Ultrastructure of the deep zone of degenerative osteoarthritic cartilage.

The deep zone of articular cartilage obtained from 22 surgical cases with advanced osteoarthritis of the hip joint and from additional 14 necropsy cases with normal hip joint were studied by aids of ultrastructural, electron histochemical and elemental analytic techniques. The deep zone of osteoarthritic cartilage showed significant degenerative changes of the extracellular matrix including fibrillar or non-fibrillar components and/or abnormal calcification. The electron histochemical method used revealed prominently decreased concentration of proteoglycan complex in the osteoarthritic cartilage as compared with that in the normal articular cartilage.