There are some very serious diseases that are characterized by the development of severe strain long bones in children, against violations of bone quality: First of all it concerns the so-called “crystal” children (osteohenez- imperfect osteogenesis imperfect ) .   It is also related to a group of some other diseases (fibrous dysplasia, neurofibromatosis, birth defects and some others). To fix mainly the tubular bones of the skeleton in children and adolescents in the period of incomplete growth in the correction of their deformations and internal “reinforcement” in order to prevent fractures and recurrence of deformities.   To fix the neck of the femur in the “growing” mode, the proximal part of the femur has a larger diameter in which a sliding telescopic screw is installed in the threaded hole at the appropriate angle, which fixes the neck and head of the femur.