Go to the doctor and have your knee checked out. I had problem for years. After my stroke it was more of a problem. I have terrible balance issues and it was really difficult to deal with both the balance issues and knee problem at the same time.

One day it was bothering me so I got on the exercise bike, which has always helped in the past. When I got off I could hardly walk. A few months later I had arthroscopic surgery. The surgeon said what he did was clean up a lot of loose stuff in the knee. It took a number of months to totally heal. I am very glad I had the surgery. That was in 2001 and I have had no problem since.

An Orthopedic Surgeon can order the appropriate tests and provide the correction needed. It is well worth the time, effort, and money.