[Extemporaneous lengthening of the femur, fixed with a centromedullary locked nail]

The authors expose a new method for extemporaneous femoral lengthening osteotomy with intra-medullary locking nailing. The procedure is described with a stair-step osteotomy. The first results are presented and the main stages of the operation are discussed especially those preventing any loss in the surgical lengthening.