A pilon fracture is a type of break that occurs at the bottom of the tibia (shinbone) and involves the weight-bearing surface of the ankle joint. With this type of injury, the other bone in the lower leg, the fibula, is frequently broken as well. A pilon fracture typically occurs as the result of a high-energy event, such as a car collision or fall from height. Pilon is the French word for "pestle"—an instrument used for crushing or pounding. In many pilon fractures, the bone may be crushed or split into several pieces due to the high-energy impact that caused the injury. In most cases, surgery is needed to restore the damaged bone to its normal position. Because of the energy required to cause a pilon fracture, patients may have other injuries that require treatment as well. Pilon fractures vary. The tibia may break in one place or shatter into multiple pieces. The severity of the injury depends on several factors, including: The number of fractures, The amount and size of the broken bone fragments, The amount each piece is out of place (displaced)—In some cases, the broken ends of bones line up almost correctly; in more severe fractures, there may be a large gap between the broken pieces, or the fragments may overlap each other. The injury to the surrounding soft tissues, such as muscle, tendons, and skin. If the bone breaks in such a way that bone fragments stick out through the skin or a wound penetrates down to the broken bone, the fracture is called an "open" or compound fracture. This type of fracture is particularly serious because, once the skin is broken, infection can occur in both the wound and the bone.