What Causes Numbness And Tingling Sensation In The Legs While Having Rheumatoid Arthritis?

I have recently been experiencing extreme fatigue in my legs with tingling or buzzing that seems like it is going to make me fall or my legs give out. It almost felt like I was not going to make it to the bathroom at the other end of the house which I would guess is approximately 75 feet. I am a long term rheumatoid arthritis and have two new knees as of 2010. I also have significant lower back problems with one vertebra being 16 mm out of place. I ve had 2 back surgeries to fuse S1 and L4/5 due to a ruptured disc. I can t think of the term but I ve been told my spine column has some filling in problems. Could the buzzing or tingling be from the spine being pinched off due to degenerative arthritis of the spine?? I have a consult tomorrow for getting a stimulator test for my back to see if it would help my lower back pain. I may postpone the test because we are probably moving to another State because of my husband s problems with dementia.