I have severe arthritis in both knees and just completed arthroscopy surgery.
The best thing to do is to find a good orthopedic physician and request an MRI. There may be more going on with your knee than you realize. In addition to arthritis, I had a torn miniscus, a sprained ligament and some other cartilage damage, that happened when I exercised. Your doctor will know how to proceed from there.
While my arthroscopy helped a lot, it didn't solve all of the pain from arthritis. I now take anti-inflammatory medication and Tylenol, ice my knee periodically, and wear a knee brace. Eventually, I may need a knee replacement.
My doctor emphasized the importance of weight loss to relieve pressure on the knees. For every one pound of weight lost, that takes four pounds of pressure off of the knee.
I know that what you are going through is very difficult, but a good doctor is the best place to start.
Please keep posting and let us know how you are doing. I am sending you hugs
and wishing you the very best.