BackgroundMusculoskeletal Ultrasonography (MSUS) is an important tool for the clinical assessment in Juvenile Idiopathic Arthritis (JIA). The objective of this study was to evaluate the reliability of MSUS to detect elementary lesions: synovitis, tenosynovitis, cartilage damage and bone erosions in the wrist and metacarpal (MCP) joints of patients with JIA.MethodsThirty children in various subgroups of JIA according to ILAR criteria, were included in this cross-sectional study. Clinical data including painful, swollen and limited joints were recorded. Five rheumatologist ultrasonographers, blinded to the clinical evaluation, evaluated the presence of elementary lesions in the wrist and MCP 2 and 3 joints bilaterally. The synovitis was graded in B-Mode and Power Doppler (PD). In addition to descriptive statistics intra- and inter-observer reliability was calculated using Cohen’s kappa according to Landis and Koch.ResultsUS detected more synovitis than the clinical examination (62% vs 28%, 30% vs 23% and 22% vs 17% in the wrist, second and third MCP joints respectively). The intra-observer concordance for synovitis in all joints was excellent in B-Mode (k 0.84 .63–1.0 p = 0.001), except for MCP 2, where it was good (0.61, IC 95% .34–89, p = 0.001). For both modalities (PD, B-Mode) tenosynovitis, cartilage damage and bone erosions it was also excellent. Regarding synovitis grading the concordance was excellent for all grades (0.83–1.0, IC 95% 0.51.1.0, p = 0.001), except for grade 1 where it was good (0.61, IC 95% 0.43–.83, p = 0.001). Reliability inter-observer for grayscale synovitis (0.67–0.95, IC 95% 0.67–1.0, p = 0.001), tenosynovitis grayscale (0.89, IC 95% 0.78–0.99, p.001), damage cartilage (0.89, IC 95% 0.78–0.99, p = 0.001), PD (0.66, IC 95% 0.39–1.0, p = 0.001). The concordance for grading synovitis was excellent, but for grayscale grade 1 and 2 (.66, IC 95% .53–.74, p = 0.007) and PD grade 1 and 2 (0.63, IC 95% .58–.91, p = 004) was good.ConclusionsThe intra- and inter-observer reliability of MSUS for inflammatory and structural lesions is good to excellent for the wrist and MCP in patients with JIA.

BackgroundClinical evaluation has limitations to detect inflammation in JIA. Musculoskeletal ultrasonography (MSKUS) is a useful tool to detect inflammation in various arthropathies, but in children has not been validated for detection of elementary lesions such as synovitis [effusion (SE) and synovial hypertrophy (SH)], erosions, tenosynovitis (TNS) and cartilage damage.ObjectivesTo evaluate the reliability of MSKUS to detect carpal and metacarpal joint synovitis in patients with JIA.MethodsSeven patients with JIA diagnose according to ILAR criteria were included; they were evaluated by MSKUS for 5 ultrasonographers to evaluate synovitis, erosions, TNS and cartilage in the carpal joint, 2nd and 3rd metacarpophalangeal joints bilaterally; in 2 rounds in one day. Intra- and interobserver variability was established with Cohen's kappa, according to Landis and Koch classification.ResultsThe mean age of the children was 9 years old; disease duration of 5 years. The inter-observer DS, HS, TNS and erosions agreement was good to excellent (k=.88 0.5889–1.0 95%, p=0.0000) and moderate for cartilage (k=0.43, 95% CI 0.0545 to 0.8964, p=0). The intra-observer variability was good (0.71, IC95% from 0.591 to 0.8498, p=0.0000).ConclusionsThe US is reliable for assessing the presence of synovitis, tenosynovitis, erosion and cartilage in hands, in patients with JIA.Disclosure of InterestNone declared