[Acute ankle injuries].

The diagnosis of lateral collateral ankle ligament trauma is based on patient history, clinical examination, and clinical stress tests. If the clinical stress test is positive, stress radiography could be performed. There is no consensus about the usefulness of stress radiography in acute ankle sprain, particularly about the cut-off talar tilt angle beyond which a two-ligament rupture would be certain, ranging from 5 degrees to 30 degrees. Today MRI is not used for this indication, although it allows, with controlled positioning of the foot and with defined sections, visualization of injured lateral collateral ankle ligaments. In ankle injuries, plain radiographs form the established basis of diagnostic imaging and can provide definitive answers in most cases. CT is used in complex fractures for complete visualization. MRI is the method of choice for several diagnostic problem cases, including occult fractures and post-traumatic avascular necrosis. In tendon injuries, MRI is important if ultrasound is not diagnostic. Generally, for the evaluation of acute ankle injuries, MRI is the most important second-step procedure when radiographs are nondiagnostic.