To evaluate the role of ultrasonographic indices (Color Fraction and Resistive Index) in assessing the effect of intra-articular steroid (IAS) injection on synovial inflammation in knee joints of Juvenile Idiopathic Arthritis (JIA) patients and to determine the correlation between these ultrasonographic indices and clinical and laboratory parameters in JIA patients after IAS.
Twenty seven patients of JIA and equal number of age and sex matched healthy controls were enrolled. Thirty six knee joints were injected with IAS. Duration of morning stiffness, swelling score, tenderness score, range of motion, visual analogue scale for pain, Physician global assessment of disease activity, Patient/Parent assessment of general well being, Juvenile Arthritis Disease Activity Score, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), synovial thickness, synovial effusion, Color fraction (CF) and Resistive index (RI) were measured at base line and at one and two months of follow-up.
At baseline, a significant difference was found in ESR, CRP, CF and RI values between cases and controls. A significant decrease in various clinical, core set variables and ultrasonographic parameters was observed at each follow-up. Synovial thickness, synovial effusion and CF decreased by 51.78%, 64.67% and 49.35% respectively and range of motion and RI increased by 166% and 31.94% respectively at second follow-up. Both CF and RI showed a significant correlation with active joint count. Both CF and RI had a high inter and intra-class correlation.
Power Color Doppler and Spectral Doppler ultrasonographic indices (CF and RI) may have a role in assessment of the response to IAS injection of inflamed knee joints.