Pseudogout. Arthroscope (endoscope) view of a knee affected by pseudogout or chondrocalcinosis, a type of arthritis. The joint inflammation is due to crystals of calcium pyrophosphate dihydrate in the cartilage of the joint. Each knee has two crescent-shaped pieces of cartilage called menisci. Gout is a similar joint disease caused by crystals of uric acid. Arthritis is treated with anti-inflammatory drugs.