1. Department of Biomedical Engineering Duke University Pratt School of Engineering Room 1427, Fitzpatrick Center (FCIEMAS), 101 Science Drive, Campus Box 90281 Durham NC 27708‐0281 USA
2. Department of Orthopaedic Surgery Duke University School of Medicine 203 Research Drive Durham NC 27710 USA
3. Department of Mechanical Engineering and Materials Science Duke University Pratt School of Engineering Duke University Box 90300 Hudson Hall Durham NC 27708‐0300 USA