My 16 year old daughter, who is a very athletic individual (lifeguard, hiker, bike rider, swimmer), has recently experiences swollen
. At times, in the morning especially, she finds it difficult to walk and almost impossible to bend at the knee. It is obviously a tissue swelling that causes this, but what is causing the tissue to swell? Is it a form of Bursitis, perhaps, or are there other issues that have these common symptoms.