An aspect of metabolic bone disease with idiopathic osteonecrosis of the femoral head.

In spite of vast varieties of investigations on osteonecrosis, there is no report concerning the serum vitamin D metabolite concentrations and quantitative assessment of histological parameters of undecalcified section of bone. In this study, we examined the relations between biochemical and histological parameters in four patients with idiopathic osteonecrosis of the femoral heads. Serum 25-hydroxyvitamin D3 concentrations showed lower value within normal range. However, 1, 25-dihydroxyvitamin D3 and 24, 25-dihydroxyvitamin D3 concentrations were far below the normal value in all patients. Serum immunoreactive parathyroid hormone concentrations were within normal range. Histomorphometric parameters of iliac crest biopsy specimens were as follows. Relative osteoid volume, osteoid surface, and resorption surface were increased in all patients. Calcification front was decreased in all patients. Mean osteoid seam width was increased in two patients. These results suggest that microfractures created in such fragile trabeculae of femoral heads in our patients with deficiency of active vitamin D metabolites, will not be repaired well.