Sharon, I have osteoarthritis in my knees and am currently having acupuncture at the hospital for it.
Have only had 1 session up to now but will be having it every week for the next 5 weeks.
I purposely went on a diet as I felt I needed to lose some weight, and I've lost a stone, but it hasn't made any difference to the pain.
Saw my Rheumatologist on Tuesday who noticed I'd lost weight but she just said she didn't think I was overweight in the first place and made no mention of it being of help to my joints.
Taking up swimming sounds like a great idea, hope that will help you.