27.6.2: Osteochondral fragmentation and OCD Flashcards

1
Q

Osteochondrosis

A

failure of endochondral ossification

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2
Q

Osteochondrosis dissecans

A

the ultimate result of osteochondrosis; we call it OCD when pathology progresses to ostechondral fragmentation

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3
Q

Cause of osteochondrosis in horses

A
  • Multifactorial
  • Focal failure of endochondral ossification (epiphyseal or metaphyseal growth cartilage)
  • Polygenetic heritable disease
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4
Q

What defect is visible here? What breeds is it most commonly seen in?

A
  • Circled = radiolucent defect
  • The fragment is not visible but could be made of cartilage
  • This is avulsion fragmentation from short sesamoidean ligaments
  • Occurs on the palmar/plantar aspect of P1
  • Seen in Warmbloods and Standardbreds
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5
Q

What defect is visible here? Which horses do we see this in?

A
  • Defect on the dorsoproximal aspect of P1/ dorsal margin of proximal P1
  • Occurs due to overextension of fetlock at high speed/ sometimes trauma suspected -> repetitive impact of dorsal P1 eminences
  • Seen in racehorses
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6
Q

Where is the fragment? What kind of horse would you expect this injury in?

A
  • Fragment is on the dorsal margin of P1
  • Seen in racehorses
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7
Q

Which of the following is often the presenting complaint of a horse with osteochondrosis?
* Lameness
* Lies down more
* Bucks under saddle
* Joint effusion

A

Joint effusion

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8
Q

What are the most common sites of OCD in the forelimb?

A

Shoulder
Fetlock

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9
Q

What are the most common sites of OCD in the hindlimb?

A
  • Stifle
  • Hock
  • Fetlock
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10
Q

What lesion is visible at Site 1?

A

This is a DIRT lesion (distal intermediate ridge of tibia)
This is a common site for osteochondrosis lesions.

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11
Q

Which trochlear ridge of the talus is abnormal is this image? (Site 2)
a) medial
b) lateral

A

b) lateral trochlear ridge of talus is abnormal

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12
Q

Which view is shown here and what is the pathology?

A

View: dorsoplantar
Pathology: osteochondrosis of the medial malleolus of the tibia

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13
Q

True/false: this is normal.

A

False
The sagittal ridge of the distant metacarpus is affected

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14
Q

Which view is shown here?

A

This is a flexed lateromedial metacarpophalangeal / flexed metatarsophalangeal view

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15
Q

Which view is being taken here? Which joint is being imaged? What is the most common site of OCD in this joint?

A
  • This is a lateromedial view of the stifle
  • Specifically, we are imaging the femoropatellar joint
  • The most common site of OCD in the stifle is the lateral trochlear ridge of the femur
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16
Q

Which joint is being imaged here? What pathology is present?

A
  • Femorotibial joint
  • There is a subchondral cyst-like lesion in the medial femoral condyle
17
Q

You suspect a fragment on the palmar/ plantar surface of the joint (metacarpo/metatarsophalangeal joint). What views will you take?

A
  • Dorsopalmar
  • Lateromedial (make this one good and fragment may be visible)
  • Obliques with special angles (not day 1)
18
Q

You suspect a fragment on the dorsal surface of the metacarpophalangeal joint. What imaging will you perform?

A

Radiography
* Dorsal 60 medial-palmarolateral oblique (DMPLO)
* Dorsal 60 lateral-palmaromedial oblique (DLPMO)

If still not sure -> ultrasound

19
Q

What radiographic view will you take to assess OCD in the tarsus?

A
  • DP (slightly modified)
  • LM
  • DMPLO (slightly modified)
  • DLPMO
20
Q

Diagnostic approach to osteochondrosis / osteochondral fragmentation

A
  • Physical exam
  • Lameness exam: flexions, reactions to intra-articular blocks
  • Radiographs: certain view for each joint/ condition
21
Q
A

Joint effusion in the stifle

22
Q

You suspect OCD in the fetlock. Which radiographic views will you take?

A
  • DP
  • LM
  • ± Flexed LM
  • DMPLO
  • DLPMO
23
Q

What view is this?

A
  • DMPLO
  • The sesamoid is always palmar in the limb
  • The fragment therefore has to be palmar
  • We have highlighted the fragment
24
Q

What views do you want to take when imaging the stifle for OCD?

A
  • LM
  • Caudo-cranial
  • Caudolateral-craniomedial oblique
25
Q

Which view is this? How can we tell the medial and lateral trochlear ridges apart?

A
26
Q

Which view is being taken here? What does it highlight?

A
27
Q

Which view is being taken here? What does it highlight?

A
28
Q

Which view is shown here? What does it highlight?

A
29
Q

If we have OCD, should we remove the fragment, or leave it there?

A

Remove the fragment

30
Q

If we have a fragment on the dorsal surface of P1, should we remove the fragment, or leave it there?

A

Remove the fragment

31
Q

If we have a fragment on the palmar/ plantar aspect of P1, should we remove the fragment, or leave it there?

A
  • Only remove the fragment if the horse is working at high speed
  • If embedded in the sesamoidean ligament, can leave it as it is unlikely to cause future problems
32
Q

Conservative treatment of OCD/ osteochondral fragmentation

A
  • Box rest/ small paddock
  • Joint injection with corticosteroids -> for subchondral cyst-like lesions
  • Remember the 5 month mark (hock) and 8 month mark (stifle) - lesions may go away by themselves
33
Q

This is the distal femur. Which is lateral and which is medial?

A

Lateral trochlear ridge - main site of OCD in the femur

34
Q

True/false: some osteochondral lesions can disappear on their own.

A

True
* Tarsocrural (hock) joint -> lesions can disappear up to 5 months of age
* Femoropatellar (stifle) joint -> lesions can disappear up to 8 months of age