1. Division of Orthopedic Research, Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA
2. Division of Musculoskeletal Radiology, Department of Radiology, Mayo Clinic, Rochester, MN 55905, USA
3. Department of Orthopedic Surgery, University of Minnesota, Minneapolis, MN 55455, USA
4. Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
5. Rehabilitation Medicine Research Center, Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN 55905, USA