Anatomy of the Ankle
- Tibia – the shin bone. The tibia at the ankle has two parts: the medial malleolus (inside) and the posterior malleolus (back).
- Fibula – the small bone on the outside of the ankle. The end of the fibula is referred to as the lateral malleolus.
- Talus – a foot bone
- Calcaneus – heel bone
In turn, the ankle is made up of 3 separate joints:
- Talocrural Joint: This is a hinge joint formed by the ends of the fibula and tibia that enclose the upper surface of the talus.
- Inferior tibiofibular Joint: This is the joint between the lower surfaces of the tibia and fibula.
- Subtalar Joint: This joint comprises of the articulating surfaces of the talus and the calcaneus.
Types of Ankle Fractures
There are a wide range of ankle fractures, and they can happen to people of all ages.
Distal fibula fracture – this is the most common type of ankle fracture, and involves only the end of the fibula. The ligaments on the medial side may be torn as well. These fractures are usually stable and can be treated non-operatively unless there is significant displacement of the bone or there is complete tearing of the medial ligaments causing instability. Sometimes special stress or gravity X-rays may be taken to determine if the fracture is stable.
Bimalleolar fracture – these fractures are more severe and often require surgical intervention. These fractures involve both the distal fibula (lateral malleolus) and the medial malleolus of the tibia. They are generally unstable and need plates and screws to hold the bones in place.
Trimalleolar fractures – these fractures are the most severe and can often be associated with a complete ankle dislocation. They involve all three malleoli – lateral, medial, and posterior. These almost always require plates and screws to secure the bones.
Pediatric ankle fractures – children often have different patterns of ankle fracture since their growth plates are still open and are weaker than the surrounding bone. The most common is a fracture through the growth plate of the distal fibula. This may not be obvious on X-ray if there is no displacement and may be difficult to differentiate from an ankle sprain – diagnosis and treatment is often based on clinical exam. The Tillaux fracture and the triplane fracture are examples of more unstable pediatric fractures that usually require surgical attention.
There are numerous causes of ankle fractures. Some examples include:
- Twisting or rotating the ankle
- Rolling the ankle
- Impact, such as from a car accident
Common symptoms of a broken ankle include:
- Severe and immediate pain
- Inability to bear weight on the injured leg
- Obvious dislocation
Generally your physician will perform a physical exam and order x-rays of the leg, foot, and ankle to determine the extent of the injury. A CT scan or MRI may also be ordered to provide further evaluation and assess the ligaments.
Treatment of ankle fractures will depend on several factors, including whether or not the bone is displaced, where the bone is broken, and whether or not the patient has other significant health problems.
If the fracture is not out of place and the ankle is stable, surgery may not be necessary. Surgery may also be undesirable if the patient has other major health problems and the risk of complications is too great. Typically the patient will be put into an immobilizer such as a brace or cast and the physician will restrict the patient from bearing weight on the injured leg. The doctor will regularly examine and x-ray the patient to monitor the healing process.
Without surgery, there is a risk that the fracture will form a malunion, in which the bones move out of place and heal improperly. Malunion can increase the risk of arthritis.
Ankle fractures that are unstable may require surgical fixation. The goal of surgical treatment is to restore the normal anatomy of the ankle joint to minimize the risk of future arthritis. The most common fixation method is placing a plate and screws on the distal fibula to stabilize the fracture. Fractures of the medial malleolus are often treated with screws alone, but occasionally wires or plates are used as well. In severe fractures where the ligaments between the tibia and fibula have been disrupted as well, screws or devices with strong suture may be used to hold the bones together to allow the ligaments to heal.
Some of the risks of surgery are:
- Blood clots
- Pain from the plates and/or screws used to fix the fracture
- Damage to nerves, tendons, or blood vessels
- Malunion, where the bones heal in an incorrect position
People who smoke, have diabetes, or are elderly are at a higher risk for complications after surgery. It may take longer for the bones to heal in these patients.
Rehab following an ankle fracture depends on the type of fracture, severity, and amount of instability of the fracture. There is generally a period of non-weight bearing followed by incremental return to full weight bearing. A splint, cast, or walking boot is generally used during the initial phase to help stabilize the ankle. Typically, 6-12 weeks are needed before a return to unrestricted weight bearing is allowed. It may take 3-6 months to return to sporting activity after surgical fixation of an ankle fracture.
Physical therapy is often used to regain flexibility and strength after surgical repair of an ankle fracture. The timing and duration of therapy will vary based on the individual and the severity of the fracture.
- How long will I have to be off work after an ankle fracture?
This depends on both the severity of your fracture and the type of job that you have. People with a sit-down job and a non-operative ankle fracture can often return to work in a cast or walking boot after several days. Heavy laborers with a severe fracture that requires operative fixation could be off as long as 4-6 months.
- Will I develop arthritis after my ankle fracture?
This depends on several factors, including the severity of the fracture and individual factors such as weight. There are varying degrees of damage to the cartilage of the ankle joint with fractures that enter the joint. The most important factor is getting the bones to heal back in their anatomic position, which sometimes requires surgical fixation.
If you have more questions, please call my office at 502-394-6341.