Not to scare you but this is NOT a comfortable surgery to recover from. I frequently tell my patients who are planning this surgery to expect to be miserable for 1-3 weeks. Miserable is a very strong word yet very few of my patients say it wasn't as bad as they thought it was going to be. What surprises many of my patients is how long the knee remains uncomfortable after surgery, many of them think "I am tough" or "I am in good shape going into surgery" so it shouldn't be that bad. Unfortunately this is basically carpentry of the body and it hurts. Toughing it out for a few days isn't enough because it still hurts after week one and two. With that said, the outcomes are EXCELLENT and almost everyone is glad they had their surgery and often wish they had it sooner.
Fortunately the pain gradually subsides and the new complaint is STIFFNESS. If you leave your knee straight too long it hurts and if you leave it bent too long it hurts. Stationary bikes are really helpful at keeping the knee from getting too stiff and it is quite rewarding the first time you make a full revolution on the bike. Most of my patients will struggle to get knee extension (straightening) OR knee flexion (bending), rarely do patients have trouble getting both directions. Knee extension is the priority as it allows you to stand and walk properly. If you are fortunate enough to have your range of motion come back easily, your rehab is much more comfortable. The stiffer you are, the hard/longer it needs to be pushed on by the patient or therapist.