Pyrophosphate arthritis with local amyloid deposition

Pyrophosphate and capsular chondromatosis were demonstrated histologically in 15 cases, 14 of which also exhibited local deposition of amyloid. A systematic examination of the joint capsule in 57 consecutive hip replacement operations for osteoarthritis revealed these changes in 6 of the cases (10.5 per cent). Microscopic examination which was done if intraarticular calcifications were grossly visible at operation, showed the same changes in 8 knees, 4 with osteoarthritis and 4 with meniscal disease. The changes were also seen in the menisci. Only one patient was suffering from chronic, polyarticular pyrophosphate arthritis. In the other cases neither change had been expected a priori, and the patients had no signs of systemic articular disease or amyloidosis. Most of them were elderly, but in good health.