Radiological approach to a child with hip pain.

Hip pain in a child can be a diagnostic challenge partly because of barriers to communication in the paediatric age group. Pain or limp may result from infective, inflammatory, traumatic, neoplastic, or developmental causes. A meticulous history and detailed clinical examination guide the radiological investigation in the appropriate direction. The age of the child further helps to narrow the differential as certain diseases are more common in certain age groups. In most patients plain radiograph and/or ultrasound is adequate. Ultrasound has the added advantage of being real time and can be used to guide aspiration. Magnetic resonance imaging (MRI) and bone scintigraphy can be used for problem solving, looking for multifocal disease, and staging. Computed tomography (CT) has a limited role to play because of the risks associated with ionizing radiation. In this review we discuss the approach to imaging a child who presents with pain in the hip or with a limp. The various common and rare, but important, diseases are illustrated with examples from our clinical practice.