Utility of CT scans for detecting operative malleolar fractures associated with tibial shaft fractures

The purpose of this study was to define the utility of CT scans for detecting articular extension in tibial shaft fractures and determine if radiographic parameters can predict the presence of operative distal tibia articular fractures (DTAFs). Design: Retrospective cohort study Single Level I Trauma Center Patients ages 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 (OTA/AO 43B/C), ballistic injuries, and absence of a pre-operative CT scan. 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 multiple binary logistic regression model to determine independent predictors of operative DTAFs. 144 patients were included with a mean age of 52 years. 76 patients (53%) were male. CT utility was 41% for 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). CT scans identified distal tibia articular fractures (DTAFs) that were unrecognized on plain radiographs in 41% of cases. CT scans were most useful in identifying non-posterior DTAFs. CT scans may be considered for all distal third tibia fractures, but especially those with spiral tibial shaft patterns and low fibular fractures, to avoid missing operative articular injury. Level III