An Osseointegrated Transfemoral Prosthesis Offering Long-Term Bi-Directional Efferent-Afferent Neural Transmission

Inclusion Criteria: * 1 Male or Female age 22-65 at the time of surgery. * 2 The patient must have a medical condition requiring performance of a unilateral transfemoral amputation with a minimum of 13 cm of residual femur after amputation, and: A. At a minimum level of amputation of 20 cm or greater above the knee joint line if physical therapy and prosthetist evaluation is commensurate with a standard K3 ambulatory status; or, B. At a minimum level of amputation of 16 cm above the knee joint line as part of a single- stage procedure if physical therapy and prosthetist evaluation is commensurate with a more active K3 or less active K4 postoperative ambulatory status. * The subject must have undergone independent consultation with at least two lower extremity surgical specialists to ensure they have exhausted all limb salvage options prior to undergoing amputation, as well as a psychiatric evaluation to ensure appropriate capacity and volition. * The patient must have the ability to ambulate at variable cadence (an expected lower extremity prosthesis functional level of K3 or above). * The patient must have adequate bone stock to support the implanted device. * In the opinion of the investigators, normal cognitive function and absence of any physical limitations, addictive diseases or underlying medical conditions that may preclude patient from being a good surgical and/or study candidate. * Willingness, ability and commitment to participate in baseline and follow-up evaluations for the full length of the study including the prescribed rehabilitation program. * Written informed consent to participate in the study provided by the patient or legal representative. Exclusion Criteria: * Women who are pregnant, lactating or planning a pregnancy during the first twelve (12) months of the post-surgical follow- up. * Subjects who have not been completely abstinent from tobacco use for at least 6 weeks preoperatively. * Active infection or dormant bacteria. * Subjects would have less than 2 mm of remaining cortex bone available around the implant, if implanted. * Evidence of or a documented history of severe peripheral vascular disease, diabetes mellitus (type I or type II), skin diseases, Neuropathy or neuropathic disease and severe phantom pain, or osteoporosis, such that, in the opinion of the investigator, will not allow the subject to be a good study candidate. * Evidence of any active skin disease involving the proposed surgical limb. * History of systemically administered corticosteroids, immune- suppressive therapy or chemotherapy drugs within six (6) months of implant surgery. * Severe co morbidity, atypical skeletal anatomy, or poor general physical/mental health that, in the opinion of the Investigator, will not allow the subject to be a good study candidate (i.e. other disease processes, mental capacity, substance abuse, shortened life expectancy, vulnerable patient population, BMI \>40, etc.). * The patient is currently involved in another clinical study where that participation may conflict or interfere with the treatment, follow-up or results of this clinical study.