Diagnosing Fractures of the Distal Tibial Articular Surface in Tibia Shaft Fractures: Is Computed Tomography Always Necessary?

Objectives: To identify the incidence of distal articular fractures in a series of distal third tibia shaft fractures and to report the utility of both computed tomography (CT) scans and Radiographic Investigation of the Distal Extension of Fractures into the Articular Surface of the Tibia (RIDEFAST) ratios for identification of articular involvement. Design: Retrospective cohort. Setting: Level 1 trauma center. Patients: Four hundred seventeen patients with distal third tibia shaft fractures were included in the study. Intervention: Intramedullary nail or plate fixation. Main Outcome Measures: Type of articular fracture, time of diagnosis, and RIDEFAST ratios. Results: One hundred one of the 417 distal third fractures (24%) had a fracture of the distal tibia articular surface. Of these 101 fractures, 41 (41%) represented an extension of the primary fracture line and 60 (59%) were separate malleolar fractures. Of the 101 articular fractures, 95 (94%) were identified preoperatively and 6 (6%) were identified intraoperatively. Of the 95 fractures identified preoperatively, 87 (92%) were identified on plain radiographs and 8 (8%) by CT scan. Thirty-five preoperative CT scans were performed on distal third tibia shaft fractures in search of an intra-articular fracture. In 27 patients (77%), no articular fracture was present, representing an overall yield of 23% among CT scans performed to rule out an articular fracture in distal third tibia shaft fractures. RIDEFAST ratios for all 101 distal tibia shaft fractures with articular involvement and 100 fractures with no articular involvement were not significantly different (P > 0.05) using both coronal and sagittal plane measurements. Conclusions: CT scans performed on distal third tibia shaft fractures in search of articular fractures had a low yield (23%). Widespread use of CT scan to diagnose fractures of the distal tibia articular surface in the setting of distal tibia shaft fractures does not seem warranted. No statistically significant differences in RIDEFAST ratios were found between fractures with and without articular involvement, indicating that more work is necessary before RIDEFAST can be used to reliably rule out articular involvement in this setting.