Do you wash your hands a lot? I saw many health care workers at the nursing home my mother lived in with terrible cracked hands (bleeding even) that was from the hundreds of times they had to keep washing their hands every day between patients. (yes they wore gloves but were supposed to wash their hands after removing the gloves too). One ointment that helped them a lot was called "Skin Food"- it's Swedish, orange scented, and has a LOT of natural lanolin in it, I get mine in the health food store. They would put it on at night and a bit more in the morning. Might help to massage it on your knees too?
I know my circulation has improved a lot through biking- I used to have perpetually cold hands all my life but not much anymore.