I had right hip replacement 5 weeks ago. I was progressing extremely well with my physical therapy, even walking without a cane. Last week, quite suddenly, my right knee (on the operative side) became very painful when I place weight on it. It is not swollen or red. It does not hurt while I am at rest, but it is very painful to walk, even with my cane. Can this be typical after replacement? I had my left hip done four years ago & did not experience this knee problem. Can you offer any insight? Thank you.