I have been having pain in my right knee for a few months. For the past several years (or a decade?) my knee occasionally will ‘click’ when I run downhill when very fatigued, or on an occasional swim day when I am flutter kicking. The pain has been growing over the summer and fall, finally making it so painful to run downhill that I have had to stop running. I made an appointment to visit an orthopedist. A few xrays and a quick physical exam and history, and the diagnosis of patellar osteoarthritis was made.