Open tibia fractures have a 15% or higher rate of not healing. Those fractures which do not heal are typically treated with bone from the hip (iliac crest autograft; or ICBG). The use of ICBG bone with the treatment of delayed unions/non-unions with critical defect, although successful, has its drawbacks. The bone graft sources are limited and the procedure is associated with additional operating room time plus a second incision with increased risk of infection, post operative pain and increased hospital stay. The purpose of this study is to determine if Rh-BMP2, a new bone graft substitute, is at least as effective as using bone from the hip (autograft) to help promote healing of open, tibia (shin bone) fractures.