A fracture that rattles when the bone is moved but does not hurt may be caused by factors such as slight displacement of the fracture, bone fragments entering the joint cavity, non-healing or delayed healing of the fracture. 1. Slight displacement of the fracture: After fracture, because it is a stable fracture, the fracture will rattle when it is slightly moved, but it does not hurt. 2. Bone fragments enter the joint cavity: when small fragments of the fractured bone enter the joint cavity, the bone will rattle when the limb is moved, sometimes causing pain. 3. Decrease in synovial fluid at the fracture site: When the fracture healing is delayed or not healed, because the fracture site is already more adhesive and more stable, slight movement of the fracture will increase the friction between the fracture end and the surrounding tissues, which will cause the bone to rattle, but will not cause pain. Since there are many reasons for moving bones without pain, it is necessary to go to the orthopedic department of the hospital for examination in order to clarify the cause of the problem as soon as possible.