No cartilage left in knees

I have been told by my orthopedic surgeon that I have no cartilage left in my knees. Walking is beginning to be more difficult but not terrible. Stepping up and down even a curb is awkward. Stairs are a one step up or down with one leg and then bringing the other beside it and slow going.
I am having hyaluronic acid injections six months apart that help some. I am now wearing the right kind of shoe. I had been wearing a rubber soled platform sandal that I figured (because of all the rubber) cushioned my knees). Recently I developed tendon pain in both legs which I was told was due to shortening of the tendons behind and inside of my legs below my knees. I think the platform shoes might have been responsible for this because ,with running shoes now ,I feel the tendons stretching.
I do NOT want knee replacements!
What do others of you do in my situation that helps?
P.S. I know that losing weight would help. My weight has been a challenge all my life.. I am 5 foot seven and weigh 185. I am 73 years old.
I do swim laps regularly with no problem. I haven't tested whether I can still walk around a block.