[1] Gillette Childrens, Res Dept, St Paul, MN USA
[2] Henry Ford Hlth Syst, Dept Orthopaed Surg, Detroit, MI USA
[3] Gillette Childrens, Dept Orthopaed, 200 Univ Ave East, St Paul, MN 55101 USA
[4] Univ Minnesota, Dept Orthopaed Surg, Mineapolis, MN USA
[5] Univ Minnesota, Med Sch, Minneapolis, MN USA
[6] Univ Minnesota, Dept Rehabil Med, Minneapolis, MN USA
[7] Univ Washington, Dept Rehabil Med, Seattle, WA USA
[8] Twin Cities Spine Ctr, Minneapolis, MN USA