A fibula fracture occurs when there is an injury to the smaller of the two bones of the lower leg (the segment between the knee and ankle), the fibula.
The larger bone of the lower leg, the tibia, carries most of the body weight. The smaller bone, the fibula, is located on the outside of the leg.
The fibular bone starts just below the knee joint on the outside of the leg and extends all the way down to the ankle joint. The bone is a long, thin bone, hollow in its center. While the bone does little to support the weight of the body, it is a critical site of attachment for ligaments at both the knee and the ankle joint and is also connected to the tibia bone by a thick ligament called the syndesmosis.
While the fibula is an important bone, it is possible to excise much of the bone for surgical procedures where bone is needed elsewhere in the body.1 When these grafting procedures are performed, people are able to function very normally, despite missing a large part of the fibula bone.
Types of Fibula Fractures
There are a number of different types of injury to the fibula bone:2
Fibula fractures that result from injury to the ankle joint
Fibula fractures that occur in conjunction with tibia fractures
Stress fractures of the fibula
These are not the only types of injury that can occur to the fibula but account for the vast majority of injury to the fibula bone. By far the most common are injuries that occur when the ankle joint is damaged.3 Typically, the ankle buckles or is twisted and the fibula is damaged as part of the injury.
As mentioned, fibula fractures can occur in association with injuries to other bones, ligaments, and tendons around the knee and ankle.
The most common symptoms associated with the fibula fracture include:
Pain directly over the fibula bone (outside of the leg)
Swelling in the area of the fracture
Bruising over the site of the injury
Diagnosis of a fibular fracture can typically be made with an X-ray image.4 Other imaging studies such as MRI or CT scan are typically not necessary, but there are some situations where a fibular fracture may not show up on a regular X-ray. These situations include injuries such as stress fractures (described below). Your physician will examine the site of the injury, and also examine the knee and the ankle joints for associated injuries which may impact the treatment of the fibular fracture.
Fibula fractures typically occur as part of an ankle injury. Whenever a fibula fracture is found, the ankle joint should also be examined for possible injury.
The most common type of fracture to occur to the fibula bone is an isolated injury to the end of the fibula bone at the level of the ankle joint. These injuries occur in a similar manner to a badly sprained ankle,5 and often the injury can be treated similarly to a badly sprained ankle.
Ankle-Level Fibula Fracture Without Other Injury to the Ankle: Isolated fibular fractures, when the ankle joint is unaffected, often can be treated with simple protection. Known as a "lateral malleolus fracture," these injuries occur when the ankle twists or bends awkwardly and the inner (medial) side of the ankle is unaffected.
In these situations, a brace is sufficient to support the ankle.6 Crutches are often used for a few days or weeks to allow swelling and pain to subside. Once the pain has lessened, patients begin rehabilitation to resume mobility exercises, strengthening, and walking.
Fibula Fracture With Associated Ankle Injury: Fibula fractures that are associated with injury to the inner side of the ankle, the medial malleolus or deltoid ligament, often require more aggressive treatment. In these situations, called "bimalleolar ankle fractures," surgery is usually necessary to stabilize the ankle joint. Without surgery, the ankle joint often heals in abnormal alignment, leading to the development of ankle arthritis.
Another type of injury that can occur with a fibular fracture is damage to the syndesmosis of the ankle. The syndesmosis is the group of ligaments that hold the two bones of the leg together, just above the ankle joint. When the syndesmosis is damaged at the ankle, an injury that can occur along with a fibula fracture, surgery is often required to restore the alignment of the bones.
Fibular fractures with ankle injuries will usually require surgery to correct.
Fibula and Tibial Shaft Fractures
Severe injuries resulting from car crashes, sports injuries,7 or falls may lead to an injury of both the tibia and the fibula above the ankle joint. These injuries, often referred to as "tib-fib" fractures, typically require surgery to support the alignment of the leg.
When the tibia is surgically repaired, the fibula does not normally require a separate surgery to align this bone. In some tib-fib fractures, a long-leg cast (thigh to foot) will provide necessary support without requiring the surgery.
Stress Fractures of the Fibula
In some people, particularly long-distance runners8 or hikers, the fibula may be injured as a result of repetitive stress. This type of injury is known as a stress fracture. The pain of a stress fracture may begin gradually. Usually, the pain worsens with increasing levels of activity and is relieved by rest.
Could You Have a Stress Fracture?
How a fibula fracture is treated depends on a number of factors, including where the fracture is located and if other injuries have occurred in association with the fracture. Surgery may be recommended, but usually, a splint or cast is given to help prevent movement.9 If possible, your doctor can realign your broken bones without open surgery as well.
While isolated fibula fractures usually heal quickly, more complex injuries may require further treatment. That's why it's of critical importance that a medical professional familiar with the treatment of fibula fractures evaluate your injury and ensure that appropriate treatment is recommended.
Because only a small amount of body weight is transmitted through the fibula (most weight is transmitted through the larger tibia bone) many types of fibula fractures can be treated nonsurgically. However, as described, fibula fractures that occur in association with other fractures or ligament injuries often do require more invasive treatment.
Surgery on the Fibula: The most common way to repair a fractured fibula bone is with a metal plate and screws.10
Typically the plate is applied to the outside of the bone, with at least three screws above the location of the fracture, and at least three screws below. Sometimes if the fracture is close to the end of the bone, there may not be room for three screws on both sides of the fracture, but usually, these will fit.
When reviewing an operative report from the time of surgery, your surgeon will dictate the method in which they repaired the broken fibula, as well as any other treatment needed. The diagnosis of a fibula fracture is recorded as ICD-10 code S82. Any modifying codes can designate fracture side, mechanism, and other characteristics.
Complications: Common complications associated with surgery for treatment of a fibula fracture are related to the incision and the underlying hardware.11 Because there is very little soft tissue between the skin and the bone, wound healing problems, infection, and painful hardware are by far the most common surgical complications. Wound healing complications are most worrisome in people who have underlying conditions such as diabetes which may inhibit wound healing. Smokers are also at increased risk of wound complications.11 Infection can occur after any surgical procedure, but again are most common in people who have conditions that may impair immune defenses. Lastly, pain associated with implanted hardware is not uncommon. Some people may choose to have surgical plates and screws removed after the fracture has healed.
A Word From Verywell
Have an open conversation with your doctor about the best solution for your fracture. You may be nervous if more invasive treatments are required. Ask if they're truly the best option and confirm that alternatives would not be helpful. Remember that ultimately, the procedure is meant to heal your injured fibula.
Once healed, make sure to ask your doctor for prevention and safety tips to reduce your risk of further injury, particularly if your injury resulted from an activity. It may be frustrating to wait until you're better to continue doing what you love, but it's well worth it.
In general, you can reduce your risk of a fibula fracture by working to maintain your bone mass. Some factors such as age and gender are out of your control, but others such as quitting smoking and practicing sports safety can help.