The fractures fixation has been evolved from rigid mechanical internal fixation (association for osteosynthesis, AO) to biolog-ical osteosynthesis (BO), and further to elastic osteosynthesis (EO). In history of internal fixation, the development and innovation at eachstage was based on the outcomes of previous period. The EO theory believes that the minimized stress-shielding might produce a controlla-ble stress in fractures area due to strain effect, which is beneficial to fractures healing. However, relative stability of fixation should be con-sidered except controlled stress in EO, and a balance between flexibility and stiffness of the EO is essential for successful fractures healing.The interfragmentary strain (IFS) is a simple mechanical parameter that could be used to describe the fractures stability, and leads to vari-ous bone healing outcomes. In this paper, a review involving a large number of literatures was presented on EO.