STAGE 1a
STAGE 2b
Noyes Classification
- 0: Normal articular cartilage
- 1a: Mild softening or discoloration of articular cartilage
- 1b: Severe softening or discoloration of articular cartilage
- 2a: Partial-thickness defect of <50% of the total thickness of articular cartilage
- 2b: Partial-thickness defect of >50% of the total thickness of articular cartilage
- 3a: Full-thickness articular cartilage defect with normal subchondral bone
- 3b: Full-thickness articular cartilage defect with erosion of subchondral bone
A classification like this is really a 'shorthand' for the doctor's notes, so that just a glance at past notes brings to mind an image of how far the arthritis had progressed when the note was made.