Results of a computed tomography protocol evaluating distal third tibial shaft fractures to assess noncontiguous malleolar fractures.

BACKGROUND: Intra-articular tibia fractures are reported to occur in 1% to 25% of tibia diaphyseal fractures. The objective of this study was to create a standard protocol to evaluate noncontiguous malleolar fractures associated with distal third tibial diaphyseal fractures using computed tomography (CT).

METHODS: Sixty-six patients with 67 distal third tibia fractures were treated at a level one trauma center from December 2005 to November 2007. These patients were then evaluated using a CT protocol to assess the ankle joint. There were 45 men and 21 women with average age of 44 years (range 18-69 years). All films were independently examined by two orthopedic traumatologists and one musculoskeletal radiologist.

RESULTS: Twenty-nine of 67 (43%) distal third tibial shaft fractures had associated intra-articular fractures determined by CT scan. There were 23 posterior malleolus fractures, 3 anterolateral fragments, and 3 medial malleolus fractures. Twenty-seven of 29 fractures (93%) were associated with spiral type fracture patterns (p = 0.001). Seventeen of 29 (59%) intra-articular fractures required operative fixation. Seventy-six percent were noncontiguous fractures. The radiologist detected 20 of 29 (69%) intra-articular fractures using high-resolution monitors, and the orthopedic surgeons averaged 13 of 29 (45%) using initial injury radiographs in the emergency department.

CONCLUSION: Plain radiographs are often insufficient for detecting posterior malleolus fractures in conjunction with ipsilateral distal third diaphyseal tibia fractures. Using a preoperative CT protocol for tibial shaft fractures can significantly improve the ability to diagnose associated intra-articular fractures that may not be evident on plain radiographs. Knowledge of these associated intra-articular fractures may prompt fracture stabilization and can prevent displacement during intramedullary nailing of tibia shaft fractures.