sounds like chondromalacia!
Try strengthening the muscles, specifically the inner portion of the quadriceps through low-impact exercises such as swimming, or other exercises that do not require the knee to bend more than 90 degrees. If the condition fails to improve, arthroscopic surgery may be required to smooth the surface of the articular cartilage and remove cartilage fragments that interfere with the joint during bending and straightening.
There could be a few possibilities to your symptoms such as patellar malalignment, meniscal tears, loose bodies, arthritis, fractures etc. I would suggest getting this evaluated by an orthopedician for an accurate diagnosis. If an attributable cause is found, it can be managed accordingly.
Hope this helps.
Thanks for your responses.
This morning when I was working I thought it had disappeared and thought that it must have just been an alignment problem but I guess that was just wishful thinking.
I'll talk to my doctor about it and take it from there.
Thanks again for the feedback.
It sounds like crepitation--if you google that term you will get a description as well as potential causes. I have it in one knee also, but not the other. I am normal/low weight, and have had it for years. I hope your MD can help you limit any damage and shed light on the cause.
I saw my doctor today. He said that he thought it was patellofemoral ?syndrome. He said that my patella was quite loose. He has advised strengthening my quads. He recommended cycling and leg extensions.
Thanks all for your posts.