Diagnosis and management of foot pain Flashcards

1
Q

What information would you want to gather on the history of a horse with foot pain?

A
  • Type of problem: acute or chronic, intermittent; uni- or bilateral lameness; shifting lameness; worse when worked/surface type; stumbling
  • Response to previous treatment/farriery
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2
Q

Describe the steps of a clinical examination for a horse with foot pain

A
  • Resting stance (weight shifting)
  • Foot balance/conformation; shoeing type and fitting; hoof capsule quality and distortions; shape and size of foot
  • Presence of wounds/injuries; presence of effusion/swellings; heat/increased digital pulse; presence of scars
  • Hoof testers!
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3
Q

Following history and clinical exam what would you do to diagnostically approach a horse with foot pain?

A

Dynamic examination
Local anaesthesia
Imaging

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4
Q

Which nerve block is being described:
Lateral and medial palmar metacarpal nerves (just below palpable button of the splints) and lateral and medial palmar nerves (dorsal to DDFT laterally and between DDFT and SDFT medially)

A

Low 4 point nerve block

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5
Q

Which nerve block is being described:
Just proximal to collateral cartilage, abaxial to edge of DDFT

A

Palmar digital nerve block

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6
Q

Which nerve block is being described:
Immediately palmar to the neurovascular bundle at the abaxial surface of the base of the proximal sesamoid bone

A

Abaxial sesamoid nerve block

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7
Q

How should a foot be prepared before radiography?

A

Clean, remove dirt, stones, etc. may need remove shoes but not always necessary

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8
Q

What are the 5 standard views for a foot radiography series?

A

Dorsopalmar
Laterodorsal
Dorsoproximal-palamarodistal oblique (P3 and NB)
Palmaroproximal-palmarodistal oblique

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9
Q

Describe how to position a horse for a lateromedial projection

A
  • Horizontal beam
  • Foot on block/weight bearing
  • Centre 1-2cm below coronary band, half way between dorsal hoof wall and heels
  • Look at heels – primary beam perpendicular
  • Do not collimate too tight!
  • Markers (dorsal hoof wall/frog)
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10
Q

What can you assess on the lateromedial projection?

A
  • Phalangeal/solar angle
  • Relationship to dorsal hoof wall and sole/shoe
  • P3/P2/NB/DIP joint (P1/PIPJ)
  • P3 extensor process
  • Navicular bone
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11
Q

How can the navicular bone be assessed?

A

Corticomedullary definition
Cortex = white
Medulla = grey/black
Problem with side bone

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12
Q

What is ‘side bone’

A

Mineralisation of the collateral cartilages
- not detected on lateromedial view due to superimposition

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13
Q

Describe how to position for a horizontal dorsopalmar image

A
  • Horse stood on blocks
  • Important that horse is standing straight!
  • Horizontal beam centred 2cm below coronary band and perpendicular to limb
  • Turning 90 degrees from the lateromedial view, no change in height
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14
Q

What can you assess on the dorsopalmar projection?

A
  1. P3 margins
    - Relationship to hoof wall: lateromedial balance with markers
    - Sidebone
  2. DIPJ and PIP joint space
  3. PIPJ joint margins
  4. Navicular bone margins but not very visible due to superimposition
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15
Q

Name the two versions of positioning for a dorsoproximal-palmarodistal oblique image

A

Upright-pedal
High coronary

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16
Q

Describe upright pedal positioning for a dorsoproximal-palmarodistal oblique image

A

“Truer” image as beam perpendicular to the plate
Horse’s toe in a Hickman block

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17
Q

Describe a high coronary positioning for a dorsoproximal-palmarodistal oblique image

A
  • Easier to perform with horse standing on tunnel containing a cassette
  • Angle down about 65o through coronary band
  • Slight elongation of foot
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18
Q

What can you assess on the dorsoproximal-palmarodistal oblique (P3) view?

A

P3 body, solar margin and wings

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19
Q

How can the dorsoproximal-palmarodistal oblique view be used to image the navicular bone?

A

Upright pedal (as below) or high coronary view
Collimate well – narrow
Centre 1-2cm above coronary band
Aiming for the back of the foot (slightly higher than for P3)
Horses toe is resting in a wedge to get the correct angle

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20
Q

What can you assess on the dorsoproximal-palmarodistal oblique (nav bone) view?

A

Proximal and distal borders of the navicular bone
Lateral and medial wings of the NB
Palmar processes of P3
DIPJ margins

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21
Q

Which radiographic view is known as the skyline view?

A

Palmaroproximal-palmarodistal oblique

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22
Q

Describe how to position a horse for a Palmaroproximal-palmarodistal oblique image

A
  • Foot on cassette tunnel
  • Leg back/fetlock extended
  • Tube head under horse – vulnerable!
  • Centre between bulbs of heels; 45o
  • Look at LM view or foot conformation
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23
Q

What can you assess on the palmaroproximal-palmarodistal oblique (“skyline”) view?

A

Articular surface of the navicular bone
Synovial fossae
Corticomedullary definition
Endosteal surface
Normal variant in sagittal ridge
Flexor cortex and surface
Palmar process of P3

24
Q

List some possible causes of primary pain of the distal interphalangeal joint and associated structures

A
  • Synovitis/DJD/osteoarthritis/osteochondral fragmentation
  • Joint trauma/subchondral bone pain
  • Collateral ligament desmitis
  • OCLL = osseous cyst like lesions
25
Q

How can you diagnose the cause of primary pain of the distal interphalangeal joint and associated structures?

A
  1. Clinical features
    - Uni- or bilateral lameness
    - DIPJ effusion (non-specific)
  2. Lameness localised to the foot by diagnostic anaesthesia
    - Beware of lack of specificity of DIP block!
  3. Diagnostic imaging
    - Radiography
    - Ultrasound – often unrewarding
    - MRI – collateral ligament desmitis
26
Q

How can you manage/treat synovitis/osteoarthritis/OC frag?

A
  • Intra-articular medication e.g. hyaluranon/corticosteroids, IRAP
  • NSAIDs
  • Remove fragment (if significant )
27
Q

What is IRAP?

A

IRAP = interleukin receptor antagonist protein – can be used in joint disease. Uses the bodies interleukin 1 (one of the main cytokines for osteoarthritis) and blocks it

28
Q

How do you manage/treat joint trauma/subchondral bone pain?

A

Rest, NSAIDs

29
Q

How do you manage/treat collateral ligament desmitis

A

Rest
Farriery/shoeing (rolled toe)
Shockwave, intra-articular medication

30
Q

How do you manage/treat osseous cyst like lesions

A

Intra-articular medication

31
Q

Are pedal bone fractures common?

A

One of the more common fractures encountered in equine practice
But still relatively uncommon c.f. subsolar abscessation

32
Q

How do pedal bone fractures occur?

A

Kicking wall; blunt trauma
Penetrating injury/hoof wall trauma

33
Q

What are the clinical signs of a pedal bone fracture?

A

Acute foot pain (occ.chronic)
Increased digital pulse
Hoof tester +ve; percussion +ve
- May not be specific
+/- DIPJ effusion

34
Q

How can local anaesthesia be used to diagnose pedal bone fractures?

A

Usually improves but may not fully block out

35
Q

How is radiography used to diagnose pedal bone fractures?

A
  • Standard views plus other obliques to evaluate the “wings” of P3
  • Fracture types described: non-articular/articular, sagittal/ parasagittal, comminuted, extensor process, marginal
  • Occ. need advanced imaging (e.g. nuclear scintigraphy/MRI/CT)
36
Q

Describe conservative management of pedal bone fractures

A
  • Immobilisation and rest using a bar shoe or hoof/foot cast
  • Fracture heals by fibrous union
  • Most foal P3 fractures heal without casting/shoeing (can lead to foot contraction)
  • Prognosis reduced if articular involvement
37
Q

Describe surgical management of pedal bone fractures

A
  • Removal of fragment(s) e.g. extensor process fractures
  • Internal fixation e.g. sagittal articular fractures
  • PD neurectomy for non-healing wing fracture (type I and II)
38
Q

What is non-septic pedal osteitis?

A

Vague term covering radiographic changes in pedal bone in horses with chronic foot soreness
Often associated with foot imbalance

39
Q

How is non-septic pedal osteitis diagnosed?

A

Lameness localised to foot
Variable radiographic changes - demineralisation/widening of vascular channels

40
Q

How is non-septic pedal osteitis treated?

A

Correct foot imbalance/reduce abnormal stresses through foot

41
Q

Are navicular bone fractures common?

A

Uncommon
Traumatic aetiology
Occasionally see bi- or tri-partite navicular bones

42
Q

How are navicular bone fractures diagnosed?

A

Moderate lameness
Diagnostic anaesthesia localised to foot
Radiography

43
Q

How are navicular bone fractures treated?

A

Conservative (heal by fibrous union)
Surgical repair difficult

44
Q

How does navicular disease present - history and clinical exam?

A
  • Important cause of chronic bilateral forelimb lameness
  • History of intermittent chronic forelimb lameness often worse on a hard surface and exacerbated in a circle
  • Horse may stumble, be unwilling to go forward, refuse jumps etc
  • Associated with low heel/long toe conformation
45
Q

Describe the pathology/pathogenesis of navicular disease

A
  • Age related: thinning of fibrocartilage and roughening of DDFT
  • Defects in palmar surface fibrocartilage: palmar cortex erosion and medullary lysis
  • DDFT damage: surface fibrillation, core lesions, adhesions
  • Defects in palmar cortical bone: replacement of normal medullary tissue with highly vascularised connective tissue
  • New bone formation along collateral sesamoidean ligament
  • Degenerative changes around DIP/NB articulation
46
Q

How is navicular disease diagnosed using clinical evaluation?

A

History; signalment; age
Foot conformation
Hooftester+ve over frog not consistent finding

47
Q

How is navicular disease diagnosed using dynamic evaluation?

A

Land toe first
Start to point toe when landing
Lameness worse on hard, circle

48
Q

How is navicular disease diagnosed using diagnostic analgesia?

A

PD+ve; DIP+ve; NB+ve
May “switch” lameness or worsen lameness on other limb

49
Q

Describe the radiographic abnormalities seen with navicular disease

A
  • Medullary cyst formation
  • Flexor cortex erosion/ irregularities
  • Loss of corticomedullary definition
  • Endosteal sclerosis
  • Distal border fragmentation
  • Entheseophytes on lateral (or medial) border
  • Enlarged or increased number of synovial fossae
50
Q

What are Entheseophytes?

A

A bony spur forming at a ligament or tendon insertion into bone

51
Q

How is farriery used to treat navicular disease?

A
  • V. important as navicular disease is primary chronic degeneration due to abnormal biomechanical stress
  • Balance foot: remove any hoof distortions and improve hoof-pastern axis
  • Reduce breakover by rolling toe/reducing leverage/improving centre of rotation of DIPJ
  • Engage frog with ground/shoe and improve heel support
52
Q

How is navicular disease treated using medical management ?

A
  1. NSAID’s
    - Often mainstay of management with farriery
  2. Intra-articular or intra-bursal medication
    - e.g. hyaluranon/corticosteroids
  3. Bisphosphonates
    - Tiludronate; clodronate licenced
    - Significantly improved lameness but not resolved
53
Q

How is navicular disease treated using surgical management ?

A

Neurectomy - certain nerves are blocked or severed to relieve severe chronic pain
Around 75% sound after 1yr

54
Q

List the complications linked to a neurectomy

A

Neuroma formation
Incomplete desensitisation
Re-innervation
DDFT rupture
Navicular bone fracture
Foot penetration
(hoof capsule slough)

55
Q

How are primary DDFT lesions in the foot diagnosed?

A
  • Mild-severe acute onset unilateral lameness
  • Clinical exam often unrewarding
  • Diagnostic analgesia: most (but not all) positive to PDNB and NB
  • Radiography often NAD
  • MRI diagnosis
56
Q

How are primary DDFT lesions in the foot managed?

A

Conservative - Rest; shoeing
Surgical - Debridement of lesion via navicular bursa