1. Department of Biomedical Engineering, University of California, Davis, California 95616, USA
2. Department of Orthopedic Surgery, Division of Sports Medicine, Boston Children's Hospital, Harvard Medical School, Massachusetts 02115, USA
3. Department of Biomedical Engineering, University of California, Irvine, California 92617, USA;
4. Department of Orthopaedic Surgery, University of California, Davis, Sacramento, California 95816, USA