Let's assume PEMF doesn't help either with fixing the non-union. What's the last option to fix a non-union before the doctor decides to amputate the leg?
First of all, amputation is only needed if the leg or part of it dies off and only amputation would save it. Seeing how people can live with a bone gap for month before they realize they have non-union, and other than the non-union they have no other issues with their legs, it means you could theoretically live with that bone gap and a weight beaing rod. Amputation is not the last resort.
-> Closing the bone gap back fully or to a certain degree is what would be the last resort, not amputation.
With that said, bone consolidation requires blood flow and stability. Do you even do exercises that raise your pulse above 100 bpm? Do you use supplements such as vitamin D3 + K2 and calcium?
And do you not drink any alcohol and not smoke?
If if have tried all that first for a few weeks without progress, then you can start worrying.