I can do walks well, on a flat surface. But if I walk on uneven ground like in grass, my knee implant will sometimes pinch a muscle near it. That hurt like getting a shot with one of those 6" needles. The more I exercise the less pain and swelling I have around it. Now my right knee it's worn out, I partially tore my PCL in the right leg. Never got it fixed, that was back in 2007, and me being overweight doesn't help any. I had fluid just below the kneecap on the right side of the knee which is where that PCL is at. Plus I'm sure there isn't much cartilage left in that knee. Moral of this post is, take very good care of your knees! Stay at a good weight, don't lift more than you have to. Remember everything you pick up all the weight ends up on your hips, knees and ankles. Lose you knee mobility and you could end up in a wheelchair or with a artificial knee implant.