Is painless synovitis different from painful synovitis? A controlled, ultrasound, radiographic, clinical trial

OBJECTIVE This study compares the clinical, ultrasonography, radiography, and laboratory outcomes of painless and painful chronic synovitis in patients with established rheumatoid arthritis. METHODS This cross-sectional study involved 60 patients with rheumatoid arthritis and synovitis in the metacarpophalangeal joints; 30 of the patients did not experience pain, and 30 had experienced pain for at least 6 months prior to the study. The radiocarpal, distal radioulnar, and metacarpophalangeal joints were evaluated using the ultrasound gray scale, power Doppler, and radiography. Past and present clinical and laboratory findings were also evaluated. RESULTS There were no statistically significant differences between the groups for most of the outcomes. The group with pain scored worse on the disease activity indices (e.g., DAS 28 and SDAI), function questionnaires (HAQ and Cochin), and pinch strength test. A logistic regression analysis revealed that the use of an immunobiological agent was associated with a 3-fold greater chance of belonging to the group that experienced pain. The painless group had worse erosion scores in the second and fifth metacarpophalangeal with odd ratios (ORs) of 6.5 and 3.5, respectively. The painless group had more cartilage with grade 4 damage in the third metacarpophalangeal. CONCLUSIONS The rheumatoid arthritis patients with both painless and painful synovitis exhibited similar disease histories and radiographic and ultrasound findings. However, the ultrasonography evaluation revealed worse scores in the second and fifth metacarpophalangeal of the synovitis patients who did not experience pain.