Objective: To describe the ultrasonographic (US) findings in the hips of patients with juvenile idiopathic arthritis (JIA) and the association between these findings and the signs, symptoms, and activity of the disease.
Materials and methods: The present retrospective study included 92 patients with JIA. The disease subtypes, age at disease onset, length of disease progression, disease activity, and clinical manifestations of the hip pathology were assessed. US examinations were routinely performed, and the images were analysed by two ultrasonographers who were blinded to the patients' clinical conditions.
Results: Of the 92 patients included in the study, 69.6% were girls, and the average age was 12.4 ± 5.1 years. Thirty-three (35.9%) participants exhibited the persistent oligoarticular subtype, and 30 (32.6%) exhibited the rheumatoid factor (RF)-negative polyarticular subtype. Forty-four participants exhibited signs and/or symptoms of hip pathology. Twenty-nine (31.5%) participants exhibited abnormal US findings, and 34.4% exhibited subclinical synovitis. The US alterations exhibited an association with subclinical synovitis in 34.4% of the cases. The US alterations bore a correlation with the presence of hip-related signs and/ or symptoms (P = 0.021), particularly joint limitations (P = 0.006), but were not correlated with the disease activity (P = 0.948) or subtype (P = 0.108). Clinical synovitis was associated with polyarticular involvement (P = 0.002) and disease activity (P = 0.017). Subclinical synovitis was not correlated with the investigated variables.
Conclusion: Clinical affection of the hip in JIA, particularly joint limitation, is associated with synovitis (revealed by US assessment) independently of the activity and subtype of the disease. Therefore, healthcare professionals should consider the possible occurrence of silent disease and subclinical synovitis, which might contribute to hip deterioration.