Detection of butterfly fractures of long bones through multi-slice computed tomography and micro-computed tomography

Abstract

Motor-vehicle accidents often result in lower limb injuries with biosseous fractures. The present study aimed at comparing multi-slice computed tomography (MS-CT), micro-computed tomography (micro-CT) and external fractography for the analyses of experimentally produced biosseus leg fractures. Briefly, 48 human legs amputated for medical reasons were defleshed and then experimentally fractured using a 3-point dynamic bending model (70,6 J of impact energy at the middle of the anterior surface of the tibia) producing 38 biosseous and 10 mono-osseous fractures with a total of 86 fractured bones. External fractography detected 63 (73,2%) "butterfly" fractures (24 (27,9%) complete and 39 (45,3%) incomplete), 14 (16,3%) "oblique" fractures, 6 (7,0%) "comminuted" fractures and 3 (3,5%) "transverse" fractures. Forty-three (43) of the 48 included legs displayed at least one butterfly fracture located at the tibia or fibula. MS-CT correctly detected and classified 16 complete and 20 incomplete butterfly fractures, failing to properly classify 27 fractures; 19 of these misclassifications led to an interpretative error on the trauma direction (i.e., 16 incomplete butterfly fractures classified as oblique fractures and 3 incomplete butterfly fractures classified as transverse). Micro-CT correctly detected and classified 22 complete and 37 incomplete butterfly fractures, failing to properly classify 4 fractures; two of these misclassifications led to an interpretative error on the trauma direction (i.e., two incomplete butterfly fractures classified as oblique fractures). Although further studies evaluating a wider number of fractures and fracture patterns are required to drive any definitive conclusions, this preliminary experimental investigation showed that MS-CT and micro-CT represent useful tools for reconstructing the morphology of leg fractures and could be crucial for trauma analysis in the forensic context. MS-CT could be used as a screening tool, micro-CT as second level analysis and external/internal fractography as third level, confirmatory analysis.

Keywords: Butterfly fracture; Car crashes; Computed tomography; Forensic pathology; Forensic radiology; Fractography; Micro-CT.