Week 2 Osteoarthritis

Question 1

Define osteoarthritis.

Answer 1

• A degenerative joint disease that usually affects people after middle age
• characterized by progressive cartilage loss subchondral bone thickening (bone under cartilage), and marginal osteophytes
• most common articular disease worldwide
• prevalence increases with age, female predominance

Question 2

Describe normal articular cartilage.

Answer 2

• only cell is chondrocyte: makes proteins needed for ECM and enzymes that degrade the matrix
• Mostly Type II collagen
• different layers of chondrocytes and collagen fibrils and proteins

Question 3

Describe the pathogenesis of OA.

Answer 3

Chondrocytes affected by

• biomechanical
• increased matrix degradation (increased cytokines, enzymes, NO)
• decreased matrix synthesis (decreased IGF and TNFb)
• ->leading to loss of matrix integrity (also influenced by metabolic and genetic factors

Question 4

What is the difference between primary and secondary osteoarthritis (OA)?

Answer 4

1. Primary: no identifiable cause
   - affects weight bearing joints such as spine, knee, hip and hands and foot
2. Secondary: identifiable cause
   - can involve any joint
   - includes congenital and developmental disorders, trauma, endocrine diseases
   - metabolic disorders: acromegaly, alkaptonuria (ochronosis-buildup of homogentistic acid in joints and tissues–>pigmentation, calcification, and inflammation of cartilaginous and related tissue), gout, hemochromatosis, chondrocalcinosis
   - consider secondary OA if arthritis is present in unusual locations or below age 50

Question 5

*What are the physical exam features of OA?

Answer 5

1. Bony enlargement
   -cartilage is worn down and body tries to repair, leading to bone hypertrophy
2. Effusions-swelling
3. Hand nodes
   Heberden’s-on DIPs
   Bouchard’s-on PIP
4. Crepitus: grating, crackling, popping sounds obtained when affected joint is passively moved with one hand while other hand is placed conjoint to feel the crepitus

Question 6

*What are the strongest risk factors for OA?

Answer 6

1. Age
2. Obesity
   Other risk factors
   -female vs. male
   -sports activities
   -previous injury
   -quads muscle weakness
   -genetic elements: type II collagen gene linkage

Question 7

What are the treatments for osteoarthritis?

Answer 7

1. for mild to moderate joint pain
   - acetaminophen
   - topical agents: methylsalicylate and menthol
   - capsaicin
2. for moderate to severe pain
   - joint aspiration
   - intra articular injections: glucocorticoids, hyaluronan
   - cox 2 inhibitors
   - NSAIDs
   - tramadol
   - opioids
3. Non pharm therapy
   - weight loss!

Question 8

OA versus inflammatory arthritis

Answer 8

OA
-progressive onset
->50 age
-morning stiffness <30 mins
-worse with wt bearing, worse with activity
-better with rest
-non inflammatory synovial fluid
-normal ESR
-osteophytes, joint space narrowing, sclerosis, subchondral cysts on radiograph
Inflammatory arthritis
-acute or progressive
--any age
-morning stiffness 1hr
-better with activity
-worse with rest
-inflammatory synovial fluid
-elevated ESR
-radiograph: varies with disease can be helpful to distinguish the two