A complete dislocation, simple or compound, at the tibiotalar joint without a fracture is extremely rare.1 A lesion of this type when it does occur is usually compound. The ligaments about the ankle are usually stronger than the malleoli, and for this reason a fracture of one or both of the malleoli usually accompanies such an injury, since the bone in most instances breaks before the ligaments will rupture.
Böhler2 states that a lateral dislocation of the ankle without a fracture of one or both of the malleoli is possible only when the joint between the tibia and the fibula is broken. In the case reported here a separation did not occur at the tibiofibular joint, as shown by roentgenograms and by open inspection of the joint.
Complete dislocations of the ankle joint are classified as follows, according to their order of frequency: (a) posterior, (b) anterior, (c) external lateral
Conwell HE, Alldredge RH. COMPLETE COMPOUND DISLOCATION (INTERNAL LATERAL) OF THE ANKLE JOINT WITHOUT FRACTURE, WITH PRIMARY HEALING. JAMA. 1937;108(24):2035-2036. doi:10.1001/jama.1937.92780240002008a