Pathophysiology of osteochondroses

Question 1

What is Osteochondrosis

Answer 1

temporary focal or multifocal failure of endochondral ossification–therefore growing animals–lesions at physis or articular epiphyseal (AE) complex

Question 2

Dyplasias

Answer 2

Retention of cartilage (that should have been replaced by bone) at the AE-complex or physis due to localized failure of endochondral ossification

Question 3

Osteochondritis Dissicans (OCD)

Answer 3

AE complex dysplasias that have fractured through to the surface (exception: OCD in horses due to zinc toxicity is not associated with dysplasia

Question 4

Bone cysts

Answer 4

Are due to osteochondrosis result from necrosis (liquefaction) of dysplasias

Question 5

Epiphysiolysis

Answer 5

Separation of the epiphysis (or apophysis) from the metaphysis at the physis (physeal fracture–usually atraumatic) associated with disorganizationof the chondrocytes and variable coagulation and liquifactive necrosis of the physeal catilage.

Question 6

associated condition of epiphysiolysis

Answer 6

minimal and uniformly thick dysplasia across the growth plate often that are open beyond normal closure.
Example: ununited anconeal process in dogs

Question 7

predisposing factors for Osteochondrosis

Answer 7

animals bred for rapid growth are predisposed

Question 8

Known causes of Osteochondrosis

Answer 8

mycotoxins; zinc toxicity; copper deficiency are likely the exceptions

Question 9

Pathogenesis of Osteochondrosis

Answer 9

• -primary and reversible failure of maturation/ mineralization/ vascular invasion of growth cartilage
• -ischemic coagulation necrosis and retention of growth
• -mechanical factors likely play a role in causing clinical signs (fractures/fissures)