Extracellular matrix changes regulate calcium crystal formation in articular cartilage.

Purpose Of Review: The pathologic matrix mineralization seen in calcium pyrophosphate dihydrate and basic calcium phosphate deposition diseases identifies a subset of osteoarthritis patients with an unusual joint distribution and rapid progression of disease. Several factors contribute to pathologic matrix mineralization, including changes in the extracellular matrix of articular cartilage. The factors contributing to extracellular matrix changes that promote crystal formation are important and not well understood.