The remedy given was originally made from a plant called comfrey. The plant is also known colloquially as "knitbone" and "boneset" due to its abilities to help bones heal after fractures. In this case, the remedy was composed of one part comfrey to one trillion parts water (or 6C, in homeopathic terminology). Even at this dilution, the remedy was effective at increasing bone density around the titanium rods over the control group.
For patients, I routinely use and recommend using homeopathic comfrey (also known as Symphytum officinale, or simply Symphytum) to help bone fractures heal more quickly. Comfrey is not commonly used in herbal medicine because of concerns regarding potential toxic effects on the liver. Homeopathic doses, however, are safe, and by the evidence seen in this study, are effective as well.
Study: Homeopathic Symphytum officinale increases removal torque and radiographic bone density around titanium implants in rats.