I have pain in one knee. the pain eases when i walk or use it. i think it might just be arthritis. i'm worried about knee replacement?

It : It may be osteoarthritis, but without further information, it is difficult to be 100% certain. Typically, one would need to know some of the following: how long has it be bothering you, any history of injury, has it ever swelled up or turned red, and do you have similar problems in any of your other joints. The starting point should be to see your primary care doctor and let them discuss diagnosis and treatment options.

X-ray for djd dx: Usually a simple x-ray will tell us if you have arthritis. There are many other treatments for arthritis prior to knee replacement.