My grandmother had a total knee replacement, which is pretty close to the same thing, just smaller. Hers was due to osteoarthritis(she had no cartilage in either knee and was in terrible pain. They did one at a time, of course). She was in the regular hospital on a morphine pump for 5 days (including the day of her surgery). They then moved her to a rehabilitation hospital once they had switched her to oral pain meds. She was there for 2 weeks, then home with a walker. She had physical therapy every day in the rehab hospital (that is their purpose) and I drove her to PT for a month (she wasn't allowed to drive for 6 weeks, and even then her surgeon said she had bounced back REALLY fast). After that she was back on her feet. She just had her other knee done last year, and she's in great shape. Good luck!
Chronic Pain Patient