My good news is I can still walk, meaning go for as long a walk as I want to. The bad news is, unless I have surgery I probably have a chronic problem now. I would need an MRI to confirm, however it appears I have a torn meniscus.
For now I need to ice my knee, for the swelling, and avoid walking downhill. Walking uphill on the treadmill and using the recumbent bike, both of which I can use in our workout room at the clubhouse, should be good for me.