Ankle fractures are common injuries, and are seen in people of all ages. These fractures occur during sports injuries, as well during ankle sprains and twisting injuries in other situations. This fracture has many different forms, and can be a significant injury if not appropriately treated. The ankle is a very important joint, and injury to it can have a significant effect on the ability to move. The ankle is where the body translates motion of the leg onto the ground by connecting a vertical leg with the horizontal foot. There are three bones that make up the ankle joint. The top of the joint consists of the end of the shin bone, called the tibia. The tibia is a long, thick bone that forms a significant part of the top of the ankle joint. This bone is supported by the end of the smaller and thinner fibula bone, which forms the outer side of the top of the ankle joint. The bottom of the joint, also known as the dome of the ankle, is created by the saddle shaped talus bone in the foot. The talus forms much of the gliding surface of the ankle. Together, these three bones form a joint that allows the foot to bend up and down at the ankle, along with a lesser degree of rotation. There are strong bands of tissue called ligaments that bind the joint together, and keep it held in place. These ligaments consist of a very strong, roughly triangular shaped band on the inner side, and three weaker strips of tissue on the outer side of the ankle.
When a significant enough twisting force is placed on the foot, the ankle will bend. Bending can take place inward, with the foot rolling under the leg, or outward, with the foot rolling in the other direction. The more common rotation direction is inward. If the force of this rotation is stronger than the binding strength of the ligaments, they will tear. This is the essence of an ankle sprain. The tearing can be partial, or the ligaments can shear completely off. As this force increases, the bones will also crack under the pressure, or less commonly the tearing of the ligaments pulls off a piece of the bone it is attached to. Ankle fractures have several different mechanisms depending on how the foot rotates on the ankle during the injury. These fractures involve the tibia and the fibula, as a fracture of the talus is a completely different injury. The tibia and fibula can fracture independently or at the same time, and can be a simple chip all the way up to a spiral fracture that moves the bone out of place. The pattern of rotation and placement of the foot during the injury determines the pattern of the fracture, which bone will break, and the severity of the injury. Minor fractures may only involve a simple chip of the end of one of the bones or a straight crack across their width. In severe fractures, the bones can break in several different places, and the tibia can even shatter into multiple smaller pieces, making repair very difficult.
The main issue with ankle fractures beyond the cracking of the bones themselves is the movement of the ankle bones out of position. The ankle has to function perfectly in place, and any disruption of that movement leads to ankle instability and eventual arthritis. The key to repairing these fractures is to ensure that the ankle is in as close to a normal position as possible, and hold it there while the bone mends. Ankle fracture treatment can involve several techniques. Very minor chip fractures or ones that are stable only require a cast or walking boot to hold the bone in place during healing. Unfortunately, many fractures cannot be healed in this way and require surgery to obtain the best result. The goal of surgery is to bring the ankle bones back to a normal position, and then use hardware (usually a combination of metal plates and screws) to keep the bone stable. After surgery the ankle is protected exteriorly by a cast, and the bone will mend ideally in a normal position, lessening the likelihood of arthritis developing. This recovery can take place over the course of six weeks to three months depending on the severity of the fracture. Many factors can also influence the healing time, including bone density, smoking, the presence of diabetes, and even general health.