P035 Hip involvement in Tunisian Juvenile Idiopathic Arthritis patients

Abstract Background Juvenile idiopathic arthritis (JIA) is characterized by a widely variable clinical course and outcome. If uncontrolled, joint damage may occur. In this context, coxitis is a feared complication. The aim of our study was to determine the prevalence and patterns of hip involvement in Tunisian JIA patients. Methods A retrospective study including children with JIA according to the International League of Associations for Rheumatology (ILAR)) was conducted between 2012and 2021. Sociodemographic data as well as disease characteristics were collected. Laboratory markers including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were recorded. Hip involvement was assessed clinical exam and imaging (standard radiograph, ultrasound or magnetic resonance imaging (MRI)). We compared these parameters between the two groups: G1: presence of coxitis and G2: absence of coxitis. Results The study included 40 patients with a male predominance: sex ratio was 1.6. The mean age was 11.1 years-old [3–16]. The mean age at onset of the disease was 18.1 years old [8–30]. The distribution of the different subsets was as follows: polyarticular with rheumatoid factor (n = 1), polyarticular without rheumatoid factor (n = 2), enthesitis-related arthritis (n = 29), oligoarthritis (n = 7), psoriatic arthritis (n = 1). Extra-articular manifestations were found in 21.2% of cases: ocular (n = 4), pulmonary (n = 2) and cardiovascular (n = 1). The mean ESR and CRP was 30.9 mm/h [2–90] and 15.8 mg/l [1–70] respectively. A high ESR or CRP were found in 67% of cases. Hip involvement concerned 70% of the patients and was bilateral in 67.9% of them. Hip radiographs were normal in 50% of cases. Ultrasound was performed in 9 patients and revealed a positive Doppler synovitis (n = 2), a negative Doppler synovitis (n = 7) and joint effusion (n = 2). MRI was performed in 20% of cases and revealed synovitis (67%) and joint effusion (33%). Overall, 79.3% of patients had medical treatment combining NSAIDs and rehabilitation, 39% of the patients had had local infiltration with Hexatrione and only two patients had hip replacement. Hip involvement was not correlated with age at onset (P = 0.2), subtype (P = 0.8), sex (P = 0.7), extraarticular manifestations (P = 0.4). Similarly, there was no correlation between the presence of coxitis and ESR (P = 0.07) as well as CRP (P = 0.5). Conclusion Our study showed that hip involvement is frequent among Tunisian patients with JIA. Although not correlated with disease characteristics, hip involvement should be assessed frequently and carefully.