Analysis of Structural Behavior of a Proximal Femur Bone Scaffold with a Cement Mantle According to Pore Geometry, Pore Size, and Cement Mantle Elastic Modulus

A cement mantle influences load transfer in proximal femur scaffolds. Extending circular pore analysis, this study assessed pore geometry, pore size, cement mantle elastic modulus, and insertion site effects on strain-energy distribution. Pixel-based finite element analysis evaluated 108 conditions: four pore geometries, three pore sizes, three cement mantle elastic moduli, and three insertion sites. The normal-bone model (MN), scaffold without cement mantle (MS), and scaffold with cement mantle (MSC) were compared using the mean absolute pixel error (MAPE), three-region strain-energy sharing ratio (SESR), and pixel-wise median and interquartile range (IQR). In the scaffold region (SR), MSC showed lower MAPE than MS under all 108 conditions, accompanied by attenuation of the positive strain-energy bias and a reduction in total scaffold strain energy toward the normal-bone reference in most conditions. This reduction coincided with changes in strain-energy magnitude; the present comparisons do not isolate an independent change in the spatial pattern from these magnitude changes. MAPE declined with an increasing cement mantle elastic modulus. In the surrounding bone region (SBR), MSC better matched the normal-bone strain-energy distribution in the femoral head and intertrochanteric region; femoral neck responses varied. Cement mantle application reduced SR strain-energy share and increased cement mantle region (CMR) share. Pixel-wise median and IQR generally decreased in SR and increased in CMR; SBR changes were smaller and site-dependent. The cement mantle acts as an intermediate load-transfer component modifying interregional sharing and intraregional distribution. Its application and elastic modulus require evaluation with pore design and insertion site to maintain scaffold mechanical stimulus.