I used to run to keep my scale down but my knees finally told me that's not cool. I miss it, mentally and scale wise. I've put back on some weight but not all that I had originally lost. I know that is part of my most recent knee pain. I have had knee issues since I was 27 and didn't take up running regularly until I was about 39. It was only a short lived new found passion. About 3-4 yrs long.
Recently I have been going to PT for chondromalacia/arthritis. My PT said I could run again someday as it's not out of the ? but I don't dare. I'd rather save my knees and find something different to do more long term. So I'm dusting off my mountain bike and going to start riding that again (now that my kids are older and I can leave them home alone for an hour or 2. That was part of my not using my bike the past few years).
Has anyone taken up riding their bike instead of running?
How many days a week were you running at your peak?
If you are able to run in the future, perhaps running twice a week or 3 times a fortnight and then do other stuff like cycling, would be a better fit for your situation.
And as corrado33 stated, treadmill running is much kinder on the joints.