May also be called: Pott's Fracture A bimalleolar (bi-MAL-ee-uh-lur) fracture is a type of broken ankle that happens when parts of both the tibia and fibula called the malleoli are fractured. More to Know The bony knobs on the inside and outside of the ankle are called the malleoli, which is the plural form of malleolus. The knob on the inside, the medial malleolus, is part of the tibia, or shinbone. The knob on the outside, the lateral malleolus, is part of the fibula, the smaller bone in the lower leg. The prefix "bi" means "two," so a bimalleolar fracture is one that involves both the medial malleolus and the lateral malleolus. This type of fracture often happens as a result of the foot and ankle rolling inward, but it can also be caused by a trip or fall, or by a direct blow to the ankle. Bimalleolar fractures can cause severe pain, swelling, and bruising in the injured ankle. They also can be tender to the touch and make walking or putting any weight on the affected foot very difficult and painful. Bimalleolar fractures make the ankle unstable and typically require surgery to implant metal plates, screws, and rods to keep the bones aligned. Following surgery, the ankle is usually put in a short leg cast. In general, it takes at least 6 weeks for the broken malleoli to heal. Keep in Mind A bimalleolar fracture usually requires someone to keep weight off the affected foot for a few weeks, but in most cases, people return to normal daily activities within 3 to 4 months. Stretching and strengthening exercises supervised by a doctor or physical therapist can help improve ankle function and mobility during the healing process. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Bones, Muscles, and Joints Our bones, muscles, and joints form our musculoskeletal system and enable us to do everyday physical activities. Read More Bones, Muscles, and Joints Without bones, muscles, and joints, we couldn't stand, walk, run, or even sit. The musculoskeletal system supports our bodies, protects our organs from injury, and enables movement. Read More Broken Bones Many kids will have a broken bone at some point. Here's what to expect. Read More Broken Bones Bones are tough stuff - but even tough stuff can break. Find out what happens when a bone fractures. Read More Casts This article for teens has tips on taking care of a cast so it keeps working as it should. Read More Casts Some injuries will heal best if a cast is used. Find out how they work and how to take care of them in this article for kids. Read More Broken Bones What happens when you break a bone? Read More Ankle Sprains A sprained ankle is a very common injury that happens when the ligaments that support the ankle get overly stretched or torn. Find out how to avoid ankle sprains and what to do if you get one. Read More X-Ray Exam: Ankle An ankle X-ray can help find the cause of symptoms such as pain, tenderness, and swelling, or deformity of the ankle joint. It can also detect broken bones or a dislocated joint. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.