Calcium pyrophosphate and pseudogout.

Calcium pyrophosphate deposition disease (CPDD) is a condition in which calcium pyrophosphate dihydrate crystals are deposited in joint articular cartilage, menisci, and synovium. The main clinical presentations of CPDD are chondrocalcinosis--calcification of cartilage, pseudogout--acute joint inflammation due to crystal-induced synovitis, and pyrophosphate arthropathy--degenerative joint disease similar to osteoarthritis associated with calcium pyrophosphate crystal deposition. The clinical importance of CPDD for the arthroscopist is the ability to recognize the condition so that appropriate treatment can be instituted. Arthroscopy is valuable for diagnosis as well as lavage and intraarticular debridement or meniscectomy. Tissue removed for microscopic examination should be sent to the laboratory in saline, since formalin dissolves the crystals. Postarthroscopy treatment of CPDD should include oral antiinflammatory medication. Asymptomatic chondrocalcinosis does not require treatment.