By studying the underlying differences in gene expression during healing after a bone break in young versus aged mice, Jaimo Ahn, MD, PhD, assistant professor of Orthopaedic Surgery at the Perelman School of Medicine, University of Pennsylvania, and his colleagues aim to find specific pathways of fracture healing in humans. The team of researchers will present their findings in a poster presentation beginning Tuesday, March 19, 2013 at the 2013 American Academy of Orthopedic Surgeons annual meeting in Chicago.