I was told that osteoarthritis hits the back, hips and knees. Why did the doctor tell me that I have osteoarthritis in the base of my thumb?
Osteoarthritis is, as you say, more common in the back (spine), hips and knees. However, it can occur in any joint. It's called the wear-and-tear arthritis and, if you think about it, you usually do use your thumb quite a bit. And, some people - manual laborers, for example - put a lot of pressure on their thumb and that joint. As the tissue in the joint begins to wear away, this is what causes the pain.