The risk of fracture to the tibia from a fragment simulating projectile

A New Understanding of the Mechanism of Injury to the Pelvis and Lower Limbs in Blast

“…No comparable human research has been performed previously with which to evaluate these findings. Research investigating the risk of fracture to human cadaveric tibiae when impacted by a gas-gun delivered 4.5 mm fragment simulating projectile, however, has shown that similar velocities resulted in fracture: the v 50 for fracture was shown to be 271 m/s (95% CI: 241-301 m/s) (Nguyen et al, 2020). No previous research has quantified the risk of soft tissue injury (degloving, perineal or open abdominal injury) or pelvic fracture caused by energized soil or fragments.…”

Mapping the Risk of Fracture of the Tibia From Penetrating Fragments

“…The bones were potted in cylindrical cups with polymethylmethacrylate (PMMA) bone cement (Simplex Rapid ACR300 Autopolymerising Acrylic Resin, Swindon, United States) as shown in Figure 1B. The ovine tibia has similar size to the tibia of a 5-year-old boy (Nguyen et al, 2020), thus, axial compression of 90 ± 5 N [half the body weight of a 5-year-old boy (World Health Organisation [WHO], 2007)], measured by a 6-axis load cell (Sunrise Instruments, United States), was applied to the potted sample. This boundary condition was considered relevant, assuming that the individual would be standing at the time of injury.…”

“…The face and lower leg are the most commonly affected body areas as observed by Breeze et al (2015), reflecting the location of the explosive device that are commonly detonated on the ground as well as the use of personal armor covering mainly the regions of vital organs such as the thorax, abdomen, and the upper legs. Secondary blast injury by which fragments cause penetrating injury to the tibia is the most frequently observed wounding pattern in modern conflicts and associated with risk such as infection, slow recovery rate, potential amputation due to secondary complications; it can also contribute to the risk of traumatic amputation of the limbs (Khatod et al, 2003;Enninghorst et al, 2011;Davis Sears et al, 2012;Covey and Ficke, 2016;Nguyen et al, 2020). Energized fragments may be primary, such as those from the device itself, or secondary, such as debris from surrounding structures.…”

“…The injury mechanism and pathophysiology of such loading is, however, very different to that of secondary blast injury and thus their results cannot be extrapolated to quantify the risk of secondary blast injury to the tibia. Our previous study (Nguyen et al, 2020) was the first to quantify the risk of secondary blast injury to the tibia. It proposed an experimental model of injury due to a fragment simulating projectile (FSP) using a gas-gun system and used it to generate (a) injury-risk curves of different fracture severities, and (b) a scaling method for extrapolating animal results to the human.…”

“…In this study, we hypothesize that the severity of tibial fracture caused by a blast fragment and the injury thresholds depend on the orientation of the tibia relative to the fragment's flight. The aim of this paper is to expand our previous work (Nguyen et al, 2020) to investigate the fracture pattern by the directional effect of FSP impact on the tibia. In addition, it generalizes the scaling approach for more representative demographics and includes the energy attenuation of the soft tissue surrounding the long bone.…”