A 30 year old woman comes in complaining of knee pain after a Lord of the Rings marathon. She gets anterior knee pain after long periods of sitting. The same pain also happens when she climbs hills, runs, and walks on uneven surfaces. She sometimes complains of a noisy knee. She is not an athlete.
Challenge: This does not seem like a whole lot of information, but the most likely diagnosis can be made based on this simple history. What is it?