[Remodelling in rickets and osteomalacia (author's transl)].

Based on our experience on more than one hundred cases, bone remodelling in rickets and osteomalacia was investigated. Histomorphometry using tetracycline labelling on nineteen ribs and fibula biopsy specimen revealed a marked increase in number of osteon with osteoid seam, a slight decrease in number of resorption cavity, and extremely depressed tetracycline uptake, of 9.7% on average. The attempt to measure bone formation rate by double tetracycline labelling has failed. Analysing the dynamic behaviour of serum alkaline phosphatase, the hypothesis that the serum alkaline phosphatase was regulated by the three factors, activity of osteoblast, number of osteoblast and elution coefficient from the cell, was presented. Both accretion rate and urinary hydroxyproline excretion showed variable values, from low to high. Although bone remodelling in rickets and osteomalacia was always low at the cellular level, it could be low, normal or high at tissue or organ levels.