Ultrasonographic Assessment for Tenosynovitis in Juvenile Idiopathic Arthritis with Ankle Involvement: Diagnostic and Therapeutic Significance

Background: The role of musculoskeletal ultrasound in JIA is still controversial, although there is growing evidence on its utility, especially in the diagnosis of tenosynovitis. Methods: We presented a retrospective cross-sectional study of a group of patients with JIA with ankle swelling followed in a Pediatric Rheumatology Service of a tertiary-level pediatric hospital in Northern Italy during the follow-up period between January 1st 2003 and December 31st 2019. Preliminary results have been presented at the EULAR Congress 2021. We enrolled only patients who underwent msk-US, and we identified those with a clinical and sonographic diagnosis of tenosynovitis. For each patient, we collected data on demographics, clinical characteristics, and therapeutic strategies during the follow-up. Results: On December 31st 2019, 56 swollen ankles of 48 patients were assessed with msk-US. Twenty-two ankles showed sonographic signs of joint synovitis, sixteen ankles presented signs of both joint synovitis and tenosynovitis, and fourteen ankles presented sonographic signs of tenosynovitis only. Overall, tenosynovitis was detected on 27 (56%) out of 48 children with at least a swollen ankle. In 13 patients out of 27 with tenosynovitis (48%), there was no joint synovitis of ankle or foot. Twenty-five patients with tenosynovitis (92%) achieved clinical and radiological remission: seven patients achieved remission of tenosynovitis with methotrexate only, and fifteen patients with biological drugs alone or in combination therapy. Conclusions: We observed that more than half of the patients with ankle swelling presented a tenosynovitis, and about 50% of them did not show sonographic signs of an active joint synovitis. Among patients with tenosynovitis, biological therapy alone or in association with DMARDs showed effectiveness in inducing disease remission.