This technique is a minimally invasive and effective treatment for children aged 6-12 years with fractures of the extremities, using the principle of multi-point fixation, while protecting the epiphyseal plate from damage. Under the guidance of the C-arm, a 2-3 cm incision is made at the distal and proximal ends of the fracture, and a flexible intramedullary nail of appropriate diameter is inserted into the medullary cavity from the distal end of the fracture to reach the proximal end through the fracture, and then removed through the original incision after 3-6 months of healing. This method does not require stripping the periosteum and cutting the fracture end, so it does not interfere with epiphyseal growth and does not disrupt the blood flow of the fracture end, and it is elastic and fixed with minimal local movement, with little trauma and fast fracture healing, and functional exercise can be performed 3 weeks after surgery, and the function returns to normal 1 month after surgery. In contrast, it not only effectively avoids the disadvantages of large trauma and scars of internal fixation with incision and repositioning plate, but also effectively avoids the disadvantages of exposed steel pins of external brace fixation and not easy to care.