Following lower limb amputation, quality of life is highly related to the ability to use a prosthetic limb. The conventional way to attach a prosthetic limb to the body is with a socket. Many patients experience serious discomfort wearing a conventional prosthesis because of pain, instability during walking, pressure sores, bad smell or skin irritation. In addition, sitting is uncomfortable and pelvic and lower back pain due to unstable gait is often seen in these patients. The main disadvantage of the current prosthesis is the attachment of a rigid prosthesis socket to a soft and variable body. The socket must fit tightly for stability during walking but should also be comfortable for sitting. The implantation of an osseointegrated, intramedullary, transcutaneously conducted prosthesis is a new procedure for attaching a limb prosthesis to the human body without the disadvantages of the conventional prosthesis. The intramedullary prosthesis is designed with a rough surface resembling cancellous bone to enable a secure solid integration with the long bone. We treated two patients with this new prosthesis, a 44-year-old man after a transfemoral amputation, and a 32-year-old woman after a lower leg amputation; both amputations were necessary because of trauma. Those two patients are now, more than one year after the operation, showing excellent functional results without infectious complications. We assume that endo-exo prosthesis may be a promising option for selected patients unable to use a conventional prosthesis because of a problematic amputation stump.