Effect of rehabilitation exercise durations on the dynamic bone repair process by coupling polymer scaffold degradation and bone formation

Implantation of biodegradable scaffold is considered as a promising method to treat bone disorders, but knowledge of the dynamic bone repair process is extremely limited. In this study, based on the representative volume cell of a periodic scaffold, the influence of rehabilitation exercise duration per day on the bone repair was investigated by a computational framework. The framework coupled scaffold degradation and bone remodeling. The scaffold degradation was described by a function of stochastic hydrolysis independent of mechanical stimulation, and the bone formation was remodeled by a function of the mechanical stimulation, i.e., strain energy density. Then, numerical simulations were performed to study the dynamic bone repair process. The results showed that the scaffold degradation and the bone formation in the process were competitive. An optimal exercise duration per day emerged. All exercise durations promoted the bone maturation with a final Young's modulus of 1.9 ± 0.3 GPa. The present study connects clinical rehabilitation and fundamental research, and is helpful to understand the bone repair process and further design bone scaffold for bone tissue engineering

4D Numerical Analysis of Scaffolds: A New Approach

A large range of biodegradable polymers are used to produce scaffoldsfor tissue engineering, which temporarily replace the biomechanical functions ofa biologic tissue while it progressively regenerates its capacities. However, the mechanicalbehavior of biodegradable materials during its degradation, which is an importantaspect of the scaffold design, is still an unexplored subject. For a biodegradablescaffold, performance will decrease along its degradation, ideally in accordanceto the regeneration of the biologic tissue, avoiding the stress shielding effect or thepremature rupture. In this chapter, a new numerical approach to predict the mechanicalbehavior of complex 3D scaffolds during degradation time (the 4th dimension)is presented. The degradation of mechanical properties should ideally be compatibleto the tissue regeneration. With this new approach, an iterative process of optimizationis possible to achieve an ideal solution in terms of mechanical behavior anddegradation time. The scaffold can therefore be pre-validated in terms of functionalcompatibility. An example of application of this approach is demonstrated at the endof this chapter