Hi -- I know what you are describing about your knee -- several years ago, I tore the cartiledge in my left knee (ballet class, so this was MANY years ago) and didn't have surgery, just let it heal - took months of hobbling around -- but every now and then, the knee cap moves out of place, kind of like your elbow might do that or your shoulder -- and it seems to just put itself back, eventually. I remember the orthopedic doctor telling me that I needed to do things -- make sure my thigh and calf muscles were strong -- because they help keep the knee cap in place -- AND to stretch, so that the thigh muscles don't get so tight they PULL the knee cap out of whack. I tend to have really tight ham strings, and they also cause my back to hurt sometimes.... Now that the weather is warming up here in Connecticut, I am psyching myself up to (1) at least three times a week and (2) get back into yoga and/or beginning Pilates. By the way, I am listening to a book on tape called Making a Good Brain Great, and one of the best protections against Alzheimers (among other things) is regular exercise. It also helps with ADD, which is why I am listening to this book -- looking for ways to make my brain function better so I can deal better with eliminating clutter and storing those things that I actually need and/or value. -- Brenda