Arthritic ankle. Coloured X-ray of an ankle joint affected by rheumatoid arthritis, viewed from the side. The disease has caused the bones to become demineralised. It has also narrowed the spacing at the joint between the ankle bone (talus, centre) and the tibia (shin bone, purple, upper centre). Rheumatoid arthritis is a condition where the body's immune system attacks healthy tissue, usually the membranes of joints in the hands and feet. The immune response causes inflammation and the enzymes released as a result cause the damage to surrounding bone and cartilage. The disease can be treated with drugs, including anti-inflammatory and painkilling medication.