It has been reported recently that the detection of synovitis by ultrasonography was more sensitive than clinical examination (Wakefield et al. Ann Rheum Dis).

An OMERACT and EULAR working party recently produced guidelines on the best way to record and score quantitatively synovitis of the small joints of the hands and feet (Wakefield R, D'Agostino MA).

It has also been presumed recently that ultrasonography was more sensitive to changes than clinical examination after anti-TNF treatment (Ref. Taylor et al). If this better sensitivity to change were to be confirmed, ultrasonography would be preferred to clinical examination in studies evaluating new treatments.

In everyday practice, better intrinsic validity of the evaluation of synovitis by ultrasonography would lead to widespread use of this technique in the diagnosis and treatment of rheumatoid arthritis patients.

Objective of this study is to compare the sensitivity to change in synovitis score according to the monitoring method used (clinical examination versus ultrasonography).

This is a multicenter, (10 French centers and 1 Belgian center), prospective (4-month patients' follow-up) interventional study in 120 patients with rheumatoid arthritis justifying anti-TNF treatment.

The overall duration of the study will be 8 months composed of a 4-month inclusion period and a 4-month follow-up period for each patient. Moreover, X-ray evaluations of hands and feet will be performed 2 years from the beginning of the study in order to assess the changes in structural damage.

During the patients' participation, 6 visits are planned: an inclusion visit then, a follow-up visit at 1, 2 and 3 months from the inclusion visit, and a final evaluation visit at 4 months from the inclusion visit. At each visit, synovitis will be evaluated using both methods: clinical examination and ultrasonography. For a same patient, clinical evaluation of synovitis will have to be performed - during the entire study - by the same rheumatologist and the ultrasonographic evaluation will have to be performed by the same ultrasonographist (different from the rheumatologist) and always using the same ultrasonograph.

Finally, patients will be performed anterior X-rays of hands and feet two years from the beginning of the study whatever the ongoing RA treatment.

Inclusion Criteria:

• Patients with rheumatoid arthritis meeting ACR criteria.
• Justifying anti-TNF alpha treatment (switch or first administration).
• To have at least 6 synovitis at the clinical examination necessary for the DAS evaluation
• To accept to participate in this study (informed consent signed).

Exclusion Criteria:

• Minor patients.
• Pregnancy.
• Breastfeeding.