So it's 23 days after my surgery, and I hit a big milestone on my road to recovery today: I actually pedaled a bike. OK, so it wasn't my regular road bike--it was a big, plush stationary bike at outpatient physical therapy, and the therapist raised the seat way up high, but I was able to bend my knee enough to crank out a revolution.
To pedal a bike comfortably, I've read that you need 110 degrees of flex in your knees. With the seat post raised high, I've found that it takes less bend--even 95 to 100 degrees to get started. Today, by raising the seat a couple of extra notches, I was probably bending at about 100 degrees. We didn't bother to measure it. Those first few revolutions hurt quite a bit, and I raised my left hip a bit to cheat the angle, but after about dozen slow revolutions, I was able to pedal the bike slowly but steadily for about five minutes. For an avid cyclist like me, that's a big milestone after a total knee replacement (TKR).
The bike I have set up on my stationary trainer at home doesn't have quite enough seat post length to allow me to crank the pedals around, but I'm able to do loosening exercises at this bike by pedaling one way, and then the other, without actually doing a complete spin. I think I'll set up a different bike with a longer seat post so I can start pedaling at home in a couple of more days. It sure feels good to crank a set of pedals around--even it's very gingerly and with a bit of pain at first.