I Have Been Having A Strange Sensation On The Bottom

I have been having a strange sensation on the bottom half of my right leg for a few weeks now both night and day. It feels like a worm or an electrical current crawling up my leg. That is the same leg which needs a total knee replacement. Any connection? This sometimes keeps me awake at night. I am a healthy 70 year old female with no health issues apart from arthritis in several of my joints . I am not overweight and do not smoke or drink. What is going on??? Thank you .