Investigation of tibia and fibula fracture risk during football impacts using finite element human body models

Injuries in football are prevalent, and while shin guards reduce these, current test standards are primarily intended to evaluate contusion risk rather than more serious outcomes such as fractures. In this study, a finite element human body model was used to assess fracture risk in the lower leg subjected to conditions representative of football impacts. Various impactor shapes, impact locations and orientations were explored to identify conditions where fractures may be more likely to occur (based on element strain) and the associated force and bending moment. The lower leg was most susceptible to fractures at the 35% tibial height. Fractures occurred most frequently from the anterolateral direction, resulting in fibula injuries. In terms of geometry, the stud impactors were the most effective at inducing fractures and fracture was highly sensitive to bone alignment. Force to fracture ranged from 1595 to 2612 N. Susceptibility to fractures was influenced by the cross-sectional area of the bone, as well as the soft tissue thickness, with increased force attenuation associated with greater tissue thicknesses. This study showed various parameters affect the fracture tolerance of the lower leg, and identified the impact energies required to induce fractures, to better inform test standards for protective equipment.