P077 Ultrasound features of a traumatic hip pain in paediatric population

Abstract Background Atraumatic hip pain in children is a serious condition that may require urgent investigations. Conventional radiographs are often normal in early stage of the diseases. However, further imaging techniques such as hip ultrasonography (US) are needed. The main objective of this study is to describe Hip ultrasound findings in patients with atraumatic hip pain. Methods We conduct a retrospective monocentric study. Children with atraumatic hip pain and undergoing joint ultrasound were included. Sociodemographic, clinical and biological characteristics were collected. The data were analyzed using the SPSS statistical package. Results: Thirty patients (21 boys and 9 girls) were enrolled. The male to female sex ratio was 2.3. Mean age at disease onset was 9.1 ± 4.6 [1.3–16]. Median diagnosis delay from symptoms onset was 1.2 months [0.2–48]. Chief complaints were as following: 80% of inflammatory hip pain (n = 24), 20% of mechanical hip pain (n = 6) 76.7% of limping (n = 23), 23.3% of functional impotence (n = 7) and 23.3% of fever (n = 7). Physical examination noted a pain on passive joint mobilization and restriction of hip movement in 90% (n = 27) and 54% (n = 18) of cases respectively. A biologic inflammatory syndrome was found in 66.6% of cases (n = 20). Median ESR and CRP were 30 mm/h [2–101] and 4.5 mg/l [1–38] respectively. Hip X-ray was abnormal in 46.6% (n = 14) of cases. All patients had hip ultrasound. US findings were as following: 80% (n = 24) of joint effusion, 50% (n = 15) of synovial thickening, 36.7% (n = 11) of synovitis and 23.3% (n = 7) of positive power Doppler signal. Hip Ultrasound was normal in 13.3% (n = 4) of cases. Causes of hip pain were in decreasing order of frequency: septic arthritis (n = 10), juvenile idiopathic arthritis (n = 10), transient synovitis (n = 7), osteoid osteoma (n = 2) and osteosarcoma (n = 1). Conclusion Hip Ultrasonography is a noninvasive and useful screening technique for the management of atraumatic hip pain in children. Though, imaging features are often various and nonspecific. Radiologists should be more familiar with sonographic anatomy of infant hip.