Validation of the Chicken Femur as a Model for the Human Metacarpal: An In-Vitro Analysis

<b>Background:</b> The aim of this study was to evaluate the chicken femur as a laboratory model for the human metacarpal by comparing the bone microarchitecture and mechanical properties of chicken femurs to human cadaveric metacarpals. <b>Methods:</b> Sixteen fresh chicken femora and 20 fresh frozen cadaveric human metacarpals were imaged using a micro computed tomography scanner. The bones were then mechanically tested using four-point-bending and torsional testing. <b>Results:</b> There were no significant differences in macroscopic features between chicken femora and human metacarpals, including overall length, external radius, internal radius, cortical width and cross-sectional area of the diaphyseal cortex (<i>p</i> > 0.05). There were no significant differences in the trabecular number and spacing in the distal metaphysis of both groups (<i>p</i> > 0.05). The diaphysis and proximal metaphysis did not share any microarchitectural similarities. Four-point bending tests resulted in significantly higher yield forces, ultimate force, failure points and stiffness in human metacarpals (<i>p</i> < 0.05). Torsion tests resulted in significant higher ultimate torque and torsional rigidity in human metacarpals (<i>p</i> < 0.05). <b>Conclusions:</b> The chicken femur has structural and biomechanical differences to the fresh frozen human metacarpal despite the similarity in their macroscopic features.