I recently had the same problem with a young one (5cm long) who had shattered his leg - advice here said to leave it be, but a good friend who is a vet suggested that 'snipping' it off above the break with VERY sharp scissors & a steady hand. She argued that if anyone had the option to regrow a perfect limb compared to trying to repair a severe break (especially when the broken limb is not resting in a position that will enable the healed bone to be positioned correctly - unlikely when the limb inverts & floats above the body like its waving

) so after much observing of my injured little one I decided to snip it off!
It was not easy at all & if you are not confident or you're scared then I don't recommend it. I guess it all depends on your axie too. I put my axie in a small container & left him to calm down for a while in the dark. Meanwhile I unwrapped a sterilized very sharp pair of surgical scissors (nurse friend brought me scissors & forceps - they were way too huge to use) I put on latex gloves & rinsed them thoroughly then rinsed again in aquarium water removed from large tank. While the axie was in the small tank I slid my hand under him & waited till he relaxed on my hand, once relaxed I gently pinned his toes with my thumb & had the scissors ready in my other hand - when he squirmed the leg straightened & I carefully but quickly snipped just above the break in the upper arm. It sounds easier than it was & I was lucky that the timing worked out. I have had a lot of experience with docking of Dobermanns over the years so can remain calm whilst handling an animal in this kind of situation. If you are not confident - call & find a vet who is able to do it for you.
If my axie had been any larger/older I would've definitely taken it to the vet - unfortunately my friend the vet was over in the states at the time.
After the procedure I put the axie straight back into his tank & he didn't seem bothered by it at all - if anything he was more active than he was with the badly broken limb dangling. The healing began within days & now 3 weeks later the limb has fully grown back & the toes are getting longer & stronger

like I said it isn't easy & most people on the forums here did not recommend the removal - I opted to follow the vets advice - I'm guessing 'splat' the axie (named after leaping from tank to floor - the cause of the broken front leg

) is pretty happy with his new leg too
Here are some pics of the break & regrowing...
The broken limb

Week 1 regrowth

Week 2 regrowth

Week 3 regrowth (taken today)
<3 >o_o< <3