Chondrocalcinosis
（重定向自Calcium pyrophosphate deposition disease）
Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, also known as pseudogout and pyrophosphate arthropathy is a rheumatologic disorder with varied symptoms and signs arising from the accumulation of crystals of calcium pyrophosphate dihydrate in the connective tissues. The alternative names emphasize particular aspects of the clinical or radiographic findings. The knee joint is the most commonly affected.