Objective: To assess the sonographic frequency of synovial effusion, synovial hypertrophy, synovitis, and double contour sign at joints commonly affected by gout and whether these features differ according to serum urate levels, disease duration, and use of urate-lowering therapy.

Methods: Participants with gout were recruited from rheumatology clinics. A detailed clinical assessment was undertaken of gout history, co-morbidities, medication, alcohol consumption, height, weight, clinical synovitis, tophi, and serum urate. Sonographic examination of the metatarsophalangeal joints, ankles, knees, metacarpophalangeal joints, wrists and elbows for synovial effusion, synovial hypertrophy, synovitis and double contour sign was undertaken. The mean number of joints affected were compared according to serum urate (<360 μmol/L versus ≥360 μmol/L), urate-lowering therapy (yes/no), and disease duration (≤5 years versus>5 years).

Results: Forty patients participated in the study. Synovial effusion, synovial hypertrophy, synovitis, and double contour sign were identified in 36 (90%), 38 (95%), 24 (62%) and 37 (93%) participants respectively. Synovial effusion was seen most frequently at the knee (right 70%, left 68%) followed by the first metatarsophalangeal (right 48%, left 40%) and lesser metatarsophalangeal joints (right 45%, left 35%). Synovial hypertrophy, synovitis, and double contour sign were seen most frequently at the first metatarsophalangeal joint (hypertrophy: right 65%, left 60%; synovitis: right 18%, left 18%; double contour: right 60%, left 68%). These findings did not differ according to serum urate, disease duration, or use of urate-lowering therapy.

Conclusion: Polyarticular sonography frequently identifies synovial effusion, synovial hypertrophy, synovitis and double contour sign in patients with gout, particularly at the metatarsophalangeal joints and knees.