pTOG Study

pTOG Study


rhBMP-2 vs. Autograft for Treating Critical Size Tibial Defects: A Multi-center, Randomized trial


Co-Principal Investigators: Dr. Lisa Cannada and Dr. Paul Tornetta III

The purpose of this study is to determine if rhBMP-2, a bone graft substitute, is as effective as using bone from the hip (iliac crest autograft) to help promote healing of open, tibia fractures with a bone defect.

Open tibia fractures occasionally are missing a segment of bone due to the severity of the injury. Those fractures will not heal and will need an amputation if surgeons are not able to fill in the bone defect. The defect is usually treated with bone from the hip (iliac crest autograft or ICBG). While the use of ICBG bone to treat fractures with bone defects is generally successful, it has some drawbacks. The bone graft sources are limited and the procedure requires additional operating room time plus the need for a second incision. This may increase the risk of infection, pain after surgery and a longer hospital stay.


Recombinant human bone morphogenetic protein 2 (rhBMP-2 – or bone protein made in a test-tube), is a bone graft substitute and provides an alternative to the use of ICBG. rhBMP-2 was first approved for use in the spine and then in open tibia fractures. A small study has shown rhMBP-2 and allograft (cadaver donated) bone is as effective as ICBG to fill a bone defect in a tibia. The pTOG study will include a larger number of patients to assess if rhBMP-2 is as effective as ICBG.


The purpose of this study is to determine whether rhBMP-2 will promote healing in an open tibia fracture with a bone defect without the need to use the patient’s own bone and avoid the complications that come from using this procedure. Overall, we hope to show rhBMP-2 is a safe substitute for the patient’s own bone in fracture healing. rhBMP-2 is commercially available (Medtronic Sofamer Danek, Memphis TN). It is currently approved for use within the first 14 days in open tibia fractures treated with an intramedullary nail. The FDA has granted an Investigational Device Exemption (IDE) for use of rhBMP-2 for this study as it is a device to promote bone formation and healing of fractures with bone defect.


Patients who are seen at follow up with a tibia fracture with bone loss requiring surgical intervention to heal will be considered for enrollment. Study participants will be prospectively randomized to one of two treatments: (1) Illiac Crest Autograft or (2) delayed grafting with rhBMP-2/allograft. Patients randomized to delayed grafting will have an antibiotic spacer placed in the segmental defect to develop a bioactive membrane. Patients will be followed for 12 months to determine the number of unplanned hospital readmissions, non-unions, infections and reoperations, as well as assess pain, functional outcome, and medical costs. Completion of this project has the potential to alter the standard of care for these severe injuries and improve outcomes of infection, nonunion and re-hospitalization, at decreased costs and morbidity.


This study is being funded by the Orthopaedic Trauma Association and the DOD OETRP METRC Consortium Award (W81XWH-09-2-0108).