Children are lively and active by nature, and falls and bruises are inevitable in the process of growth. What is scary is not getting the right treatment, which can cause many problems. One of the most common is the supracondylar fracture of the humerus in children. In the past, the practice was to fix the fracture according to the adult’s internal fixation by incision and repositioning or plate, and also to fix the fracture by external fixation in plaster without rectification. As a result, the treatment effect is not good and even serious sequelae are often left. The supracondylar humerus is one of the most common fractures in children because it is a weak point of the humerus with a coronoid fossa in front and a hawk’s nest in the back. Supracondylar fractures of the humerus mostly occur when a child falls accidentally while playing sports or playing. When the elbow joint is in the extended position during the fall, the palm of the hand touches the ground and the violence is conveyed to the lower end of the humerus through the forearm, with the hawk’s beak against the hawk’s fossa as the fulcrum, resulting in an extension type supracondylar humerus fracture. The flexion type is less common. A 6-year-old child, Xiaoyi, was diagnosed with a right supracondylar humerus fracture after a film was taken at a local hospital a year ago when she accidentally fell while playing a game with a child. After the cast was removed 2 months after the injury, she found that her right elbow joint movement was limited, and the doctor recommended active passive movement of the right elbow joint for exercise. There was no significant improvement in the range of motion of the right elbow 6 months after the injury, and the elbow inversion deformity gradually appeared. After examination, it was found that Xiaoyi’s elbow joint had stiffened and developed an inward elbow deformity due to the defective initial treatment. In recent years, our department has seen many children like Xiaoyi, who were not treated properly after the fracture and were left with sequelae. Some doctors who are not specialized in pediatric orthopedics do not understand the anatomical and physiological characteristics of children’s bones and do not know enough about children’s fractures, so they blindly treat children’s fractures as a reduced version of adults, which leaves sequelae. Professional pediatric orthopedic surgeons generally treat displaced supracondylar humerus fractures in children by closed reduction and percutaneous internal fixation through pins, which can make the fracture well repositioned without aggravating the trauma. In children, the supracondylar humerus fracture is one of the most deformed areas, and as children grow, the chances of an undisplaced fracture developing into a deformity increase significantly. The repeated revision causes further damage to the soft tissues of the elbow and the formation of hematoma, leading to heterotopic ossification and eventually ossifying arthritis, which affects the movement of the elbow joint. At present, the pediatric orthopedic departments of large hospitals in China have a special treatment method for children with supracondylar humerus fractures. For displaced supracondylar humerus fractures in children, closed reduction internal fixation is generally used, and functional exercises are feasible at an early stage. Closed reduction internal fixation is a minimally invasive procedure that does not require incision, and is performed by internal fixation with steel pins after manipulation. The cast is fixed for 2 weeks after surgery, and the pin can be removed after 8-10 weeks when the bone scab grows well on review radiographs. Regular follow-up and early functional exercise can reduce the sequelae of joint stiffness. In some cases, supracondylar osteotomy is required to correct the deformity of the elbow.