The Types and Symptoms of Ankle Fractures

Treatment depends on which bones of the ankle are broken

Fractured ankle
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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. Understanding what to do about a broken ankle requires some information about how these injuries occur.

The Bones of the Ankle Joint

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 percent is carried by the tibia. The fibula is the smaller bone on the outside of the leg. It only carries about 10 percent 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.

Stable and Unstable Ankle Fractures

The most important aspect of ankle fracture treatment is understanding how the talus moves in relation to the ends of the tibia and fibula.

Fractures of the ankle are either stable (they 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, a more invasive treatment is needed.

Types of Broken Ankles

When a broken ankle occurs, the injury may be to the end of the tibia (the medial malleolus) or to the fibula (the lateral malleolus), or both.

Determining how to proceed with treatment depends on where the injury has occurred. There are many types of ankle fractures, here are the most common:

  • Lateral Malleolus Fractures (fibula only): 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 or the ligaments are damaged, then surgery is likely to be recommended. One clue to look for to determine if the fibula fracture may require surgery is the distance of the fracture to the end of the bone. Fibula fractures within 4 centimeters of the end of the bone are generally safe to treat nonsurgically, as long as there is no injury on the inner side of the ankle (see below).
  • Medial Malleolus Fractures (tibia only): This fracture of the inner side of the ankle occurs to the bone on the end of the tibia; that part of the bone is called the medial malleolus. An isolated medial malleolus fracture is much less common than an isolated lateral malleolus fracture. In general, a displaced (out of position) medial malleolus fracture is treated with surgery.
  • Bimalleolar Ankle Fractures (both tibia and fibula): Bimalleolar ankle fractures occur when there is an injury to both the inner and the outer side of the ankle. These injuries always result in an unstable ankle joint, and in most active patients, surgery will be recommended. If the fracture heals in anything less than a perfect position, the ankle joint alignment will be affected and could lead to accelerated arthritis of the ankle. Even with surgical treatment, ankle cartilage can be damaged at the time of the fracture leading to a higher chance of arthritis, but you should aim to do as much as possible to repair these fractures properly to keep the chance of long-term problems as low as possible.
  • Bimalleolar Equivalent Fracture (fibula and ligaments): This injury is only a fracture of the fibula, but there is 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.
  • Trimalleolar Fracture (both tibia and fibula): A trimalleolar ankle fracture is essentially the same as a bimalleolar ankle fracture, but the bone in the back of the tibia is also fractured. The bone in the back of the tibia is called the posterior malleolus. Sometimes, if a large enough fragment of bone is fractured, the surgery must also address that fragment. However, most commonly, the surgery is no different than for a bimalleolar ankle fracture.​
  • Posterior Malleolus Fracture (tibia only): This is a rare injury in isolation. Fractures of the posterior malleolus are generally found in association with bimalleolar ankle fractures—in which case the injury is called a trimalleolar ankle fracture.
  • Maisonneuve Fracture (tibia and fibula): A Maisonneuve fracture is a less common injury, but needs to be considered as can easily be missed without a thorough examination. In the Maisonneuve fracture, the bone is injured on the inner side of the ankle (the medial malleolus). While the lateral malleolus is intact, there is a fracture much higher up on the fibula bone, typically around the knee. The force of this injury passes through the large ligament that connects the two leg bones, called the syndesmosis. Because of the damage to this supporting ligament, the ankle is unstable and surgery is most often necessary.

Symptoms of a Broken Ankle

Common symptoms of an ankle fracture include:

  • Pain to touch
  • Swelling
  • Bruising
  • Inability to walk on the leg
  • Deformity around the ankle

There are clinical criteria used to differentiate ankle fractures from ankle sprains. These guidelines, called the Ottawa criteria help to determine if x-rays should be done in people who have ankle pain.

Treatment of a Broken Ankle

Once an ankle fracture is diagnosed, it is important to begin appropriate treatment. There are many treatments, both surgical and nonsurgical, and the right treatment depends on having the correct diagnosis. Your surgeon can guide you on treatment specifics.

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