Lower extremity injuries are prevalent in motor vehicle collisions. Therefore, it is necessary to accurately quantify lower extremity kinetics in order to evaluate strategies for mitigating these injuries. Current methods for quantifying lower extremity loads in post-mortem human subjects (PMHS) have limitations that could affect the accuracy of the measured loads. Hence, the purpose of this study is to evaluate the efficacy of using strain gauge arrays (SGAs) to quantify axial and anterior-posterior shear femur forces in PMHS during fullscale frontal sled tests. Six PMHS were instrumented with SGAs to measure bilateral axial and shear femur forces before undergoing frontal sled tests. Several calibration procedures were performed to convert the SGA outputs (mV) to forces. The resulting forces were compared to knee bolster reaction forces and femur forces from matched sled tests performed using anthropomorphic test devices. Overall, the PMHS SGAs measured reasonable axial forces during the sled tests, but more work is necessary to validate the shear forces. Given the degree of crosstalk observed during the calibration procedure, future studies should use axial, anterior-posterior shear, and medial-lateral shear SGAs together to facilitate full crosstalk compensation. Furthermore, precise post-test calibrations capable of evaluating crosstalk should be performed on long bones instrumented with SGAs.