The different sequences of fracture healing and their development are regulated by the physical environment of bone. Among them, the mechanical solicitation can drastically modify the callus formation. The type of osteosynthesis as well as the rehabilitation program must be adapted to each individual case to optimize the healing. Transducers placed on the osteosynthetic material allow the monitoring of the implant and of the callus formation to adapt the mechanical solicitation to the higher strain regime without risk of implant failure or refracture. New treatment like ultrasound and electromagnetic fields (EMF) are expected to act on specific sequences of the bone healing. Our experimental results confirms the effect of EMF on the differentiation of cartilage into bone during the enchondral ossification and non union healing.