The overall objective of the total project is to develop knowledge sufficient to predict changes in bone structure associated with the biomechanical factors resulting from devices capable of achieving a biological attachment to skeletal bone. This is to be accomplished using a combination of studies involving in vivo testing and engineering stress analyses. Initially, cylindrical implant specimens are to be placed in the femurs of dogs and finite element analyses of that implant system will be conducted to determine the effect that the material properties and the biological attachment mechanism have on the biomechanics of the tissue-implant system. These data will be used to establish design criteria intended to improve the biomechanical compatibility of implant devices placed in bone tissue.