Oh geez, yeah, rowing with a fused ankle sounds impractical.
My back only hurts badly when the particular exercise I'm using forces me to row fast with low power. In that case, I basically use no arms or body, and my back can't tolerate that pitched forward position for minutes on end.
I appreciate the thoughtful offer, but I kinda doubt exercises will make that position easier. And I don't have to do that much.
I knocked out about 7500m this morning. Got up at 4:30 because I had a 6:30 AM meeting, which was stupid but worth it.