Articular cartilage in the degenerative arthropathy of hemochromatosis.

Iron was readily demonstrated in chondrocytes in 3 of 4 hemochromatosis articular cartilages studied. Either apatite, calcium pyrophosphate dihydrate crystals, or both were found in all cartilages including those of 3 patients who had no radiographic or light microscopic evidence of calcification. These crystals, which may be secondary to degenerative changes or may play a role in cartilage degeneration, were not seen in any consistent morphologic relationship with the iron deposits. In fact, apatite was found in one cartilage in which no iron was identified in the sections studied. If iron, as demonstrated in the chondrocytes, is contributing to the calcium crystal deposition, it would most likely do so indirectly, for example by altering chondrocyte enzymes or connective tissue components.