I am 4 weeks post partial knee replacement. This was the second knee I had done. The healing process has been toitally different than the other knee which was done four months ago. I had very little pain with the first knee but this time around I am having quite a lot of pain my therapist says is muscle pain. It is often so bad I can hardly put any weight on it. The pain is in the back of the leg somewhat lower. The knee often buckles. Has anyone else dealt with a situation such as this?