Radiological assessment of outcome in rheumatoid arthritis.

Radiographs are an accepted method of assessing disease severity and progression in rheumatoid arthritis. The advantages of using radiological damage as an outcome measure are that it reflects the history of the joint pathology, it can be objectively scored, radiographs provide a permanent record necessary for sequential studies and they do relate to other measures of disease outcome. However, measurement of radiological damage is fraught with methodological problems and studies to define what is the best approach have only recently been performed. There is also the problem of differentiating between radiological progression which is unavoidable due to mechanical derangement and that which is due to currently active disease. The effect of treatment on radiological damage remains controversial. A better understanding of how to use this important outcome measure should now provide rheumatologists with a more critical assessment of new therapies as well as providing a better knowledge of the disease process.