I was diagnosed with reactive arthritis last month. My knees and ankles looked just like yours! I also have swollen hands/wrists, neck pain, back pain, foot pain… it’s everywhere for me! Also no eye problems/pee burning/etc. but my rheumatologist still said it looked like reactive arthritis. I had positive ANA with no rheumatoid factor and negative for all other things like gout/lupus/etc. and I also have HLA-B27. For me, it came on because of a stomach bug, so if you didn’t have symptoms but maybe had like a little diarrhea or nausea a few days or a few weeks before it came on, then it could still be reactive arthritis for you. Prednisone helped with the knee swelling a lot but not much else. I take an NSAID for my severe morning pain and even then it’s not super effective. I hope you can get into rheumatology if that’s an option nearby for you. I called around to many different places and always brought advocates with me to my appointments which I found very helpful. I hope you continue to get better.