Forty children with displaced diaphyseal femur fractures were quasi-randomized by hospital ID parity to elastic stable intramedullary nails (ESIN) (n=22) or submuscular plating (SMP) (n=18). The primary outcome was 12-month function by Flynn’s criteria. Secondary outcomes included operative time, incision length, blood loss, fluoroscopy time, pain (VAS at discharge), analgesic days, time to union, hospital stay, and complications, with surveillance to a minimum of two years. Overall, the results revealed SMP yielded a higher proportion of “excellent” Flynn grades and shorter time to union, whereas ESIN had substantially shorter operative time, smaller incisions, less blood loss, and lower fluoroscopy time. In sum, functional outcomes with ESIN were broadly comparable and ESIN appears safe even for length-unstable fractures; thus, implant choice may reasonably hinge on surgeon preference, patient factors, and cost.