Role of mechanical loading in the progressive ossification of a fracture callus

Abstract

The progressive ossification pattern in a fracture callus was predicted based on a theory that relates the local stimulus for ossification to the tissue mechanical loading history. Two-dimensional finite element analyses of a fracture callus were considered at three different stages of ossification. The sites of callus ossification represented in the initial model were predicted by previous analyses relating mechanical stress and vascularity to the differentiation of mesenchymal tissue in the early callus. The zones of further ossification, bone bridging, and bone consolidation predicted in the present study were found to be similar to the ossification patterns that have been documented by other researchers. The approach used to predict fracture healing is identical to that of previous studies predicting joint morphogenesis, with the exception that fracture healing requires continuous, attached skeletal elements, whereas joint morphogenesis requires discontinuous, articulating skeletal elements.

An Idealised Biphasic Poroelastic Finite Element Model of a Tibial Fracture

“…Therefore fluid pressures appear to be more sensitive to longitudinal interfragmentary displacements than to the callus-porosity in the present study. Fluid pressure distribution patterns correlate with the general pattern of ossification, as reported by others (Blenman 1989, Sarmiento 1995, Yamagishi 1955. Blenman and Carter (1989) suggested that ossification progresses through the stages of `bone tuft', `bone wedge' and `bone bridge' and poroelastic models appear to corroborate this if it is believed that ossification may not take place in the regions of high fluid pressures.…”

“…Van Driel et al (1998) and Prendergast et al (1997) modelled tissue adjacent to prostheses using poroelastic material properties to investigate tissue differentiation. In the field of fracture healing however, only monophasic material properties of callus have been simulated , Carter 1998, Blenman 1989, Cheal 1991, DiGioia 1986, Claes 1999and 2000. This is probably because of the paucity of data in the literature on the values of parameters required to define the biphasic material properties of fracture callus.…”

From Wolff's law to the Utah paradigm: Insights about bone physiology and its clinical applications

“…small strains help to guide the remodeling and modeling phases of bone healing (Blenman et al, 1989;Carter et al, 1988;Claes et al, 1994;Frost, 1989b;Hanafusa et al, 1995;Kenwright and Goodship, 19889;Mosely and Lanyon, 1988;Wolff et al, 1981). Lacking any strains, disuse-mode remodeling tends to remove the callus, modeling stays off, and healing can retard or fail** (see "disuse" in the Glossary).…”

Relationships between tissue dilatation and differentiation in distraction osteogenesis

“…Forces arising from muscle contraction, contact at joint surfaces and different growth rates in adjacent tissues produce a variety of local mechanical stimuli in skeletal tissues, including pressures, strains and fluid flow. Using the concept that specific combinations of these stimuli regulate the differentiation of multipotent mesenchymal tissue, previous studies have investigated the mechanobiology of fibrocartilaginous metaplasia (Giori et al, 1993;Wren et al, 1998), implant integration (Prendergast et al, 1997), the development of pseudarthroses (Loboa et al, 2001), fracture healing (Blenman et al, 1989;Carter et al, 1998;Claes and Heigele, 1999;Gardner et al, 2004Gardner et al, ,2000Lacroix and Prendergast, 2002;Smith-Adaline et al, 2004) and distraction osteogenesis Loboa et al, in press). Results from these studies suggest the possibility of using the physical environment as a factor that can be controlled in order to promote a specific healing or development outcome.…”