Pediatric femur and tibia fractures are more common, and the traditional pediatric tibial fracture treatment method is based on manipulative reset plaster and splint fixation; pediatric femur fracture treatment method is based on traction: generally, hanging traction is done within 3 years old, skin traction is done from 4 to 8 years old, and bone nail traction is done from 9 to 14 years old. Although the traditional treatment method can obtain good efficacy, there are also disadvantages such as long braking time and difficulty in caring for the child. However, if the child’s fracture is fixed with an incisional plate, it increases the trauma to the limb, disrupts the blood flow at the fracture, and leaves a long scar on the limb. The use of the AO elastic nail solves the concerns of patients and physicians by providing ideal fixation of the fracture without affecting the aesthetics of the limb. The AO elastic nail technique uses a C-arm X-ray machine to reposition the fracture under fluoroscopy, avoiding the epiphysis at the bone epiphysis (distal femur or proximal tibia), and inserting two appropriately pre-curved elastic nails percutaneously to the other end of the fracture, forming a figure-of-eight cross in the bone marrow cavity to reposition and fix the fracture, which requires only two small 1CM incisions at the point of entry and easy extraction for the second time (Figure 1-3). The AO elastic nail technique has the advantage of minimally invasive treatment, but its application also has certain indications, generally for children aged 4-8 years old, and for small children aged 9-12 years old, but those over the age and weight will make the internal fixation steel pins not strong enough to affect bone healing or even re-fracture, so the clinical application is also carefully chosen. Figure 1, the arrow refers to the small scar at the entrance of the surgery Figure 2, the pin insertion and extraction are through two incisions of about 1CM, small trauma Figure 3, the femur almost no scar after surgery