I lived with very serious knee pain for 20 + years. I blew my knee out in football in the late 60's in my junior year of high school football . I had it repaired playing football and than wrestled my senior year in high school wearing a brace. Fast forward to the 80's when I coach junior high and freshmen wrestling team at our local schools. When coaching my younger son caught my knee in a move damaging it again. Oh well! That's the story.
Now, I lived with this limping and using everything I could to relieve the pain in my knee joint. I finally went to a one of the best orthopedic surgeons in the area. I did had my knee examined and replaced three years ago, I have never felt better. My only regret is that I did not do this 10 to 15 years earlier. We tried the shots but he said that they only work in about 10% of his patients, but lets try just to make sure. The shots did not work in my case.
My wife has had her hip replaced by the same surgeon two years ago and she feel like a new woman now. We both walk a minimum of three miles a day at one time doing about 17 min miles.
My advice is go find a very very very good orthopedic surgeon and have them evaluate the knee joint. Ask around and do a google review on them see how many surgeries that they have done, talk to the Doctor. They can do wonders and do not listen to the quacks on TV trying to get your hard earn money.