An Evaluation of Tibia-Level Predictors of Fracture Characteristics in Human Tibiae

Tibia fracture incidence accounts for over 36% of long bone fractures in adults across loading mechanisms. Additionally, the tibia is the most commonly fractured lower extremity bone in pedestrian-motor vehicle impacts. Increased fracture severity, especially in the tibia, causes increases in both the physical and financial burden associated with recovery. Current research encompasses quantification of cross-sectional tibia features, trends of these features across ages and between sexes, and how tibia features are related to fracture risk. Research is lacking, however, in identification of predictors of differences in fracture severity and identification of populations at risk for increased tibia fracture severity. Therefore, the objective of this study was to investigate relationships between individual-level and tibia-level variables with fracture severity, specifically, the number of fractures per tibia. Sixteen human tibiae (8 male, 8 female) were loaded to failure in a 4-point bending scenario at 6 m/s in a lateral-medial direction. Prior to testing, computed tomography (CT) scans of each tibia were obtained and tibia-level variables (cortical area, cortical thickness, percent cortical area, total area, endosteal area, and volumetric bone mineral density) were collected at the 50% site of each tibia. Relationships between individual-level and tibia-level variables and number of fractures per tibia were explored; however, no significant relationships were observed. General trends observed included fewer fracture numbers in females, likely influenced by smaller tibiae and thus smaller ratios of cortical area when compared to male tibiae. Male tibiae facilitated more fractures in this study, as the more robust nature of male tibiae allowed for propagation into multiple fractures when traumatic force was applied. Future research should include a larger sample size, as well as expanded tibia-level and fracture-level variables to further investigate populations at risk for increased fracture severity.No embargoAcademic Major: Anthropological Science