Radiographic clues to fractures of the unossified medial humeral condyle in young children.

A fracture involving the trochlear ossification center as well as the medial epicondyle is a more serious injury than simple avulsion of the medial epicondyle. This diagnosis may be difficult in young children before the secondary centers are ossified. Radiographic clues to this injury in a young child are localized soft tissue swelling over the medial aspect of the elbow accompanied by a metaphyseal flake and/or a positive fat pad sign. In the older child, separation of the ossified medial epicondyle with a positive fat pad sign suggests a more complex injury.