Osteoarthritis

Question 1

What is osteoarthritis?

Answer 1

degenerative joint disease

Question 2

What happens in osteoarthritis?

Answer 2

there is loss of cartilage and subchondral bone in joints

Question 3

What joints are affected first in osteoarthritis?

Answer 3

weight-bearing joints

Question 4

Is osteoarthritis fast or slow progressing?

Answer 4

slow progressing

Question 5

What are the two forms of osteoarthritis?

Answer 5

primary and secondary osteoarthritis

Question 6

What causes primary osteoarthritis?

Answer 6

idiopathic

• wear and tear with aging plays a role
• there may be a genetic predisposition (a defect with a gene coding for proteins involved in maintaining hyaline cartilage in joints, if there is a defect the cartilage isn’t maintained and it is more easily damaged and poorly repaired)

Question 7

What causes secondary osteoarthritis?

Answer 7

• injury

- obesity (puts more stress on the joints, there may be a metabolic impact on the joints also)

Question 8

What is the pathology of osteoarthritis?

Answer 8

• chondrocytes maintain cartilage
• articular cartilage is smooth, weight bearing, dissipates force to bone (through physiologic deformation)
• (if the chondrocytes are abnormal) there is a change in the composition and properties of the cartilage
• this leads to a release of cytokines (TNF, interleukin-1)
• the cytokines trigger the release of proteases, which cause tissue destruction (this normally happens in order for normal maintenance, but it happens in excess now)
• the cartilage deteriorates, leaving bone unprotected
• the unprotected bone scleroses (the body tries to increase the density of the bone in an attempt to prevent erosion but it doesn’t help)
• synovial fluid enters cracks in the bone, leads to formation of cysts and fissures
• osteophytes form and the joint enlarges and deforms

Question 9

What are the manifestations of osteoarthritis?

Answer 9

• initially, non-localized aching pain
• later, activity-related weight bearing joint pain
• crepitus
• stiff, inflamed joints (hurts with movement, becomes still with rest)

Question 10

How is osteoarthritis diagnosed?

Answer 10

• history and presentation
• x-ray (won’t show anything in early stages)
• labs (will mostly be normal, use to rule out septic arthritis, psoriatic arthritis and gout)

Question 11

How is osteoarthritis treated?

Answer 11

• monotherapy PRN to treat pain:
  i) tylenol is drug of choice
  ii) 2nd choice is a cox 2 inhibitor (cox 2 is an enzyme that mediates inflammation, leads to formation of prostaglandin)
• infrequently, for severe cases, inject steroids into the joint (intra articular injection)
• rehabilitation (physio)
• joint replacement surgery