Juvenile joint disease: osteochondral and subchondral pathology Flashcards
How do juvenile osteochondral conditions present?
- Varying degree of
- joint effusion
- lameness
- heat
- Positive to joint flexion
- Inflammation due to synovitis & osteitis
- cartilage has no nerves
- Often no clinical signs
- lesions detected on pre-sales radiographs
How are juvenile osteochondral conditions diagnosed?
- History
- Palpation
- Lameness assessment
- Regional anaesthesia (IA)
- Radiographs
- Ultrasound
MRI
CT
Nuclear scintigraphy
How should you interpret a radiographic lesion? What are Roentgen signs?
Radiographic description
* Number – 1/4/multiple
* Size – large/3cm/thin
* Shape – round / triangular/ irregular/ coallescing
* Opacity – radiolucent/ radiodense/ heterogenous
* Location – on distal lateral……
Make an assessment of pathology
- Lysis / sclerosis / new bone formation
Diagnosis
How would you describe this lesion?
One, large, oval, radiodense lesion on the distal intermediate ridge of the tibia.
What challenges are associated to juvenile joint disease diagnosis?
- Experience of owners/carers
- Owners expectations/purpose of the horse
- Lesions often silent until significant increase in exercise regime
- Horses from different disciplines will start at a different age
- Temperament may not be amenable to all diagnostic steps
- Some lesions may be cartilaginous only so not visible on radiographs
- It is possible for lesions to heal
What disease process is associated to osteochondrosis? What can it progress into? How is the process different to that of osteochondral fragmentation?
- developmental disease
- due to failure of endochondral ossification
- may progress into2 conditions:
- Osteochondritis Dissecans (OCD)
- Subchondral Cystic Lesions (SCL)
Osteochondral fragmentation (OCF)
- traumatic disease
What are treatment options for juvenile joint disease? What are gold standard for loose fragments in joint and thickened cartilage?
- Conservative
- no treatment
- Medical
- intra-articular medication
- Surgical
- arthroscopic fragment removal
- debridement of disease cartilage & necrotic subchondral bone
- other procedures
- Euthanasia
- Choice depends on disease severity and intended use
Loose fragments in joint (OCD & OCF)
- arthroscopic removal
Thickened cartilage (OC)
- Can monitor and see
What age and breeds are more likely to develop ostechondrosis and osteochondral fragmentation? When do clinical signs occur?
Osteochondrosis
Age - <2yo
Breed - thoroughbreds, warmbloods
Clinical signs - immediately, when horse begins work or never
Osteochondral fragmentation
Age - any age
Breed - any athlete
Clinical signs - immediately or never
Describe pathogenesis of osteochondrosis
- Focal failure of endochondral ossification at epiphyseal growth cartilage
- Follows trauma to microvasculature
- Strong location predispositions
- Lesions form during periods of fast growth
- all lesions originate <2yo
- Dynamic process in <8mo – lesions may heal
- Multifactorial
- Polygenetic heritable disease
- Overnutrition
- Rapid growth
- Mineral imbalances
How does osetochondrosis progress to further pathology?
Defect in endochondral ossification
- splitting of cartilage to give osteochondritis dissecans lesions
* Fissures appear in thickened cartilage
* Mineralisation occurs within the lesion
* Sometimes break free - fragmentation
- retention of cartilage and its necrosis leads to subchondral cystic lesion
* Blood supply failure within thickened epiphyseal cartilage
- Necrosis of thickened cartilage
* Cyst has an inflammatory lining, so is self-propagating - lysis
When does osteochondritis dessicans occur?
- Lesions form during periods of fast growth
- all lesions originate <2yo
- Dynamic process in <8mo – lesions may heal
What is the typical presentation of osteochondritis dessicans?
- Common in large Thoroughbreds and Warmbloods
- Strong predilection sites - locations where bones slide over each other:
- Stifle (lateral trochlear ridge femur)
- Hock (distal intermediate ridge of tibia)
- Other locations less common: e.g. shoulder / fetlock / other locations in the hock
- Clinical signs may appear:
- straight away (as a 1yo)
- when horse begins work (2/3/4yo depending on discipline)
- never (lesion remains sub-clinical)
- Mild to moderate lameness – worse after flexion
- Joint effusions & heat
- Diagnosis usually by radiography
How would you describe this lesion?
Multiple, small, round, radiodense lesions cranial to the lateral trochlear ridge of the femur
How would you describe this lesion?
One, large, oval, radiodense lesion proximal to the palmar/plantar medial/lateral aspect of the proximal phalanx
What are treatment options for OCD?
- Conservative
- do nothing
- if no clinical signs and not for sale
- Medical
- IA medications, NSAIDs
- Temporary improvement (the sticking plaster approach)
- Likely to lead to OA in future due to ongoing synovitis
- Surgical
- arthroscopic fragment removal
- Euthanasia
- rarely required
How would you describe this lesion?
One, large, oval, radiolucent lesion in the medial femoral condyle
How would you describe this leison?
One, large, round, radiolucent lesion within the proximal aspect of the middle phalanx, (also considerable periarticular new bone formation and joint collapse).
What are the SCL grades?
1 - flattening or small defect on subchonral bone
2 - indentation
3 - round cyst
4 - oval with open neck
5 - small neck and large cyst
6 - SCL with other SCL on adjacent bone
Describe this lesion.
One, medium size, rectangular, radiodense lesion on the dorso-distal aspect of the radiocarpal bone
Describe this lesion.
One, small, round, radiodense lesion dorsal to the proximal aspect of the proximal phalanx.
