I Am 60 Y/o. While Studying Abroad In My 20s,

I am 60 y/o. While studying abroad in my 20s, I fell go up some stairs, hitting my knee cap on the corner of one of the stairs. It was 6 months before I went to the doctor (when I returned to the States), and my doctor told me that eventually I would need a knee replacement (in my 50s or 60s). I have had knee pain and swelling on and off, and have been able to take care of it with pain pills.
2 years ago I had a bad fall, tearing ligaments on that knee (left) and breaking right ankle - I spent 4 weeks on a wheelchair before I could even start walking. Two days ago I attended a function at work which required professional dress. I wore low heels for the first time in over 2 years and now my knee is hurting badly. I will be travelling home on Monday, and will not be able to see a doctor before I leave. A nurse friend of mine told me that from my symptoms, I might have a torn meniscus. What would you recommend for treatment until I see a doctor on my return (December 30)? Mary