• Ultrasonography
• Rheumatoid Arthritis
• Corticosteroids

Intra-articular corticosteroid injections are widely used to treat rheumatoid arthritis (RA).1 Although they are useful in combination with other antirheumatic agents, some side effects have been reported including subcutaneous atrophy, septic arthritis, avascular necrosis, and rarely, periarticular calcification.2–4 We report here two RA cases that presented with periarticular calcification.

Case 1. A 51-year-old woman suffering from RA for 6 years was treated with methotrexate 16 mg weekly, abatacept 500 mg monthly and triamcinolone acetonide injection on the radial side of the right third proximal interphalangeal (PIP) joint approximately once a month (22 times for the third PIP joint in total). While disease activity scores for 28 joints maintained low disease activity, a hand radiograph showed progressive periarticular calcifications on the injected radial side (figure 1A–C). Joint ultrasonography revealed hyperechoic regions in the joint cavity with posterior power Doppler (PD) signals (figure 2A). Spectral Doppler sonography was performed to evaluate the nature of the PD signals, and an artefactual spectral signal without any definable flow pattern was observed (figure 2B). This finding was obviously different from the true RA synovitis finding detected on her right first metacarpophalangeal joint (figure 2C). …