I also have osteoarthritis in my right knee, Learning to spin a granny gear that does not put pressure on the joint works well for me,instead of pushing down a higher gear.From time to time you will have to apply the weight on the knee joint but you can deal with it if you don't over do it.Have also met people who have had surgery to replace part of the cartilage between the knee joint with teflon,etc.They report it works almost as good as the original.I am thinking of trying that next.
Have heard also about some folks who mountain bike using a biopace elliptical chain wheel that reduces the pressure at the point you are applying the most pressure,the best I can explain it is that at that point the gearing suddenly drops into a much lower gear reduceing the amount of pushing needed.Can't say if it works or not but I am going to look into it.
Also,depending on how much damage you have to the knee,you might try some of the yoga stretches just before you ride this seems to help me well.I am 72 and will keep on riding till I drop.
Edit: I took a ride later and was thinking over your idea to find a way to use one pedal,letting the one good leg do the work.Then had a thought about just apply most of the power with my left foot and just ease off the pressure with my right( my bad knee) but still keeping some pressure on the right pedal.It felt rather awkward at first but after a few moments seemed to work well as long as I concentrated on it.After a bit it started seeming very natural, like mashing with the left, spinning with the right with both feet contributing to the power input. How useful it maybe I won't know until I have ridden awhile like that.
I don't think it would be a technique to use all the time but may have it's uses.Only time will tell.
Last edited by sdwphoto; 06-15-14 at 12:29 AM.
Reason: additional information