I found that the knee pain was more from the narrow MH steps. You don't even realize it but you have to twist your ankle as you exit the RV to fit your foot on the step as you go down. Which puts stress on the knee.
For months I wrote it off and thought it was just bad knees and arthritis. Until I pulled off the road for a few months and the knees got better.
Next time out I added different types of added steps that allowed me to walk straight out on real adult size steps to exit the MH instead of turning an twisting using those darn narrow stock RV steps and gone was all the pain.
As we get older I think we tend to write everything off to old age instead of really looking at the whole picture of how and what we are doing and if it can be changed to assist us.
Those RV steps are murder on the legs, ankles and knees! :B