[1] Univ Med Ctr Hamburg Eppendorf, Dept Osteol & Biomech, D-22529 Hamburg, Germany
[2] Harvard Med Sch, Massachusetts Gen Hosp, Harvard Stem Cell Inst, Dept Orthopaed Surg,Ctr Regenerat Med, 185 Cambridge St, Boston, MA 02114 USA
[3] Univ Texas Austin, Dell Med Sch, Dell Pediat Res Inst, Dept Pediat, Austin, TX 78712 USA
[4] Harvard Med Sch, Boston Childrens Hosp, Dept Orthoped Res, Dept Genet, 300 Longwood Ave, Boston, MA 02115 USA
[5] Univ Washington, Dept Mech Engn, Inst Stem Cell & Regenerat Med, Dept Orthopaed & Sports Med, Seattle, WA 98195 USA