Fracture healing is a very unique process in the human body. Bone is a unique tissue in that it can regenerate itself during the process of healing. This requires a very complex process which is regulated by various metabolic and hormonal factors to include various growth factors. These biological processes occur at the cellular level requiring recruitment proliferation and differentiation of many cells including endothelial cells, osteoprogenitor cells, platelets, macrophages, mesenchymal stem cells (MSCs) , and monocytes. These cells secrete various biologically active molecules at the site of injury to facilitate fracture repair. The bone morphogenetic proteins (BMPs) are osteoinductive agents which promote the proliferation and differentiation of undifferentiated cells to become either osteoprogenitor or chondroprogenitor cells. Although our bodies have the inherent capability to repair the fracture, the fracture healing process can be impaired for numerous reasons. When the fracture healing cascade stalls, a delayed union may develop, but the process may altogether cease. In a delayed union , both clinical evidence and radiographic evidence of healing do progress, but it lags behind what the normal healing time should be for a particular bone. There are however many factors to take into consideration such as the particular bone involved, the specific anatomic regions of the particular bone, the fracture pattern, as well as the method of treatment.