Coloured frontal (left) and profile (right) X-rays of the left thumb of a 76 year old male patient affected by chondrocalcinosis, or pseudogout. In this condition, crystals of calcium pyrophosphate are deposited in soft tissues such as cartilage, the connective tissue found in joints. Affected joints are red, swollen and extremely tender. Treatments include the use of nonsteroidal anti-inflammatory drugs. If these fail a corticosteroid drug may be injected into the affected joints. The underlying cause of pseudogout is unknown.