Sheep Femur Research Articles

Osseoconductive CaTi4-zZrz(PO4)6 Ceramics: Solutions Towards Nonunion, Osteoporosis, and Osteoarthrosis Conditions?

Transition (Ti, Zr) metal-substituted calcium hexaorthophosphate CaTi4-zZrz(PO4)6 coatings with an NaSICon structure were deposited by atmospheric plasma spraying (APS) onto Ti6Al4Veli substrates using a statistical design of experiments (SDE) methodology. Several coating properties were determined, including chemical composition, porosity, surface roughness, tensile adhesion strength, shear strength, and solubility in protein-free simulated body fluid (pf-SBF) and TRIS-HCl buffer solution. The biological performance evaluation involved cell proliferation and vitality studies and osseointegration tests of coated Ti6Al4Veli rods intramedullary implanted in sheep femora. After a 6 months observation time, a satisfactory gap-bridging potential was apparent as shown by a continuous, well-adhering layer of newly formed cortical bone. These tests suggest that the coatings possess a suitable osseoconductive potential and present an enhanced expression of bone growth-supporting non-collagenous proteins and cytokines, a high cell proliferation, spreading and vitality, and substantial osseointegration by strong bone apposition. The moderate intrinsic ionic conductivity of CaTi4-zZrz(PO4)6 compounds can be augmented by doping with highly mobile Na+ or Li+ ions to levels that suggest their use in electric bone growth stimulation (EBGS) devices, able to treat nonunion (pseudoarthrosis) and osteoporosis, and that may also support spinal stabilisation by vertebral fusion.

Precision pore structure optimization of additive manufacturing porous tantalum scaffolds for bone regeneration: A proof-of-concept study

Currently, the treatment of bone defects in arthroplasty is a challenge in clinical practice. Nonetheless, commercially available orthopaedic scaffolds have shown limited therapeutic effects for large bone defects, especially for massiveand irregular defects. Additively manufactured porous tantalum, in particular, has emerged as a promising material for such scaffolds and is widely used in orthopaedics for its exceptional biocompatibility, osteoinduction, and mechanical properties. Porous tantalum has also exhibited unique advantages in personalised rapid manufacturing, which allows for the creation of customised scaffolds with complex geometric shapes for clinical applications at a low cost and high efficiency. However, studies on the effect of the pore structure of additively manufactured porous tantalum on bone regeneration have been rare. In this study, our group designed and fabricated a batch of precision porous tantalum scaffolds via laser powder bed fusion (LPBF) with pore sizes of 250 μm (Ta 250), 450 μm (Ta 450), 650 μm (Ta 650), and 850 μm (Ta 850). We then performed a series of in vitro experiments and observed that all four groups showed good biocompatibility. In particular, Ta 450 demonstrated the best osteogenic performance. Afterwards, our team used a rat bone defect model to determine the in vivo osteogenic effects. Based on micro-computed tomography and histology, we identified that Ta 450 exhibited the best bone ingrowth performance. Subsequently, sheep femur and hip defect models were used to further confirm the osteogenic effects of Ta 450 scaffolds. Finally, we verified the aforementioned in vitro and in vivo results via clinical application (seven patients waiting for revision total hip arthroplasty) of the Ta 450 scaffold. The clinical results confirmed that Ta 450 had satisfactory clinical outcomes up to the 12-month follow-up. In summary, our findings indicate that 450 μm is the suitable pore size for porous tantalum scaffolds. This study may provide a new therapeutic strategy for the treatment of massive, irreparable, and protracted bone defects in arthroplasty.

Osseointegration of photodynamic active biomaterials for bone regeneration in an animal bone model over a period of 12 months.

Previous efforts led to the development of two different polymeric biomaterials for periodontal regeneration with antibacterial photodynamic surface activity. The present study aimed to investigate osseointegration and bone formation of both materials in an ovine model. Both biomaterials: 1) urethane dimethacrylate-based Biomaterial 1 (BioM1) and 2) tri-armed oligoester-urethane methacrylate-based Biomaterial 2 (BioM2) are enriched with beta-tri-calcium phosphate and the photosensitizer meso-tetra(hydroxyphenyl)chlorin (mTHPC). These materials were implanted in non-critical size bone defects in the sheep femur (n=16) and tibia (n=8). Empty defects served as controls (n=16). Polyfluorochrome sequential bone labeling was carried out at baseline and after 3, 6, and 12 months. Animals were sacrificed after 12 months. Bone specimens (n=40) were fixed and subjected to microtomographic analysis (µCT) for the evaluation of the bone-volume-fraction (BV/TV), trabecular number and trabecular thickness. Subsequently, histological sections were arranged and polyfluorochrome sequential bone labeling was analyzed by confocal laser scanning microscopy (cLSM). cLSM analysis revealed that highest remodeling and bone formation activity occurred during the second half of the study period (6-12 months). Bone formation in the tibia was significantly lower for the control (2.71±1.26%) as compared to BioM1 (6.01±2.99%) and BioM2 (6.45±2.12%); (p=0.006, p=0004). Micro-computed tomography revealed a BV/TV volume fraction of 44.72±9.01% in femur defects filled with BioM1 which was significantly higher compared to the control (32.27±7.02%; p=0.01). Bone architecture (trabecular number, trabecular thickness) did not significantly differ from the self-healed defects. Both biomaterials, especially BioM1 showed good osseointegration and bone formation characteristics and can be recommended for further examination in periodontal regeneration studies.

Microwave bone fracture diagnosis using deep neural network

This paper studies the feasibility of a deep neural network (DNN) approach for bone fracture diagnosis based on the non-invasive propagation of radio frequency waves. In contrast to previous “semi-automated” techniques, where X-ray images were used as the network input, in this work, we use S-parameters profiles for DNN training to avoid labeling and data collection problems. Our designed network can simultaneously classify different complex fracture types (normal, transverse, oblique, and comminuted) and estimate the length of the cracks. The proposed system can be used as a portable device in ambulances, retirement houses, and low-income settings for fast preliminary diagnosis in emergency locations when expert radiologists are not available. Using accurate modeling of the human body as well as changing tissue diameters to emulate various anatomical regions, we have created our datasets. Our numerical results show that our design DNN is successfully trained without overfitting. Finally, for the validation of the numerical results, different sets of experiments have been done on the sheep femur bones covered by the liquid phantom. Experimental results demonstrate that fracture types can be correctly classified without using potentially harmful and ionizing X-rays.

Hydroxyapatite 3D-printed scaffolds with Gyroid-Triply periodic minimal surface (TPMS) porous structure: Fabrication and an in vivo pilot study in sheep

Bone repair is a major challenge in regenerative medicine, e.g. for large defects. There is a need for bioactive, highly percolating bone substitutes favoring bone ingrowth and tissue healing. Here, a modern 3D printing approach (VAT photopolymerization) was exploited to fabricate hydroxyapatite (HA) scaffolds with a Gyroid-“Triply periodic minimal surface” (TPMS) porous structure (65% porosity, 90.5% HA densification) inspired from trabecular bone. Percolation and absorption capacities were analyzed in gaseous and liquid conditions. Mechanical properties relevant to guided bone regeneration in non-load bearing sites, as for maxillofacial contour reconstruction, were evidenced from 3-point bending tests and macrospherical indentation. Scaffolds were implanted in a clinically-relevant large animal model (sheep femur), over 6 months, enabling thorough analyses at short (4 weeks) and long (26 weeks) time points. In vivo performances were systematically compared to the bovine bone-derived Bio-OssⓇ standard. The local tissue response was examined thoroughly by semi-quantitative histopathology. Results demonstrated the absence of toxicity. Bone healing was assessed by bone dynamics analysis through epifluorescence using various fluorochromes and quantitative histomorphometry. Performant bone regeneration was evidenced with similar overall performances to the control, although the Gyroid biomaterial slightly outperformed Bio-OssⓇ at early healing time in terms of osteointegration and appositional mineralization. This work is considered a pilot study on the in vivo evaluation of TPMS-based 3D porous scaffolds in a large animal model, for an extended period of time, and in comparison to a clinical standard. Our results confirm the relevance of such scaffolds for bone regeneration in view of clinical practice. Statement of significanceBone repair, e.g. for large bone defects or patients with defective vascularization is still a major challenge.Highly percolating TPMS porous structures have recently emerged, but no in vivo data were reported on a large animal model of clinical relevance and comparing to an international standard.Here, we fabricated TPMS scaffolds of HA, determined their chemical, percolation and mechanical features, and ran an in-depth pilot study in the sheep with a systematic comparison to the Bio-OssⓇ reference.Our results clearly show the high bone-forming capability of such scaffolds, with outcomes even better than Bio-OssⓇ at short implantation time. This preclinical work provides quantitative data validating the relevance of such TMPS porous scaffolds for bone regeneration in view of clinical evaluation.

Finite element analysis (FEA) of femur to predict biomechanical properties and its validation

The aim of this preliminary study is to predict the biomechanical properties as strain of the femur using computed tomography medical image-based finite element analysis. Further, the finite element results were compared with the experimental results for validation purpose. The main objective of the study was to establish and validate a finite element model used to analyse biomechanical properties. For this, four sheep femur specimens were used to predict normal strain in x-x direction. Computed tomography scans were taken from each femur sample. Subsequently, an accurate image-based 3D model of each femur specimen was segmented and reconstructed with its material properties. Furthermore, the experimental test was performed at 8° bone inclination in the coronal plane and a compressive load was applied at displacement rate of 0.2 mm/s to the femur head in a vertical downward direction until fracture. Consequently, the numerical results of predicted normal strain were compared with the experimental measured normal strain. The average deviation between finite element and experimental results was found to be −11.11%–20.10% in strains. Hence, it is concluded that the results obtained using finite element analysis are in good agreement with the experimental results.

An Eco-Friendly Process to Extract Hydroxyapatite from Sheep Bones for Regenerative Medicine: Structural, Morphologic and Electrical Studies

Hydroxyapatite (HA) promotes excellent bone regeneration in bone-tissue engineering, due to its similarity to bone mineral and its ability to connect to living tissues. These factors promote the osteointegration process. This process can be enhanced by the presence of electrical charges, stored in the HA. Furthermore, several ions can be added to the HA structure to promote specific biological responses, such as magnesium ions. The main objective of this work was to extract hydroxyapatite from sheep femur bones and to study their structural and electrical properties by adding different amounts of magnesium oxide. The thermal and structural characterizations were performed using DTA, XRD, density, Raman spectroscopy and FTIR analysis. The morphology was studied using SEM, and the electrical measurements were registered as a function of frequency and temperature. Results show that: (i) an increase of MgO amount indicates that the solubility of MgO is below 5%wt for heat treatments at 600 °C; (ii) the rise of MgO content increases the capacity for electrical charge storage; (iii) sheep hydroxyapatite presents itself as a natural source of hydroxyapatite, environmentally sustainable and low cost, and promising for applications in regenerative medicine.

Spatial Variation in Young Ovine Cortical Bone Properties.

Significant effort continues to be made to understand whether differences exist in the structural, compositional, and mechanical properties of cortical bone subjected to different strain modes or magnitudes. We evaluated juvenile sheep femora (age = 4 months) from the anterior and posterior quadrants at three points along the diaphysis as a model system for variability in loading. Micro-CT scans (50 micron) were used to measure cortical thickness and mineral density. Three point bending tests were performed to measure the flexural modulus, strength, and post-yield displacement. There was no difference in cortical thickness or density between anterior or posterior quadrants; however, density was consistently higher in the middle diaphysis. Interestingly, bending modulus and strength were higher in anterior quadrants compared to posterior quadrants. Together, our results suggest that there is a differential spatial response of bone in terms of elastic bending modulus and mechanical strength. The origins of this difference may lie within the variation in ongoing mineralization, in combination with the collagen-rich plexiform structure, and whether this is related to strain mode remains to be explored. These data suggest that in young ovine cortical bone, modulation of strength occurs via potentially complex interactions of both mineral and collagen-components that may be different in regions of bone exposed to variable amounts of strain. Further work is needed to confirm the physiological load state of bone during growth to better elucidate the degree to which these variations are a function of the local mechanical environment.

Experimentally characterizing the spatially varying anisotropic mechanical property of cancellous bone via a Bayesian calibration method

Traditional experimental tests for characterizing bone's mechanical properties usually hypothesize a uniaxial stress condition without quantitatively evaluating the influence of spatially varying principal material orientations, which cannot accurately predict the mechanical properties distribution of bones in vivo environment. In this study, a Bayesian calibrating procedure was developed using quantified multiaxial stress to investigate cancellous bone's local anisotropic elastic performance around joints as the spatial variation of main bearing orientations. First, the bone cube specimens from the distal femur of sheep are prepared using traditional anatomical axes. The multiaxial stress state of each bone specimen is calibrated using the actual principal material orientations derived from fabric tensor at different anatomical locations. Based on the calibrated multiaxial stress state, the process of identifying mechanical properties is described as an inverse problem. Then, a Bayesian calibration procedure based on a surrogate constitutive model was developed via multiaxial stress correction to identify the anisotropic material parameters. Finally, a comparison between the experiment and simulation results is discussed by applying the optimal model parameters obtained from the Bayesian probability distribution. Compared to traditional uniaxial methods, our results prove that the calibration based on the spatial variation of the main bearing orientations can significantly improve the accuracy of characterizing regional anisotropic mechanical responses. Moreover, we determine that the actual mechanical property distribution is influenced by complicated mechanical stimulation. This study provides a novel method to evaluate the spatially varying mechanical properties of bone tissues enduring complex mechanical loading accurately and effectively. It is expected to provide more realistic mechanical design targets in vivo for a personalized artificial bone prosthesis in clinical treatment.

Древневенгерское погребение у с. Глиное на левобережье Нижнего Днестра

The article analyzes the early medieval grave Glinoe 13/2 investigated in 2008 on the left bank of the Lower Dniester. The burial was sunk into the Scythian barrow. The inventory included a knife, an earring, an awl and a fireflint. The sheep femur lay behind the skull of the buried. An analysis of the funerary rite and inventory made it possible to date the Glinoe 13/2 grave to the 9th—10th centuries. Radiocarbon dating of human and sheep bones made it possible to specify the time of the internment until the end of the 9th — the first half of the 10th century. An analysis of the peculiarities of the placement of sacrificial food remains and the composition of species in it in the medieval burials of the North Black Sea region confirms the Early Hungarian attribution of the published grave. This burial is included in the group of Early Hungarian graves near the Glinoe village, which reflects the presence of a large family in this microregion. These circumstances, together with the date of the Frumusica graves and evidence from the written sources, allow us to state the presence of the Early Hungarians in the Lower Dniester region at the beginning of the 10 th century.

Zirconia versus Titanium Implants: 8-Year Follow-Up in a Patient Cohort Contrasted with Histological Evidence from a Preclinical Animal Model.

Zirconia ceramic (ZC) implants are becoming more common, but comparisons between preclinical histology and long-term clinical trials are rare. This investigation comprised (1) 8-year clinical follow-up of one-piece ZC or titanium (Ti) implants supporting full overdentures and (2) histomorphometric analysis of the same implants in an animal model, comparing implants with various surface treatments. Methods: (1) Clinical trial: 24 completely edentulous participants (2 groups of N = 12) received 7 implants (one-piece ball-abutment ZC or Ti; maxilla N = 4, mandible N = 3) restored with implant overdentures. Outcomes after 8-years included survival, peri-implant bone levels, soft-tissue responses, and prosthodontic issues. (2) Preclinical trial: 10 New Zealand sheep received 4 implants bilaterally in the femoral condyle: Southern Implants ZC or Ti one-piece implants, identical to the clinical trial, and controls: Southern ITC® two-piece implants with the same surface or Nobel (NBC) anodised (TiUnite™) surface. %Bone-implant contact (%BIC) was measured after 12 weeks of unloaded healing. Results: 8 of 24 participants (33%) of an average age of 75 ± 8 years were recalled; 21% of original participants had died, and 46% could not be contacted. 80.4% of implants survived; excluding palatal sites, 87.5% of Ti and 79% of ZC implants survived. All failed implants were in the maxilla. Three ZC implants had fractured. Bone loss was similar for Ti vs. ZC; pocket depths (p = 0.04) and attachment levels (p = 0.02) were greater for Ti than ZC implants. (1.7 ± 1.6 mm vs. 1.6 ± 1.3 mm). All implants in sheep femurs survived. %BIC was not statistically different for one-piece blasted surface Ti (80 ± 19%) versus ZC (76 ± 20%) or ITC® (75 ± 16 mm); NBC had significantly higher %BIC than ITC (84 ± 17%, p = 0.4). Conclusion: Short-term preclinical results for ZC and Ti one-piece implants showed excellent bone-implant contact in unloaded femoral sites. This differed from the long-term clinical results in older-aged, edentulous participants. While ZC and Ti implants showed equivalent performance, the risks of peri-implantitis and implant loss in older, completely edentulous patients remain a significant factor.

Osteochondral regeneration in rabbit using xenograft decellularized ECM in combination with different biological products; platelet-rich fibrin, amniotic membrane extract, and mesenchymal stromal cells.

This study aimed to investigate the regenerative effect of decellularized osteochondral ECM xenograft in combination with various biological products in an osteochondral (OC) defect. OC tissue from the sheep femur were obtained and decellularized. The decellularized ECM (dECM) was combined with either platelet-rich fibrin (PRF), amniotic membrane extract (AME), or rabbit bone marrow-derived mesenchymal stromal cells (rBMSCs). The hybrid dECM-biological products were then utilized for the treatment of rabbit OC critical size defects. The regenerative potential of different groups was compared using; MRI, macroscopic assessment, histopathology, and histomorphometry. All characterizations analysis verified successful decellularization. Three months post-surgery, macroscopic findings indicated that dECM was better compared to controls. Also, dECM in combination with AME, PRF, and rBMSCs showed enhanced OC regeneration compared to only dECM (AME: +100%, PRF: +61%, rBMSCs: +28%). In particular, the dECM+AME group results in the best integration of new cartilage into surrounding cartilage tissue. The histomorphometric evaluations demonstrated enhancement in new cartilage formation and bone tissue (86.5± 5.9% and 90 ± 7.7%, respectively) for the dECM+AME group compared to other groups. Furthermore, histological results for the dECM+AME elucidated a mature hyaline cartilage tissue that covered the new and symmetrically formed subchondral bone, exhibiting a significantly higher regenerative effect compared to all other treated groups. This finding was also confirmed with MRI images. The current study revealed that in addition to the benefits of dECM alone, its combination with AME indicated to have a superior regenerative effect on OC regeneration. Overall, dECM+AME may be considered a suitable construct for treating knee OC injuries.

A Micro-computed Tomography Database and Reference Implementation for Parallel Computations of Trabecular Thickness and Spacing

We provide a well-defined accurate brute force implementation without approximations as a reference to support future development of correct and fast algorithms to measure the trabecular thickness and spacing. Using artificial ellipsoid examples, the systematic error is shown to be related to the voxelization, which can be reduced by upsampling. Furthermore, we collected a database of 40 three-dimensional micro-computed tomography images of trabecular bone regions of a sheep femur. With the coverage of a broad range of trabecular thickness and spacing, the database is suitable for assessing the correctness of algorithms for the measurements of trabecular thickness and spacing. The bone data is shared publicly in the online repository ‘Figshare’ and the brute force code is freely available in Code Ocean. Scientists are encouraged to implement faster algorithms, e.g., graphic processing unit-accelerated, with accurate or controlled approximate behaviour to compute trabecular thickness and spacing. Especially, the provided data can be re-employed together with the reference algorithm to evaluate their accuracies.

Comparison of Human and Sheep Femur with Finite Element Method

İnsan ve hayvan sağlığı araştırmalarında sonlu elemanlar yöntemi (SEY) kullanılarak gerçekleştirilen analiz çalışmaları, bilgisayar teknolojisinin de gelişmesiyle birlikte önem kazanmıştır. SEY analiz çalışmaları fare, köpek, tavşan, domuz, at ve koyun gibi hayvanlarda yapılmaktadır. Bu hayvanlarda bulunan kemiklerin modelleme çalışmaları büyük hayvanlarda yapılması daha doğru sonuçlar vermektedir. Bu çalışmanın amacı, insan ve koyun femurununlarının katı modellemelerinin oluşturulup, sonlu elemanlar yöntemi kullanılarak bir paket program yardımıyla gerilme, şekil değiştirme ve deformasyon değerlerinin karşılaştırılmasıdır. Analizler sonucunda koyun femurundaki mekanik değerlerin insan femurundakilere kıyasla daha düşük olduğu tespit edilmiştir.

COMPARISON OF ROE DEER (CAPREOLUS CAPREOLUS) AND SHEEP (OVIS ARIES) FEMUR MORPHOLOGICAL CHARACTERISTICS AS A METHOD OF DETERMINATION ANIMAL SPECIES

Forensic analysis of the osteological characteristics of femurs of roe deer and sheep was performed by the method of comparison. In this study, 6 femurs of adult roe deer and 6 femurs of adult sheep were used. After the soft tissue remains were removed from the bones, they were boiled and then bleached in 3% the solution of hydrogen peroxide (H2O2). After bleaching, the bones were air-dried and then photographed. The roe deer femur is on average 2.3 cm longer than the same bone in sheep. The body of roe deer femur is strongly curved cranially, and in sheep it is slightly curved. The caudal surface of the femur body in sheep has two rough lines that were absent in the middle third in roe deer femoral body. The supracondylar fossa in roe deer is deep and in sheep shallow. The deep fovea in roe deer and shallow fovea in sheep were observed on the middle of the femoral head. The greater trochanter in roe deer femur is higher and narrower in comparison to sheep. The lateral surface of the greater trochanter of femur in roe deer is rough and in sheep it is smooth. The trochanteric fossa in roe deer femur is narrow and deep, while in sheep it is wide and shallow. On the distal extremity of the femur, the trochlea in roe deer is shallower than in sheep. On the lateral condyle, the popliteal muscular fossa in roe deer is narrow and shallow and in sheep wide and deep. The roe deer patella is on average 0.3 cm shorter and 0.4 cm narrower compared to sheep.

The Use of Sulfur Waste to Protect Against Corrosion of Metal Implants

Metal parts of endoprosthesis have a detrimental effect on the bones that come into contact with them and on the entire body of the patient. Coating them with biocompatible layers (hydroxyapatite and bioglass) has not yet brought about permanent results. In this study, the author showed the possibility of using a binder containing sulfur waste for this purpose. The sulfur binder is used industrially in electrical engineering and construction applications. The chemical properties of elemental sulfur indicate that it is a biocompatible material. Previous studies on rats have shown that sulfur binder is a biocompatible material. A steel surgical nail covered with sulfur waste, placed in a sheep's femur, showed excellent stabilization by adhering bone tissue to the composite layer. From the results, it is convinced that the composite made of sulfur waste creates new possibilities in the field of production of biocomposites for surgical applications. The prepared biocomposite composition was sulfur waste-69.5%, mineral quartz dust-30%, and technical soot-0.5%. There is no information on similar studies in the world literature. So far, sulfur waste has been used in the electrical and construction industries. The literature shows that no researcher has used sulfur waste in biocomposites. So, the current study is a pioneering experimental study in this area.

In vitro estimation of fracture load and strain in sheep femur bone: Experimental approach

The purpose of the study is to estimate biomechanical properties such as fracture load and strain in sheep femur bone at 0.2 mm/sec and 2 mm/sec displacement rate. Uniaxial strain gauges (SG) are bonded on a neck-head region of femur bone specimens. The strain is measured by using NI 9236 module and fracture load is measured by using NI9237 module using LabVIEW software. A compressive load is applied on femur head using hydraulic actuator with solenoid operated direction control valve (DCV) during experimentation. The study is intended for compressive loading in-stance configuration at a different displacement rate. A sheep femur bone inclined at 8° in a coronal plane from the distal end and fixed in bone holding fixture. In this study, estimated fracture load of sheep femur bone at a displacement rate of 0.2 mm/sec is 2456.04 ± 324.92 N and strain as 0.00315 ± 0.00107. The tests were conducted at a displacement rate of 2 mm/sec and got the fracture load as 1669.45 ± 269.37 N and strain as 0.0005 ± 0.00025 respectively. It is also found that the fracture load decreases as the displacement rate increases. From experimental testing, it is observed that each one fracture of specimens occurs in a neck-head region. This is often and may be because of the lower mass density in this region of the femur bone. This study also helps to develop material properties for implants and fixation.

Estimation of mass apparent density and Young’s modulus of femoral neck-head region

The purpose of this study is to estimate mass apparent density and Young’s modulus to investigate biomechanical properties of the proximal femur bone. In this study eleven specimens of sheep femur bone having age between 1–1.25 years and human femur bone having age between 14 and 81years are used. In the present study, the first technique attempts to estimate the density from the image-based Hounsfield unit which is obtained directly from a computed tomography image. The modulus of elasticity is estimated from density-elasticity relation which is available in the literature. Another technique is used to develop a correlation between computed apparent density and greyscale based coefficient obtained by material mapping method using commercial Simpleware ScanIP software. Estimated mean deviation in apparent mass density and Young’s modulus is 4.34% and 4.69% in sheep bone and 4.35% and 4.94% in human bone respectively. It is found that apparent density and Young's modulus obtained shows close agreement with values reported in the literature. Moreover, the study attempts to build up a new material model between human and sheep for orthopaedics clinical trials and research in Indian context. In addition, it is also observed that bone mass density of sheep is 1.60 times human. This method can also be useful to study and analyse biomechanical properties of the human femur bone.

A New Breakthrough Detection Method for Bone Drilling in Robotic Orthopedic Surgery with Closed-Loop Control Approach.

Breakthrough detection is a crucial task to reduce the risks of damaging soft tissue bone drilling operations during orthopedic surgery. Conventional drills are not equipped with this function while the recent literature has offered this capability with high cost and complex modification needs. In this study, a new breakthrough detection approach based on closed-loop control characteristics of the drilling operation is proposed. A feature set containing closed-loop signals and force sensor data is created to train K-Nearest and Ensemble Classifier for breakthrough detection tasks with drilling the synthetic bone model and animal bone with a robot manipulator. The best accuracy of breakthrough detection with only closed-loop control signal attributes is achieved as 96.9 ± 0.8% for the synthetic bone model and 98.1 ± 0.2% for sheep femur bone. Breakthrough detection delay which included sampling and operation time of the method guarantees that the drill bit would stop with acceptable breakthrough range of 1.0413mm. The proposed method can be used to detect breakthrough and also to estimate the state of the drill bit in robotic orthopedic bone drilling processes using only closed-loop signals so that it would be no need to use extra high-cost sensors.

Trabecular bone attenuation and velocity assess by ultrasound pulse-echoes

Attenuation and velocity (Speed-of-Sound) in a trabecular bone were calculated and evaluated from ultrasound pulse-echoes detection and their processing, applying a single US transducer that operates in transmit/receive mode. The processing of US pulse-echoes utilized development of algorithms for the attenuation and the Speed-of-Sound in trabecular bone. These ultra-sound pulse-echoes were obtained from the front and rear surfaces of a trabecular bone sample. The motivation for this work was to develop an efficient intraosseous monitoring device that provides the Speed-of-Sound and attenuation intraoperatively and in real-time and therefore can be implemented during a surgery.Ultrasonic measurements were performed in the frequency range of 3.5–6.5 [MHz]. In these experiments, the fresh trabecular bone samples were from sheep femora and humerus. The measuring results were correlated (R2 ≥ 0.95) with those obtained previously, mainly during transmission mode studies.According to the obtained results, the presented method presumably will be utilized as a clinical tool in bone surgical procedures and therefore will be able to provide better outcomes, while monitoring intraoperatively and in real-rime intraosseous trabecular bone attenuation and its velocity: In the next stage of this study, the method will be carried out on human tissues and also intraoperatively, during human clinical trials. It is planned to perform it on long bones/tibia, vertebra, in neurosurgery – for drilling the skull and also in dental implantation surgery.