A delay in the union of bone regenerate in surgical lengthening procedures and the healing index (HI) are major factors in the quality of the results in progressive bone lengthening. Early removal of the external fixator (EF) is associated with a low rate of postoperative complications, including pin track infection, and with better muscle and joint function recovery. Addition of intramedullary wires (IMWs) to the EF led to a 9-49% decrease in the HI depending on the clinical series. We hypothesized that IMWs may accelerate the ossification process of bone regenerate and tested it in this experimental study.