What force typically causes a supracondylar fracture?

A supracondylar fracture of the humerus is most commonly associated with a hyperextension force, particularly in pediatric patients. This type of fracture typically occurs when a child falls onto an outstretched hand, causing the elbow to extend beyond its normal range of motion. The mechanism of injury often involves the application of force directly to the elbow while the arm is positioned in extension, leading to fracture at the distal humerus above the condyles.

Hyperextension forces lead to the typical presentation of this injury, as they create stresses on the bone that exceed its tensile strength, causing it to fracture. The classic position of the arm at the time of injury—outstretched—plays a crucial role in the occurrence of this fracture type.

In contrast, other mechanisms such as rotational forces or hyperflexion forces tend to lead to different types of injuries, often involving the shoulder or other areas of the arm, while direct trauma is more likely to result in fractures at the site of impact rather than the more specific supracondylar location.