Tibial plateau fractures are among the most severe lower limb injuries suffered in car crashes in terms of long-term impairment. Axial loading of a flexed, entrapped knee by an impact delivered to the plantar surface of the foot is a likely injury scenario for a number ‘of lower limb injuries sustained in frontal crashes, including tibia1 plateau fractures. In order to determine the injury tolerance of the leg to axial loading, axial impact tests at injurious load levels were conducted using 20 above-knee cadaver leg specimens in which the ankle was neutrally positioned and the knee was constrained and flexed 90”. Injury to the foot/ankle complex was generated in 15 specimens, and tibia1 plateau fractures were generated in 5 of these specimens. All tibia1 plateau injuries were Schatzker VI type bicondylar fractures associated with severe comminution and disruption of the articular surface. However, the fact that tibia1 plateau fractures never occurred independently of foot and ankle injury suggests that an axial loading injury criterion based on the injury tolerance of the foot/ankle complex is sufficiently conservative to protect against tibia1 plateau fractures in this impact scenario.