ObjectiveTo compare the effectiveness between open reduction and closed reduction of pediatric subtrochanteric fractures using elastic stable intramedullary nailing (ESIN). MethodsBetween January 2010 and January 2014, 22 children with subtrochanteric fractures were treated by ESIN internal fixation combined with hip cast fixation, and the clinical data were retrospectively reviewed. Closed reduction was used in 12 cases (group A) and miniopen reduction in 10 cases (group B). There was no significant difference in gender, age, sides, fracture causes, type of fracture, complications, and time from injury to operation between 2 groups (P>0.05). The operation time, intraoperative blood loss, fracture healing time, and complications were recorded and compared between 2 groups, the limb function was evaluated according to the Flynn et al. outcome score. ResultsThe intraoperative blood loss of group A was significantly less than that of group B, but the operation time of group A was significantly longer than that of group B (P<0.05). All the patients were followed up 12-36 months (mean, 14.9 months). There was no major complications in the other patients of both groups except 1 patient having delayed wound healing in group B. There was no significant difference in fracture healing time between 2 groups (t=-1.006, P=0.327). Inverted angle of 10° and shortened limb of 1.8 cm were observed in 1 case of group A, and sagittal plane angle of 15° and shortened limb of 2 cm in 1 case of group B. There was no abnormal walking and function of hip and knee activity at last follow-up. According to the Flynn et al. outcome score, the results were excellent in 8 cases and good in 4 cases in group A, and were excellent in 6 cases and good in 4 cases in group B, showing no significant difference between 2 groups (χ2=0.041, P=0.956). ConclusionBoth closed and open fracture reduction using ESIN have satisfactory outcomes for treating pediatric subtrochanteric fractures. A mini-open reduction should be selected intraoperatively if closed reduction proves to be difficult.