 The purpose of this study is to investigate the clinical implementation of a new percutaneous prosthetic attachment system by determining the resident microbial ecology of the implant exit site and to simultaneously study the systemic and local stomal immune responses. This study will follow 10 patients implanted with percutaneous osseointegrated prosthetics POPs for a period of one year. Two state-of-the-art, pre- and post-surgery bacterial monitoring technologies will be used; these procedures are intended to facilitate the early prediction, detection, and treatment of infection, as well as to provide follow-up data that can potentially be used to advantageously manipulate the stomal microbial environment in future clinical trials. 