I have had both knees replaced, three years apart. Both are a success. The second (right knee) was more painful, but not horrible. The second also needed a bit more effort to achieve full extension. My right knee (2nd replacement) was in quite bad shape. I had very little pain pre surgery with either knee, but more pain post surgery with the second knee. Now, 7 months post second surgery, I am walking daily, and climbing the hills in my yard. Happy, happy. I am so glad I had my knees replaced, and also so glad it's over.