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*Most common type of physeal fracture in small animals and the proximal femur is the most common site
 
*Most common type of physeal fracture in small animals and the proximal femur is the most common site
 
*In horses, physeal dysplasia is synonymus with [[Physitis|physitis]]
 
*In horses, physeal dysplasia is synonymus with [[Physitis|physitis]]
*[[More about Physeal dysplasia]]
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'''More about Physeal dysplasia'''
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*Also seen in the coypu with minimal trauma
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*Femoral head physes contribute 30-40% of longitudinal growth of the femur in small animals
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*Slipped epiphysis -> Salter-Harris type I where only the physis is involved
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**Most common type of physeal fracture in small animals and the proximal femur is the most common site
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**In traumatic cases, the fracture crosses through mutiple zones of the physis, with chondrocytes maintaining their linear arrangement on both sides of the fracture site for 1-4d following trauma
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*Slipped capital femoral epiphysis – seen in humans, mainly adolescent boys, autosominal dominant with variable penetrance
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In cats:
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*'''[Physeal dysplasia with slipped capital femoral epiphysis in 13 cats. Craig LE. Vet Path (2001) 38 92-7]'''
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**Age 12-21months
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**90%  males
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**Often obese, lots of Siamese cats
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**Normal growth plates close at 7-9mths so these physes should have been closed
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**Histology – physeal dysplasia with persistence of an open, disorganized growth plate
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***Wide physis, necrotic cartilage at the cleavage site
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***Irregular clusters of chondrocytes separated by abundant chondroid matrix. Similar lesions in femoral neck.
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**No necrosis of the femoral head, although there is usually a small areas of peripheral attachment at the perichondral fibrocartilagenous complex – could provide some vacularization **The ligamentum teres provides no blood supply to the femoral head
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**Clusters of chondrocytes present on either side of the cleavage site
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**Differs from [[Joints Developmental - Pathology#Osteochondrosis|osteochondrosis]] by:
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***More diffuse affecting the whole physis (in OC – focal failure of endochondral ossification)
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***Chondrocytes are arranged in disorganized clusters rather than parallel rows
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***The cat breeds have not been selected for rapid growth
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**Insulin may have a role to play – most of the cats were obese....Similar deal to horse osteochondrosis
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[[Category:Bones - Degenerative Pathology]]
 
[[Category:Bones - Degenerative Pathology]]
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