An intramedullary osteosynthetic device includes an intramedullary nail, a hip helical implant, a sliding sleeve, a lateral set screw, and at least one distal locking screw. The intramedullary nail is cannulated. The cannulation is at least partially threaded to receive a coaxial set screw. The intramedullary nail includes at least one oblique slotted bore in communication with the cannulation, where the at least oblique slotted bore receives a sliding sleeve, and further includes a threaded notch compatible with the lateral set screw. The hip helical implant includes a frontal helical portion having a truncated conical shape, at least two helical twisted blades attached to the frontal helical portion, and a rear smooth shaft, the shaft having an external flat surface. Each blade of the hip helical implant has a hole for receiving a peg from a step helix fixating the hip helical implant to the step helix. The hip helical implant is cannulated to receive a Kirschner wire during insertion of the implant into a femoral head. The sliding sleeve includes a tube having an internal flat corresponding to the external flat of the hip helical implant and has external threads at the rear of the sleeve engaging the lateral set screw. The coaxial set screw fixes the sliding sleeve to the intramedullary nail by tightening the sliding sleeve inside the oblique bore.