My mom always was bowlegged and arthritis later in life, but the pain was finally too much to walk when she was in her mid 60's so she had both knees replaced- one at a time. The first one was a cake walk and mirrored wh06's experience. Up and walking next day, had the leg exerciser going pretty much 24 hours a day and released on the second or third day, can't remember now. The second one was more like the OP's experience and she experienced quite a bit of pain but was able to get through the PT and finally got back to normal. She always said it was one of the best decisions she ever made. She was able to walk and get around right up until she passed at 85 .... seems like just about everyone I've talked to who had knee replacement or hip replacement has said the same thing- they wish they had done it sooner...
Bob
