A theoretical framework for strain-related trabecular bone maintenance and adaptation.

Area of Science:

• Biomechanics
• Bone Physiology
• Computational Biology

Background:

• Mechanical forces are known to influence bone density and morphology.
• The precise mechanisms linking mechanical stimuli to osteoclast resorption and osteoblast formation remain unclear.
• Previous work proposed a mathematical theory linking osteocyte strain to osteoblast activity and microcracks/disuse to osteoclast activity.

Purpose of the Study:

• To develop and validate a 3-D Finite Element Analysis (FEA) model based on a proposed mechano-biological theory.
• To investigate the model's ability to predict morphological changes in trabecular bone in response to mechanical loads.
• To simulate and understand bone metabolic reactions to various loading conditions and deficiencies.

Main Methods:

• Development of a 3-D Finite Element Analysis (FEA) model.
• Application of a previously proposed mathematical theory of bone mechano-biology.
• Simulation of bone growth, mechanical loading variations, and estrogen deficiency effects.
• Comparison of simulation results with data from growing pigs.

Main Results:

• The 3-D FEA model realistically simulated trabecular bone development during growth.
• The model confirmed that the proposed mechanisms lead to optimal stress transfer.
• Simulations accurately predicted changes in trabecular orientation with altered loading directions.
• Reduced loading led to decreased bone thickness, connectivity, and mass, mimicking disuse osteoporosis.
• Simulated estrogen deficiency resulted in morphologies consistent with post-menopausal osteoporosis.

Conclusions:

• The developed 3-D computational framework effectively models bone mechano-biological pathways.
• The model demonstrates predictive capability for trabecular bone's response to mechanical stimuli and metabolic changes.
• This approach offers a valuable tool for investigating the relationship between bone loading and metabolic bone diseases.