Five years ago I had a right TKR. At the time I was not very active and had a lot of pain doing normal work and activities. Like you my other knee was bone on bone but did not bother me as much so I only had my right one done. Since then I have been riding a lot and have lost close to a 100 lbs. My regret know is that I did not get both done because the left knee is hurting and starting to hold me back. At this point I am afraid to interrupt my cycling for fear of gaining weight back so I take pain meds and put up with it.
If I had it to do again I would have done both and got it over with. If you decide to go forward I would check with a Drs. It is not a very long procedure, little over and hour for one, so there may be a Dr. who would do both with your condition.