Have you ever encountered or heard that when you or a friend was injured, the fracture did not show up on X-ray until a week later? Or the doctor told you to get an X-ray after a week instead of right after the injury?
Can't X-rays tell if there's a fracture right away? Why do you have to wait a week before taking an X-ray?
When a minor fracture occurs, it might result in very thin cracks in the bone which would be invisible on X-ray because the cracks are so tiny. These fractures are often called hairline fractures, where the fracture cracks are as thin as a hairline.
When a fracture occurs, the bone cells undergo a repairing process. The osteoclasts, which are the bone-breaking cells, will first remove the dead tissues or debris on the edge of the fracture line that has been injured or damaged by the injury. This takes about a week for the osteoclasts to remove the dead tissues. The removal of the dead tissue on the edge will make the crack appear bigger, and hence we will see the crack on X-ray after a week but not right after an injury. When the osteoclasts complete their work, the osteoblasts, which are the bone-forming cells, start to repair and build bone tissue, allowing the fractures to heal. The healing time varies depending on the severity of the injury. It may take about one to several months to heal for minor injuries.
Therefore, if the mechanism of injury or clinical examination makes the doctor or therapist think that there is a possibility of a fracture, the doctor or therapist will treat it as a fracture even though the fracture cannot be seen on immediate X-rays. And of course, if the fracture line is huge and severe, it will show up on immediate X-rays.
The best course of treatment for fracture healing is to immobilize the injured area so that the bone can heal properly. After the fracture has healed, it is important to follow a rehabilitation exercise program so that you can regain the muscle strength lost by immobilization.