The role of sonography in detecting radial head subluxation in a child.

Injuries around the elbow joint in children can be difficult to diagnose on the basis of findings on physical examination and radiographs. We present the case of a 4-year-old girl with a probable subluxation of the radial head, based on the findings on physical examination and radiographs. Radiography raised the possibility of a radial head subluxation. Sonography demonstrated displacement of the cartilaginous head of the radius away from the capitellum in the affected elbow. The child underwent corrective surgery. During fluoroscopy, results of an ulnar stress test were positive for lateral ligament tears. The patient's arm was put in a cast for 6 weeks. At 1-year follow-up, the patient had full range of motion of the elbow without pain. We present the findings of sonographic studies used to confirm the diagnosis.