I knew research were being done on tissue regeneration but I thought it was still at the animal models stage (lizards and its kind, like salamanders are the usual animals being studied). I didn't know there were actually human trials already and that there is 'MatriStem', probably a solution containing tissue growth factors.

It helped that the pinky was amputated above the base of the nail, the nail-growing base is a specialized tissue and it may not be possible yet to regenerate these kinds of tissues. No x-rays were shown, hence I have no idea if the bone did grow back, most probably not, but then it still is a great scientific advance.