This study will consist of 25 trans-femoral amputees meeting the inclusion and exclusion criteria. We will recruit participants from the OHSU clinics, Primary Care Clinics, and specialty clinics including orthopaedic surgery, general surgery, pain centers, neurology, and orthotics and prosthesis clinics and offices. We anticipate that the majority of subjects will be recruited from the Department of Orthopaedics and Rehabilitation's clinical practice. Potential subjects will be identified from the investigators' clinic and medical records. Recruiting outside of the Department of Orthopaedics and Rehabilitation will be done using recruiting posters and letters addressed to the primary care physicians, specialists and at prosthetic clinics. Recruitment notices will be posted on the OHSU and Department of Orthopaedics and Rehabilitation's Web sites and the OHSU Study Participation Web site. We intend to enroll 30 subjects.