Ankle Anatomy: The 8 Different Types of Ankle Breaks You Can Sustain
Updated: Aug 21, 2021
While we don’t always think about it, our ability to stand in the morning, walk to the car, run in sports, jump over obstacles, and pivot at a moment’s notice, is all thanks to our ankles. Composed of 4 bones, and 2 joints, our ankles are susceptible to all kinds of breaks from trips, missteps, falls, heavy impacts, sports, and automobile accidents. If not treated properly, the fracture can lead to long-term complications such as reduced range of motion and mobility. With broken ankles being so common, here is what you need to know about the types of breaks that can happen.
Myth: The Ankle’s Anatomy Is Not One Single Joint
Before we jump right into the breaks you can experience, it is important to understand the anatomy of the ankle and how it joins together. While ankles are often referred to as a single joint, it is actually made up of 2.
1. Joint One - The True Ankle Joint. This is an ankle joint that you know as your ankle. It is made up of 3 different bones that work together to form the inside, outside, and heel portions of your ankle. The bones are:
l The tibia is what you know as your shinbone. This is the larger and longer bone in your leg that runs all the way down your leg to form the inside part of your ankle.
l The fibula is what you know to be your calf bone. It runs along the lateral side of the tibia and serves as the main way for your muscles to attach in the leg. This bone runs all the way down your leg and forms the outside part of the ankle.
l The talus bone(s) is a grouping of very small bones that form the tarsus, which is what shapes the lower portion of your ankle joint. It runs between the tibia and fibula, and the calcaneus, which is your heel bone.
2. Joint Two - The Subtalar Joint. This joint is found at the meeting point between the talus and the calcaneus in your ankle. It is a “gliding” joint which allows you to tilt the sole of your foot either away from or towards your body.
If the talus bone moves during the ankle fracture, it means that the joint is no longer in a symmetrical position, causing the ankle to be unstable. When this happens, invasive surgery is often needed to both address the fracture and stabilize the joint as a whole. If the talus bone does not move, you have a stable fracture.
8 Types of Ankle Fractures You Can Experience
The type of treatment you get for your ankle break is dependent on the location of the fracture.
1. A Lateral Malleolus Fracture. This is a fibula-only fracture that occurs at the bottom portion of the fibula. It is a fracture of that “bony” knob on the outside portion of your ankle, which is called the lateral malleolus. This is an extremely common type of ankle break and permitting that the talus is stable and your ligaments are undamaged, then no surgery is needed. If the talus bone is unstable or ligaments are damaged, surgery is needed to repair these conditions.
2. A Medial Malleolus Fracture. This is a tibia-only fracture that occurs at the end of the tibia. It is a fracture of the “bony” knob portion of the inside of your ankle which is called the medial malleolus. Unfortunately, an isolated fracture of this kind is quite rare and so it almost always needs surgery to fix because the lining of the bone folds into the fracture site at the time of the injury. When this lining folds inward, the bone cannot heal properly on its own.
3. A Bimalleolar Ankle Fracture. This is a tibia and fibula-based fracture, where you sustain a break to both the inner and outer “knobs” of your ankles. This almost always results in an unstable fracture, requiring surgery to fix, as the ankle joint alignment is almost always affected. This type of fracture must be repaired properly to forego arthritis and long-term complications with walking, running, jumping, and so on.
4. A Bimalleolar Equivalent Fracture. This is a fracture of the fibula accompanied by a tear in the inner side ankle ligaments. The ankle joint with this injury is unstable, therefore, requires surgery to fix.
5. Posterior Malleolus Fracture. This is a tibia-only fracture that is rather rare to experience as an isolated fracture. Essentially, this is a fracture of the back of the tibia bone at the level of the ankle joint. It is much more likely to see this type of fracture with a lateral malleolus fracture as the tibia and fibula share ligament attachments. You may also see this with a bimalleolar or a trimalleolar ankle fracture.
6. Trimalleolar Fracture. This type of fracture is similar to a bimalleolar ankle fracture in that both the tibia and fibula are broken, but the posterior malleolus is also broken. The posterior malleolus is the bone in the back of the tibia. This means that your medial (inner tibia knob), lateral (outer fibula knob) and posterior (back of tibia) are all broken, requiring surgery.
7. A Pilon or Plafond Fracture. This type of fracture is often a result of a high-impact injury caused by something like an automobile accident or heavy fall from great heights. This fracture is found in the “roof” of the ankle, found at the end of the tibia. With this kind of break, your talus is almost always damaged, the cartilage that covers the talus is damaged, and the fibula becomes fractured. Surgery is required and arthritis is a common side effect.
8. Maisonneuve Fracture. If you have the unfortunate experience of falling while rotating, it can cause your foot to hit the ground at an awkward angle, causing a fracture in the upper part of the fibula near the knee. This is also accompanied by an ankle sprain and is experienced by individuals who ski, dance, or do gymnastics.
A final type of fracture that gets an honorable mention because it’s not classified as an ankle fracture specifically, is a syndesmotic injury. There is a grouping of ligaments that bind your distal tibia and your fibula together (syndesmosis), which are prone to becoming sprained (syndesmotic injury). However, during extreme external rotations or dorsiflexion of the talus bone, you can easily fracture the lower part of your ankle joint.