Application of the Strain Energy Density criterion for Patient-Specific Bone Remodeling Simulation

Strain energy density-based algorithms are widely applied in modelling bone healing, yet their use under patient-specific conditions remains underdeveloped. This study aims not only to perform patient-specific bone healing simulations, but specifically to identify which postoperative loading condition provides the most favourable mechanical environment for callus remodeling and thus supports optimal fracture healing. Using postoperative radiographic data of a 63-year-old male patient with a distal diaphyseal tibial fracture and concomitant proximal and distal fibular fractures, a three-dimensional finite element model of the tibia was reconstructed, imported into a multiphysics simulation environment, and coupled with an iterative numerical algorithm. An initial uniform callus density of 750 kg/m³ was assigned to represent the later stage of secondary healing. The effects of different mechanical loading conditions (partial weight-bearing, physiological loading, and supraphysiological loading) on the mechanical response and density evolution of the callus were evaluated. Partial weight-bearing resulted in insufficient mechanical stimulation and progressive density loss within the callus. Physiological loading generated strain energy density levels consistent with known osteogenic ranges and promoted continuous cortical shell formation and overall density increase. Supraphysiological loading led to overload-related resorption and spatial heterogeneity, ultimately compromising callus stability. The findings demonstrate that loading magnitude significantly influences bone healing. Depending on the healing stage, an optimal load can be determined to minimize the risk of non-union formation and enhance bone remodeling via this methodology. Furthermore, by additionally evaluating unphysiological overloading, this study provides a more robust validation of the model’s behaviour outside the optimal mechanobiological window.