The reliability of a novel magnetic resonance imaging-based tool for the evaluation of forefoot bursae in patients with rheumatoid arthritis: the FFB score

Objective. The aim of this study was to determine the reliability of an MRI-based score that evaluates forefoot bursae (FFBs) in patients with RA.Methods. Items for inclusion, grading criteria and MRI sequences were determined iteratively. The score was evaluated in 30 patients with established RA. Reader agreement was evaluated using the percentage of exact/close agreement, Bland–Altman plots, kappa and intraclass correlation coefficient analyses.Results. The FFB score assesses nine forefoot regions and contains four items: presence, shape, enhancement and magnetic resonance characteristics. The FFB score showed moderate to good intra- and interreader agreement (κ range = 0.5–0.9 and 0.47–0.87, respectively).Conclusion. The FFB score is adequately reliable in the evaluation of bursa-like lesions of the forefoot in patients with RA