Pulled elbow in childhood.

In this injury, a sudden pull on the pronated, extended arm of a child up to 5 years of age is followed by refusal to use the arm. After a simple flexion, supination and extension manoeuvre the child starts using the arm in minutes. Radiographs are said to be normal. At least 13 theories of the mechanism have been advanced. Anterior subluxation of the radial head has never been proved radiographically or experimentally. Available evidence favours momentary distraction of the radiocapitellar joint in pronation which allows upward slip of the annular ligament upon the radial head at its shortest diameter and interposition of part of the anterior capsule between the two bones. Radiography is difficult, usually producing oblique views in pronation which are not easy to interpret. The main differential diagnosis is from epiphyseal rotation. In any doubtful case early repeat radiography is essential taking matched views of both elbows, even if non-standard. A collection of 28 radiographs has been analysed, two recent typical contrasting cases are presented, two signs to identify an oblique view of a normal elbow are described and the literature is reviewed. If the best radiograph available in an injured elbow in a child is a normal oblique view in pronation, pulled elbow is a likely diagnosis.