摘要Objective To present some new concepts in the treatment of fractures and bone defects of long bones with internal fixation.Methods Animal experiments, mechanical tests and clinical analyses were done.Results and Conclusions Reduction of fracture should be perfect, bone defect can be reconstructed by intramedullary and extramedullary bone graft. Relatively rigid fixation at the early stage and elastic fixation at the later stage are beneficial not only for fracture healing, but also for bone remodeling. In order to avoid complications including non-union, immobilization syndrome of the bone and joint, and implant failure, radiographs should be taken periodically; if there is any bone resorption, weight-bearing should be restricted.