Keep in mind that it is best doing these exercises after the RA flare-up has subsided. Since you are probably using different muscles then you would when you are not in pain, you may do more damage then good. Don't try to be a tough cookie either by pushing through the pain. That could totally defeat the purpose.
To strengthen and balance out the muscles around your knee, stand next to something that will support you in case you need it. Stand up straight, press your hands together in front of and close to your chest.
Lift up your head and then one leg to where the knee is level with your hip. If that is not possible, simply lift it as high as you can. Swing the lower portion of your leg from side to side about 25 times and then switch to the other leg.
Another good exercise to strengthen the muscles in the front of your upper thighs is standing with your back against the wall. This is meant in the literal sense of the word, grin. Step your feet forward slowly. Your back will slide down the wall while doing this.
Once you reach a position which resembles sitting on a chair, press your back flat against the wall, place your hands together as if praying in front of your chest and maintain this position for about one minute.
There are several more exercises which I will address in another post. In the meantime, you can always put your hands together in front of you to pray. God hears all of them!
And whatever things you ask in prayer, believing, you will receive.”