<P> Secondary healing (also known as indirect fracture healing) is the most common form of bone healing . It usually consists of only endochondral ossification . Sometimes, intramembranous ossification occurs together with endochondral ossification . Intramembranous ossification, mediated by perisoteal layer of bone, occurs without formation of callus . For endochondral ossification, deposition of bone only occurs after the mineralised cartilage . This process of healing occurs when the fracture is treated conservatively using orthopaedic cast or immobilisation, external fixation, or internal fixation . </P> <P> There are three major phases of fracture healing, two of which can be further sub-divided to make a total of five phases: </P> <Ol> <Li> Reaction <Ul> <Li> i . Inflammation </Li> <Li> ii . Granulation tissue formation </Li> </Ul> </Li> <Li> Repair <Ul> <Li> iii . Cartilage callus formation </Li> <Li> iv . Lamellar bone deposition </Li> </Ul> </Li> <Li> Remodeling <Ul> <Li> v. Remodeling to original bone contour </Li> </Ul> </Li> </Ol> <Li> Reaction <Ul> <Li> i . Inflammation </Li> <Li> ii . Granulation tissue formation </Li> </Ul> </Li>

Formation of bony callus in fracture repair is followed by