We aimed to assess static and dynamic bone changes in patients with rickets.

Transcortical iliac crest biopsies of 40 hospitalised children with rickets were taken after administration of two cycles of tetracycline 10 days apart to label new bone formation. Histomorphometric analysis was performed on appropriately stained undecalcified sections. Static and dynamic bone changes measured included the volume of bone and osteoid, trabecular and cortical bone dimensions and resorptive and mineralisation activities. We compared the results with normal values and noted the nature of the mineralisation fronts.

Trabecular osteoid volumes of 31 (78%) patients were above the normal range of 1.9% (±. 0.4%). Nine patients (22%) had atrophic osteoid. Of these, five patients were over the age of 20 years and therefore regarded as having osteomalacia and excluded from the series. Of the remaining four patients, one had renal disease, two had rickets associated with kwashiorkor-marasmus syndrome, and in one no cause could be found.

Tetracycline labelling was found more sensitive than subjective evaluation of the mineralisation fronts. Despite a balanced hospital diet, a bone formation rate of zero was found in three patients, indicating a need for vitamin D and mineral supplementation. In seven cases, decreased mineralisation lag times indicated a response to the balanced diet.

This study shows that histological analysis of labelled bone biopsies is helpful not only diagnostically but also in assessing response to management of deficiency states in children.