Avulsion fractures of the medial and lateral malleoli of the ankle in cadavers: new radiographic projections for improved diagnosis.

The malleolar attachment sites of the tibionavicular (TN), tibiocalcaneal (TC), posterior tibiotalar (PTT), anterior talofibular (ATF), and calcaneofibular (CF) ligaments of 3 cadaveric ankles were dissected. Standard and new radiographic projections of the ankle were obtained with the foot in different positions and various degrees of beam angulation. Simulated avulsion injuries related to these ligaments were created, and the visibility of these structures was assessed. Avulsion injuries of the TN ligament were better assessed in the plantar-flexed radiographs with lateral beam angulation. Standard projections were found to adequately depict avulsion fractures related to the TC and CF ligaments. Radiographs in external ankle rotation were best for evaluating injuries of the PTT ligament. Avulsion injuries related to the ATF ligament were best visualized in the plantar-flexed views with medial beam angulation. Modified radiographic projections of the ankle improve visualization of ligamentous structures of the malleoli and avulsion injuries related to those.