Table 1 Traditional model for rheumatoid arthritis (RA) based mainly on radiographic findings and modern concepts emerging from magnetic resonance imaging in RA
Traditional paradigms for RA | Modern imaging paradigms | |
|---|---|---|
Erosions | A relatively late feature | Present in the majority at clinical presentation |
Synovitis and damage | Synovitis not necessarily linked to damage – uncoupling | Linear link between synovitis with damage |
Erosion mechanism | Immunologically mediated or autonomously by synovial fibroblasts | Major biomechanical contribution – such factors may mechanically uncouple synovitis from damage. |
Cutting edge of erosions | Synovial fibroblasts and osteoclasts destroy tissue from outside in. | Recognition that magnetic resonance imaging bone oedema represents a diffuse osteitis – at least some of erosive process occurs within the bone. |
Synovitis locations | Considered as diffuse | Regional variations within and between joints |
Pathophysiological perspective | Erosion formation and cartilage pannus junction key to understanding RA | Erosion and pannus are inevitable and predictable consequences of chronic synovitis, RA being the most common cause. |