Developmental disease (Yr 3) Flashcards
what is the precursor to bone in utero?
cartilage
where are the two sites of endochrondral ossification?
metaphyseal growth plate
articular-epiphyseal cartilage complex
what are the main areas of longitudinal bone growth?
metaphyseal (growth plates)
epiphyseal (articular epiphyseal cartilage complex)
how do cuboidal bones grow?
epiphyseal articular cartilage complex (don’t have a secondary centre of ossification/growth plate)
what anatomical sections are there at the growth plate?
resting cartilage
proliferative cartilage (when they divide)
hypertrophic cartilage (cells get bigger)
calcifying cartilage (cells die and get calcified)
secondary spongiosa
is blood supply needed for endochondral ossification?
yes
when may endochondral ossification malfunction at the physical growth plate?
abnormal deposition of the matrix
abnormal mineralisation
poor conversion to bone
retention of cartilage
what are the results of malfunction in the process of endochondral ossification at the physical growth plates?
slow or uneven growth
what are the results of malfunction in the process of endochondral ossification at the articular-epiphyseal cartilage complex?
slow or uneven growth
cartilage flaps
what are the affects of abnormal endochondral ossification?
affects the…
rate of growth
direction of growth
health of articular cartilage
what is chondrodysplasia?
abnormal endochondral ossification leading to stunted growth
what is osteochondrosis?
broad term describing abnormalities associated with the cartilages found in joints
what is osteochondritis?
inflammation associated with osteochondrosis
what is osteochondritis dissecans?
clinical manifestation of abnormal endochondral ossification leads to cartilaginous or osteochondral flaps/defects within the joint
what are some abnormalities that can lead to OCD?
disruption of blood supply
abnormal chondrocyte maturation
defective matric production
persistence of hypertrophic chondrocytes
what do the abnormalities in development during OCD lead to?
thickened retained hypertrophic cartilage
disruption of the subchondral bone plate
how does disrupted blood supply lead to OCD?
affects the mineralisation of subchondral bone which then alters the biochemical/biomechanical properties of cartilage and subchondral bone that then affects its ability to adapt and withstand forces
what are the sequelae to the cartilage and subchondral bone of OCD cases to not be able to withstand forces?
inability to withstand forces/weight bearing
separation at osteochondral junction
cartilage flaps/fragments form
subchondral bone becomes exposed leading to inflammation
what are the clinical signs of OCD?
effusions
fragments on radiographs
arthritis and lameness
what can predispose animals to OCD?
rapid growth
genetic predisposition
nutrition (excess energy/protein, calcium/phosphorous imbalances)
trauma
when is surgical management of OCD carried out in horses?
only after 12 months of age, some can resolve themselves as the horse grows
what can untreated osteochondrosis dissecans lead to?
osteoarthritis
what is the difference between osteochrondrosis dissecans and osteochondritis dissecans?
no clinically relevant difference (treat them as the same thing)
what radiographic abnormalities can be seen with OCD?
irregular subchondral bone
osseous densities (mineralised cartilage, osteochondral fragments)
what are the developmental orthopaedic diseases of horses?
osteochondrosis (OCD, subchondral bone cysts)
physitis
angular limb deformities
flexural deformities
what are the developmental orthopaedic diseases of dogs?
osteochondrosis (uninvited anconeal process, fragmented medial coronoid process)
hypertrophic osteodystrophy
legg calve perthes
hip dysplasia
what are the developmental orthopaedic diseases of cows?
oestochondrosis
flexural deformities
what is the aetiology of subchondral cyst-like lesions?
abnormal endochondral ossification leading to retention of a cartilage core and collapse of the cartilage under pressure from synovial fluid
what is physitis?
enlargement of the physis caused by inflammation and disrupted endochondral ossification
what are the clinical signs of physitis?
lameness and stiff gait
how is physitis treated?
self-limiting (just supportive therapy)
what plane is an angular limb deformity in?
frontal
what is valgus and varus?
valgus - lateral deviation
varus - medial deviation
what are the sites angular limb deformities are most commonly seen at?
metaphyseal growth plate
epiphysis
cuboidal bones (carpus, tarsus)
metaphysis
