartilages?
Ossification of ungual cartilages is usually an asymptomatic condition but they are predisposed to trauma
166
What is the presentation of fractures of the ossified ungal cartilages?
Acute severe lameness
Increased digital pulses
Pain on palpation of heel bulbs
Careful – as separate centres of ossification this may be a misdiagnosis
167
How are fractures of the ossified ungal cartilages treated?
Bar shoes with quarter clips and rest
168
What condition might a pony have, which would predispose it to laminitis?
EMS, PPID, being a pony
169
What is the developmental stage of laminitis?
Causal event until clinical signs, act now if you can, ice boots are protective
170
What is the acute stage of laminitis?
From onset of sign to 72h, may include structural failure
171
What is subacute stage of laminitis?
Repair over 2-3 months
172
What is chronic stage of laminitis?
Structural failure develops over indefinite period
173
How might endocrinopathies cause laminitis?
- PPID
- EMS
- Corticosteroid administration – only unsafe when undetected or uncontrolled PPID or EMS. Test and if safe, can give, this will not be a risk
174
What are the possible aetiologies of laminitis?
Endocrinopathies
Excess carbohydrate intake
Toxaemia
Contralateral limb lameness
175
Describe the pathogenesis of laminitis.
Dermal-epidermal separation of lamellae
Basement membrane lysis
176
What are the clinical signs of laminitis?
Weight on heels
Reluctant to move/pick up foot
Increased digital pulses
Warm feet?
Pain on hoof testers
Change in solar surface – flatter
Coronary band depression
Solar bruising
Divergent growth rings
Change in hoof shape
177
How is laminitis diagnosed from imaging?
Rotation
Sinking
Gas
Remodelling/lysis
178
How does subsolar gas form in laminitis cases?
Inflammation > haemorrhage > haemorrhage reabsorbed > end up with a pocket where gas accumulates
179
What are the aims of treatment of laminitis?
- Manage primary cause
- Alter laminar perfusion
- Reduce inflammation
- Mechanical support
- Pain relief
180
How is laminitis treated in the developmental stage?
- Treat primary cause – PPID/EMS, feed room gorge, endotoxaemia
- Alter laminar perfusion – cold to decrease flow
- Prevent inflammation and analgesia – NSAIDs
- Mechanical support – rest on deep bed
181
How is laminitis treated in the acute stage?
Increase laminar perfusion
NSAIDs
Mechanical support:
- Rest on deep bed
- Frog supports
- Styrofoam pads/lily pads/plaster of paris sole casts/sole putty
- Remove toe
- Elevate heel? (Reduces DDFT pull)
182
How is laminitis treated in the chronic stage?
- Gradually withdraw acute treatments
- Normalise anatomy with trimming – shorten toe, remove heel height, takes months-years
- Support from heart bar shoes/silicone filler
183
What structures are subject to strain or sprain injuries in chronic lameness cases?
- Collateral ligaments of the distal interphalangeal joint
- Distal deep digital flexor tendon
- Impar ligament of the navicular bone
184
What are the osteoarthritic causes of chronic laminitis?
- Navicular disease/syndrome
- Chronic infections (thrush, canker, quittor)
- Keratoma
185
What is present in the distal interphalangeal joint with osteoarthritis present?
Enthesiophytes - mid-distal P2
Osteophytes - proximal P3, palmar P3, navicular
186
What is present in the proximal interphalangeal joint with osteoarthritis present?
- Osteophytes – distal P1, proximal P2
- Small joint motion so arthrodesis possible
187
What are the clinical signs of subchondral bone cysts in P3?
Lameness
Effusion of DIP
188
How are subchondral bone cysts treated?
Translesional screw used from dorsal aspect
189
What is the aetiology of navicular disease?
Unclear, likely degenerative predisposed by poor foot conformation
190
What are the clinical signs of navicular disease?
- Chronic, often bilateral, low grade forelimb lameness
- Worse when lunged on hard circle
- Positive response to PDNB
191
What are the radiographic changes that occur as a result of navicular disease?
- Circumscribed lucent lesions within the flexor cortex or medulla of the bone
- Disruption or alteration of the opacity, contour or thickness of the flexor cortex
- Medullary sclerosis with blurring of the trabecular pattern and loss of corticomedullary definition
- Increased number and/or size or change in shape of lucencies on the distal border of the bone
192
How is navicular disease treated conservatively?
- Farriery – egg bar shoe with heel cushioning
- Analgesia – NSAIDs
- Vasodilator? Isoxuprine
- Bisphosphates
193
How is navicular disease treated surgically?
- Navicular suspensory desmotomy
- Palmar digital neurectomy – removing innervation to foot
194
What are the clinical signs of keratomas?
- Mild intermittent lameness
- Recurrent abscesses
- Defect in white line at sole
- Distortion of hoof wall
195
How are keratomas diagnosed?
Blocks to PDNB and imaging
196
How are keratomas treated?
Surgical resection
Minimally invasive resection
197
What is the aetiology of thrush in the hoof?
- Infection and necrosis in sulci
- Predisposed by poor environment hygiene
- Fusobacterium necrophorum invades as opportunist
198
What are the clinical signs of thrush in the hoof?
Black malodourous discharge around frog
199
How is thrush in the hoof treated?
Pare, foot hygiene – keep clean and dry
200
What is the aetiology of seedy toe?
Disruption of the white line, often sequelae of multiple abscesses
201
What are the clinical signs of seedy toe?
- Mild-moderate lameness, associated with severe lameness when abscess forms
- Large defect when paring
202
How is seedy toe treated?
Resect defect with paring, consider filling
203
What is the aetiology of canker?
Poorly understood, bovine papilloma virus?
204
What are the clinical signs of canker?
- Predominantly draught horse hindlimbs
- Chronic, moist hypertrophic pododermatitis
- Starts at frog slowly extends
205
How is canker treated?
- Debride
- Antiseptics and dressings
206
What is the aetiology of quittor?
Wound to coronary band
Deep puncture wound to sole
207
What are the clinical signs of quittor?
Painful swelling, ruptures and drains
208
How is quittor treated?
Surgical removal of necrotic cartilage and tissue
209
What are the causes of equine fractures?
- External trauma – kicks, falls
- Stress fracture – repetitive trauma on bone with no time to rest and heal
210
What is done for clinical examination of fracture patients?
- Hydration status
- Physiological state
- Sedation necessary?
- Analgesia necessary?
- Which limb and where
- Bone and soft tissues affected
- Synovial involvement
- Open/closed
211
What drugs might you need to give such a patient to facilitate examination and treatment?
Alpha-2 agonists – detomidine, bromithedine
NSAID – flunixin, phenylbutazone, meloxicam
Opioids – butorphanol, morphine
212
When is euthanasia appropriate for fracture patients?
Open fracture of long bone?
Leg clearly unstable?
213
What are the treatment options available for fractures?
Lag screws
Cerclage wire
Dynamic Compression Plates
Limited Contact DCP
Locking Compression Plates
Tension band wiring
External fixator
214
If you can’t identify a cause on palpation or radiograph but you have a highly valuable non-weightbearing horse what imaging modality would you choose next?
Gamma scintigraphy
215
What is fracture stabilisation needed for short term?
- Reducing stress
- Comfort
- Limiting dmage to soft tissues including skin - minimise displacement, minimise fragmentation
- Safe onward transport
216
What is the long term goal for fracture stabilisation?
To maintain bones in a static position to allow complete healing
217
What is fracture zone 1?
Distal metacarpus to hoof
Distal metatarsus to hoof
218
How are zone 1 fractures stabilised?
- Align dorsal cortices to neutralise dorso-palmar bending force
- Tiptoe – don’t want heel to touch the floor
- Forelimbs – full length on dorsal aspect
- Hindlimbs – full length of plantar aspect
- Also use for catastrophic tendon injuries – takes all the pressure off the tendons at the back
219
What is fracture zone 2?
Distal radius to mid metacarpus
Proximal to mid metatarsus
220
How are zone 2 fractures stabilised?
- Align bony column and immobilise distal limb
- Full limb Robert Jones bandage (3x limb diameter) from floor to elbow/point of hock or stifle
- Splints
- Forelimbs – caudal and lateral as long as bandage
- Hindlimbs – plantar splint and lateral as long as bandage
221
What is fracture zone 3?
Proximal to mid radius, tibia and tarsus
222
How are zone 3 fractures stabilised?
- Prevent abduction of limb to avoid radius/tibia penetrating skin medially
- Full limb Robert Jones bandage (3x limb diameter) from floor to elbow/near stifle
- Splints
- Forelimbs – caudal as long as bandage extended lateral splint to withers
- Hindlimbs – lateral wide splint to level hip
223
What is fracture zone 4?
Proximal to elbow, proximal to stifle
224
How are zone 4 fractures stabilised?
- Stabilise carpus for triceps function
- Minimise moment
- Splints
- Forelimbs – caudal on radius and metacarpus
- Hindlimbs – no bandage nor splint
225
What is considered when transporting horses with fractures?
If travelling with horses in trailers, in case of emergency stops, face the fracture away from the front
226
what are the top 3 musculoskeletal injuries causing fatalities in racing?
- Forelimb sesamoid fracture
- Suspensory ligament rupture
- 3rd metacarpal condylar fracture
227
Name the situational risk factors for race horse fractures.
Global location
Race distance
Jumps
Surface
Going - how hard ground is, increased risk with firmer going
228
Name the horse risk factors in racehorse fractures?
Age
Number of starts
Bone density
Medication - phenylbutazone has increased risk for fracture
Breeding - fracture heritability low
229
How does fracture risk change with age in race horses?
- Increased risk after 6-7yo – likely accumulated pathology
- Young horse – skeletal adaptations are likely protective so starting young actually appears to be protective
230
How does fracture risk change with number of starts in race horses?
Subclinical damage such as microcracks in bone will not be repaired whilst intense loading is frequent (active training) – mini rest means osteoclasts will attempt to repair bone but bone gets weaker before it gets shorter so need a holiday of 3 months, or will be weaker after this mini holiday for micro cracks
231
Where are the palmar nerves in horses located?
Just dorsal to DDFT and proximal to DFTS
232
Where do you inject to inject the palmar metacarpal nerves?
Inject distal and axial to button of splints
233
What is the area of desensitisation of the low 4 point nerve block for fore and hindlimbs?
The distal cannon dorsally and may block the palmar metacarpal region and beyond
234
Where is injected for the high 4 point/high palmar nerve block on fore and hindlimbs?
- Level of proximal metacarpus/metatarsus
- Palmar nerves – just dorsal to DDFT
- Palmar metacarpal nerves – axial to splint bones
235
Where is the lateral palmar nerve located and what does it supply?
On the medial aspect of the accessory carpal bone
Deep branch of the lateral palmar nerve > medial and lateral metacarpal nerves
236
Where will the lateral palmar nerve block desensitise?
Should block the splint bones and proximal suspensory region
It will not anaesthetise distal limb because the palmar nerves ramus communicans allows cross over between medial and lateral too
237
Where is the deep branch of the lateral plantar nerve in the hindlimb located?
Just plantar and distal to the head of MTIV (lateral splint bone)
238
Where does a nerve block of the deep branch of the lateral plantar nerve desensitise?
Desensitise entire origin of the suspensory ligament
239
How is the cross over between the deep branch of the lateral plantar nerve and tarsometatarsal block distinguished?
Is positive to both blocks do again and see which has a quicker response (slower more likely to be positive based on diffusion)
240
How is the proximal interphalangeal joint blocked?
The pastern joint has a small joint pouch which means it is harder to inject so radiographic guided injections
241
What are the 4 standard views to radiograph the pastern?
Lateromedial
Dorsopalmar
Dorsolatero-palmaromedial Oblique
Dorsomedio-palmarolateral Oblique
242
What are the 5 standard views to radiograph the fetlock?
Lateromedial
Dorsopalmar
Dorsolatero-palmaromedial Oblique
Dorsomedio-palmarolateral Oblique
Flexed lateral
243
What are the 2 additional views to radiograph the fetlock?
Proximolateral-distomedial oblique
Proximomedial-distolateral oblique
244
What are the 4 standard views to radiograph the metacarpus?
Lateromedial
Dorsopalmar
Dorsolatero-palmaromedial Oblique
Dorsomedio-palmarolateral Oblique
245
How are the splint bones radiographed when imaging the metacarpus?
Splint bones are more axial proximally and abaxial distally so angle to skyline these changes upon the level
246
What is ultrasound used to visualise in the metacarpus?
Soft tissues
247
What is the presentation of pastern osetoarthritis?
- Mature working horse problem
- Low grade lameness
248
What is the appearance of pastern osteoarthritis on radiographs?
- Periarticular osteophytes on dorsoproximal P2 radiographs - mall lip on distal surface of dorsal aspect of P1
- Subchondral sclerosis
- Narrow joint space
249
How can be done for pastern osteoarthritis?
Can perform arthrodesis
250
What is the aetiology of lateral/medial pastern luxation?
Trauma
Collateral ligament damage
251
What is the aetiology of DP (distal/proximal?) pastern luxation?
Chronic overload
Complication of desmotomy
252
What are the differential diagnoses for lateral luxation of the pastern?
Salter harris type 1 fracture in foals – where fracture crosses the growth plate instead of luxation so need radiography to confirm (stress may show more effectively than standing radiograph)
253
What is fetlock OCD?
- Effused joint
- Flexion positive
- If fragment then remove
254
Distinguish type 1, 2 and 3 fetlock OCD.
Type 1 – flattening of sagittal ridge
Type 2 – flattening with in situ fragment
Type 3 – floating fragment
255
What is the aetiology of fetlock osteoarthritis?
Subsequent to OCD, fracture or trauma
256
What is the radiographic appearance of fetlock osteoarthritis?
Periarticular osteophytes and remodelling – on margins of sesamoid bones and dorso proximal P1
257
What is the aetiology of sesamoiditis?
Likely repetitive strain injury at suspensory ligament insertion
258
How is sesamoiditis visualised on radiographs?
- Lytic lesions on radiographs
- Proximo-distal obliques may aid visualisation
259
What orthopaedic issues can affect the cannon bone?
Sclerosis of palmar MCIII/MTIII – with PSD/proximal suspensory desmitis
Enostosis like lesions – idiopathic, sclerosis near nutrient foramen. Scintigraphy shows active hotspot
260
What is the aetiology of sore/bucked shins?
Stress adaptation mismatch
261
How are sore/bucked shins visualised on radiographs?
- Periosteal and endosteal new bone
- Intracortical fissures/lucencies
262
How are sore/bucked shins managed?
Period out of work resting is best treatment
263
What is sequestrum formation/septic osteitis?
- Direct trauma
- Sequestrum forms
- Discharging tract
264
How is sequestrum formation/septic osteitis treated?
- Surgical removal/curettage
- Aggressive antimicrobials with septic osteitis
265
What is the presentation of splints/periostitis?
Localised swelling, painful when forming but incidental finding in older horses
266
How are splints/periostitis managed?
6w rest
267
How are comminuted P2 fractures treated?
Transfixion cast or salvage arthrodesis
268
How are P1 fractures treated?
Lag screw fixation standing or GA
269
How are condylar fractures treated?
Lag screw fixation
270
List the possible fractures affected the metacarpals?
- Condylar fractures
- Stress fractures - dorsal and proximal palmar cortex
- Avulsion fractures of the origin of the suspensory ligament
- Incomplete transverse fractures of the distal metaphysis/diaphysis
- Major diaphyseal fractures
- Fractures of the distal physis
271
What are the possible sesamoid fractures?
Apical
Mid body
Basal
Abaxial
272
How are sesamoid fractures treated?
Prompt surgical removal for articular apical, basillar or abaxial
Mid body may need lag screw – reduction challenging due to pull of suspensory ligament
273
What is the prognosis of sesamoid fracture treatment dependent on?
Amount of concurrent soft tissue damage
274
How are splint bone fractures managed?
- If proximal may need stabilisation
- If distal may be associated with suspensory ligament desmitis
- May manage conservatively, or by surgical removal or plate if proximal
275
Describe the approach and area of desensitisation for median and ulnar nerve blocks?
Ulnar nerve – approached from caudal aspect of the limb, proximal to accessory carpal bone
Median nerve – on medial antebrachium just ventral to pectorals, caudal to radius
Will desensitize tissues distal to distal radius
276
What are the 2 effective spaces used for carpal joint blocks?
Antebrachial carpal joint
Metacarpal with carpometacarpal joint
277
How are carpal joint blocks approached?
- Diffusion between these 2 spaces when blocking
- 2 divots when bend knees, put needles in here, hear a pop when in
- Dorsal and palmer approaches available
278
What are the 5 standard views used to view the carpus?
Lateromedial
Dorsopalmar
Dorsolatero-palmaromedial Oblique
Dorsomedio-palmarolateral Oblique
Flexed lateral
279
What are the additional views used to view the equine carpus?
Sorsoproximal dorsodistal flexed views (Skylines). Angle depends on region of interest
280
What are the 2 radiographic views to visualise the elbow?
Mediolateral – extended leg, might be painful
Craniocaudal – weight bearing
281
What are the 2 radiographic views to visualise the shoulder?
Mediolateral
Craniomedial caudolateral Oblique
Extend limb cranially
282
What anatomical feature allows us to see the shoulder joint more clearly when superimposed?
Trachea
283
How does treatment of of carpal osteoarthritis differ in young racehorses and mature pleasure horses?
Young racehorses – rest and intra-articular hyaluronic acid and steroids or arthroscopy
Mature pleasure horses – rest, intra-articular hyaluronic acid and steroids or arthroscopy or NSAIDs
284
What are the diagnostic measures for enostosis like lesions on the radius and cannon?
- Show on nuclear scintigraphy – can take 6 months to quiesce
- May block to median and ulnar nerve block when in distal radius or high 4 point when in cannon
- Diagnosis by exclusion
285
What is the presentation of shoulder OCD?
- <1y old with prominent lameness
- Muscular atrophy over shoulder, possible club foot
- Pain on palpation and manipulation
286
What are the radiographic changes for shoulder OCD?
- Loss of congruity of articular surfaces
- Flattening of humeral head/ glenoid
- Irregular lucencies in subchondral bone with surrounding sclerosis
- Cystic lesions in glenoid
- New bone formation indicative of arthritis
287
What are the treatment options for shoulder OCD?
- Conservative (poor outcome)
- Surgical debridement – arthroscopy difficult
- OA a likely consequence
288
What is the aetiology of carpal fractures?
Chronic repetitive trauma
Single episode overload
289
What is the presentation of carpal fractures?
- Effusion
- Pain on flexion
- Crepitus/instability only in severe/multiple fractures only
- Chips moderately lame at onset but may improve rapidly
- Slabs severe and persistent
290
How are carpal fractures investigated?
- If severe lameness may do survey radiographs
- If clear, may need scintigraphy
291
What are the characteristics of carpal chip fractures?
- Single articular surface involved
- Can get multiples/joint
- Usually dorsally
- Particularly from radial and 3 carpal bones in midcarpal joint
292
What are carpal chip fractures managed?
- Arthroscopic removal
- Curette bone
- Resect proliferative synovium
- Still prone to OA later in life
293
What are the characteristics of carpal slab fractures?
- Usually frontal plane
- Radial facet of 3rd carpal bone
- Occasionally sagittal
- Occasionally multiple slabs
294
Which radiographic view is best placed to visualise the radial facet of the 3rd carpal bone?
DLPMO and skyline
- 3rd carpal is biased to medial aspect of joint so DLPMO will highlight this
- A skyline view will help, but a very large slab may be concealed by the bones above overlapping it
295
Which radiographic view is best placed to visualise the accessory carpal bone?
Latero-medial
296
What are the characteristics of accessory carpal bone fractures?
- Highlighted on Lateral/DLPMO views as on Plantarolateral aspect of joint
- Can manage conservatively if no articular
- Usually sagittal
297
What are the characteristics of elbow fractures?
- Ulna > radius
- Often associated with kick wounds
298
How are elbow fractures treated?
- Can manage medically or surgically
- Consider surgery if joint involved
- Box rest as non loading bone
- Bad for catastrophic breakdown in the recovery period, when you need to euthanise
299
List the possible shoulder fractures locations.
Supraglenoid tubercule
Neck and body of scapula
Deltoid tuberosity
Humeral tubercles
Major humeral shaft
Stress fractures of humerus – caudoproximal, craniodistal
300
What is a tail nerve block?
Proximal to point of hock on medial aspect dorsal to DDFT
301
Where is a deep and superficial peroneal nerve block located?
Lateral gaskin at similar level between long and lateral digital extensor muscles, the superficial nerve is palpable here. This block may induce stumbling and toe drag
302
What are the synovial structures in and around the hock?
The DIT is access on the dorsomedial hock
Most commonly used is the dorsolateral one
303
What are the joint levels and communication of the stifle?
Medial femorotibial and femuropatellar joints usually communicate
Lateral femorotibial usually independent
304
What are the standard views to view the hock radiographically?
Lateromedial
Dorsolatero-plantaromedial
Dorsoplantar
Dorsomedial-plantaro lateral
305
What are the additional views to view the hock radiographically?
Flexed lateral
Skyline calcaneous
306
What are the standard views to radiograph the stifle?
Lateromedial
Caudocranial
Caudolatero-dorsomedial oblique
307
What are the additional views to radiograph the stifle?
Patellar skyline
308
What is assessed on ultrasound of the stifle?
Effusion
Fat pad
Meniscus
Patellar tendons
Collateral ligaments
309
What is the presentation of osteoarthritis of the small hock joints (bone spavin)?
- Lame/poor performance/loss of action/back issues
- Swelling on medial distal hock
- Shortened cranial phase, limb carried medially and then stamps laterally to ground
- Positive to hock flexion
310
What are the radiographic signs of osteoarthritis in the small hock joints?
- Irregularity of the joint margin – marginal demineralisation, periarticular new bone
- Irregular joint space – subchondral bone erosions, partial fusion
- Sclerosis of subchondral bone – tarsometatarsal, distal intertarsal or both
311
What are the treatment options for tarsometatarsal or distal intertarsal osteoarthritis?
- NSAIDs
- Shoeing – rolled toe, lateral extensions
- Arthrodesis - surgical where you drill across the joint or chemical with ethanol, which can be painful
312
What is the presentation of OCD of the hock?
- Tarsocrural joint effusion
- Variable lameness?
- Increased incidence in warmbloods, standardbreds, shires
313
Where is hock OCD located?
- Distal intermediate ridge of the tibia/dirt lesions – most cases
- Lateral trochlear ridge of the tibial tarsal bone
- Medial trochlear ridge of the tibial tarsal bone
- Medial tibial malleolus
314
How are DIRT lesions treated?
Distal intermediate ridge of the tibia/dirt lesions - arthroscopic removal advised
315
Where is OCD in the stifle located in most cases?
Lateral trochlear ridge of the distal femur
But can also see on patella and medial trochlear ridge
316
What is the presentation of stifle OCD?
- Lateral - subchondral bone defect, free mineralised flaps/fragments
- Joint effusion
- Variable lameness
317
What is the presentation of osseous cyst like lesions/subchondral bone cysts in the hock and stifle?
- Persistent mild – moderate lameness
- Usually medial condyle
- Communicate with joint
- Sclerotic rim
318
What is curb and how does it present?
- Plantar ligament desmitis – strain/trauma
- Occasionally SDFT injury
- Firm swelling above chestnut and below point of hock
- Lameness at onset later incidental
319
What is bog spavin/tarsocrural effusion?
Clinical signs of OCD, trauma, sprain injury and idiopathic
320
When might you get tarsal sheath effusion?
- Biaxial swellings cranial to calcaneal tendon
- Sound/lame
- If lame review sustentaculum tali for new bone
321
What is the presentation of displaced or luxation SDFT?
- Usually goes laterally occasionally medially
- Pops of the calcaneous as extends leg
- Acute injury with subsequent swelling
322
What are the treatment options for displaced/luxated SDFT?
Conservative treatment
Surgical – can rebuild retinaculum but is prone to dehiscence/reluxation, so only do if horse is bothered by this
323
What is capped hock?
Acquired distension of bursa – effusion, oedema
324
How is capped hock treated? Why might we not treat?
Conservative management - cosmetic
Interference risks sepsis and breakdown
325
What is peroneus tertius rupture?
- Part of the reciprocal apparatus so rupture can allow independent carpus/hock flexure
- Lateral femur, dorsolateral cannon, splint and 4th TB
- Rupture when over extended hock
326
How is peroneus tertius rupture treated?
6 weeks box rest
327
How is lateral patella luxation diagnosed?
Determine from upwards fixation
328
Why is lateral patellar luxation congenital in shetland foals?
May/may not have hypoplastic trochlear ridge
329
Name 3 soft tissue stifle injuries.
Meniscal injuries
Cruciate ligament injuries
Collateral ligament injuries
330
Define rhabdomyolysis.
Term used to describe the rapid breakdown of skeletal muscle cells
331
What are the 2 main muscle conditions that present as emergencies?
Atypical myopathy
Sporadic exertional rhabdomyolysis - exercise-induced myopathy, tying up, azoturia
332
How does exertional rhabdomyolysis typically present as?
Reluctance to move due to muscle cramping, stiffness and pain, associated with exercise
333
Distinguish neurogenic and disuse muscle atrophy.
Neurogenic atrophy is rapid and disuse atrophy is slower
334
Define myalgia.
Muscle pain, generalised or localised. Localised pain in back musculature from poorly fitting saddle or delayed onset muscle soreness occurs 24-48hours after overexertion
335
What are muscle muscle fasciculations?
Fine tremors. Can occur with muscle weakness, EPM, EMND
336
What are the main 2 diagnostic techniques for investigating muscle diseases?
Muscle enzymes
Muscle biopsy
337
What are the muscle enzymes used to measure muscle disease and how?
- CK (creatine kinase) and AST (aspartate aminotransferase)
- CK muscle specific, peaks 4-6 hours after muscle insult, rises to a higher level
- AST peaks 24 hours after muscle incidence, can take couple of weeks to return to normal
338
How often are CK and AST sampling done for measuring muscle disease?
- Single – single sample at the time of examination
- Dynamic – before and after (4-6 hours) an exercise
- CK at 4 hours should not be more than double baseline value
- Some clinicians take 3rd sample 24 hours later
339
What is the CK and AST interpretation of a normal or mild tying injury?
High CK and AST is normal. Mild tying up incident 4-6 hours earlier that day, as AST has not had chance to raise yet.
340
What is the CK and AST interpretation of a pony with atypical myopathy?
Severe muscle damage as CT is very high and AST is very high so at least 24 hours since this muscle incident
2 weeks later - AST starting to rise
341
When might CK and AST be misleading?
CK is muscle specific and AST is not. AST can come from liver and not from the muscle
342
What is the presentation of myoglobinuria?
- Myoglobin is released from the muscle cells as they break down
- Excreted in the urine
- Dark coloured urine
343
What is the consequence of myoglobinuria?
Nephrotoxic so can cause acute renal failure, typically only seen in severe rhabdomyolysis cases
344
When are muscle biopsies done?
- Use clinically affected muscle
- For exertional rhabdomyolysis, typically semimembranosus is used
- For equine motor neurone disease, use sacrocaudalis dorsalis - craniolateral to tail head
345
Name 3 exercise induced myopathies.
- Sporadic exertional rhabdomyolysis/azoturia/tying up
- Recurrent exertional rhabdomyolysis
- Polysaccharide storage myopathy
346
When might you get recurrent episodes of exercise induced myopathies, such as exertional rhabdomyolysis?
Frequently results from underlying heritable conditions, including polysaccharide storage myopathy and recurrent exertional rhabdomyolysis/RER
347
What is the presentation of sporadic exertional myopathy?
- Occurs during or after exercise
- Reluctance to move
- Typically affects hindlimb muscles
- Stiff, short striding hindlimb gait
348
What are the findings on clinical examination of exertional rhabdomyolysis?
- Reluctance to move hindlimbs, can move forelimbs
- Stiff, short striding hindlimb gait
- Muscles may be hard, painful and swollen
- May appear distressed – severe cases high HR, RR, sweating, muscle tremors, pawing the ground, can mimic ‘colic’ signs (but don’t do the get up get down over and over again thing)
- Owners think of it as ‘muscle cramp
349
What is the aetiopathogenesis of exertional rhabdomyolysis?
- Can be triggered after a rest period
- Overexertion above the level of fitness
- Dietary deficiencies of electrolytes, vitamin E and selenium, or exercise in conjunction with herpes or influenza virus infections.
- Lack of appropriate warm up or cool down, hot, humid days may increase the risk due to high body temperatures, loss of fluid and electrolytes in sweat, and depletion of muscle energy stores
350
How is exertional rhabdomyolysis treated?
- Rest to stop inciting muscle damage
- NSAIDs – typically single iv dose to manage acute pain
- IV fluids if severe and myoglobinuria present
351
How is exertional rhabdomyolysis prevented?
- Improved management, regular turn out/exercise, warm up and cool down, don’t overexert, reduce feed when exercise drops, provide salt lick/electrolyte supplement, may consider Vitamin E/Selenium supplement.
- Care excessive exercising in heat, care exercising if suspect respiratory infection
- If horse has ‘tied up’ once, may be more likely to do it again, so appropriate management important
352
What advice would you give an owner for a suspected tying up case mid hack or at yard?
Get transport to get horse back to safe stable to limit inciting muscle damage
If at yard, make sure they have water, if exercising hard cool them down, but do nothing and do not walk the horse
353
What are the differential diagnoses for a suspected tying up case?
Laminitis
Colic
Foot abscess
Tendon injury
Fracture (pelvic?)
354
Should you sample of a visit to a suspected tying up case? Which blood tube is used?
Yes, try to get close to 4 hours, and bear in mind with results if very close to inciting incident
Blood tube - lithium heparin (green) or plain tube (red top)
355
How would you treat a suspected tying up cases while awaiting blood results?
NSAIDs IV single dose
Check urine colour
Rest
Feed
356
When might a suspected tying up case be allowed to be ridden again?
Not until horse is comfortable, mild should be reasonably comfortable 24 hours after but suggest turning out for a few days and reintroduce work gradually. Can wait until CK or AST normalise but this may be excessive but if severe we can monitor these
357
What should be measured for recurrent exertional rhabdomyolysis cases?
Electrolytes - abnormality in IM calcium regulation
358
How are acute episodes of recurrent exertional rhabdomyolysis treated?
Same as for sporadic. Often returned to exercise quite quickly, as soon as comfortable, no need to wait for normal CK/AST
359
How are recurrent exertional rhabdomyolysis episodes prevented?
Diet – change to high fat low starch. High fat diet appears to decrease muscle damage by reducing anxiety/excitability
Exercise/turn out daily
Dantrolene – muscle relaxant
360
What is PSSM?
Polysaccharide Storage Myopathy
361
What are the clinical signs of PSSM?
- Painful firm back and hindquarter muscles
- Gait abnormalities
- Muscle atrophy
- Difficulty lifting limbs
362
How is PSSM diagnosed?
- Measure CK and AST
- Muscle biopsy to identify abnormal glycogen accumulation
- Genetic testing to identify GYS1 mutation
363
What is the aetiopathogenesis of PSSM?
- PSSM is a glycogen storage disorder due to enhanced insulin sensitivity
- So ncreased skeletal muscle glycogen concentrations and the accumulation of abnormal amylase resistant polysaccharide in type 2 muscle fibres
364
Distinguish type 1 and type 1 PSSM.
A mutation in the glycogen synthase enzyme has been identified, leading to enhanced glycogen synthase activity - type 1
Horses with abnormal muscle glycogen on biopsy without the GYS1 mutation - type 2
365
How is PSSM treated?
Diet – high fat low starch diet
Believed to be the result of less glucose uptake into muscle cells and provision of more plasma free fatty acids for use in muscle fibres during aerobic exercise
366
What is the presentation of atypical myopathy?
- Often found recumbent or sudden death in the field
- Not associated with exercise
- More than one horse may be affected
- Typically, young horses
- Most common in autumn
- Fatal in approximately 75% of affected horses
367
What are the clinical signs of atypical myopathy?
- Sudden onset muscle weakness, leading to recumbency
- Depressed - low hanging head/neck
- Muscle trembling
- Dysphagia due to weakness of masticatory muscles or muscles of the oesophagus
- May show respiratory difficulty
- May have cardiac arrhythmias
- Brown or dark red urine due myoglobinuria
368
How is atypical myopathy diagnosed?
Clinical signs, measurement of CK and AST, and myoglobin in urine
369
What is the aetiopathologenesis of atypical myopathy?
- Hypoglycin A toxin from seeds and leaves of Sycamore tree
- Hypoglycin A inhibits the enzyme acyl-CoA dehydrogenase, which is involved in the metabolism of fatty acids to form ATP
- So normal energy supply to muscle cells is impaired
370
Why is atypical myopathy more common in the autumn?
Sycamore seeds and leaves to fall onto pasture
Can occur in spring through ingestion of new shoots
371
How is atypical myopathy treated?
- Intensive care and nursing – regular turning if recumbent, monitor urine output
- IV fluids (supplementary calcium)
- Analgesics
372
How is atypical myopathy prevented?
- Avoid affected fields
- Fence off around trees
- Pick up seeds/leaves
- Limit grazing
- Ensure plenty of grass and supplementary feed
- Feed horses before letting them out to pasture
- Do not put hay on the ground (in affected fields)
373
How do strains and sprains occur?
- Caused by an overstretching
- Palmar metacarpus > plantar metatarsus
- Predominantly collateral ligaments of joints
374
What are the clinical signs of sprains and strains?
- Visual appearance
- Response to palpation
- Lameness
- DFTS effusion
- MCP Joint hyperextension with suspensory ligament
375
Which nerve blocks can be used to diagnose which tendon is damaged?
Palmar digital – distal DDFT
Abaxial sesamoid:
- Distal DDFT and SDFT
- Oblique and straight sesamoidean ligaments
- Annular ligament
Low 4 point
High 4 point
Deep branch of lateral palmar/plantar nerve
376
Which intrasynovial blocks can be used to diagnose which tendon is damaged?
Digital flexor tendon sheath. Desensitises the surface of the structures that run within it – DDFT, SDFT, manica flexoria, intersesamoidean ligament
Also carpal canal, bicipital bursa, tarsal canal and calcaneal/gastrocnemius bursae
377
What structures run through or border the DFTS, such that they might be affected by local anaesthetic infiltration?
DDFT
Intersesamoidean ligament
Manica flexoria
378
Describe the deep branch of the lateral plantar nerve block?
- Palmarolateral aspect of distal hock
- Some cross over between this and TMT block
- Likely to affect lateral plantar nerve too
379
What are the 4 common entry portals to the digital flexor tendon sheath block?
Proximal
Axial sesamoidean
Basilar
Distal
Runs from lower 1/3 cannon (half on rear) on palmar aspect of limb into hoof capsule. Observe/palpate effusion at these points
380
Give the layers superficial deep of ultrasounding the plantar/palmar aspect of the distal limb.
DSFT
DDFT
Inferior/accessory check ligament of DDFT
Suspensory ligament
Cannon bone/MCII
381
Which soft tissue structure is the most dorsal in the palmar metacarpus?
Suspensory ligament
382
What are the risk factors for superficial digital flexor tendonitis?
Conformation
Ground surface
Training
Fitness
383
What is the aetiopathogenesis of a strain?
- Overstretching during fast exercise
- Initial mechanical disruption, fibre slippage and tearing with haemorrhage
- Subsequent inflammation, debrided by enzymes and macrophages
- Repair by fibroblasts and capillary buds
384
How is remodelling of a strain done?
- Reduced collagen content
- Type III tendon fibres (Type I in healthy tendons)
- Less collagen cross linking
- Loss of crimp pattern
- Excessive interfibrillar matrix persists
385
How do strains appear on ultrasound?
Starts with anechoic core lesion. Becomes more echoic as repairs. Once healed we may use off incidence scanning to view scarring
386
What is the presentation of proximal suspensory desmitis?
- Hindlimbs predominantly
- Severe changes drop fetlock
387
How is proximal suspensory desmitis surgically treated?
Fasciotomy and neurectomy:
- Denervates the proximal suspensory ligament – removes pain communication, neurogenic atrophy?
- Opens fascia – reduces pain and pathology associated with pressure
- Often poor post op cosmesis
388
What is a suspensory ligament branch lesion?
- Medial or lateral
- Possibly associated with fetlock effusion
- Foot imbalance may predispose
389
What is inferior check ligament desmitis, and how is it diagnosed and treated?
- Forelimb problem
- Ultrasonography – off incidence scanning, care of interpretation at insertion
- Conservative management usually successful
390
Where are DDFT desmitis lesions located?
Hoof/distal pastern, within DFTS, proximal to DFTS (rare)
391
What are the possible deep flexor tendon sheath problems?
- Septic tenosynovitis (as septic joints)
- Annular ligament syndrome
- Tenosynovitis
- DDFT/SDFT/Manica flexoria injuries
- Adhesions
392
What is the manica flexoria?
SDFT wrapping around the DDFT in DFTS, continuous with sheath
393
What does injury to the palmar/plantar annular ligament result in?
Causes thickening of the ligament
394
How is palmar/plantar annular ligament injury treated?
Transection PAL desmotomy to release the constriction
- Tenoscopic – improves access around sheath
- Open
- Care post op to avoid sepsis
395
How does chronic DFTS tenosynovitis present?
- Synovial proliferation
- Adhesions in sheath
- Masses in sheath
396
How are manica flexoria tears and adhesions treated?
Resection and removal of entire manica
397
Where do the sesamoidean ligaments lie?
Intersesamoidean ligaments – between PSBs
Distal sesamoidean ligaments are functional continuation of the SL in the palmar pastern
- Straight sesamoidean ligament
- Oblique sesamoidean ligaments
- Cruciate sesamoidean ligaments
- Short sesamoidean ligaments
398
How are severed tendons treated?
- Repair with permanent or long-lasting resorbable monofilament suture material
- Use suture pattern to give good holding power in tendon end
- Cast for post-operatively support
399
How does DDFT rupture present?
Toe elevates when loading limb
400
How is acute DDFT rupture treated?
Cryotherapy
Bandaging
NSAIDs
Intralesional steroids?
PSGAGs?
401
When are ultrasonographic changes viewed with acute DDFT rupture?
Ultrasonographic changes will become evident over several days – 71% return to race with rehab vs 25% is just turned out
402
What is vital for management of acute DDFT rupture?
Movement is vital to regain correct fibre alignment
403
How is chronic DDFT rupture managed?
- Regenerative medicines
- Controlled rehabilitation program
- Monitor ultrasonographically in incremental time periods
404
What are some regenerative medicines?
- Growth factors
- Platelet rich plasma
- Mesenchymal stem cells
- Autologous mesenchymal stem cells
- IRAP
405
How is SDFT rupture managed?
- Rest and rehabilitation
- Intralesional stem cells
- Manica flexoria tears – surgical excision
- Superior check ligament desmotomy, tendon splitting, tendon firing have no improvement when performing (value in completing treatment?)
406
How is tenescopy used to DDFT lesions within the DFTS?
- Debridement helps those with manica flexoria tear – no benefit over rest and rehab for dorsal border lesions or saggital splits
- Core lesions are inaccessible
407
What is the difference between DLPMO and PMDLO?
DLPMO = PMDLO in view
Which we pick depends on where we are
408
Order the nerve blocks from distal to proximal.
Palmar distal
Accessory sesamoid
4 point
Lateral palmar
Median and ulnar
409
What are the clinical signs of acute thoracolumbar vertebral disease?
- A history of trauma
- Acute deformation
- Severe hindlimb lameness
410
What are the clinical signs of chronic thoracolumbar vertebral disease?
- Poor performance
- Bucking
- Evasion when ridden
- Sensitivity to back palpation
- Resentment to saddle
- Mild hindlimb lameness?
411
What is assessed from physical examination suggesting thoracolumbar disease?
- Asymmetry of back/pelvic musculature
- Kyphosis
- Lordosis
- Scoliosis
- Asymmetry of bony prominences
- Range of motion of joints – dorsal, ventral, lateral flexion of spine
- Pain on palpation of back/pelvis
- Rectal examination
- Look, palpate, manipulate
412
What is the diagnostic anaesthesia used in thoracolumbar spine?
- Local intramuscular diffusion
- Ultrasound guided intra-articular facet joint injections
413
What is the diagnostic anaesthesia used in the sacroiliac joint?
- None are truly intra-articular
- Risk of sciatic nerve denervation, ataxia and/or collapse
414
What is the diagnostic anaesthesia used in the hip joint?
Possible under ultrasound guidance
415
How is radiography of the back done?
- Lateral-lateral views for DSPS – beware of false positives
- Lateral and oblique views for APJs/vertebral bodies
416
How is radiography of the pelvis done?
- Standing latero-lateral
- Dorsolateral-ventrolateral oblique - fractured tuber coxae
- Ventrodorsal view – very dangerous. GA if concerned about a pelvic fracture
417
How is ultrasonography of the back done?
Oblique lateral approach
To assess supraspinous ligament - dorsal aspect of dorsal spinal processes
418
How is ultrasonography of the pelvis done?
- Limited due to depth of pelvis
- Transcutaneous ultrasound
- Transrectal ultrasound
419
What can nuclear scintigraphy of the back and pelvis be used to diagnose?
- Pelvic fractures/stress fractures
- Looking for areas of increased radiopharmaceutical uptake - fractures will have marked IRU
- Artefacts from urinary tract
420
What are the common lumbosacral conditions?
- Soft tissue pain
- “Kissing spine” – impinging dorsal spinous processes
- Thoracolumbar facet joint osteoarthritis
- Sacroiliac joint disease
- Dorsal spinous process fractures
- Pelvic fractures
- Hip luxation
421
How is non-specific soft tissue pain in the lumbosacral region diagnosed?
- Palpation of back musculature reveals tension/evasive movement
- No significant radiographic findings/IRU on scintigraphy
422
How is non-specific soft tissue pain in the lumbosacral region treated?
- Rest
- Physiotherapy
- Regional infusion of corticosteroids?
- Acupuncture
423
How are impinging dorsal spinal processes diagnosed?
Radiographs will reveal regions of sclerosis and lucency within DSPs, and loss of the interspinous process space (close, impinging, overriding)
Scintigraphy will show increase in radiopharmaceutical uptake in affected locations
424
What is the triad of diagnosing impinging dorsal spinal processes?
Radiographic findings
Positive response to regional nerve block
Nuclear scintigraphy
425
How are impinging dorsal spinal processes conservatively treated?
- Systemic pain relief e.g. phenylbutazone
- Medication of the back – corticosteroids
426
How are horses with impinging dorsal spinal processes rehabilitated?
- Exercise modification – usually approx. 6 weeks out of ridden exercise
- Physiotherapy, static stretches
- Acupuncture, massage, mesotherapy?
427
How are impinging dorsal spinal processes surgically treated?
- Interspinous ligament desmotomy – cutting the ligament between the dorsal spinous processes
- Ostectomy – removing a section/sections of bone
428
How is osteoarthritis of thoracolumbar articular process/facet joints diagnosed?
Radiography – Lateral-20˚ views, ventral and dorsolateral oblique views and latero-lateral
Ultrasonography – new bone formation
Nuclear scintigraphy – usually only mild-moderate IRU
429
How is osteoarthritis of thoracolumbar articular process/facet joints treated?
Corticosteroid intra-articular medication
With/without tiludronate
430
What are the clinical signs of sacro-iliac joint disease?
Chronic pelvic pain
Poor canter
Bunny hopping
Disuniting at canter
Poor impulsion
431
How is sacro-iliac joint disease diagnosed?
- Clinical signs
- SIJ block?
- Transrectal ultrasonography
- Scintigraphy
432
How is sacro-iliac joint disease treated?
- Corticosteroid medication – methylprednisolone
- Physiotherapy and increasing exercise programme
433
How are dorsal spinous process fractures diagnosed?
- Acute deformation of wither region and localized pain/swelling
- Radiography – lateral-lateral DSP views
434
How are dorsal spinous process fractures treated?
- Often conservative
- Surgical removal of fragments can be performed but not usually re-apposed
435
What are significant displacements due to traumatic pelvic fractures at risk of?
Significant haemorrhage
436
How are pelvic fractures diagnosed from nuclear scintigraphy?
- Most sensitive/specific, only possible if you can transport a horse safely
- Rely on regions of IRU – ideally performed at 5-7 days post-injury
437
How are pelvic fractures treated?
Analgesia and box rest with/without cross tied
438
What also happens often in conjuncture with hip luxation?
Rarely occurs without acetabular damage/avulsion fracture of femoral head
439
How are hip luxations treated?
- Closed reduction very rarely successful
- Surgical options exist e.g. total hip arthroplasty, toggle, femoral head ostectomy – limited success rates
440
What ligament holds the femoral head into the acetabulum?
Ligament of the head of the femur
441
What are the risks of ultrasound guided injections of the articular process joints?
Ataxia/paralysis if using local anaesthetic
442
What are the radiographic views for the neck?
- Latero-lateral views
- Latero-50˚ views ventral – laterodorsal oblique
443
What ais the most common cause of wobblers in horses?
Cervical vertebral stenotic myelopathy (CVSM) most common
444
What is stenosis of the vertebral canal the result of?
- Narrowing of the cervical vertebral canal
- And/or malformation/malalignment of the cervical vertebrae
445
What does stenosis of the vertebral canal result in?
- Ataxia – compression of ascending proprioception pathways
- Paresis – compression of descending upper motor neuron pathways
- Usually HLs more severely affected than FLs
446
What are the abnormalities of type 1 cervical vertebral stenotic myelopathy?
- “Flare” of the caudal epiphysis of the vertebral body
- Extension of the dorsal laminae
- Malalignment/angulation between adjacent vertebrae
- Osteochondrosis within the APJs
447
How is type 1 cervical vertebral stenotic myelopathy treated?
- Restrict exercise/diet
- Surgical stabilisation – fair prognosis if mild neurological signs, poor prognosis if severe
448
What are the osteoarthritic changes of type 2 cervical vertebral stenotic myelopathy?
- Narrowing of the APJ
- Periarticular proliferation of the articular process
- With/without fractures of the APJ
449
What are the radiographic signs of type 2 cervical vertebral stenotic myelopathy?
- Enlargement of the APJ
- Sclerosis or lucencies evident on the articular process
- Fragmentation of articular process
450
How is type 2 cervical vertebral stenotic myelopathy treated?
- Systemic NSAIDs/corticosteroids
- Ultrasound guided medication of the APJs
