Ankle fractures are common injuries to the bones around the ankle joint. There are many types of ankle fractures, and treatments vary significantly depending on the location and severity of the injury.

The ankle is a complex joint that forms where three bones come together. The bones of the lower leg, the tibia and the fibula, are above the joint, and the talus is below the joint. When a doctor talks about an ankle fracture, he or she is usually talking about a broken bone of the tibia or fibula.

The tibia, also called the shin bone, is the larger, weight-bearing bone of the lower leg. Of the weight transferred through the leg, about 90% is carried by the tibia. The fibula is the smaller bone on the outside of the leg. It only carries about 10% of your body weight.
Both the tibia and the fibula wrap around the talus to form the ankle joint. The bony prominences at the ankle are called the medial malleolus (the end of the tibia) and the lateral malleolus (the end of the fibula). The ends of these bones form a cup-shape that the talus bone sits within. Fractures of the ankle are either stable (the movement of the talus is unchanged) or unstable (the talus does not move in a normal manner). This means that the joint is not held in a symmetric position–when the ankle fracture is unstable, more invasive treatment is needed.
Signs and symptoms of ankle injuries and fractures tend to be obvious. Pain is the most common complaint. Often the pain will not come from the exact area of the fracture. The person may experience associated fractures of the foot (especially on the side of the small toe) or knee that also cause pain similar to ankle pain. It is usually pain in the ankle that stops individuals from walking. Swelling frequently occurs around the ankle. ◦Swelling suggests either soft tissue damage with possible blood around the joint or fluid within the joint itself, most likely blood. ◦When blood is in the joint, it is called hemarthrosis. A person may see bruising around the joint, although not immediately. The bruising can track down toward the sole of the foot or toward the toes. In severe fractures, there may be obvious deformities of bones around the ankle. Skin may be stretched over an underlying broken bone.

The main concern is whether there is a broken bone. Frequently it is difficult to distinguish a fracture (broken bone) over a sprain, dislocation, or tendon injury without X-rays of the ankle.

On X-rays, there can be a fracture of the medial malleolus, the lateral malleolus, or of the anterior/posterior margin of the distal tibia. If both the lateral and medial malleoli are broken, this is called a bimalleolar fracture . If the posterior malleolus is also fractured, this is called a trimalleolar fracture.

Treatment of ankle fractures is dictated by the stability of the ankle joint. Certain fracture patterns are deemed stable, and may be treated similar to ankle sprains. All other types require surgery, most often an open reduction and internal fixation (ORIF), which is usually performed with permanently implanted metal hardware that holds the bones in place while the natural healing process occurs. A cast or splint will be required to immobilize the ankle following surgery.

Fractures of the fibula alone are the most common type of ankle fracture. Most fibular fractures can be treated without surgery, but it is important to ensure the ankle joint remains stable. This means that even though there is a break in the bone, the ankle joint still functions normally. If the ankle joint is unstable, then surgery is likely to be recommended.

Medial malleolus fractures are relatively uncommon. In general, a displaced (out of position) medial malleolus fracture is treated with surgery.

Bimallelolar ankle fractures occur when there is injury to both the inner and the outer side of the ankle. These inuries always result in an unstable ankle joint, and in most active patients, surgery will be recommended. One important point is that sometimes an injury called a bimalleolar-equivalent fracture can occur–this means there is only a fracture of the fibula, but also a tear of the ligaments on the inner side of the ankle. This leads to instability of the ankle joint, just as if the inner side were fractured, and therefore requires surgery.