Ultrasound imaging for the rheumatologist. XXVIII. Impact of sonographic knee joint involvement in recent-onset inflammatory polyarthritis.

OBJECTIVES: To assess the impact of the knee joint inflammation, detected by ultrasonography (US), on functional disability in patients with recent-onset inflammatory polyarthritis (IP). METHODS: We included patients who had IP for less than 12 months and who had more than 5 swollen joints. All patients were assessed clinically at baseline. US was used to identify joint inflammation at multiple joint sites including: hands, wrists, elbows, shoulders, knees, ankles and feet. Joint group involvement was defined when at least one joint showed intra-articular signs of inflammation (synovial fluid abnormalities and/or synovial hypertrophy), according to the OMERACT definitions. Functional disability was measured using the health assessment questionnaire (HAQ) score. All patients with complete clinical and US data were included in the analysis. RESULTS: Patients with US knee involvement showed more active and severe disease at baseline. The mean difference of HAQ between patients with and without US knee inflammation was 0.42 (95%CI 0.22, 0.62; p