My knees act up now and then. I used to wear a neoprene brace, the kind available at pharmacies, but it finally began to fall apart. Lately I've been experimenting with kinetic tape which seems to be working as well as the brace but is more comfortable and can be worn for several days and in the shower. Kinesiology Tape | KT Tape

My other line of defense is to step up knee exercises, especially exercises that work muscles involved in lateral moves. My reasoning is that pedaling strengthens front to back muscles and ligaments but lateral ones are neglected. I have the theory that the body should be balanced with all aspects of moving ability being of equal capability. In any case, knee strengthening works for me as after stepping up efforts knee discomfort subsides.