Several methods are available for progressive limb lengthening, including centromedullary nailing, external fixation, or a combination. Each technique has its own advantages and drawbacks. In trauma victims, use of centromedullary nailing is associated with potentially fatal fat embolism. This fatal outcome might also occur during limb lengthening, particularly in bilateral procedures. To our knowledge, fat embolism has not been reported with the use of centromedullary nail for limb lengthening. This was a multicentric study of three cases of fat embolism, including one fatal outcome. In all, 36 centromedullary lengthening nails were inserted in the three centers before these acute episodes. The first two cases occurred during single-phase bilateral procedures, the third during unilateral lengthening. Fat embolism could result from several factors, as reported in the literature. While the bilateral nature of the procedure has been incriminated, the observation of an embolism during a unilateral procedure suggests other factors may be involved. Considerable increase in endomedullary pressure during reaming and insertion of the nail has been demonstrated. At the same time, there is the question as to whether the reduction of the diminution of medullary pressure by corticotomy would be an efficient way of reducing the risk of fat embolism. Based on the analysis of our three cases, we suggest that the best way to avoid fat embolism might be to drill several holes within the area of the osteotomy before reaming, in order to reduce endomedullary pressure. This can be achieved via a short skin incision, sparing the periosteum before low energy osteotomy. Since applying this protocol, the three centers have implanted 17 lengthening nails, without a single case of fat embolism.