Old man Johnson limped into the doctor's office and said, "Doc, my right knee hurts so bad, I can hardly walk!"
The doctor slowly eyed him from head to toe, paused and then said, "Mr. Johnson, just how old are you?"
"98!" Johnson announced proudly.
The doctor just sighed, and looked at him again.
The old man said, "Well, my other knee is 98 years old too, and it don't hurt!"