Video image analysis of hands: development of an 'anatomic index' as a potential outcome measure in rheumatoid arthritis.

In this study, we used video image analysis for the measurement of hand dimensions to reflect destructive changes in rheumatoid arthritis. Thirteen dimensions were measured from anteroposterior and lateral views of the hands, open and closed. Comparison of measurements in 19 patients and 19 control subjects showed significant differences for nine of the 13 measurements. Five were reproducible on retesting in a subset of patients and normals. Two were eliminated because they were similar to other measurements. The three remaining measurements selected for differentiation of patients and normals, and reproducibility, were combined in an arbitrary 'anatomic index'. This enhanced separation of normals and patients with rheumatoid arthritis. The results demonstrate that measurement of certain hand dimensions and their combination in an 'anatomic index' could provide a measure reflecting the progressive anatomical abnormality caused by rheumatoid arthritis. Validation of this concept could provide a further outcome measure in patients with rheumatoid arthritis.