Ultrasound changes in synovial abnormalities induced by treatment in juvenile idiopathic arthritis

To investigate the capacity of ultrasound (US) to detect improvement of synovial abnormalities induced by treatment in juvenile idiopathic arthritis (JIA).

Eighty-three joints (33 knees, 22 tibiotalar, 10 wrists, 9 elbows, 9 subtalar joints) of 33 patients with new-onset JIA were assessed by US at study entry and 6 months after a therapeutic intervention. Each joint was scored for grey-scale (GS) and power Doppler (PD) abnormalities according to a 4-point semiquantitative scale. Pre- and post-treatment US scores were compared and the sensitivity to change of GSUS and PDUS was estimated. Clinical response was assessed using the ACR paediatric (ACRp) response criteria.

Seventeen patients (51.5%) underwent intra-articular corticosteroid injection (IACI) only, 15 (45.5%) were given IACI and systemic medications, and 1 (3.0%) was started with systemic therapy alone. Both GSUS and PDUS scores improved significantly (p<0.0001) from baseline to follow-up. US revealed strong sensitivity to change with standardised response mean for GSUS and PDUS of 2.44 and 1.23, respectively. At the follow-up visit, 13/20 (65.0%) joints with residual US abnormalities were judged in remission on clinical grounds. Six/21 (28.6%) patients who were ACRp90 responders did not display complete resolution of synovial abnormalities on US.

US is a sensitive tool to assess therapeutic response in patients with JIA. Subclinical disease on US is common in joints with clinically-defined remission. An ACRp90 response may not be coupled with complete resolution of synovial abnormalities on US. Further studies are needed to establish the impact of US on therapeutic decision-making in JIA.