The duration of external fixation of a child’s fracture in a cast depends on the age of the child. If the child is less than 1 year old, the cast can be removed after 2-3 weeks of braking. It is possible that the child’s bones will grow very well in 2-3 weeks, and after the cast is removed, functional exercises of the upper and lower joints should be performed to prevent joint adhesions. If the child is more than 1 year old, the cast should be removed within 4-6 weeks after braking, and the cast should be removed according to the healing condition of the fracture on the X-ray. If the fracture is not healing well, it may be possible to extend the cast for a longer period of time, but it is recommended not to exceed 6 weeks, after which there will be some impact on the joint.