73. Osteochondrosis Flashcards
What developmental process is disrupted in osteochondrosis?
Endochondral ossification
Define osteochondrosis latens.
Early, microscopic lesion
What term describes osteochondrosis lesions that are visible but subclinical?
Osteochondrosis manifesta
What term is used when osteochondrosis involves loose cartilage flaps?
Osteochondrosis dissecans
Which gender is more commonly affected by osteochondrosis in dogs, except in the talus?
Male
Which breed size is more predisposed to osteochondrosis?
Large and giant breeds
At what embryonic stage do mesenchymal cells begin forming a cartilaginous bone model in dogs?
Days 19 to 35 after fertilization
What primary process converts cartilage to bone in developing skeletons?
Endochondral ossification
Name the four zones of the growth plate.
Resting, proliferative, hypertrophic, mineralization
Which growth plate zone contains vascular structures?
Resting zone
In which growth plate zone are chondrocytes primarily small and randomly oriented?
Resting zone
What hormone influences stem cells in the resting zone to produce IGF-1?
Growth hormone
Which feedback loop is involved in chondrocyte differentiation?
PTHrP and IHH feedback loop
Which protein is key to the conversion of proliferative chondrocytes to hypertrophic chondrocytes?
Bone morphogenetic protein (BMP)
What is the primary function of the perichondral ring of Lacroix?
Limits circumferential growth of the growth plate
Which law states that growth is inhibited by mechanical compression and promoted by reduced loading?
Hueter-Volkmann law
What stimulates chondrocyte clonal expansion in the growth plate?
IGF-1
During what time of day is mineralization most active in the growth plate?
Night
What type of ossification occurs at the growth plate-metaphyseal junction?
Endochondral ossification
Which growth plate zone is characterized by apoptosis?
Mineralization zone
How does VEGF contribute to osteochondrosis?
Promotes vascular ingrowth
What is the primary contributor to epiphyseal enlargement?
Chondrocyte proliferation and matrix formation
What is a retained cartilaginous core?
Local thickening of growth plate cartilage
What is the likely outcome when the epiphyseal growth front meets newly formed cartilage?
Chondrification
What is the main histologic feature of osteochondrosis manifesta?
Thickened cartilage
Which layer of the articular epiphyseal complex develops into mature articular cartilage?
Outer layer
What dietary factor is linked to developmental orthopedic diseases in Great Danes?
High calcium
How does overfeeding energy affect chondrocytes in young dogs?
Increases differentiation and proliferation
Which hormone levels increase with overnutrition in young dogs?
Growth hormone, IGF-1, T3, T4, insulin
What joint shape-related factor has been associated with osteochondrosis in humans and pigs?
Certain joint shapes and conformations
Name one joint morphological feature linked to canine osteochondrosis.
Joint incongruity (e.g., elbow incongruity)
Which condition results from a failure of the anconeal process to unite with the olecranon?
Ununited anconeal process
In which joint does hyperextension potentially contribute to osteochondrosis?
Tarsocrural joint
What histological finding is typical in osteochondrosis of the growth plate?
Persistence of hypertrophic chondrocytes
What is a clinical sign of osteochondritis dissecans in dogs?
Lameness or joint effusion
What imaging method is primary for detecting subchondral bone defects in osteochondrosis?
Radiography
Which diagnostic technique is highly specific for cartilage lesions in osteochondrosis?
MRI
What is a joint mouse in the context of osteochondrosis?
Detached cartilage fragment
Which zone of the growth plate has the highest chondrocyte proliferation?
Proliferative zone
What is the typical age range for rapid longitudinal bone growth in dogs?
12 to 26 weeks