Ultrasound-detected tenosynovitis in ankles with clinical arthritis and short-term outcome of patients with new-onset juvenile idiopathic arthritis.

OBJECTIVES: To determine features and frequency of ultrasound (US)-detected tenosynovitis in ankles with clinically active disease and to investigate whether its detection may affect the achievement of inactive disease in patients with new-onset juvenile idiopathic arthritis (JIA).

METHODS: The study included children with new-onset JIA and clinically active disease of the ankle. Based on US, patients were stratified as having isolated arthritis or as having tenosynovitis irrespective of the presence of concomitant arthritis in the ankle. Estimation of patients who were able to achieve clinically inactive disease 6 months after starting treatment was assessed by the Kaplan-Meier method. Cox model was used to calculate hazard ratio (HR) and 95% confidence interval (CI). Reliability of US was tested using kappa statistic.

RESULTS: Forty-five patients were recruited. On US, tenosynovitis of the ankle was detected in 28 patients (62.2%); isolated arthritis was found in 17 patients (37.8%). The medial and lateral tendon compartments were the tendon sites most frequently inflamed. Patients with tenosynovitis had similar likelihood of those without tenosynovitis to achieve clinically inactive disease (60.7% and 58.8%, respectively; HR 1.12, 95%CI:0.51-2.45). In the subanalysis excluding patients who were given biologics, the probability of experiencing inactive disease was slightly higher for patients with tenosynovitis compared to those without (64.7% and 54.5%, respectively; HR 1.56, 95%CI: 0.58-4.24). The rate of US reliability was high.

CONCLUSIONS: US-detected tenosynovitis is frequent in ankles with clinical arthritis at JIA onset but does not impair the chance of achieving clinically inactive disease in the early disease phase.