Bone and Joint pathology
Response to injury (limited)
Inflammation
Degeneration
Degenerative Joint Disease
IV disk degeneration
Osteochondrosis drecans
Infectious arthritis
Bacterial
Synovitis
Extent
Subchondral bone involvement
Vascular fibrous tissue infiltration
Metaplasia --> fibrocartilage
Superficial cartilage involvement
Inflammatory
Persistent defects
Synovitis
Hyperaemia; inflammatory oedema
Degrade collagen/proteoglycan
Fibrillation (clefts)
↪ further cartilage loss
➡ eburnation
Degenerative
Villous hypertrophy + hyperplasia
Hyaluronic acid degradation
Loss of lubricating properties
Pannus formation
Fibrovascular histiocytic tissue
Promote destruction of underlying cartilage
Glucocorticoids 🚫
⬇ Synthesis of cartilaginous matrix
⬇ Mechanical strength
⬆ Proteoglycans depletion
Causes
Trauma
Chronic, low grade
Unstable joints
Eg. Hip dysplasia; ruptured cruciate ligament (stifle)
Pathogenesis
⬆ periosteum bone formation around joints
Altered socket conformation
Mismatched coverage of bone head
Haematogenous; direct extension
Immune-mediated
Eg. Actinobacillus; erysipelothrix; e.coli
Pathogenesis
"Wobble syndrome"
Focal failure of endochondral ossification
Degeneration of overlying articular cartilage
Types
Serous; fibrinous; purulent; chronic (lymphoplasmacytic)
Viral
Encephalitis virus
Erysipelas (superficial cellulitis)
Ataxia due to vertebral column malformation
Articular-epiphyseal cartilage complex separation from epiphyseal bone
Humeral head 🐕
Slow healing
➡ DJD
Subchondral bone cysts
Predispostition
Young, fast growing males
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