Knee osteoarthritis is the most common cause of disability in adults in the US, recent data indicate, and the problem is growing. Yet Stefan Coombs, an orthopedic surgeon at Johns Hopkins, says not all knee pain is caused by osteoarthritis.
Coombs: There are many other relatively common causes of knee pain which can include fractures, you can have an ACL injury or tear, inflammatory conditions or tendonitis of both the patella and the quadriceps tendon, or you can have a meniscal tear and very rarely there's a potential of an infection within the knee. In addition to inflammatory causes it should be highlighted that the sensation of knee pain is not always attributed to a structural problem within the knee joint itself.    :31
Coombs says a careful history by someone with expertise in this area and perhaps imaging will begin the process of defining what’s going on in someone’s knees, and that’s foundational to addressing it. At Johns Hopkins, I’m Elizabeth Tracey.