Osteoarthritis Flashcards
Osteoarthritis (OA)
Degenerative arthritis of the articular cartilage, typically affecting the weight bearing (larger) joints and seen mostly over the age of 45 years
Osteoarthritis: Signs and Symptoms
- Joint pain (e.g., knee, hip) with a gradual onset unilaterally. Often worsened by activity and relieved by rest.
- Associated joint stiffness.
- Joint swelling , deformity (due to osteophytes), crepitus.
- Heberden’s nodes: Swelling at the distal interphalangeal joints.
Articular cartilage composition
- Extracellular matrix (water, collagen, proteoglycans) and chondrocytes.
- The normal turnover of matrix components is mediated by chondrocytes, which synthesise ECM components and the proteolytic enzymes responsible for their breakdown.
- Proteoglycans are formed of glycosaminoglycan (GAG) chains such as chondroitin sulphate , which is bound to hyaluronic acid . This provides osmotic properties critical to resist compressive forces.
Osteoarthritis: Pathophysiology
- Proteolysis
- Enzymes such as collagenase degrade the extracellular matrix, releasing fragments into synovial fluid → inflammation (e.g., IL-1β, TNF-α).
- As the level of proteoglycans drop, the cartilage softens, thins and loses elasticity, compromising joint surface integrity.
- The loss of cartilage results in loss of joint space. Erosion of the damaged cartilage in an osteoarthritic joint progresses until the underlying bone is exposed.
- Subchondral bone responds with bone thickening (‘eburnation’) and bone spurs (osteophyte formation)
Osteoarthritis: Causes and risk factors
- Increasing age
- Previous joint trauma
- Overweight / obesity
- T2DM
- Genetics
- Inflammation
- Nutrient deficiencies: Vit D
Osteoarthritis: Supplements
Glucosamine sulphate
Chondroitin sulphate
MSM
Vitamin C
Vitamin E
Vitamin D
Tart cherry
Vitamin K2
OA: Glucosamine sulphate
Dose: 500mg 3x/daily
- GAG synthesis, also stimulates chondrocyte production of collagen.
- A provider of sulphate ions for the synthesis of the chondroitin sulphate.
- Inhibits: MMPs (e.g., collagenase) reducing cartilage degradation; COX-2, PGE2 and downregulates NF-kB in chondrocytes.
OA: Chondroitin sulphate
Dose: 200 - 400mg/day
- Chondroitin increases the amount of hyaluronic acid in joints keeping synovial joints lubricated.
- Inhibits many cartilage degrading enzymes.
OA: MSM
Dose: 1g - 3/4g/day
- NF κB inhibition and free radical scavenging.
- Stimulates proteoglycan and hyaluronic acid synthesis; inhibits proteolytic enzymes.
OA: Vitamin C
Dose: 1 -5000mg/day
- Anabolic effect on cartilage; required for chondrocyte protein synthesis (e.g., collagen)
- Antioxidant properties reduce impact of ROS on genomic stability in chondrocytes.
OA: Vitamin E
Dose: 200 - 400 IU/day
Synergistic with vitamin C. Antioxidant, inhibits lysosomal enzymes, increases proteoglycan deposition.
OA: Vitamin D
Dose: 2000 - 10,000iu depending on levels
- Prevents articular cartilage erosion by regulating
collagen II turnover and bone metabolism.
OA: Tart cherry
Dose: up to 3000mg/day
- Rich in anthocyanins and other flavonoids.
- Anti-inflammatory
- Reduces pain and hsCRP
OA: Vitamin K2
Dose: 50-100mcg
Inhibits cartilage calcification
OA: Herbs
Turmeric
Boswellia
Devil’s Claw
Ginger