A short Larsen score is effective when evaluating radiographs in early rheumatoid arthritis

To compare the efficacy of the short Larsen score (LS 12) based on analysis of 12 areas with the original Larsen score (LS 40), which includes 40 areas for assessing radiographic changes in rheumatoid arthritis.

The radiographs of the hands, wrists, and feet of 122 patients with early rheumatoid arthritis were evaluated by two radiologists using both the LS 40 and LS 12 methods. Cross-sectional analysis of radiographs of 122 patients and longitudinal analysis in 68 patients were performed.

There was no significant difference between the mean LS 40 and mean LS 12 in the cross-sectional study. LS 12 correlated strongly (r=0.93, P<0.01) with LS 40 at the baseline, and the rate of progression was similar in both methods (r=0.89, P<0.01) in the longitudinal study.

The short Larsen score was as efficient as the original method.