Fracture healing, delayed union and nonunion / 中华创伤骨科杂志

ABSTRACT

Fracture healing consists of four stages: hematoma and inflammation, granulation tissue formation, membranous and endochondral ossification, and remodeling. During these stages, the pathological changes are continuous and overlapping and numerous inflammatory factors and growth factors play a central role in the tissue regeneration and ossification. The fracture will eventually reach primary bone healing or callus healing depending on the stability of fracture site after treatment. The delayed union and nonunion can be assessed according to the treatment time, clinical examination, radiology and biomechanical testing. It is important to understand the differences between hypertropic and atrophic nonunions and the reasons that lead to nonunion. At last, methods to promote fracture healing are summarized and classified into four groups: biological, systemic, mechanical and biophysical ones.