Joint Pathology Flashcards
What should the bones at synovial joints be like?
Fit nicely together with even distribution of pressure
Not touch - separated by cartilage
What type of cartilage is articular cartilage?
Hyaline
What attracts water in cartilage?
Glycosaminoglycans
How is the collagen arranged in articular cartilage?
To hold glycosaminoglycans compressed together
Are there any blood vessels in articular cartilage?
No
How is articular cartilage perfused?
Compression/decompression of cartilage > pushes water in and out
What do the capsule, tendons, and ligaments at the joint do?
Hold everything together
Crucial to joint stability and movement
Where is the synovium?
Lines joint space
Where is the synovium attached?
Firmly anchored to capsule and bone at edges of cartilage
What is the synovium?
Vascular connective tissue with synovial membrane
What are the cell types of the synovium?
25% type A “macrophage-like” synoviocytes
75% type B “fibroblast-like” synoviocytes
Why is the synovial membrane not an epithelium?
No basement membrane
No junctional complexes
What makes up synovial fluid?
Plasma filtrate - easily crosses in and out of joint space
Hyaluronic acid - makes viscous
Lubricin - makes slippery
Etc
How thick is the synovial membrane?
1-4 cell layers
Why is osteoarthritis classified as a degenerative disease?
Cartilage wears away
Does osteoarthritis present symmetrically?
No
When is pain worst in osteoarthritis?
At end of day
What is released by the cartilage matrix and synovial cells in osteoarthritis?
Enzymes - Collagenases - MMPs Cytokines - IL-1
What parts of the joint does osteoarthritis affect?
Capsule
Synovium
Bone
What is the pathophysiology of osteoarthritis?
Damage stimulates chondrocyte - Hypertrophy - Proliferation - Enzyme/cytokine secretion Unravelling of cartilage matrix, release of enzymes, loss of frictionless mechanical function Changes in bone - Thickening - Microfractures Shedding of cartilage - Fibrillation - Erosions Bone-on-bone - Eburnation - Cysts - Osteophytes
What is the morphology of osteoarthritis?
Remaining cartilage looks rough Eburnation of bone Fibrillation of articular cartilage Subchondral cysts Non-uniform loss of cartilage Subchondral thickening Osteophytes