Variation of chemical composition with age in human femoral head cartilage.

The chemical composition of intact femoral head cartilage was investigated with age. Full-depth cartilage showed a decrease in water content and an increase in keratan sulphate and noncollagenous material with age. When analyzed through the depth of the cartilage, keratan sulphate was shown to appear first in the deep zones and later in the surface, while water content was lost mainly in the deep zones. On a dry weight basis collagen content decreased with age. This was not a real loss but was due to a change in the proportions of other materials, mainly in the deep zones.