A HYPOTHETICAL REGULATION MECHANISM OF ADAPTIVE BONE REMODELING - (TRANSPORT OF GROWTH-FACTORS BY MECHANICAL LOADS)

A hypothetical regulation mechanism of adaptive bone remodeling is pro posed. In this hypothesis, the growth factors and bone cells are invol ved in the mechanim as follows: first osteoclasts activate the growth factors contained in the bone matrix and release them into bone fluid, then the growth factors are transported to the bone surface with flui d flow induced by the mechanical loads applied to the bone, and finall y the growth factors transported regulate the activities of osteoblast s which are responsible for bone formation. It is shown that many curi ous features which have been reported for adaptive bone remodeling are explained by the proposed hypothesis. Furthermore, a simple analytica l model is constructed based on the hypothesis, which can simulate som e typical adaptation processes such as the adaptation to applied repet itive moments and the correction of abnormal curvature after misaligne d fracture.