[The biology of bones and of bone fracture healing].

For the treatment of fractures several systems are available. Biological and biomechanical aspects have to be considered in order to obtain an optimal final result. The vascular supply of the intact and of the fractured bone is reviewed. The role of the fracture hematoma with a low pO2 and a pH below the physiological range are discussed. In bone remodelling tension forces and cyclic loading are important factors in resorption and regeneration. The influence of the periosteum in bone healing after internal fixation is described.