Calcaneus (Heel Bone) Fractures
A fracture of the calcaneus, or heel bone, can be a painful and disabling injury. This type of fracture commonly occurs during a high-energy event—such as a car crash or a fall from a ladder—when the heel is crushed under the weight of the body. When this occurs, the heel can widen, shorten, and become deformed.
Calcaneus fractures can be quite severe. Treatment often involves surgery to reconstruct the normal anatomy of the heel and restore mobility so that patients can return to normal activity. But even with appropriate treatment, some fractures may result in long-term complications, such as pain, swelling, loss of motion, and arthritis.
The bones of the feet are commonly divided into three parts: the hindfoot, midfoot, and forefoot. Seven bones — called tarsals — make up the hindfoot and midfoot. The calcaneus (heel bone) is the largest of the tarsal bones in the foot. It lies at the back of the foot (hindfoot) below the three bones that make up the ankle joint. These three bones are the:
- Tibia — shinbone
- Fibula—smaller bone in the lower leg
- Talus—small foot bone that works as a hinge between the tibia and the fibula
Together, the calcaneus and the talus form the subtalar joint. The subtalar joint allows side-to-side movement of the hindfoot and is especially important for balance on uneven surfaces.
Normal foot anatomy. Together, the calcaneus (heel bone) and talus form the subtalar joint, which moves the foot side to side in walking.
Calcaneus fractures are uncommon. Fractures of the tarsal bones account for only about 2% of all adult fractures and only half of tarsal fractures are calcaneus fractures.
A fracture may cause the heel bone to widen and shorten. In some cases, a fracture may also enter the subtalar joint in the foot. When this occurs, damage to the articular cartilage covering the joint may cause long-term complications such as chronic pain, arthritis, and loss of motion.
The severity of a calcaneus injury depends on several factors, including:
- The number of fractures
- The amount and size of the broken bone fragments
- The amount each piece is out of place (displaced) — In some cases, the broken ends of bones line up almost correctly; in more severe fractures, there may be a large gap between the broken pieces, or the fragments may overlap each other
- The injury to the cartilage surfaces in the subtalar joint
- The injury to surrounding soft tissues, such as muscle, tendons, and skin
When the bone breaks and fragments stick out through the skin or if a wound penetrates down to the bone, the fracture is called an "open" fracture. An open fracture often causes more damage to the surrounding muscles, tendons, and ligaments and takes a longer time to heal. Open fractures have a higher risk for infection in both the wound and the bone. Immediate treatment to clean the wound is required to prevent infection.
The calcaneus is most often fractured during a:
- Fall from a height
- Twisting injury to the ankle
- Motor vehicle collision
The severity of a fracture can vary. For example, a simple twist of the ankle may result in a single crack in the bone. The force of a head-on car collision, however, may result in the bone being shattered (comminuted fracture).
Similar fractures can result from different mechanisms. For example, if you land on your feet from a fall, your body's weight is directed downward. This drives the talus bone directly into the calcaneus. In a motor vehicle crash, the calcaneus is driven up against the talus if the heel is crushed against the floorboard. In both cases, the fracture patterns are similar. As a rule, the greater the impact, the more the calcaneus is damaged.
In a high-energy fracture, other injuries, such as fractures of the spine, hip, or other heel, can occur.
(Left) In some injuries, the talus is forced downward and acts like a wedge to fracture the calcaneus. (Right) This computerized reconstruction of a calcaneus fracture shows the amount of damage that can occur.