Re: Osteoarthritis: Brace users
I use a brace when I practice aikido, but I do not know whether it is similar to the one you use. I use two types, a softer one bought here in Japan and a thicker one bought in the Netherlands from a sports supplier. The thicker one is used on more intensive training seminars. I am really not sure what value they have, other than to provide reassurance that nothing drastic will happen during aikido training. I do not do seiza at all.
From your description, I have a similar condition (though I am aware of Janet's point about knees). I had the medial meniscus removed (from both knees) over 30 years ago and now have osteoarthritis. (I am a few years your senior.)
I have been having regular injections of sodium hyaluronate (once weekly for five weeks), but have not had any for almost two years. The most recent benefit for my knees has been to lose weight substantially (10 - 15 kgs) and this has also stopped further degeneration.