Improving detection of pediatric elbow fractures by understanding their mechanics.

Fractures around the elbow are among the most common fractures in children, but they can also be some of the most elusive to detect. Although elbow fractures result from a variety of stresses applied to the three bones constituting the elbow joint, hyperextension-rotation injuries with valgus or varus stress are the most common cause of elbow fractures. Less common are direct impact injuries to the posterior aspect of the elbow. Because all three bones and their articulations are morphologically different, the various traumatic forces applied result in distinctly different types of fractures in each of the bones. For example, hyperextension with vertical stress produces supracondylar fractures of the distal humerus, longitudinal linear ulnar fractures, and buckle fractures; hyperextension with valgus stress causes impaction fractions of the radial head and neck, transverse olecranon fractures, and medial epicondylar fractures, whereas varus stress produces Monteggia fractures, lateral condylar avulsion fractures, transverse olecranon fractures, and longitudinal linear ulnar fractures. Understanding these forces and their effects is important because it facilitates detection of the wide variety of fractures in their more subtle forms.