The earliest stage of radiological union in fracture healing is known as the “Callus Formation” or “Soft Callus Stage.” During this stage, which occurs a few days to a couple of weeks after the fracture, there is an initial response to the injury that leads to the formation of a soft callus made up of fibrous tissue and cartilage. This callus forms around the fractured ends of the bone, helping to stabilize and bridge the gap between them.
As healing progresses, this soft callus eventually becomes mineralized and transformed into a hard callus through a process known as endochondral ossification. This hard callus, also referred to as the “Hard Callus Stage,” is eventually remodeled by the body to restore the bone’s original structure and shape.
It’s important to note that fracture healing is a dynamic process that involves several stages, including inflammation, soft callus formation, hard callus formation, and remodeling. The radiological appearance of these stages can help physicians track the progress of healing and determine the appropriate management for the fracture.