Dunno about fusing your ankle, sounds a bit like welding a sprocket on.
We can compensate for all sorts of injuries but constant pain is a hard one to deal with.
Even so I would be looking for a second opinion on the ankle, there may be someone out there that can rebuild it. Have you got private cover?
My mother had both knee joints replaced in the late 70’s because of arthritis.
They told her at the time the joints were only good for 7 years and they would have to be redone, no doubt they would have improved since then.
At the time they didn’t come with knee caps so she could never kneel down again. Would today’s joints be any different?
It was in the early nineties (with the original joints still in and working fine) when she had a fall and developed an infection in one knee. She was in hospital for some time, we thought we were going to lose her she was so bad with the infection. The problem was that the infection was in the false joint and as there was no blood flow into the false joint none of the antibiotics they were pumping her with could reach the infection to work. Eventually they had to remove both knee joints for a couple of weeks so they could get rid of the infection and then fit her with new knee joints again.