Abstract
Anti-vehicular landmines and improvised explosive devices can produce catastrophic lower-extremity injuries. As such, lower-extremity injury prevention is of high concern but requires a better understanding of high-rate impacts and fracture risk. In this study a probabilistic finite-element (FE) model of the tibia and talus was developed to produce a fracture risk assessment and was compared with experimental cadaveric testing. We developed a high-fidelity statistical shape and density model of the tibia to provide a means of generating physiologically plausible anatomies to investigate the effect of anatomical variability on the risk of injury. Probabilistic descriptions of bone material properties for the tibia were taken from literature and internal sources to account for natural variation and uncertainty. A 7.5-kN distal-tibia impact simulation was developed following the methodology of a previously described framework. This 7.5-kN load corresponds to nearly a 10% tibial fracture risk, which was experimentally derived using cadaveric specimens. Using the probabilistic descriptions of anatomy and material properties, a Latin Hypercube probabilistic FE analysis was performed using the 2nd-percentile strain as a failure criterion. The probabilistic analysis resulted in a computed risk of fracture of 10% given the 7.5-kN impact force on the distal tibia. Uncertainty and variability in the bone failure strain, material properties, and tibia anatomy substantially influenced fracture risk. The described probabilistic model reproduced experimentally derived fracture risk and can be used as a comprehensive surrogate to cadaveric testing for high-rate distal-tibia impacts. This model can be used for the design of protective equipment, identification of high-risk individuals, and development of novel injury-mitigation strategies.
