To identify joints commonly exhibiting bone erosions using an extended 36-joint sonographic (US) examination in patients with rheumatoid arthritis (RA) and to study bone erosion in relation to US-detected joint inflammation.
In this cross-sectional study, power Doppler (PD) and gray-scale (GS) joint inflammation scores (semi-quantitative [0-3] grading) at each joint recess were summed to obtain a combined US score (CUS). Bone erosion was scored as present/absent. Generalized Estimating Equations were used to compare mean US scores between joint recesses with and without bone erosion.
Bone erosion was found in 144/1080 (13.3%) joints and 189/1800 (10.5%) joint recesses in 30 RA patients. The five joints most frequently associated with bone erosion were: wrist, n = 49/144 (34.0%); first MTPJ, n = 19/144 (13.2%); thumb IPJ, n = 13/144 (9.0%); second MCPJ, n = 11/144 (7.6%); and third MCPJ, n = 11/144 (7.6%). Mean (95% CI) US scores for joint recesses with and without bone erosion were PD: 0.36 (0.21, 0.50) vs 0.01 (0.00, 0.02); GS: 1.77 (1.54, 2.00) vs 0.47 (0.40, 0.55); and CUS: 2.13 (1.78, 2.47) vs 0.49 (0.41, 0.57) (all differences significant at P < .001).
The five joints most frequently showing bone erosion were identified. Joint recesses with bone erosion are more likely to exhibit greater PD and GS joint inflammation severity.