The thumb is the most important because it accounts for approximately 50% or more of the function of the whole hand. If the thumb is missing, it will seriously affect the function of the hand and will not be able to realize actions such as pinching, gripping, grasping and holding. As long as the thumb retains a certain length, even if only one of the other four fingers remains, some of the hand’s function can be restored through moderate functional exercises to achieve grasping, pinching and other actions. Therefore, in the case of a traumatic injury to the thumb, such as a broken finger, if the conditions for replantation exist, the first priority is to replant the broken finger. In the absence of replantation, treatment such as flap grafting should be actively pursued to preserve the length of the thumb as much as possible in order to achieve the function of the thumb and to improve the quality of life of the patient as much as possible, so that the patient can do simple work and self-care activities through exercises.