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
What pathology may result from overnutrition-related rapid growth in dogs?
Biomechanical overload of joint surfaces
What effect does rapid growth have on large and giant breed dogs concerning skeletal diseases?
Increases incidence of osteochondrosis
What is the primary goal of non-surgical management of osteochondrosis?
Reduce pain and manage mild lesions
Name one common non-surgical treatment for mild osteochondrosis lesions.
Nonsteroidal anti-inflammatory drugs
What surgical method is often used for removing loose cartilage flaps in osteochondrosis?
Flap excision
What structure supports chondrocytes in the resting zone of the growth plate?
Cartilage canals with blood vessels
In the mineralization zone, how do chondrocytes end their life cycle?
Apoptosis
What process is essential for the transition of hypertrophic chondrocytes to mineralized bone?
Matrix calcification
How does the growth plate contribute to bone length?
By pushing the epiphysis away from the diaphysis
What is the histologic finding in advanced osteochondrosis dissecans?
Detached cartilage flap and subchondral bone defect
What is the primary developmental defect in osteochondrosis? (A) Disruption of endochondral ossification (B) Lack of osteoblast activity (C) Excessive bone resorption (D) Increased collagen formation
A) Disruption of endochondral ossification
Which term is used to describe an early, microscopic lesion of osteochondrosis? (A) Osteochondrosis manifesta (B) Osteochondrosis dissecans (C) Osteochondrosis latens (D) Osteoarthritis
C) Osteochondrosis latens
Which breed characteristic is most associated with a predisposition to osteochondrosis? (A) Small breed (B) Giant or large breed (C) Breeds with short legs (D) Breeds with long ears
B) Giant or large breed
According to the Hueter-Volkmann law, what effect does increased mechanical compression have on growth? (A) Accelerates growth (B) Causes rapid chondrocyte death (C) Retards growth (D) Has no effect on growth
C) Retards growth
Which zone in the growth plate is vascularized and consists primarily of stem cells? (A) Proliferative zone (B) Resting zone (C) Hypertrophic zone (D) Mineralization zone
B) Resting zone
Which condition is described by the presence of attached or loose cartilage flaps in osteochondrosis? (A) Osteochondrosis latens (B) Osteochondrosis dissecans (C) Osteoarthritis (D) Synovitis
B) Osteochondrosis dissecans
What is the main histologic feature of osteochondrosis lesions in the proliferative zone? (A) Increased chondrocyte proliferation and matrix synthesis (B) Chondrocyte necrosis (C) Extensive mineralization (D) Reduced vascularization
A) Increased chondrocyte proliferation and matrix synthesis
What role does vascular endothelial growth factor (VEGF) play in osteochondrosis? (A) Inhibits chondrocyte proliferation (B) Stimulates cartilage matrix formation (C) Promotes vascular ingrowth (D) Prevents chondrocyte apoptosis
C) Promotes vascular ingrowth
What is the common histologic feature of growth plate osteochondrosis? (A) Thickened growth plate with retained hypertrophic chondrocytes (B) Absence of chondrocytes (C) Hypervascularization of growth plate (D) Increased osteoblastic activity
A) Thickened growth plate with retained hypertrophic chondrocytes
Which of the following is not typically a risk factor for osteochondrosis? (A) Rapid growth (B) Male gender (C) Large breed (D) Frequent light exercise
D) Frequent light exercise
Which type of osteochondrosis lesion is described as macroscopically and radiologically apparent but subclinical? (A) Osteochondrosis latens (B) Osteochondrosis manifesta (C) Osteochondrosis dissecans (D) Synovitis
B) Osteochondrosis manifesta
During which period in dogs does most longitudinal bone growth occur? (A) 1 to 6 weeks of age (B) 12 to 26 weeks of age (C) 6 to 12 months of age (D) 1 to 3 years of age
B) 12 to 26 weeks of age
In the growth plate, which zone contains spheroid and relatively large chondrocytes that continue synthesizing matrix? (A) Resting zone (B) Proliferative zone (C) Hypertrophic zone (D) Mineralization zone
C) Hypertrophic zone
Which hormone acts directly on stem cells in the resting zone to promote their differentiation into cells that produce IGF-1? (A) Thyroid hormone (B) Growth hormone (C) Parathyroid hormone (D) Cortisol
B) Growth hormone
Which of the following is a key regulator involved in the differentiation of proliferative chondrocytes to hypertrophic chondrocytes? (A) Insulin (B) Bone morphogenetic protein (BMP) (C) Calcitonin (D) Adrenaline
B) Bone morphogenetic protein (BMP)
Which genetic factor is commonly associated with the predisposition of certain dog breeds to osteochondrosis? (A) Single-gene mutation (B) Autosomal dominant trait (C) Polygenetic inheritance (D) Lack of genetic influence
C) Polygenetic inheritance
Which type of traumatic event is suggested to hasten the conversion of an osteochondrosis manifesta lesion to an osteochondrosis dissecans lesion? (A) Microtrauma (B) Macrotrauma (C) Overnutrition (D) Decreased physical activity
B) Macrotrauma
What effect does overfeeding energy in young dogs have on their growth hormone levels? (A) Increases growth hormone levels (B) Decreases growth hormone levels (C) Has no effect on growth hormone levels (D) Increases growth hormone resistance
A) Increases growth hormone levels
Which dietary factor is linked to an increased risk of developmental orthopedic diseases such as osteochondrosis in some studies? (A) Low calcium intake (B) High protein intake (C) High calcium intake (D) Low vitamin D3 intake
C) High calcium intake
Which of the following is NOT a characteristic of type I osteochondrosis lesions as proposed by Olsson and Reiland? (A) Occurs at the center of the affected articular surface (B) Lacks vascular attachments (C) Commonly found in the caudal humeral head (D) Retains vascular attachments
D) Retains vascular attachments
Which anatomical feature is suggested to play an etiologic role in the development of osteochondrosis in certain species and sites? (A) Limb length (B) Limb conformation (C) Hair type (D) Body mass
B) Limb conformation
What is the primary factor influencing the enlargement of the growth plate during endochondral ossification? (A) Bone resorption (B) Vascularization (C) Chondrocyte proliferation (D) Osteoblast activity
C) Chondrocyte proliferation
In osteochondrosis, what pathology is commonly observed within cartilage matrix following chondrocyte death? (A) Cartilage mineralization (B) Cartilage necrosis (C) Increased vascularization (D) Osteoblast infiltration
B) Cartilage necrosis
In which area of the articular surface are Type I osteochondrosis lesions typically found? (A) Along the joint margins (B) At the center of the articular surface (C) Near the growth plate (D) Adjacent to tendon insertions
B) At the center of the articular surface
Which diagnostic imaging technique is considered primary for evaluating cartilage and assessing repair techniques in osteochondrosis? (A) Radiography (B) Computed tomography (CT) (C) Magnetic resonance imaging (MRI) (D) Ultrasound
C) Magnetic resonance imaging (MRI)
Which breed of dog has been the focus of studies linking high calcium diets with endochondral ossification issues? (A) Great Dane (B) German Shepherd (C) Labrador Retriever (D) Dachshund
A) Great Dane
What is the recommended treatment approach for mild cases of shoulder osteochondritis dissecans in young dogs? (A) Surgical intervention (B) Strict exercise restriction (C) Vigorous exercise (D) Nonsteroidal anti-inflammatory drugs
D) Nonsteroidal anti-inflammatory drugs
In which layer of the articular epiphyseal complex is the tidemark visible, marking the transition to mature articular cartilage? (A) Superficial zone (B) Transitional zone (C) Radial zone (D) Calcified cartilage zone
D) Calcified cartilage zone
Which factor has NOT been definitively linked to the initiation of osteochondrosis lesions in dogs? (A) Rapid growth (B) Dietary calcium (C) Vitamin D3 (D) Genetic predisposition
C) Vitamin D3
Which area of the growth plate undergoes cell division and matrix synthesis during the day, with mineralization typically occurring at night? (A) Resting zone (B) Proliferative zone (C) Hypertrophic zone (D) Mineralization zone
B) Proliferative zone
Which hormone is part of a feedback loop with Indian hedgehog (IHH) and transforming growth factor to regulate chondrocyte proliferation? (A) Growth hormone (B) Parathyroid hormone–related peptide (PTHrP) (C) Thyroid hormone (D) Insulin
B) Parathyroid hormone–related peptide (PTHrP)
What is the characteristic lesion of osteochondrosis dissecans? (A) Formation of bone spurs (B) Loose or attached cartilage flap (C) Inflammation of the synovial membrane (D) Thickened bone cortex
B) Loose or attached cartilage flap
What is a retained cartilaginous core in growth plate osteochondrosis? (A) Area of necrotic chondrocytes (B) Region with retained hypertrophic chondrocytes (C) Non-mineralized bone tissue (D) Fragmented cartilage debris
B) Region with retained hypertrophic chondrocytes
Which of the following factors has been suggested as a risk factor for osteochondrosis in dogs engaging in daily play with other dogs? (A) Limited exercise (B) Microtrauma (C) Osteopenia (D) Low vitamin intake
B) Microtrauma
What term describes the epiphyseal cartilage layer responsible for growth but lacking the organized structure seen in the growth plate? (A) Perichondral ring (B) Articular epiphyseal complex (C) Resting zone (D) Metaphyseal cartilage
B) Articular epiphyseal complex
Which diagnostic method is most commonly used to confirm osteochondrosis manifesta in clinical settings? (A) MRI (B) CT (C) Radiography (D) Ultrasonography
C) Radiography
In osteochondrosis, which tissue type fills the defect after a cartilage flap detachment? (A) Hyaline cartilage (B) Fibrocartilage (C) Elastic cartilage (D) Calcified cartilage
B) Fibrocartilage
Which therapeutic approach aims to stimulate cartilage defect healing by creating vascular access channels in subchondral bone? (A) Curettage (B) Spongialization (C) Microfracture (D) Cartilage grafting
C) Microfracture
Which of the following is NOT a common location for type I osteochondrosis lesions? (A) Caudal humeral head (B) Medial femoral condyle (C) Tarsocrural joint (D) Medial aspect of the humeral condyle
C) Tarsocrural joint
What is the primary objective of cartilage repair techniques in osteochondrosis? (A) Complete cartilage regeneration (B) Formation of a calcified bone layer (C) Restoration of a smooth cartilage surface and pain relief (D) Prevention of joint effusion
C) Restoration of a smooth cartilage surface and pain relief
Which technique involves drilling holes in subchondral bone to promote vascularization for defect healing? (A) Abrasion arthroplasty (B) Microfracture (C) Spongialization (D) Forage
D) Forage
Which cell type is responsible for creating the matrix in the growth plate’s proliferative zone? (A) Osteoblasts (B) Chondrocytes (C) Fibroblasts (D) Osteoclasts
B) Chondrocytes
Which of the following best describes the resting zone of the growth plate? (A) Lacks vascularization (B) Contains large, spheroid chondrocytes (C) Is organized in columns (D) Contains primarily stem cells and is vascularized
D) Contains primarily stem cells and is vascularized
Which surgical technique for osteochondrosis involves removing loose cartilage but keeping subchondral bone intact? (A) Curettage (B) Flap excision (C) Abrasion arthroplasty (D) Spongialization
B) Flap excision
How does increased chondrocyte matrix synthesis affect bone length growth in osteochondrosis? (A) Inhibits bone lengthening (B) Promotes bone lengthening (C) Has no effect on bone length (D) Causes joint effusion
B) Promotes bone lengthening
Which component is typically targeted in palliative cartilage repair techniques? (A) Growth plate (B) Synovial fluid (C) Cartilage defect surface (D) Subchondral bone
C) Cartilage defect surface
What is the main clinical indicator of osteochondritis dissecans in young, large-breed dogs? (A) Fever and lethargy (B) Lameness and joint effusion (C) Increased appetite (D) Vomiting and diarrhea
B) Lameness and joint effusion
In canine osteochondrosis, what type of lesion may develop due to the lack of vascular support in early cartilage? (A) Subchondral bone cyst (B) Osteophyte formation (C) Synovial hyperplasia (D) Fibrillation
A) Subchondral bone cyst
Which cartilage repair method involves transplantation of osteochondral autografts to fill a defect? (A) Curettage (B) Mosaicplasty (C) Microfracture (D) Debridement
B) Mosaicplasty
Which layer of the articular epiphyseal complex takes no part in endochondral ossification but later forms mature articular cartilage? (A) Radial zone (B) Outer layer (C) Inner layer (D) Perichondral ring
B) Outer layer
