An open fracture is usually an “in-out” injury in which the fractured bone penetrates through the soft tissue and skin, increasing the risk of contamination from skin bacteria. Conversely, the opposite mechanism can occur: an “out-in” injury is when a foreign body penetrates into the wound, thus increasing the risk of infection. With out-in injuries, the wound can become contaminated with materials such as debris, wood, or metal (e.g., from a gunshot). In a war situation or with acts of terrorism, injuries with foreign bodies are reported, especially with shrapnel. Military personnel who deal with improvised explosive devices and suicide bombers are particularly vulnerable to out-in injuries.