The tibia (shin bone) and the fibula are the bones of the lower leg. Pilon fractures are injuries that occur at the lower end of the tibia and involve the weightbearing surface of the ankle joint. The fibula also may be broken. These injuries were first described more than 100 years ago and remain one of the most challenging problems for orthopaedic surgeons to treat. Common causes of pilon fractures are falls from a height and car accidents.