Cartilage Biology And Ostheoarthiritis Flashcards
Osteoarthritis
A disease of the whole joint involving loss of articular cartilage
Articular cartilage
Contains aggregates which exert swelling pressure
Type II collagen which has high tensile strength
Water
What are the only cells present
Chondrocytes
These are producers and deragders of cartilage matrix
Highly metabolically active
No cell division after adolescence
What breaks down collagen
Collagenases break down collagen
What does MMP3 cleave
Matrix chemicals
Aggrecanases
Cleave aggregan
ADAMTS-4&5
Anabolic and catabolic factors for articular cartilage
Intrinsic
TIMPS 1-4 breakdown Extracellular matrix compartments by inhibiting metalloproteinases (catabolic)
Growth factors - fibroblasts growth factors stimulate ECM production
Extrinsic
Hormones such as testosterone and estrogen which reduces the risk of cartilage breakdown
Some drugs
Pathogenesis of OA
excessive fragmentation of proteoglycans
Collagen broken down by collagen ashes
Water is lost (swelling seen initially)
Risk factors
Age
Obesity
Joint injury
Family history
Chondrodysplasias( defects in collagen type II)
Secondary joint damage due to inflammatory arthopathies
Gene variation
Post traumatic oa
Half of those with meniscal or anterior ligament tear develop OA in 5-10 years
Inflammatory response activates MMP-3
Diagnosis
Symptoms include stiffness joint pain and loss of function
Examinations find bone deformity,joint line tenderness,warmth,loss of normal range,crepitus
X ray can show osteophytes,bone cyst,subchondral sclerosis
Blood tests show normal CRP,rheumatoid arthritis is negative
Management
Exercise
Weight management
Topical NSAID
Joint replacement trapeziectomy( removal of thumb bone)
Fibrous joints
Have no space in between bones
Are synarthroses as allow no movement
Cartilaginous joints
Have cartilage in between
Are amphiarthroses as allow limited movement
Synovial joints
Have synovial fluid in synovial cavity in between bones
Diarthroses allows free movement
