1. Department of Orthopaedic Surgery, König-Ludwig-Haus, Orthopaedic Center for Musculoskeletal Research, Julius-Maximilians-University, Würzburg, Germany.
2. Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
3. Department of Orthopaedic Surgery, Children's Hospital of Boston, Harvard Medical School, Boston, Massachusetts.