Lateral Malleolus Fracture

Injury to the Distal Fibula of the Ankle

aircast ankle
An aircast is often used for treatment of a lateral malleolus fracture. Spike Mafford / Getty Images

The lateral malleolus is the name given to the bone on the outside of the ankle joint. The lateral malleolus is the end of the fibula bone of the leg. There are two long bones of the leg: the tibia (shin bone) and the fibula. The tibia carries the vast majority of the weight of the body (about 90%), with the fibula holding only about 10% of body weight.

Fractures of the lateral malleolus are the most common type of ankle fracture.

These injuries typically occur when the ankle is either twisted or rolled, often with an awkward or uneven step. The good news is that most lateral malleolus fractures are considered stable ankle fractures, and can be treated without surgery.

Symptoms of Lateral Malleolus Fractures

Lateral malleolus fractures cause pain, swelling, and bruising around the ankle.  Pain in other areas of the foot and ankle should be reason to suspect a more serious ankle injury than an isolated lateral malleolus fracture.

Pain and swelling on the inner side of the ankle (along with a lateral malleolus fracture) may indicate the possibility of an injury called bimalleolar equivalent fracture--a specific type of unstable ankle fracture that may require surgery. Anyone with a lateral malleolus fracture should be examined for signs of a more serious, unstable ankle fracture.

An unstable ankle fracture is an injury that occurs when the fracture causes the ankle joint to not work properly.

  Therefore, if the bone heals in a position where the ankle is not functioning properly, the ankle is likely to develop early ankle arthritis.  The good news is that isolated lateral malleolus fractures are almost always stable ankle fractures, and therefore do not have this problem.

Treatment of Lateral Malleolus Fractures

Treatment of a stable lateral malleolus fracture should consist of efforts to reduce swelling following by a gradual progression in weight-bearing.

  • Ice Application: Ice application is helpful at reducing pain and minimizing swelling.
  • Elevation: Elevation is important to keep swelling limited. Be sure your ankle is above your heart (in order to do this, you have to lie down, you can't do it sitting!).
  • Anti-Inflammatory Medications: Nonsteroidal anti-inflammatory medications (including Motrin and Aleve) are helpful at controlling both swelling and pain.
  • Rest/Immobilization: While stable ankle fracture can support your weight, it helps to limit weight-bearing to help control pain and swelling. Usually a week or two with crutches will control these symptoms.

When progressing weight bearing, many studies have been done to assess how much protection of the ankle is best. Some doctors use walking casts, walking boots, aircasts, ankle braces, or even high top shoes (hiking boots). The bottom line is that no difference has been found when comparing these different types of ankle support. Whatever gives you support and comfort should work equally well.

Would Surgery Be Better

The clear answer is that surgery is a worse option for stable lateral malleolus fractures. The reason is that non-surgical treatment has been shown to be just as effective for treatment of the broken bone.

In addition, surgery has a chance of both infection and healing problems (about 2%) and these can cause significant problems. People who have has surgery for fibula fractures have more chronic swelling around their ankle. Lastly, when people do have metal implants around the ankle, they may choose to have the metal removed down the road.  This would require a second surgical procedure, when the first wasn't necessary.  So if surgery is not recommended, it is probably best for you!


Michelson JD "Ankle Fractures Resulting From Rotational Injuries" J Am Acad Orthop Surg November/December 2003; 11:403-412.

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