I have OA in my left knee, but I also have leg pain from the groin area to my ankle. If I keep the leg elevated it does not swell or hurt that much, but it can if I walk alot or use it. I have pain on the front of the leg running to the back along a vein or muscle. It comes and goes.
I need more details about onset of the pain, type of pain like pricking,  tingling,  sharpshooting. Anyhow relation of groin pain with osteoarthritis  of knee is remote.