Microhardness distribution of the tibial diaphysis and test site selection for reference point indentation technique

Abstract

Indentation hardness test is a good in vitro method of bone quality assessment. The purpose of this study is to explore the distribution characteristics of bone tissue microhardness in tibial diaphysis and provide theoretical support for the test site selection of the reference point indentation technique. Three fresh right tibias were obtained from 3 cadaver donors. The tibial diaphysis was evenly divided into 6 sections. Bone specimens with a thickness of 3 mm were cut from each part. After appropriate management, micro-indentation tests were performed in various regions of the specimens to acquire the microhardness values of the tibial diaphysis. Statistical analysis was performed by randomized block design variance analysis to study the distribution characteristics of bone microhardness. 72 regions were selected for 360 effective indentations. We found that the bone microhardness is inhomogeneous in tibia diaphysis. Mean hardness value of the anterior, medial, posterior, lateral region of tibia diaphysis was 45.58 ± 4.39 Vickers hardness (HV), 52.33 ± 3.93 HV, 54.00 ± 4.21 HV, 52.89 ± 4.44 HV, respectively. The anterior cortex exhibits lower microhardness value than the other regions ( P < .001). Within the same region, microhardness varies significantly with positions in the tibial diaphysis. The variations in indentation hardness are bound to have a significant impact on the comparability of different reference point indentation (RPI) studies. The results of this study indicated the regional microhardness difference in the human tibia diaphysis. The microhardness of different planes in the same region is also inconsistent. Inhomogeneous distribution of indentation microhardness would have considerable influence in the test site selection of RPI technique. The data collected in our study would contribute to the design of highly precise 3D printing implants and bionic bones with gradient elastic modulus.

Hardness, an Important Indicator of Bone Quality, and the Role of Collagen in Bone Hardness

“…Hardness indentation studies at the microscopic level have identified large variations in moduli and hardness for specific features such as trabeculae and lamellae in osteons. These variations have been attributed to collagen fibril orientation and variations in mineral content induced by remodeling [ 14 , 15 , 16 , 17 , 18 ]. Heterogeneity can have a positive effect on bone toughness, consequently increasing bone fracture resistance [ 6 ].…”

Ultra-Short Laser Surface Properties Optimization of Biocompatibility Characteristics of 3D Poly-ε-Caprolactone and Hydroxyapatite Composite Scaffolds

“…However, we can conclude that from the obtained results in Table 2, the 3D-printed scaffolds with a wood pile-like or a snowflake-like geometry could potentially be used for regeneration of bone tissue injuries at non-load-bearing sites. For example, Vickers microhardness tests on human tibial diaphysis showed results ranging between 36.50 HV and 65.4 HV [62]. These values were, on average, 4.5× times higher than the values we obtained for PCL and PCL/HA scaffolds (Table 2).…”

Bioceramics in the CaMgSi2O6–Li2O System: A Glass‐Ceramic Strategy for Excellent Mechanical Strength and Enhanced Bioactivity by Spontaneous Elemental Redistribution

“…[ 76 ] The decreased hardness as a function of soaking time may allow Li0.25 to be more favorable for bone repair than Ti‐based alloys as the cortical bone has a relatively low hardness around 40–60 Hv. [ 77 ] The deteriorated hardness of Li0.50, Li0.75, and Li1.00 after SBF soaking could be ascribed to the escalating CaSiO 3 formation as CaSiO 3 has been reported to have a higher dissolution rate than diopside. [ 34,35 ]…”