injuries poisoning
Ankle Fractures
Diagnosis of Ankle Fractures
X-rays Sometimes stress x-rays and/or MRI Ankle x-rays are taken in anteroposterior, lateral, and oblique (mortise) views. Specific criteria (eg, Ottawa ankle rules) are often used to avoid x-rays in patients unlikely to have a fracture. Based on the Ottawa ankle rules, ankle x-ray is required only if patients have ankle pain and one of the following: Age>55 Inability to bear weight without assistance immediately after the injury and in the emergency department (for 4 steps), with or without limping Bone tenderness within 6 cm of the posterior edge or tip of either malleolus Ankle fractures are usually evident on x-rays. In this lateral view, a fracture of the distal fibula is visible as a small lucency and discontinuity (step-off) of the cortex. DR P. MARAZZI/SCIENCE PHOTO LIBRARY This lateral view of the ankle shows a fracture of the distal fibula. GUSTOIMAGES/SCIENCE PHOTO LIBRARY This ankle fracture involves the medial malleolus (of the tibia) and lateral malleolus (of the fibula). SCIENCE PHOTO LIBRARY This ankle fracture affects the lateral malleolus but spares the medial malleolus. LIVING ART ENTERPRISES, LLC/SCIENCE PHOTO LIBRARY The proximal fibula may be fractured (called a Maisonneuve fracture—shown here), when the medial malleolus is fractured, the ankle mortise (the joint between the tibia and the talus) is open, and the distal fibula is not fractured. EDWARD KINSMAN/SCIENCE PHOTO LIBRARY This x-ray shows a disruption (widening) of the medial mortise joint (blue arrow). Normally, the space of the mortise joint should be symmetric around the talus. With a concomitant proximal fibular fracture, this is known as a Maisonneuve fracture. Image courtesy of Danielle Campagne, MD. This x-ray shows a proximal fibula fracture. With a concomitant disruption (widening) of the medial mortise joint, this is known as a Maisonneuve fracture. Image courtesy of Danielle Campagne, MD. Determining stability helps guide treatment. Instability may be obvious when the ankle is inspected or gently palpated. The knee, particularly the proximal fibula, should also be examined to look for a concomitant Maisonneuve fracture. Peroneal nerve function should be tested in patients with a Maisonneuve fracture by asking the patient to dorsiflex at the ankle. If both the medial and lateral malleoli are fractured, the injury is probably unstable. If only the fibula is fractured and the tibiotalar joint appears normal, an external rotation stress x-ray can be done; it may detect tibiotalar subluxation, which suggests deltoid ligament and thus ankle joint instability. If the medial malleolus is fractured, particularly if it is displaced and the mortise is open on the medial side, take knee x-rays to look for an associated fracture of the proximal fibula (Maisonneuve fracture). If a proximal fibula fracture seems possible, x-rays of the knee should also be taken. 