POS1333 ANKLE ARTHRITIS IN JUVENILE IDIOPATHIC ARTHRITIS: DON’T MISS TENOSYNOVITIS. CLINICAL AND SONOGRAPHIC FEATURES OF ANKLE TENOSYNOVITIS IN JIA
Authors: S. Pastore, S. Della Paolera, A. Zabotti, A. Tommasini, A. Taddio
Journal: Annals of the Rheumatic Diseases (2021)

Background: Tenosynovitis can occur in patients with Juvenile Idiopathic Arthritis (JIA) and may be clinically difficult to distinguish from joint synovitis. The role of musculoskeletal ultrasound (msk-US) is still discussed in the management of JIA but recent studies supported the utility of msk-US especially in detection of tenosynovitis. There is no consensus treatment for tenosynovitis in children with JIA and almost all studies focused on tendon sheath injection with glucocorticoids. Objectives: The aims of the study were: i) to define the prevalence of tenosynovitis of the ankle in JIA patients and ankle swelling; ii) to describe the clinical characteristics of patient with tenosynovitis and to analyze different response to treatment. Methods: We conducted an observational cross-sectional study of a group of patients with JIA followed at the Rheumatology Service of the Maternal and Child Institute “Burlo Garofolo” of Trieste. We enrolled all the patients who reported a swelling of the ankle at least once during the follow-up period and, among these patients, we included only those who underwent msk-US. Based on both clinical and sonographic examination, we identified patients with tenosynovitis and we described their demographical and clinical characteristics as well as the therapeutic approach undertaken in this group of patients. Results: On December 31st 2019, 56 swollen ankles of 48 patients were assessed with msk-US: 22 ankles showed sonographic signs of synovitis (39%), 16 ankles of both synovitis and tenosynovitis (28%), 14 ankles of tenosynovitis only (25%). Overall, tenosynovitis was detected on twenty-seven (56%) out of 48 children with at least a swollen ankle. The majority of patient were females (70%) and the most affected tendon was the tibialis posterior (66%). Twenty-five patients with tenosynovitis (92%) achieved clinical and radiological remission: seven out of 26 patients (26%) treated with methotrexate achieved clinical and radiological remission without the addition of other therapies; fifteen out of seventeen patients (88%) treated with a biological drug responded to the therapy, of which eleven (73%) were in combination therapy with methotrexate. Conclusion: We observed that more than 50% of the patients with a swelling of the ankle presented a tenosynovitis and among these patients about 50% did not show sonographic sign of synovitis. Msk-US was decisive in order to identify tenosynovitis and to characterize ankle swelling in JIA patients. Among patients with tenosynovitis biological therapy alone or in association with immunomodulating therapy showed effectiveness in inducing disease remission. References: [1]Peters SE, Laxer RM et al. Ultrasound-guided steroid tendon sheath injections in juvenile idiopathic arthritis: a 10-year single-center retrospective study. Pediatr Rheumatol Online J. 2017 Apr 11;15(1):22. [2]Lanni S, Bovis F et al. Delineating the Application of Ultrasound in Detecting Synovial Abnormalities of the Subtalar Joint in Juvenile Idiopathic Arthritis. Arthritis Care Res (Hoboken). 2016 Sep;68(9):1346-53. [3]Cimaz R, Giani T et al. What is the real role of ultrasound in the management of juvenile idiopathic arthritis? Ann Rheum Dis. 2020 Apr;79(4):437-439. doi: 10.1136/annrheumdis-2019-216358 [4]Lanni S, Marafon DP et al. Comparison between clinical and ultrasound assessment of the ankle region in juvenile idiopathic arthritis. Arthritis Care Res (Hoboken). 2020 Apr 27. [5]Laurell L, Court-Payen M et al. Ultrasonography and color Doppler in juvenile idiopathic arthritis: diagnosis and follow-up of ultrasound-guided steroid injection in the ankle region. A descriptive interventional study. Pediatr Rheumatol Online J. 2011 Jan 29;9(1):4. Disclosure of Interests: None declared