Differences in elements between intact and disrupted human ligamenta capitum femorum

To compare the element compositions between intact (i.e., intact throughout its length) and disrupted (i.e., ligament no longer attached to the attachment) ligaments, the contents of elements in the human ligamenta capitum femorum (LCF) were analyzed by inductively coupled plasma-atomic emission spectrometry. Histological and immunohistological assessments were also performed in both groups. The subjects were 8 men and 32 women. Trace element analyses showed that the sulfur and iron contents were significantly greater in the intact group than in the disrupted group, while the phosphorus and magnesium contents were significantly smaller in the intact group than in the disrupted group. The calcium and zinc contents were smaller in the intact group than in the disrupted group, with no significant differences. Histologically, there were fibrocartilage cells and extracellular matrix metachromasia in ligaments of the intact group. In contrast, fibrocartilage cells disappeared, and fat cells appeared instead of collagen fibrils in ligaments of the disrupted group. The LCFs of the intact group were immunohistologically positive for all components examined including collagens, glycosaminoglycans, and proteoglycans. The increase in sulfur suggested the presence of high glycosaminoglycan levels associated with fibrocartilaginous metaplasia in the ligament by compressive force. The reduction in iron may show a decreased number of blood vessels in the synovium after ligament disruption. The increases in phosphorus, magnesium, and calcium are indicative of degenerative changes including calcification and ossification. We conclude that differences in the contents of elements between intact and disrupted LCFs indicate degenerative alterations to the ligament structure after disruption.