Bovine Femoral Bone Research Articles

Prediction of safe zone for osteonecrosis in the cutting process of bovine cortical femur bone using Arbitrary Lagrangian-Eulerian method and multi-objective optimization

In this study, the Arbitrary Lagrangian-Eulerian (ALE) method was used to investigate the osteonecrosis in orthopedic surgery of cortical bone. As a result of mesh motion control in the ALE method, element distortions were prevented and more accurate results predicted. To consider the temperature and reaction force variation in the orthogonal cutting of bovine cortical femur bone, the coupled thermo-mechanical simulations were used. Effects of cutting depth, cutting speed, and rake angle that may cause osteonecrosis on the reaction forces and the bone temperature variations were studied. The Johnson-Cook material model was employed to observe the strain rate effects on the cutting force and temperature distribution. The results of ALE simulations represented less than 10% error in comparison with the experimental data which could be used as the alternative method for experimental predictions. Furthermore, the response surface of design of experiments (DOE) method was used for performing a multi-objective optimization. Based on the obtained results, decreasing the rake angle less than 5° is the most significant term in the reduction of osteonecrosis.

Infrared thermography of high-speed grinding of bone in skull base neurosurgery.

For skull base tumor removal neurosurgery, skull bone grinding is required. During this process, temperature rise occurs, which may result in an irrecoverable thermal damage. In the present research, temperature variations during bone grinding have been studied. Experimental tests have been conducted in 27 states in terms of the parameters of rotational speed (three states), feed rate (three states), and cutting depth (three states) on bovine femur bone samples. Attempts have been made to determine optimal processing conditions for minimizing thermal damage during the surgery through infrared thermography and measuring thermal variations of the bone. The results indicated that the temperature rise of the bone has a direct relationship with the parameters of rotational speed, feed rate, and cutting depth. In other words, with elevation of each of these parameters, temperature rise was also intensified. Out of the cutting parameters, rotational speed had the maximum impact on temperature rise, followed by cutting depth and feed rate. Therefore, to reduce the extent of thermal damage incurred to the neural tissue, the minimum values for the cutting parameters are proposed as follows: rotational speed = 45000 r min-1, feed rate = 20-30 mm min-1 with depth of cut = 0.25 mm, and feed rate = 20 mm min-1 with cutting depth = 0.50 mm.

The Effect of Formalin Preservation Time and Temperature on the Material Properties of Bovine Femoral Cortical Bone Tissue.

Literature has reported controversial findings on whether formalin affected bone properties, or not, especially when different preservation time durations and temperatures were involved. Hence, accurately and systematically quantifying the effect of formalin on the mechanical properties of bone using a large dataset is crucial for assessing biomechanical responses based on fixed specimens. A total of 154 longitudinal and 149 transverse cuboid-shaped (12mm × 2mm × 0.5mm) specimens from themidsection of 12 bovine femora from six bovines were prepared and assigned to ten groups, including fresh-frozen, formalin-preserved at 25°C for 4weeks and 8weeks, and formalin-preserved at 4°C for 4weeks and 8weeks. All specimens underwent quasi-static three-point bending tests with a loading rate of 0.02mm/s. The Young's modulus, yield stress, yield strain, tangent modulus, effective plastic strain, ultimate stress, and toughness were calculated by optimizing the material parameters to make the force-displacement curve of the finite element prediction consistent with the experimental curve, combined with specimen-specific finite element models. Preservation time and temperature both had significant effects on the Young's modulus, yield stress, effective plastic strain, yield strain and ultimate stress of cortical bone (p < 0.05). The Young's modulus, yield stress, and ultimate stress of longitudinal specimens decreased significantly with the increase of preservation time, and the yield strain increased significantly. As the preservation temperature increases, the Young's modulus of the transverse sample decreased significantly, and the yield strain increased significantly. The preservation time mainly affects the longitudinal specimens, while the preservation temperature mainly affects the transverse specimens. Formalin preservation of bovine femoral cortical bones at alower temperature and less than 4weeks is recommended for biomechanical testing.

Comparison of Natural and Nano-synthetically-Produced Hydroxyapatite Powder

Hydroxyapatite (HAp) is a bioactive material that forms the main mineral part of teeth, hard tissues, and bone in humans. The goal of the present study is to prepare hydroxyapatite from bio-waste materials such as fish bone and bovine femur bone at different calcination temperatures, selecting the optimal calcination temperatures and then comparing these with commercial nano-HAp. The HAp was synthesized from the bio-waste materials by a calcination process in a thermal dry and fire furnace with different calcination temperatures, heating rates and cooling rates all carefully controlled. The best results were obtained at 950°C since, at this temperature, the Ca/P ratio reached 1.6589 for fish bone and 1.7058 for bovine femur bone, which is close to the commercial stoichiometric nano-HAp ratio of 1.67.

Sliding behavior of zirconia porous implant surfaces against bone.

Different zirconia porous layers were produced on zirconia dense zirconia substrates by slip casting using powder with different mean sizes: 40 μm (Z40), 70 μm (Z70), and 100 μm (Z100). The dynamic and static coefficients of friction against bovine femoral bone, mimicking the implantation process, were conducted using a ball-on-flat reciprocating sliding tribometer under 3 N of normal load. Additionally, the porous layers were assessed with regard to their low temperature degradation (aging). Results revealed that the porous layers were able to keep their integrity during the sliding testes against bone, with no zirconia particles being transferred to the bone. Results did not show significant differences (p > 0.05) in kinetic and static COF values for Z40, Z70, Z100, and GRAD specimens, ranging from 0.53 to 0.77 and 0.65 to 0.90, respectively. The aging tests revealed that all surfaces were prone to low temperature degradation (~49% of monoclinic content after 18 h). In conclusion, the cohesive integrity of the layers and relatively high COF observed reveled that zirconia porous layers may be considered for replacing the current implant surfaces, and are expected to improve their primary stability. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1113-1121, 2019.

Investigation of cutting quality and surface roughness in abrasive water jet machining of bone.

The abrasive water jet machining is known as a cold cutting process and can be effective for developing cut in the bone in orthopedic surgery to prevent thermal necrosis. This research examined surface roughness and cutting quality of bovine femur bone using abrasive water jet machining. Furthermore, the effect of three parameters was studied including water pressure, traverse speed, and the type of abrasive particles. The feed rate of the abrasive particles was considered 100 g/min, and the levels obtained from pure water jet cutting, bone powder abrasive water jet machining, and sugar abrasive water jet machining were compared with each other. Application of bone powder as an abrasive particle caused improved cutting quality, when compared with pure water jet, and in the best case, it resulted Ra and Rz values of 7.36 and 54.76 μm, respectively at the pressure of 3500 bar and traverse speed of 50 mm/min. The minimum surface roughness was obtained using sugar abrasive particles at the pressure of 3500 bar and traverse speed of 50 mm/min. The values of Ra and Rz parameters measured at the most desirable state were 3.87 and 19.72 μm, respectively. The results suggested that use of sugar as an abrasive material, in comparison with pure water jet and bone powder water jet, resulted in improved cutting quality. Furthermore, elevation of water pressure and reduction of traverse speed had a significant effect on improving surface roughness.

Fracture and microstructural study of bovine bone under mixed mode I/II loading

Understanding the fracture behavior and associated crack growth mechanism in bone material is an important issue for biomechanics and biomaterial researches. Fracture of bone often takes place due to complex loading conditions which result in combined tensile-shear (i.e. mixed mode) fracture mechanism. Several parameters such as loading type, applied loading direction relative to the bone axis, loading rate, age and etc., may affect the mixed mode fracture resistance and damage mechanism in such materials. In this research, a number of mixed mode I/II fracture experiments are conducted on bovine femur bone using a sub-sized test configuration called “compact beam bend (CBB)” specimen to investigate the fracture toughness of bone under different mode mixities. The specimen is rectangular beam containing a mid-edge crack that is loaded by a conventional three-point bend fixture. The results showed the dependency of bone fracture toughness on the state of mode mixity. The fracture surfaces of broken CBB specimens under different loading conditions were studied via scanning electron microscopy (SEM) observations. Fracture surface of all investigated cases (i.e. pure mode I, pure mode II and mixed mode I/II) exhibited smooth patterns demonstrating brittle fracture of bovine femur. The higher density of vascular channels and micro-cracks initiated in the weakened area surrounded by secondary osteons were found to be the main cause of the decreased bone resistance against crack growth and brittle fracture.

Access to Optimal Calcination Temperature for Nanoparticle Synthesis from Hydroxyapatite Bovine Femur Bone Waste

Hydroxyapatite (HAp) is one of the vital and bioactive materials that are commonly used in biomedical field and concentrated in clinical area. It is a bio-ceramic powder synthesized by using different bio-waste materials such as bovine femur bone. In this study, the bovine femur bone powder was prepared to obtain nano powder. The purpose of this study was to reach the optimal temperature to obtain nanoparticles HAp. The resulted powder was calcinated in a furnace at different temperatures (900, 950, 1000, 1050 and 1100 °C) for 2 h at the heating rate of 10 °C/min and cooled slowly in a furnace. Results showed, the formation of pure HAp by the presence of peaks corresponding to (PO4)3- at 632/cm and OH- at 3,572/cm in fourier transformation infrared spectroscopy (FTIR). For the calcined samples, there were three main peaks of 211, 112 and 300 planes at 2θ near 31.8, 32.2 and 32.9 respectively. The amorphous raw bones were transformed into crystalline phase and the lattice parameters for HAp c and a were calculated in X-ray diffraction (XRD), Raman analysis showed that the calcination process removed the organic compound from the bovine femur bones matrix. Scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) showed that the shape of the granules was irregular, containing quantities of oxygen, magnesium, sodium and carbon; the ratio of calcium to phosphate was calculated, Atomic force microscopy (AFM) showed that the particles sizes ranged from nanometers to microns. EDX result found that the calcium to phosphate ratio reached 1.7058 after calcination at 950 °C which was close to stoichiometric hydroxyapatite (1.67). This result implied the formation of pure HAp phase at 950 °C.

Research on microscale skull grinding temperature field under different cooling conditions

A study of microscale skull bone grinding temperature field under different cooling conditions is presented and discussed. Micro-grinding model, heat flux density model, convective heat transfer coefficient model and intra-workpiece heat conduction model are developed, based on which, a simulation study on microscale bone grinding temperature field under dry grinding, drip cooling, mist cooling, and nanoparticle jet mist cooling (NJMC) is performed. Simulation results show that NJMC displayed the lowest temperature peak (27.5°C), followed by mist cooling, drip cooling, and dry grinding successively. A verification experiment using fresh bovine femur bone is performed under different cooling conditions. Results find that the temperature peak of dry grinding is 41.6°C, which is 10.1%, 29.3%, and 37% higher than those of drip cooling, mist cooling, and NJMC, respectively, verifying the optimal cooling effect of NJMC. The experimental results are consistent with the theoretical analysis results, confirming the validity of the theoretical models.

Thermal Changes of Bone Induced during Drilling for Dental Implants Placement: An &lt;i&gt;In Vitro&lt;/i&gt; Study

Bone Heating during Osteotomy for Dental Implant Placement is a High Risk Factor of Osteonecrosis. the Aim of this Study was to Investigate in Vitro the Temperature Changes Induced in Bone by Different Burs with External Cooling during the Surgical Step of Osteotomy. it was Used the Digital Infrared Camera FLIR SC640 (Flir Systems) that Allowed a Real-Time Infrared Thermographic Analysis of Thermal Images, Recorded 0.50 m Away from Osteotomy Site. there were Prepared 10 Osteotomy Sites with each MIS System Burs of Progressive Diameter (2 Mm ø, 2.8 Mm ø, and 3.2 Mm ø), at 2000 Rpm, on 30 Samples of Bovine Femoral Bone. the Thermographic Analysis Showed that the Mean Temperature Generated in Bone by Performing the Osteotomy was 46,5oC ± 0,48 for 2 Mm ø Bur, 59,5oC ± 1,62 for 2.8 Mm ø Bur, and 51,4oC ± 0,51 for 3.2 Mm ø Bur. Surprisingly the Maximal Temperatures were Recorded with Intermediatte 2.82 Mm ø Bur. the Infrared Thermography Proved to Be a High Accurate, Fast, and Efficient Non-Invasive Method of Bone Temperature Measurement Generated during Drilling for Placement of Dental Implants. while Drilling the Bone in a Progressive Sequence of Bur Diameters, the Temperature Raise is Non-Uniform because the Quantity of Removed Bone is Changing from One Bur to the other, and the Mechanical Friction of Following Burs in the Series is Reduced as Compared to the Pilot Bur.

Modified two-parameter fracture model for bone

The analysis of the bone fracture behaviour is fundamental for prevention, diagnosis and treatment of traumas. In the present paper, an experimental campaign on fracture behaviour of bovine femoral cortical bones is conducted to characterise the fracture toughness, KICS, which is related to the structure and load-bearing capacity of bones. Firstly, KICS is evaluated through a two-parameter model originally proposed for quasi-brittle materials. To take into account the crack deflection (kinked crack) due to osteons orientation, the two-parameter model is modified by applying the Castigliano theorem. Fracture toughness results here obtained are compared with those related to a femur of an 18-month-old bovine, available in the literature.

In-vitro analysis of forces in conventional and ultrasonically assisted drilling of bone.

Drilling of bone is widely performed in orthopaedics for repair and reconstruction of bone. Current paper is focused on the efforts to minimize force generation during the drilling process. Ultrasonically Assisted Drilling (UAD) is a possible option to replace Conventional Drilling (CD) in bone surgical procedures. The purpose of this study was to investigate and analyze the effect of drilling parameters and ultrasonic parameters on the level of drilling thrust force in the presence of water irrigation. Drilling tests were performed on young bovine femoral bone using different parameters such as spindle speeds, feed rates, coolant flow rates, frequency and amplitudes of vibrations. The drilling force was significantly dropped with increase in drill rotation speed in both types of drilling. Increase in feed rate was more influential in raising the drilling force in CD compared to UAD. The force was significantly dropped when ultrasonic vibrations up to 10 kHz were imposed on the drill. The drill force was found to be unaffected by the range of amplitudes and the amount of water supplied to the drilling region in UAD. Low frequency vibrations with irrigation can be successfully used for safe and efficient drilling in bone.

Investigation of hyperelastic models for nonlinear elastic behavior of demineralized and deproteinized bovine cortical femur bone

In this study, the hyperelastic models of demineralized and deproteinized bovine cortical femur bone were investigated and appropriate models were developed. Using uniaxial compression test data, the strain energy versus stretch was calculated and the appropriate hyperelastic strain energy functions were fitted on data in order to calculate the material parameters. To obtain the mechanical behavior in other loading conditions, the hyperelastic strain energy equations were investigated for pure shear and equi-biaxial tension loadings. The results showed the Mooney–Rivlin and Ogden models cannot predict the mechanical response of demineralized and deproteinized bovine cortical femur bone accurately, while the general exponential–exponential and general exponential-power law models have a good agreement with the experimental results. To investigate the sensitivity of the hyperelastic models, a variation of 10% in material parameters was performed and the results indicated an acceptable stability for the general exponential–exponential and general exponential–power law models. Finally, the uniaxial tension and compression of cortical femur bone were studied using the finite element method in VUMAT user subroutine of ABAQUS software and the computed stress–stretch curves were shown a good agreement with the experimental data.

Bone surface microenvironment mimicked PLA scaffolds for osteogenic stem cell differentiation

Event Abstract Back to Event Bone surface microenvironment mimicked PLA scaffolds for osteogenic stem cell differentiation Birgun Ozcolak1*, Dilara Perver1*, Serpil Ozkara Yavuz1*, Klaus D. Jandt1* and Bora Garipcan1* 1 Bogazici University, Institute of Biomedical Engineering, Türkiye Introduction: The importance and advantages of bone tissue engineering products are increasing because of the disadvantages of autografts, allografts and zenografts such as finding suitable donors, rejection of tissue by immune system or pathogen carrying properties which are commonly using for the treatment of bone defects[1]. Changing the surface properties of scaffolds such as surface stiffness, chemical and biochemical components, surface roughness and topography may influence and effect the cell-surface, cell-scaffold interface characteristics and cellular behavior and mechanism of osteoblasts, stem cells and as well as other cell types[2]. Materials and Method: Bovine femur bone surface was mimicked by using a biodegrable polymer, Poly (L-Lactic acid) on the PDMS mold to obtain bone surface mimicked scaffolds. After the optimization of bone surface mimicking conditions, bone morphogenic protein 2 (BMP-2) was loaded on bone surface mimicked PLA scaffolds and release profile was examined at in-vitro conditions. Bone surface mimicked PLA scaffolds were modified with hydroxyapatite (HA) or collagen (Col I) in order to construct these scaffolds similar to the bone`s natural microenvironment. Bone surface mimicked, BMP-2 loaded, HA or Col I modified PLA scaffolds were characterized by water contact angle measurements, Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM) and degradation tests. These scaffolds were used for the controlled and directed differentiation of adipose derived stem cells and bone tissue formation in in-vitro conditions. Results: In the study for the first time bone surface mimicked scaffolds were and characterized and the effect of these scaffolds in in-vitro conditions to the differentiation of adipose derived mesenchymal stem cells were investigated. Discussion: Hydroxyapatite (HA) or collagen (Col I) modified bone surface mimicked and PLA scaffolds have shown better osteogenic differentiation profile of Adipose derived mesenchymal stem cells then plain PLA scaffolds and control group. Conclusion: Bone surface microenvironment were physically, chemically and biochemically prepared by using PLA scaffolds. These scaffolds could be used for the controlled and directed differentiation of adipose derived stem cells to osteoblasts in in-vitro conditions. This work is supported by TUBITAK Project under Grant No. 113S730 and Boğaziçi University Research Fund by Grant Number No. 6701.

The Development of a Composite Bone Model for Training on Placement of Dental Implants

It takes a lot of training on patients for both undergraduate to develop clinical sense as regards to the placement of dental implants in the jaw bones, also, the models provided by the dental implant companies for training are usually made of strengthened synthetic foams, which are far from the composition, and tactile sense provided by natural bone during drilling for clinical placement of dental implants. This is an in-vitro experimental study which utilized bovine femur bone, where the shaft of the femur provided the surface compact layer, and the head provided the cancellous bone layer, to provide a training model similar to jaw bones macroscopic anatomy. Both the compact and cancellous bone samples were characterized using mechanical compressive testing. The elastic moduli of the cancellous and cortical femur bone were comparable to those of the human mandible, and the prepared training model provided a more lifelike condition during the drilling and placement of dental implants. The composite bone model developed simulated the macroscopic anatomy of the jaw bones having a surface layer of compact bone, and a core of cancellous bone, and provided a better and a more natural hands-on experience for placement of dental implants as compared to plastic models made of polyurethane.

Ultrasonic wave velocities in radial direction of bovine cortical bone

The ultrasonic axial transmission (AT) techniques have been proposed to evaluate the cortical bone of arms and legs. For the mode analysis of propagating waves, the information of anisotropy and heterogeneity of the cortical bone is important. Yamato has pointed that longitudinal wave velocity in the axial direction of bovine cortical bone changes due to the measurement positions and microstructures. In this study, we have investigated longitudinal wave velocities in radial direction of cortical bone. The cuboid samples were obtained from the cortical bone of bovine femur. During ultrasonic pulse immersion experiments, a sinusoidal ultrasonic wave in the range from 3 to 10 MHz was transmitted from a PVDF transducer, which passed through the sample in the radial direction. By reducing the sample thickness gradually, wave velocities were measured. The average velocities in radial direction of samples were around 3450 m/s and depended on the positions of the samples in the femur. They variation of the velocities due to the thickness was about 7 %. These data give us the information of heterogeneity of cortical bone in radial direction which should be considered in the AT techniques. [1] Y. Yamato, et al., Jpn. J. Appl. Phys., 47, 4096–4100 (2008).

Preparation of Natural Hydroxyapatite from Bovine Femur Bones Using Calcination at Various Temperatures

Calcium phosphate based biomaterials have received great interest since the main constituent of inorganic mineral component in human bone is hydroxyapatite (HAP). This study aims to extract the natural HAP from bovine femur bone at different calcination temperature with different particle size. The experiment starts with cleaning process of fresh bovine femur bones. Then bovine bones were ground into different particle size (x ≤ 45μm, 45 < x ≤ 63μm, and 63 < x ≤ 125μm). All bone samples were furnace heated at temperatures of 700°C, 900°C, and 1100°C for three hours. Obtained apatite was characterized using field emission scanning electron microscope (FESEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The results indicate that increasing calcination temperature leads to organic free and higher crystallite size of HAP. In terms of particle size, crystallite size is increasing as particle size increases but the increment crystallite size is not significant. The report here proposed that calcination temperature above 700˚C may utilize in bone tissue engineering application.

Ultrasonic welding in orthopedic implants

A critical event in hip replacement is the occurrence of osteolysis. Cemented hip replacements most commonly use polymethylmethacrylate (PMMA), not as an adhesive but rather a filler to limit micromotion and provide stability. PMMA, however, contributes to osteolysis through both a thermal response during curing and implant wear debris. In order to mitigate the occurrence of osteolysis, we are exploring ultrasonic welding as a means of attachment. Weld strength was assessed using ex vivo bovine rib and femur bones. A flat end mill provided 20 site locations for insertion of an acrylonitrile butadiene styrene, ABS pin. Each location was characterized on topography, porosity, discoloration, and any other notable features. Each site was welded using a Branson Ultrasonic Welder 2000iw; 20 kHz, 1100 W. Machine parameters include weld force, weld time, and hold time. The bond strength was determined using a tensile tester. Tensile testing showed a negative correlation between porosity and bond strength. Further evaluation and characterization of bone properties to bond strength will enable appropriate selection of welding properties to ensure a superior bond.

Radioprotective effect of N-acetyl-L-cysteine free radical scavenger on compressive mechanical properties of the gamma sterilized cortical bone of bovine femur.

Gamma sterilization of bone allografts is used as a gold standard method to provide safety against disease transmission. However, it is well documented that high dose levels of ionizing radiation can degrade bone mechanical properties. This effect, which is attributed to the formation of free radicals through radiolysis of the water content of collagen, can lead to post-implantation difficulties such as pre-failure and/or secondary fractures of bone allografts. Recently, treatment of irradiated allografts with free radical scavengers is used to protect them against radiation-induced damages. This study aimed to investigate the radioprotective role of N-acetyl-L-cysteine (NAC) during the gamma sterilization of the cortical bone of bovine femurs using the compressive test. Totally, 195 cubic specimens with a dimension of 5 × 5 × 3 cubic mm were divided into 13 groups including a control and 12 experimental groups exposed to 18, 36, and 70 kGy at three different NAC concentrations (1.25, 12.5, and 25 mM for 18 kGy; 5, 50, and 100 mM for 36 kGy; 10, 100, and 200 mM for 70 kGy). The mechanical behavior of the sterilized specimens was studied using the uniaxial compressive test. The results indicated a concentration-dependent radioprotection effect of NAC on the plastic properties of the cortical bones. The concentration dependency of NAC was in turn related to radiation dose levels. In conclusion, treatment of bone specimens with a characteristic concentration of NAC during exposure to specific radiation dose levels can provide an efficient radioprotection window for preserving the mechanical stability of gamma sterilized allografts.

Experimental and analytical investigation of the thermal necrosis in high-speed drilling of bone

Bone loss due to thermo necrosis may weaken the purchase of surgically placed screws and pins, causing them to loosen postoperatively. The heat generated during the bone drilling is proportional to cutting speed and force and may be partially dissipated by the blood and tissue fluids, and somehow carried away by the chips formed. Increasing cutting speed will reduce cutting force and machining time. Therefore, it is of interest to study the effects of the increasing cutting speed on bone drilling characteristics. In this article, the effects of the increasing cutting speed ranging from 500 up to 18,000 r/min on the thrust force and the temperature rise are studied for bovine femur bone. The results of this study reveal that the high-speed drilling of 6000-7000 r/min may effectively reduce the two parameters of maximum cortical temperature and duration of exposure at temperatures above the allowable levels, which in turn reduce the probability of thermal necrosis in the drill site. This is due to the reduction of the cutting force and the increase in the chip disposal speed. However, more increases in the drill bit rotational speed result in an increase in the amount of temperature elevation, not because of sensible change in drilling force but a considerable increase in friction among the chips, drill bit and the hole walls.