 Bioventus will provide visually identical active and sham Exogen 4000 units. The units will undergo randomization and will be given consecutively numbered labels. Devices will be securely stored at each clinical study center. All clinical centers and personnel involved will be blinded to the randomization. Two weeks post-operatively subjects will attend cast clinic and be assigned the next sequential device. The device will be applied through a window cut into the standardized cast with a center point over the anatomic snuffbox. This cast will remain in place until the fracture is united on CT, or 7 weeks at a minimum. 