"Narrowing of knee joints" is when the joint cartilage between the knee bones is deteriorating and causing the bones to rub against each other.
I haven't seen anything that would directly attribute that to Lupus. However, I can imagine that the inflammation from Lupus could possibly contribute to cartilage deterioration.
You probably want to ask your rheumatologist - they can give you the best answer for your particular combination of things. (For instance, if you've never had Lupus inflammation in the knee, it might not be related at all.)
Hope that helps...
Lynnwood, Lupus & Sjogren's ModeratorDIAGNOSING-LUPUS & LUPUS-RESOURCES
"Life is far too important to be taken seriously" - Oscar Wilde