Stage 1
Synovitis
- Proliferation of synovium, infiltration of subsynovial layer with inflammatory cells, capsular thickening, villous formation of synovium, cell rich effusion
- Painful swollen tender joints
- Mobility is maintained
- X-Ray : extra / juxta-articular osteoporosis secondary to increased vascularity
- Acute inflammation
- 1 – 3 days : increases small blood vessels
- 3 – 7 days : synovial cells proliferate
- 14 days : focal accumulation of T lymphocytes & increased interstitial fluid
- Chronic Inflammation
- Increased synovial surface area (villi)
- Increased blood vessels, lymphocytes, tissue fluid
- Radiologically apparent erosions after 8 weeks
Stage 2
Destruction
- Persistent chronic inflammation and pannus formation
- Periarticular erosions secondary to release of proteolytic enzymes, pannus and osteoclastic resorption of bone
- Similar changes occur around tendons
- X-Ray : Marginal bony erosions, reduced joint space, especially proximal joints of the hands, feet, wrists and AC joints
Stage 3
Deformity
- Secondary to articular destruction, capsular laxity and ligament ruptures
- Joint instability and deformity.
- Inflammation may have subsided.
- Deal with mechanical and functional aspects of the joint
- X-Ray : Articular destruction and joint deformity usually obvious. Cervical spine is affected, may see subluxation of Atlanto-Occipital or mid cervical levels.