This study reports on 18 cases of diaphyseal fractures of the tibia associated with ipsilateral but not contiguous ankle fractures. Thirteen of these complex fractures resulted from low-energy torsional forces, while five were caused by high-energy impact. Definitive treatment consisted solely of cast immobilization in four; 14 had operative stabilization of each fracture component. Of these 14, four patients were treated initially in long leg casts and one in a plaster splint, but each required surgical intervention to control fracture alignment. The average follow-up time was 21.2 months. In the nonoperative group of four patients, clinically significant shortening and/or rotational deformity were noted in three limbs, with ankle mobility decreased by > 50% and advanced posttraumatic arthritis evident in two ankles. Of the cases managed operatively, 10 (71%) had full structural and functional recovery, three patients regained only 75% of ankle mobility, and two patients developed slight valgus deformities, one with a concomitant rotational deformity of less than 10 degrees. These findings demonstrate the unstable nature of this complex fracture pattern and the advantages of operative management.