Osteoarthritis

Question 1

What are the risk factors?

Answer 1

1. Age
2. Inflammation IL6,1,TNF-a
3. Joint injury
4. Mechanical stress + obesity
5. Other - neurodisorders, genetics, meds

Question 2

What is the pathophysiology?

Answer 2

Damaged articular cartilage
friction from exposed bone leads to inflammation -> pain
As cartilage is damaged chondrocytes produce type I collagen and less proteoglycans (reduced elasticity of matrix in cartilage -> increased breakdown)
Over time chondrocytes die, cartilage is softer and weaker so flakes off
Macrophages and lymphocytes recruit cytokines leading to inflammation
Bone exposed -> eburnation and osteophytes

Question 3

What is the function of chondrocytes?

Answer 3

Chondrocytes maintain cartilage through balance of catabolism and anabolism (producing)

Question 4

What is eburnation?

Answer 4

A change in exposed subchondral bone in degenerative joint disease in which it is converted into a dense substance with a smooth surface like ivory.
Sclerosis

Question 5

Give the clinical features

Answer 5

1. pain following use and increasing w rest

2. Unilateral

Question 6

What joints are affected?

Answer 6

large weight bearing joints

Question 7

What can be found on examination?

Answer 7

Joint swelling - due to bony enlargement, effusion and synovitis
Limited ROM
Heberdens (DIP)
Bouchards (PIP) - from osteophyte formation

Question 8

What changes are found on XR?

Answer 8

Loss of joint space
Osteophyte formation
Subchondral sclerosis (increased bone density/thickening under the cartilage)
Subchondral cysts

Question 9

How do the XR changes differ to that of RA?

Answer 9

In RA:
junta articular osteoporosis
peri-articular erosions
subluxation

Question 10

Give the management

Answer 10

1. Weight loss and exercise
2. Analgesics - paracetamol, topical NSAIDs
3. Oral NSAIDs
4. Intra-articular CS
5. JOINT REPLACEMENT