In order to prevent permanent disability, a proper diagnosis of the fixed posterior fracture dislocation of the fibula with fracture dislocation of the ankle joint must be made. Full-length (knee to ankle) radiographs are necessary to make this diagnosis. Although a closed reduction has been described as successful, we feel that an open reduction is usually necessary. Freeing of the trapped fibula from behind the tibia results in a satisfactory reduction of this fracture dislocation. The reduction and fixation of the malleolar fragment is then simple, and an excellent result can be expected.