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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 |
| + | *Femoral head physes contribute 30-40% of longitudinal growth of the femur in small animals |
| + | *Slipped epiphysis -> Salter-Harris type I where only the physis is involved |
| + | **Most common type of physeal fracture in small animals and the proximal femur is the most common site |
| + | **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 |
| + | *Slipped capital femoral epiphysis – seen in humans, mainly adolescent boys, autosominal dominant with variable penetrance |
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| + | In cats: |
| + | *'''[Physeal dysplasia with slipped capital femoral epiphysis in 13 cats. Craig LE. Vet Path (2001) 38 92-7]''' |
| + | **Age 12-21months |
| + | **90% males |
| + | **Often obese, lots of Siamese cats |
| + | **Normal growth plates close at 7-9mths so these physes should have been closed |
| + | **Histology – physeal dysplasia with persistence of an open, disorganized growth plate |
| + | ***Wide physis, necrotic cartilage at the cleavage site |
| + | ***Irregular clusters of chondrocytes separated by abundant chondroid matrix. Similar lesions in femoral neck. |
| + | **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 |
| + | **Clusters of chondrocytes present on either side of the cleavage site |
| + | **Differs from [[Joints Developmental - Pathology#Osteochondrosis|osteochondrosis]] by: |
| + | ***More diffuse affecting the whole physis (in OC – focal failure of endochondral ossification) |
| + | ***Chondrocytes are arranged in disorganized clusters rather than parallel rows |
| + | ***The cat breeds have not been selected for rapid growth |
| + | **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]] |