M05.06: Felty syndrome Lower leg

You have a rheumatic disorder that is causing inflammation in your knee joint.

The knee joint connects the thighbone (femur) to the lower leg. The kneecap is also part of the knee joint. There are 2 bones in the lower leg. These bones are called the tibia (shinbone) and fibula. There is also a joint immediately below the knee joint between the tibia and fibula.

An inflammation in the joints can cause various symptoms. Typical is a swollen, painful joint. The skin above the joint may also be red. It may also no longer be possible to move the joint as usual.

The joint inflammation has been caused by a rheumatic disease. A rheumatic disease can affect the entire body. There may be inflammation in the bones, the connective tissue, and the joints. The symptoms can be more and less severe. It is thought that rheumatic diseases are caused by a person’s immune system producing antibodies against their own body. These antibodies attack the body’s own tissue. The tissue can get inflamed and damaged as a result.

There are various kinds of defense cells (immune cells) in the blood. As a result of the rheumatic disease you have fewer of one particular type of defense cell in your blood. As a result, you may more easily get infected by pathogens.