I was having a knee problem awhile back that seems to have almost rectified itself. It was debilitating and I had it for months and didn't walk anymore than I had to. At the moment, it's not bothering me and I'm fine in the house but when I start really walking on the street or uneven surfaces, I feel it in my calves and ankles which I attribute to lack of exercise. The ongoing problem I've had for years is my lower back with osteoporosis and scoliosis. I can't stand for long without looking for a seat. I'm pushing 85 and don't doubt that at some point I'll welcome a scooter.