Anatomy, Arthritis, Arthrology, Autoimmune disease, Complications, Immunopathology, Inflammatory, Joints, Medicine, Pannus. Root Cause of Disease Rheumatoid arthritis it is one the type of Knee Pain. The most debilitating form of arthritis, rheumatoid arthritis is an autoimmune condition that can affect almost any joint in your body, including your knees. Although rheumatoid arthritis is a chronic…