Effect of Different Preservative Methods on Fracture Behavior of Bovine Cortical Bone

Abstract

Bone specimens used for evaluating the mechanical properties of bone may not have been necessarily preserved by the same method before they become available. To this end, the mechanical properties of bone may be affected by freezing, a common preservation method, as well as by formalin and other preservation solutions. In this study, bone specimens were preserved by different methods (i.e., freezing, preservation in saline, preservation in ethanol, and preservation in formalin) to examine the effects of each preservation method on the fracture characteristics of bovine femoral cortical bone. Regarding the crack extension behavior in the fracture toughness test, microcracks accumulated at the top of the slit in the low-load region before the maximum load was reached. When such accumulated microcracks grew to a visible size, a crack was formed from the top of the slit, and then grew with subsequent expansion of the processing zone. The fracture toughness values of the bone groups preserved in formalin and neutral buffered formalin were significantly lower than those of the bone groups preserved by other methods. As the fracture surface by scanning electron microscopic observations was smoother with a loading rate of 20 mm/min than with 1 mm/min, cracks were considered to develop easily, resulting in a lower fracture toughness value. Scanning electron microscopic observations of a test section subjected to a low loading rate showed that the fracture surface of the bone groups preserved in formalin or neutral buffered formalin was flat and smooth. In the other preservation groups, the lamellae adjacent to the top of the slit had undulating contours with plastic deformation. [

Measurement of Cortical Bone Strain Distribution by Image Correlation Techniques and from Fracture Toughness

“…6. The trend of the control group corresponds well with the microcrack initiation behavior discussed in a previous report, 4) where a microcrack was assumed to start forming at a displacement w of approximately 0.2 mm, where a remarkable increase in the strain was observed. The relationship between " x and w was assumed to be a downward convex curve with increasing w, showing an exponential increase in the strain particularly in the control group.…”

On-line analysis of cracking in cortical bone under wedge penetration

“…In an effort to quantify the crack growth and fracture in bone, either indentation fracture experiments were used to measure fracture toughness or relate crack propagation with fracture toughness. [9][10][11][12][13] Online loading stages found in literature have rather small dimensions, and thus only limited loads can be applied. 14,15 For the investigation of high strength materials, such as metallic foams or cortical bone, such set-ups become inappropriate.…”

A review on experimental and numerical investigations of cortical bone fracture

“…31 Numerous experimental studies determined the effect of several parameters, that is, sugar, age, hydration, mineralization, preservative method, fatigue loading, strain rate, porosity, anisotropy, demineralization, deproteinization, type of specimen, indentation, shear deformation, bone composition, etc., on fracture parameters of cortical bone. 21–23,32–64 Many researchers have validated their numerically predicted results with the experimental analysis as well. 22,40,42,47,51,62…”

“…They concluded that damage around the fracture surface was more in saline stored bovine bone than alcohol stored bone. 45 Some researchers include studied the effect of temperature on the K C of compact bone. 124,125 Yan et al 124 prepared Single-edge V-notched (SEVN) specimens to measure the K C of the bovine cortical bone and manatee rib in the water at 0°C, 10°C, 23°C, 37°C, and 50°C.…”

“…15,45 Lucksanasombool et al 15 investigated the influence of orientation and storage medium (saline, alcohol, and alcohol-saline) on the value of K C of bovine cortical bone and found that the bones stored in the alcohol have higher K C as compared to saline and alcohol-saline stored. Similarly, Kuninori et al 45 considered saline, alcohol, alcohol-saline, and formalin as the storage medium to investigate the effect of the storage medium on fracture surface and fracture characteristics of the bovine bone. They concluded that damage around the fracture surface was more in saline stored bovine bone than alcohol stored bone.…”