1. Department of Orthopaedic Surgery, University of Pennsylvania, 424 Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, PA 19104; Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 South 33rd Street, Philadelphia, PA 19104
2. Department of Mechanical Engineering, Rowan University, 232 Rowan Hall, 201 Mullica Hill Road, Glassboro, NJ 08028