Objectives The objective of our study was to search the ultrasonography afflictions metacarpophalangeal and metatarsophalangeal joints notably ultrasonography synovitis, the intra articular liquid accumulations, the cartilaginous vascularisation, bone erosion and to compare them with the clinical aspects (pain, swolling, limitations of mobility).

Methods It was a transversal study from January 2012 to August 2012 comprising the cases of JIA ( children followed on rheumatology consultation or those hospitalised at Hospital El Ayachi CHU Rabat – Salé and the Hospital of child’s CHU Ibn Sina Morocco ) corresponding to the criteria of ILAR 2001. Consent was obtained from the children and/or their parents. All the patients were clinically examined by two seniors rheumatologists, to look for pain, synovitis, articular limitations. Linear sound echography ( 14 MHz ) with doppler power, was used. Bilateral echography of the MCP ( 2 à 5 ) and of all the MTP done on blind clinical data, less than 72h after clinical evaluation with longitudinal, transverse exploration by the dorsal route. Ultrasound examination was performed by a senior sonagrapher rheumatologist. The OMERACT criteria were utilised for evaluating the ultrasonograhy synovitis ; the other ultrasonography signs looked for were : intra-articular liquid collection, cartilaginous vascularization, bone erosion. The software Excel and Epi info were employed ; ( chi 2 ) was used as test statistic, with α fixed at 5 %.

Results 34 cases of JIA were included, or a total of 612 joints. Mean age was 10,80 ±3,29. Sex ratio was 0,90 ( 18 girls for 16 boys ). The study found 11 cases ( 32,40% ) of systemic arthritis, 8 (23,50% ) poly- articular seronegative, 2 ( 5,90 % ) poly articular seropositive, 8 ( 23,50%) oligo articular, 5 (14,70 % ) enthesitic forms. Pathological clinical examination for 33 ( 5,4 % ) articulations, with a total number of painful articulations at 31 ( 94% ) ; synovitic articulations at 4 ( 12 % ) ; limited articulations at 2 ( 6% ). Number of joints ultrasound abnormalities at 184 ( 30% ) ; total number of ultrasonography synovitis at 110 ( 18 %) ; total number bone erosions 17 ( 3 % ). Clinical examination normal was statistically significantly associated with ultrasound abnormalities in 159 (27 %), with the most frequent localization at MTP joints in 86 ( 54% ) mainly MTP1 40 ( 25% ) p<0,001. Ultrasound examination normal was statistically significantly associated with clinical examination abnormalitie in 10(30%) with the most frequent localization at MTP in 8 (80%) mainly MTP2 3 ( 30%) p< 0,001. Presence subclinical synovitis for 73 ( 66 %) p< 0,001.

Conclusions Our study detected subclinical synovitis ; this study suggest that ultrasound is a joint supplement clinical examination and should be performed in a systematic way to evaluate the activity of the disease.

Disclosure of Interest None Declared