The risk of a child sustaining a fracture with a given amount of force is no different from adults. The pattern of injury that is sustained (buckle fractures, torus fractures, greenstick fractures) is different but a full history of mechanism of injury, height fallen, force sustained and degrees of rotation, etc, should always be ascertained, just as with adults.
The hallmark features for the presence of a fracture are the same as in adults. These include:
Swelling is often seen with sprains or simple soft tissue injuries and is not diagnostic. If in any real doubt as to the presence of fracture or not then x-ray should be obtained.