The purpose of this study is to evaluate the usefulness of computed tomography (CT) for spiral tibia shaft fracture by analyzing associated distal tibia intra-articular fractures diagnosed by CT only which met the indication of surgical fixation and were fixed.

Ninety-five spiral tibia shaft fractures with preoperative ankle plain radiographs and CT were analyzed retrospectively. The incidence and type of associated distal tibia articular fractures were evaluated by reviewing ankle plain radiography and CT. The number of fractures diagnosed by CT that correspond with the indication of fixation and that were actually fixed were analyzed.

Among 95 spiral tibia shaft fractures, 62 cases (65.3%) were associated with distal tibia intra-articular fracture. There were 37 cases of posterior malleolar fracture, 5 cases of avulsion fracture of the distal anterior tibiofibular ligament, 5 cases of medial malleolar fracture, and 15 cases of complex fracture. Among 52 posterior malleolar fractures including complex fracture, 20 cases were diagnosed by ankle plain radiograph. Of these 20 cases, 16 posterior malleolar fractures (80.0%) met the indication of surgical fixation, and 14 cases were actually fixed with a screw. Among 32 posterior malleolar fractures diagnosed by CT only, 26 cases (81.3%) met the indication of surgical fixation and 18 cases (56.3%) were fixed by screw.

Approximately 50% of associated fractures were diagnosed by CT only and more than 80% of associated posterior malleolar fractures met the indication of surgical fixation and among these fractures, 18 cases (56.3%) were actually fixed by screw. This result suggests that CT is useful in diagnosis and treatment of distal tibia intra-articular fracture associated with spiral tibia shaft fracture.