MAGNETIC-RESONANCE-IMAGING OF INJURY TO THE LATERAL ANKLE LIGAMENTS

To establish the value of magnetic resonance imaging in determining wh ich patients with ankle sprains will benefit from surgical treatment, 1 uninjured volunteer and 15 patients with acute, subacute, and chroni c injuries of the lateral ankle ligaments were imaged at 1.0 tesla usi ng a fast imaging with steady-state precision three-dimensional techni que and 1.5-mm slice thickness. A dedicated knee coil was used to hold the foot in a neutral or plantar-flexed position. In cases of acute, low-grade injuries, fraying of the anterior talofibular ligaments with intact calcaneofibular ligaments was observed in the presence of edem a and hemorrhagic fluid. In cases of acute, high-grade sprains, the ca lcaneofibular ligament appeared wavy or was visualized only partially or not at all. Subacute injuries showed ligament disruption; chronic l esions, on occasion, showed atrophy of the calcaneofibular ligament bu t no edema or hemorrhagic fluid. These findings showed a good qualitat ive correlation with the results of graded stress radiography. Magneti c resonance imaging can definitely determine the ligaments involved in lateral ankle sprains and provide useful anatomic information in case s in which acute or reconstructive surgery is contemplated. However, t he magnetic resonance imaging findings do not directly correlate with degree of instability and do not replace those of physical examination or routine radiographic studies.