Figure 5. Joint accumulation hypothesis.

Over the course of arthritis, the number of joints currently inflamed varies with disease activity (blue line) but the number of joints ever involved increases stepwise, leaving each patient with a progressively greater number of joints at elevated risk for subsequent flare (joints marked red in homunculus during periods of inactive disease). Rapid, sustained disease control that prevents accumulation of at-risk joints may render arthritis easier to control in the long term, irrespective of any “window of opportunity” in the underlying autoimmune process.