If the cast of a limb becomes loose, it should be replaced in a timely manner to ensure that the cast fits, the tension of the cast and the cast is well fixed so that the treatment purpose can be achieved. Plaster is a commonly used external fixation for limbs, generally used for fractures, tendon and ligament injuries, which require the limb to maintain a certain angle and position, and then there is the protective effect of the plaster to prevent accidental injury to the limb. After the first cast is done, the local swelling will be reduced as the disease is relieved. It is common that the fat and soft tissues under the skin will atrophy after being squeezed, leading to the loosening of the cast. After the cast is loosened, you can go to the hospital for replacement in time.