That is why the goal of Regenerative Medicine is that, produce new organs or arms or basically whatever you want. I think that eventually one day we can reach the point of complete regeneration, but also there is going to be a problem with ethics & governments as usual. For example, working with embryonic stem cells is strictly regulated, to the point that if you "wash-off" the cells you can even go to jail!
Anyway, the power to achieve that as scientists relies on further investigation!