The aim of this prospective, consecutive study was to assess overgrowth and malunion after anatomical reduction and external fixation of displaced femoral shaft fractures in children. Ninety-seven closed femoral fractures in 95 children aged 3–15 were fixed with a unilateral external fixator and followed with conventional radiographs and standardized orthograms for 1 year. To evaluate further overgrowth and remodelling a subgroup of 45 patients was also seen at 2 years. Parameters known to influence overgrowth and remodeling were recorded.