Frontal X-ray of the right knee of a 62-year-old male patient with pseudogout, presenting with pain when walking at the level of the knee joint. In this condition, crystals of calcium pyrophosphate (arrows) are deposited in soft tissues such as cartilage, the connective tissue found in joints. In this case, deposits can be seen in the meniscus, a pad of cartilage between the tibia (shin bone, bottom) and femur (thigh bone, top). 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.