Chondrocalcinosis

Chondrocalcinosis is the radiographic appearance of calcification within articular cartilage, most commonly caused by deposition of calcium pyrophosphate dihydrate crystals. It is often a sign of calcium pyrophosphate deposition disease (CPPD), which can provoke inflammatory arthritis when crystals are released into the joint (pseudogout). The finding may be incidental and asymptomatic or associated with symptomatic arthritis.

The condition is more frequent in older adults and is linked with several metabolic disorders, including hyperparathyroidism, hypomagnesemia, hemochromatosis, hypothyroidism, and diabetes. It can occur without an identifiable metabolic cause and may be familial in rare cases.

Pathophysiology involves deposition of CPPD crystals in hyaline and fibrocartilage, particularly in joints such as the knee and wrist. On radiographs, this produces linear or punctate calcifications in the cartilage. Under polarized light, CPPD crystals are rhomboid and weakly positively birefringent. Small crystal deposition can irritate the joint and trigger acute attacks, while larger deposits may contribute to chronic arthropathy.

Clinically, many cases are asymptomatic. When symptomatic, patients typically experience an acute or recurrent inflammatory arthritis with sudden joint swelling, pain, and warmth, most commonly in the knee, wrist, or other large joints. Recurrence is common, and some individuals develop chronic joint changes.

Diagnosis relies on imaging and synovial fluid analysis. Radiographs reveal chondrocalcinosis in affected cartilage. Synovial fluid shows CPPD crystals that are rhomboid and weakly positively birefringent under polarized light. Infections should be excluded by culture when appropriate, and evaluation for metabolic disorders may be indicated.

Management targets acute attacks with NSAIDs, colchicine, or corticosteroids, and preventive care with low-dose colchicine in recurrent disease. Treating underlying metabolic conditions and physical therapy can help. Severe or refractory cases may require surgical intervention, such as joint replacement.