Utility of CT Scans for Detecting Operative Malleolar Fractures Associated With Tibial Shaft Fractures

OBJECTIVES: The purpose of this study was to define the utility of CT scans for detecting articular extension in tibial shaft fractures and determine whether radiographic parameters can predict the presence of operative distal tibial articular fractures (DTAFs). METHODS: Design: Retrospective cohort study. Setting: Single level I trauma center. Patient Selection Criteria: Patients age 18 years and older who were treated operatively for tibial shaft fractures occurring at or below the tibial isthmus were included. Patients were excluded for extension of the main tibial shaft fracture into the tibial plafond (AO/OTA 43 B/C), ballistic injuries, and absence of a preoperative CT scan. Outcome Measures and Comparisons: The primary outcome was CT utility, defined as the presence of a DTAF or DTAF displacement on CT that was not recognized on plain radiographs on secondary analysis at the time of the study by a senior-level resident. Secondary outcome was the association between radiographic parameters and operative DTAFs. Variables with P <= 0.2 on univariate testing were included in a multiple binary logistic regression model to determine independent predictors of operative DTAFs. RESULTS: One hundred forty-four patients were included, with a mean age of 52 years. Seventy-six patients (53%) were men. CT utility was 41% for the identification of unrecognized DTAFs. CT utility was 79% for isolated pDTAF, 57% for medial DTAF, 83% for isolated anterolateral DTAF, and 100% for multiple DTAFs. Operative DTAFs were independently associated with spiral tibial shaft fracture type (P < 0.001) and low fibular fracture (P = 0.04). In patients who had both spiral tibial shaft fracture type and low fibula fracture, the rate of operative DTAF was 46% (22/48). CONCLUSIONS: CT scans identified DTAFs that were unrecognized on plain radiographs in 41% of cases. CT scans were most useful in identifying nonposterior DTAFs. CT scans may be considered for all distal third tibial fractures, but especially those with spiral tibial shaft patterns and low fibular fractures, to avoid missing operative articular injury.