Background The double contour (DC) seen by ultrasonography (US) was recently included in the classification criteria of gout, but this injury and other ones like tophi, hyperechoic aggregates Intra -articular and/or intra-tendinous, and bone erosions have not been validated.

Objectives To evaluate the reliability of US to detect gout elementary lesions

Methods Nine patients with Gout were included; diagnosis established by demonstration of monosodium urate crystals; patients were evaluated by 5 ultrasonographers in 2 rounds to detect tophi, hyperechoic aggregates, DC and bone erosions according to OMERACT definitions (1) in knee joint recesses and 1st metatarsophalangeal (MTP) joint, quadriceps, patellar and Achilles tendons bilaterally. Cohen's Kappa was used to establish Intra and inter-observer variability; the Kappa values were assigned as follows: poor (below 0.2), just (0.21 to 0.40), moderate (0.41 to 0.60), good (0.61 to 0.80) and excellent (0.81 to 1).

Results Patients were 48+10 years old and 10+6 years of disease evolution. The inter-observer Kappa was good for DC in the knee and 1st MTP joint (0.87, 95% CI 0577–1170, p=0.000), good for hyperechoic aggregates in parapatellar recess, quadriceps and patellar tendon (distal insertion) and 1st MTP joint (0.71, -1064 to 2834, 95%, p=0.0001), moderate to proximal insertion of patellar tendon (0.46, 95% CI NA-NA, p=0.168), excellent for tophi in all tendons and in 1st MTP joint (0.82, 95% CI 0366–1270, p=0.000) and the same for erosion in 1st MTP joint (0.83, 95% CI 0349–1000, p=.0003). The intra-observer reliability was good (K=0.80; 95% CI 0758–0852, p=0.0000)

Conclusions The US is reliable for detecting gout elementary lesions in the knee and the 1st MTP joint.

1. Gutierrez M, et al. International Consensus for ultrasound lesions in gout: results of Delphi process and web-reliability exercise. Rheumatol 2015; online

Disclosure of Interest None declared