Knee replacement at two years...

[Sylvia]

The bad news is since my knee is so full of scar tissue from the five previous surgeries, my mobility is permanently compromised (you can still gain some increased range of motion in the first 18 months). I'm at 104 degrees of flexion and 5 degrees of extension; what that means is at 5 degrees extension I have a slightly impaired gait (I limp often since I can't straighten my leg all the way), and bike riding requires about 117 degrees of flexion so when I attempt it I end up tearing scar tissue loose. All in all it's better than before the surgery, but I sure wish I'd had a better result.

I have no idea if this would help or not, but would shorter crank arms help? And by shorter cranks, I don't mean going from 170mm to 165mm but maybe down to 152mm or 145s or shorter.
I ride with 145mm cranks and a very setback seatpost like this one. I had Mark Stonich at BikeSmith design shorten a pair of crank arms for me a while back and he did a great job!!

Or maybe a pendulum crank