This unfortunately is a subject I became intimately familiar with about 2.5 years ago and yes a third option would have been nice
Long story short, I found myself in emergency surgery with a surgeon telling me there was no way they could save my leg and that it had to be amputated. Not something you ever imagine being faced with. I woke up in intensive care with both my legs, after making sure they hadn't removed the wrong one. Turns out they decided to give it a go and see if they could save my leg anyway. (I found out later on they thought I would still lose my leg and was informed it was a miracle I didn't).
For a long time, I really wished it had been amputated. The pain was extreme, my leg was just a useless lump of scared flesh which I couldn't use for a long time, I was stuck in a wheel chair for 9 months and it took 2 years before I was to the stage when I could walk with the aid of a walking stick. Mentally and physically it has not been a fun trip.
I knew I was lucky but it was really re-enforced when I was a patient in a rehab hospital where there was another patient who did have their leg amputated as mine would have been. They were going through the exact same pain and problems as I was but minus a leg.
As other people have already commented, if it doesn't work out, you can get it amputated later but if it is your first choice, you can't go back. Yes I am still in pain and yes I struggle but all said and done, I am glad the surgeons 'gave it a go' and I did keep what was left of my leg but I can also see why this is becoming an increasingly tough decision. Especially since I was informed that 5 years ago they would not have been able to carry out the surgery they performed which did save my leg.