Computed tomography porosity and spherical indentation for determining cortical bone millimetre-scale mechanical properties

Abstract

The cortex of the femoral neck is a key structural element of the human body, yet there is not a reliable metric for predicting the mechanical properties of the bone in this critical region. This study explored the use of a range of non-destructive metrics to measure femoral neck cortical bone stiffness at the millimetre length scale. A range of testing methods and imaging techniques were assessed for their ability to measure or predict the mechanical properties of cortical bone samples obtained from the femoral neck of hip replacement patients. Techniques that can potentially be applied in vivo to measure bone stiffness, including computed tomography (CT), bulk wave ultrasound (BWUS) and indentation, were compared against in vitro techniques, including compression testing, density measurements and resonant ultrasound spectroscopy. Porosity, as measured by micro-CT, correlated with femoral neck cortical bone’s elastic modulus and ultimate compressive strength at the millimetre length scale. Large-tip spherical indentation also correlated with bone mechanical properties at this length scale but to a lesser extent. As the elastic mechanical properties of cortical bone correlated with porosity, we would recommend further development of technologies that can safely measure cortical porosity in vivo .

Bulk Wave Velocities in Cortical Bone Reflect Porosity and Compression Strength

“…The correlation coefficients between longitudinal wave velocities and porosity from the present study are in good agreement with the latter. Finally, the correlation found between strength and porosity in this study ( Figure 5, r=-0.74) is also consistent with the results from previous experimental studies in human cortical bone (Boughton et al, 2019;Mirzaali et al, 2016).…”

“…Then, from each cross-section, one or two rectangular parallelepiped shaped specimens were prepared using a diamond wafering blade saw (Isomet 4000, Buehler GmbH, Düsseldorf, Germany) as described in (Cai et al, 2019), see Figure 1. For each tibia, one specimen was obtained from the centre of the medial face of the bone.…”

“…Mechanical properties of cortical bone tissue are essentially determined by the vascular pore network (volume fraction of pores or, shortly, the porosity, and microarchitecture) and the properties of the extravascular mineralized matrix surrounding pores (Mirzaali et al, 2016;Cai et al, 2019). Previous studies on cortical bone have shown that US velocities depend on porosity and matrix properties (Raum et al, 2005;Grondin et al, 2012;Mathieu et al, 2013;Eneh et al, 2016).…”

Impaction technique influences implant stability in low-density bone model

“…In these cases secure implant stability is more difficult to achieve, 9 , 15 and the likelihood of fracture may increase. 16 , 17 Early instability and loosening has been reported as the main cause of cementless implant failure following revision. 7 , 18 , 19 In order to maximize the benefits of using cementless implants, particularly in more difficult cases, stability must be achieved.…”

Excessive salt consumption causes systemic calcium mishandling and worsens microarchitecture and strength of long bones in rats

“…High salt intake worsened bone microstructure along with enhancing bone loss, as seen in increased trabecular and cortical porosity and decreased trabecular vBMD in this study. Interestingly, the use of high-resolution 3D SRXTM allowed us to explore cortical bone porosity, which characterized as an important predictor of bone of fracture in human 44 . Other negative effects on bone, such as an imbalance of immune interaction (T helper 17 and regulatory T cells), have also been reported 19 .…”