Ankle Fracture

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The ankle is a ring — a mortise formed by the lower ends of the tibia and fibula cradling the talus, the small bone of the hindfoot that sits between them. Like any ring, the ankle can tolerate a single break and still hold its shape, but once it is broken in two places the structure loses its ability to keep the talus centered, and the joint surfaces begin to slide out of alignment under load. Ankle fractures typically result from a twisting mechanism — rolling the foot inward or outward during a misstep off a curb or an athletic pivot — and the direction the foot twisted at the moment of injury dictates exactly where the bone breaks.

The decisive question in any ankle fracture is not simply whether a bone is broken, but whether the ring is stable: can the ankle hold the talus in position while it heals, or will the joint drift under body weight? Stability drives the decision between a boot and surgery far more than how dramatic the X-ray looks. A single break that leaves the mortise intact usually heals in a boot; a break that disrupts the ring in two places almost always needs to be fixed in the operating room to restore alignment.

Ottawa Ankle Rules guide X-ray ordering. AP, lateral, and mortise views characterize the fracture pattern. CT is added for complex pilon fractures, posterior malleolus involvement, or preoperative planning. Gravity stress view or external rotation stress X-ray assesses mortise stability in isolated fibula fractures.

Any mortise instability, bimalleolar equivalents, and fractures with talar shift require surgical fixation to restore joint congruity.

External patient-education references and related OSI pages for additional background:

• Britannica — Bone disease (fractures)
• Britannica — Ankle (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language