Hmmm, haven't seen your knee and you don't want to listen to me as I ran down the Ben with a broken fibula but...........
If you have not had an acute recent meniscus tearing injury and there's just bits of stuff floating around in your knee from general wear and tear and they are not big enough to cause your knee to lock then gentle mobilisation with cycling would be good and you could progress as you feel able and as the swelling subsides. If your knee is very swollen and there you have recently torn a meniscus then you will have to be more circumspect and be guided by pain. Does that cover the bases???