[A clinical study of calcium pyrophosphate dihydrate crystal deposition disease].

Clinical features of calcium pyrophosphate dihydrate crystal deposition disease (CPPD c.d.d.) were studied and the following results were obtained. The prevalence of CPPD c.d.d. was 9.7% in 300 persons aged 50 or older, who stayed or worked at an old-age home. The most common type of CPPD c.d.d. was the asymptomatic type. Comparative studies between the patients with CPPD c.d.d. and subjects without it revealed that scoliosis of the lumbar spine, osteoarthritis-like changes of the knee, subchondral bone cyst and patella wrapped around the femur were statistically more frequent in the former. The clinical study of 50 patients with CPPD c.d.d. revealed calcification not only in the articular cartilage but also in periarticular tissues and ligamentum flavum. The histological study demonstrated frequent destructive changes of the tissues around the site of CPPD crystal deposition. Formation of CPPD crystals appeared to be initiated by degenerating chondrocytes and metaplastic chondrocytes.