Introduction: The diagnosis of juvenile idiopathic arthritis (JIA) is formally based on clinical examination, but ultrasound (US) examination is used increasingly. Our purpose was to compare US and clinical examination in the assessment of synovitis in JIA.
Material and methods: This study was retrospective and included 62 consecutive patients with newly diagnosed JIA admitted to the Department of Paediatrics at Gentofte Hospital, Denmark from 2003 to 2010. The included patients were examined clinically and by US at their first visit. All peripheral joints were examined clinically, 24% of these joints were examined by US. The development of new, clinically arthritic joints was followed during the next six months.
Results: The mean sensitivity of clinical examination was 48% with a clear hierarchy among joints, knees having the highest sensitivity, small joints of hands and feet the lowest. On average, 0.4 joints per child, which were arthritic by clinical examination, were negative by US. Inversely, US detected 1.3 more arthritic joints than clinical examination did per child. The latter is a minimum estimate since only 24% of the joints were examined by US. Subclinically arthritic joints had a 29% probability of developing clinical arthritis within the first six months following the initial examination.
Conclusion: Although there is no formal validation of US examination in children suspected for JIA, we recommend that it is used routinely and performed by a highly experienced US operator.
Funding: not relevant.
Trial registration: not relevant.