Knee joint swelling is caused by a buildup of fluid in the tissues surrounding the joint and is usually accompanied by pain and stiffness in the knee. It can be an indication of an underlying injury such as a bone fracture or torn muscles, tendons or ligaments. Arthritis or an infection are other possible causes. Individuals experiencing swelling in the knee area should consider the use of orthopedic supports such as those below. However, the advice of a medical practitioner should be sought as a first step and the choice of product should be consistent with guidance received from this source.