It’s great that you are extensively researching the procedure and giving it careful consideration, but delving deeply into observing people’s walking (initial burst, rhythm, behavior, etc) may be excessive. Even for individuals who have not undergone the surgery, scrutinizing their walking/running in detail may reveal imperfections (there are even coaches for correct walking posture). I have several friends I hike with, and if I observe closely, I can notice imperfections, but most of the time they are minor and probably go unnoticed by them.