Analysis of intrinsic contributing factors in geriatric tibial plateau fractures using extended finite element method

Current clinical fracture risk assessmentprimarily reliedon the Bone Mineral Density (BMD) metric butoverlookedstructural degradation caused by bone loss during aging. This studyaimedto investigate the impact of age-related changes in various factors on the load-bearing capacity of the tibial plateau. By comparing with the mechanical test data of composite tibia and Hirsch's cadaver test results, an Extended Finite Element Method (XFEM) model simulating tibial plateau fractures was constructed. The effects of changes in cortical bone thickness (Ct.Th), cortical bone mineral density (Ct.BMD), trabecular bone volume fraction (BV/TV), and trabecular bone mineral density (Tb.BMD) during aging on tibial plateau load-bearing capacity were analyzed. Results demonstrated that trabecular bone density reductionhadthe greatest impact on load-bearing capacity deterioration during aging, followed by cortical bone density, trabecular volume fraction, and cortical bone thickness. Declines in bone densityexerteda stronger influence on tibial plateau load-bearing capacity than structural degradation. Furthermore, at the onset of bone loss, women exhibited lower levels of these factors than men, and the decline rate of these factors was faster in women. Thus, at the same age, women showed reduced tibial plateau load-bearing capacity, which increased the risk of fractures. This study provides mechanical theoretical support for multifactorial prediction of elderly tibial plateau fracture risk.