Mechanische Steuerung des Skelettwachstums

Abstract

Mechanical factors control the growth pattern of bone. Epiphyseal growth cartilage especially yields to stress. The Hueter-Volkmann law explains the passive change of direction, when increased pressure parallel to the axis of epiphyseal growth will inhibit growth. The Pauwels law explains the active change by functional adaptation of bone through longitudinal growth if the pressure is exerted excentrically. So spontaneous correction of angular deformity will be mainly caused by growth cartilage. According to the Hueter-Volkmann law physeal growth is able to induce a self limiting pathological compression force by means of external devices. Blount stapling, using the axially induced compression force of the growth plate itself, is considered as a simple method of correcting angular deformities and limb length discrepancies in adolescents. Blount stapling is a good model to investigate histological and biomechanical pressure effects on growth cartilage. Tension may increase epiphyseal growth, but probably not sufficiently to be of clinical significance. Limb lengthening by distraction of the epiphyseal plate is complicated by separation of the epiphysis from the metaphysis and subseguently by impairment of growth. Rotational modelling only occurs at the epiphyseal plate. A substantially increased torsional load may be required to show rotational modelling. It is unlikely that rotational changes are induced by external devices as the laxity of ligamentous structures around the joint prevents the application of a direct force to the growth plate.