| Popis: |
Although it is well known that bone responds to mechanical stimuli, details of this phenomenon are still uncertain. To study the quantitative relation between bone formation and mechanical stimuli, experiments using rabbits and three-dimensional finite-element analysis were conducted. In the experiments, an intermittent compressive or tensile load was applied for 1 h per day to the rabbit’s tibia in which a circular defect was made at the center along the axial direction. This process continued for 1, 2, or 4 weeks, and then bone formation at the circular bone defect was evaluated histologically. The histology of bone formation and the strain energy density at the defect, which is calculated by the finite-element method, were compared. It is confirmed, by the experimental results, that bone formation is promoted by mechanical stimuli. It was necessary to establish a theoretical model of bone formation caused by mechanical stress stimuli to apply the experimental results to a clinical situation. We attempted to apply the theory of time-dependent bone remodeling proposed by Beaupre et al. to bone formation during repair of defects. Computer simulation of bone formation around the circular defect corresponding to the experiment was carried out using an algorithm based on the theory; the effectiveness of this method is discussed in comparison with the experimental results. |
