Approach to joint diseases

The first question is 'is it a joint disease?'
Hint: both sides of joints are affected usually


How to differentiate between inflammatory or degenerative joint disease?

Feature of inflammatory joint
Marginal bone erosion: intraarticular bone not covered by cartilage. Seen before subchondral bone plate erosion.
Subchondral bone erosion: subtle discontinuity of subchondral bone plate (e.g. ulnar styloid)
Then extends to trabeculae in medullary spaces.

Joint space narrowing:
Uniform narrowing: inflammatory joints
Non-uniform narrowing: degenerative joints

Soft tissue swelling:
Inflammatory arthropathy

Juxtaarticular osteopenia:
Inflammatory joint

Degenerative joint

Bone sclerosis:
Degenerative joint

Subchondral cyst:
Degenerative joint