Thanks for the input Chomps. I don't have pain in any other joints and I've never had a knee injury before so I don't think it's your type of arthritis or a degenerative condition....
OK, I'm a little confused.
My right knee (regular stance) usually bothers me about half-way through the season and I never really thought much about it figuring the torque that's placed on the joint causes it to flare up. Usually by the middle of spring everything is fine and I get on with my summer activities.
I wasn't necessarily referring to some major, immediately destructive, traumatic injury! Repeated stress, (i.e. trauma!) of the sort you are describing as having over some number of years boarding, is sometimes all that's necessary to cause the type of arthritic degeneration I was talking about.
There is a blood test to check for RH factor. It is by no means definitive for determining that you have any type of rheumatoid arthritis, as some people with this factor present never have any disease process or symptoms. But it could help you to determine if what you are experiencing is arthritic degeneration from past traumas or the beginning of a more general arthritic condition. Early detection and treatment can help with getting meds that can limit further joint degeneration that can occur from the rheumatoid types of arthritis.
These are some of the things you will want to talk over and ask questions about with your doctors.