Symmetry of radiological features in the wrist and hands of patients with early to moderate rheumatoid arthritis: a quantitative microfocal radiographic study.

Quantitative microfocal radiography was used to assess the degree of symmetry in radiological features between the dominant and non-dominant wrist and hands of 51 patients with early to moderately advanced RA. With few exceptions, erosion size and joint space width were bilaterally symmetrical between the dominant and non-dominant side in: total erosion area and total joint space width; area at each of the separate sites of erosion formation, and width at each joint space; and the change in these X-ray features over an 18-month study period. Asymmetry in the number and size of erosions and joint space occurred in a small number of patients within either extremity; these differences were not sustained over the study period. In view of this degree of bilateral symmetry, the extent and progression of the radiographic features in RA can be assessed from a single macroradiograph of either the left or right wrist and hand.