Efficacy evaluation: The efficacy endpoint is improvement in pain on a pain VAS at different times of assessment (primary endpoint at W6). A more than 50% improvement, in comparison with baseline, will be considered to be significant. Secondary endpoints are: number of tender joints, number of swollen joints, morning stiffness, global assessment of handicap by patient, global assessment of handicap by physician, the DREISER'S algofunctional index, Cochin hand index, weekly evolution of pain ( patient record), and recording of analgesic use (acetaminophen or NSAIDs).