I haven’t read all the responses yet but want to chime in with what I’ve seen. I would first get a second opinion from another doctor, and maybe seeing a PT would help too? But a word of caution and encouragement to deal with this and not let it linger, which could very likely mean having the surgery. My father-in-law is 90 and in terrible knee pain every day. He has been for years and refused surgery. Long story short, he waited too long and now his heart has issues that won’t allow for knee replacement surgery as his cardiologist won’t sign off on it. At 90 he’s actually in pretty good health and would continue to be active but his knees are in too much pain. It’s really hard to see this! If he’d done the knee replacement at age 80, they'd still be in great shape. Something I hope you’ll consider, whatever you end up choosing.