Pathobiology of Developmental Disorders Flashcards
what is osteochondrosis?
disturbance of endochondral ossification that leads to cartilage retention
what is osteochondritis dissecans?
manifestation of osteochondrosis in which a flap of cartilage is lifted from the cartilage surface
what does failure of endochondral ossification lead to?
cartilage thickening which may result in malnourished, necrotic chondrocytes
osteochondrosis does not apparently cause clinical signs until a loose flap forms, termed ____________________________
osteochondritis dissecans
what is the signalment of osteochondritis dissecans of the proximal humerus?
large and giant breed dogs
rare in small dogs or cats
males more than females
clinical signs between 4-8 months
what can be found on the physical exam of osteochondritis dissecans?
crepitus or joint swelling seldom evident
extreme extension of the shoulder elicits pain
extreme flexion of shoulder might elicit pain
muscle atrophy may be present
what is diagnosis of osteochondritis dissecans of the proximal humerus based on?
typical radiographic findings in lateral view
what is the treatment of osteochondritis dissecans?
remove flap
curette to subchondral bleeding bone
rest for 4-6 weeks
defect fills with fibrocartilage
where is canine stifle osteochondritis dissecans usually?
medial aspect of lateral femoral condyle
where is canine hock osteochondritis dissecans usually?
medial trochlear ridge of talus
where is canine elbow osteochondritis dissecans usually?
medial humeral condyle
what are the most common lesions in the equine stifle with osteochondrosis?
osteochondritis dissecans of the lateral trochlear ridge of the femur
subchondral bone cyst of medial femoral condyle
when do horses present with osteochondrosis in the stifle?
any age
usually younger horses
what are the clinical signs of osteochondrosis in the equine stifle?
joint effusion
lameness
how are lateral trochlear ridge lesions in horses treated?
arthroscopic debridement
conservative not as good
how does the prognosis of subchondral bone cysts in horses compare to that of lateral trochlear ridge lesions?
worse than lateral trochlear ridge lesions
what is the most common location of osteochondrosis in the equine hock?
cranial, distal intermediate ridge of the tibia
how is osteochondrosis in the equine hock treated?
arthroscopic debridement
of the equine joint osteochondroses, which one has the least favorable prognosis?
equine shoulder osteochondritis dissecans
what is arthroscopic debridement for equine shoulder osteochondritis dissecans best for?
mild to moderate lesions
what is canine elbow dysplasia?
a collection of developmental diseases of the canine elbow
what are the three main manifestations of canine elbow dysplasia?
fragmented medial coronoid process of ulna
ununited anconeal process of ulna
osteochondritis dissecans of medial humeral condyle
what is a fragmented medial coronoid process?
separation of medial coronoid process from the ulna
when does the anconeal process usually fuse?
13 weeks
what does the prognosis of an ununited anconeal process vary with?
degree of osteoarthritis
what induces joint inflammation in osteochondritis dissecans?
cartilage degradation products reaching synovial fluid
what can be seen on radiographs with osteochondritis dissecans?
earliest: flattening of subchondral bone of the caudal humeral head
saucer-shaped radiolucent area
calcification may allow visualization in situ or within joint
what type of cartilage heals an osteochondritis bed?
fibrocartilage replaces hyaline cartilage
what is the prognosis of canine stifle osteochondritis dissecans?
guarded
what age is usually affected by canine stifle osteochondritis dissecans?
6-9 months old
which type of osteochondritis dissecans is least common in dogs?
canine stifle osteochondritis dissecans
is a subchondral bone cyst of the medial femoral condyle or an OCD lesion of the lateral trochlear ridge of the femur a better prognosis?
lateral trochlear ridge lesions better prognosis
how often is osteochondrosis of the equine hock bilateral?
45-50%
how is prognosis of osteochondrosis of the equine hock?
good to excellent
what are some potential causes of canine elbow dysplasia?
decreased radius of curvature of the ulnar trochlear notch
asynchronous growth between radius and ulna
how does separation of the femoral medial coronoid process and the ulna occur?
calcified trabeculae then covered with fibrous connective tissue
fragmentation of coronoid
what are some indications for surgery with fragmented medial coronoid process?
persistent lameness
mild DJD
what has been implicated in osteochondrosis?
genetics
rapid growth
over-nutrition
trauma
ischemia
hormonal factors
does osteochondrosis cause clinical signs before a loose flap develops?
no
why is arthroscopy to fix osteochondritis dissecans of the humeral head difficult?
overlying muscle mass
