Improved Healing of Large, Osseous, Segmental Defects by Reverse Dynamization: Evaluation in a Sheep Model

: Although this is officially an annual report, the release of the funds was delayed until July 2014 because of the PI s transfer from Beth Israel Deaconess Medical Center to the Mayo Clinic. Activities since then have succeeded in obtaining ICACUC and ACURO approvals, which was the first task in the statement of work, months 0-3. We have also initiated work on the second task, months 3-6 in which the design of the adjustable stiffness fixators will be finalized and the manufacturing initiated. One such fixator has been tested on a cadaveric sheep tibia. In the unlocked, loose position, the axial stiffness of the tibia and fixator was 102 N/mm. In the locked, stiff position it was 218 N/mm. This result is better than expected and close to the target of a 2.5-fold increment suggested by our previous studies using rats. This aspect of the project is the present focus of attention, and additional cadaver legs will be tested in due course.