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Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is imperative to enhance the mechanical properties and corrosion resistance of magnesium (Mg)-based metallic glasses for orthopedic implants to further their development. The addition of yttrium (Y) significantly improves both of these characteristics. The Mg52.5Zn40.5Ca5Y2 alloy was chosen for its optimal glass-forming capabilities, as evidenced by thermodynamic parameter, PHHS. This alloy demonstrates remarkable enhancements in both mechanical and corrosion properties, despite the presence of a stable Mg12YZn phase in the liquid, which precludes the complete formation of glass. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a substantial increase in hardness, surpassing the Mg66Zn30Ca4 metallic glass by up to 30 HV. The compressive strength of this alloy is 690 MPa, which is approximately 138 MPa greater than that of the Mg66Zn30Ca4 alloy. The Mg52.5Zn40.5Ca5Y2 alloy exhibits a higher noble corrosion potential and a lower corrosion current density demonstrating a corrosion current density of 6.970 µA/cm2 and a corrosion potential of − 1.240 V. These values suggest a significant increase in corrosion resistance when contrasted with the baseline alloy, Mg66Zn30Ca4. The primary cause of this improvement in mechanical behavior and corrosion resistance is the formation of Mg12YZn long-period stacking ordered (LPSO) phases and Mg3YZn6 icosahedral phases. The material's overall strength and durability are enhanced by these phases, rendering it a promising candidate for applications that necessitate high performance in both mechanical and corrosive environments. As per the results, Mg52.5Zn40.5Ca5Y2 alloy is an exceptional choice for advanced material applications due to its distinctive phase composition, which results in superior properties. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Medical Equipment Journal is the property of Chinese Medical Equipment Journal Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Inadequate osseointegration at the interface is a key factor in orthopedic implant failure. Mechanistically, traditional orthopedic implant interfaces fail to precisely match natural bone regeneration processes in vivo. In this study, a novel biomimetic coating on titanium substrates (DPA‐Co/GFO) through a mussel adhesion‐mediated ion coordination and molecular clicking strategy is engineered. In vivo and in vitro results confirm that the coating exhibits excellent biocompatibility and effectively promotes angiogenesis and osteogenesis. Crucially, the biomimetic coating targets the integrin α2β1 receptor to promote M2 macrophage polarization and achieves a synergistic effect between immunomodulation and vascularized bone regeneration, thereby maximizing osseointegration at the interface. Mechanical push‐out tests reveal that the pull‐out strength in the DPA‐Co/GFO group is markedly greater than that in the control group (79.04 ± 3.20 N vs 31.47 ± 1.87 N, P < 0.01) and even surpasses that in the sham group (79.04 ± 3.20 N vs 63.09 ± 8.52 N, P < 0.01). In summary, the novel biomimetic coating developed in this study precisely matches the natural process of bone regeneration in vivo, enhancing interface‐related osseointegration and showing considerable potential for clinical translation and applications. [ABSTRACT FROM AUTHOR]

Using orthopedic devices or prosthetic joints to treat various conditions is expected in a Traumatology and Orthopedics Unit. Recently, the materials used to build these different devices have evolved; however, pathogens can still infect these materials. Additionally, the immune system has limitations when defending against these pathogens, which results in bacterial infections like Staphylococcus aureus, Methicillin-susceptible Staphylococcus aureus (MSSA) and Methicillin-resistant Staphylococcus aureus (MRSA). A total of 276 patients who attended the Traumatology and Orthopedics Unit of our hospital from 1 June 2018 to 1 June 2019, were included in the present study. Our study analyzed the incidence of S. aureus and other bacterial pathogens in the surgical sites of patients with orthopedic implants, as well as the most used types of implants and implant materials. The specimens obtained from the surgical sites of the patients were cultured in anaerobic and aerobic media for subsequent identification using their phenotypic characteristics. Subsequently, antibiotic susceptibility tests were performed to establish the appropriate treatment. The primary pathogens identified were Staphylococcus aureus (26.4%), followed by Escherichia coli (21.0%) and Staphylococcus epidermidis (15.8%). The most commonly used implants were plates (41.7%), followed by endomedullary nails (20%), Kirschner wires (14.1%), and fixators (10.1%). As for the anatomical regions of the implants, the most frequent sites were the legs, followed by the thighs, wrists, and ankles. The pathogens were more susceptible to ciprofloxacin (95%), clindamycin (89%), and cefotaxime (86%). S. aureus is the primary infectious agent in our hospital, with an incidence of 26.4% after the placement of orthopedic implants. Although its incidence was lower compared to other tertiary hospitals, it is necessary to improve aseptic techniques in such a way as to reduce the incidence of this pathogen further. [ABSTRACT FROM AUTHOR]

For orthopedic implants, biocompatibility is essential to ensure that they integrate with biological systems without causing negative reactions or impairing tissue function. Orthopedic implants must be cellularly acceptable to interact with neighboring tissues, including muscle, cartilage, and bone. Implant materials should not cause cytotoxic reactions or inflammatory responses that might hinder healing or result in long-term inflammation. Progress in surface engineering and biomaterials science is discovering implants that work well with the body, benefiting patients in the long run. The biocompatibility of orthopedic implants, their interaction with surrounding tissues, and the potential for biological problems are all important aspects of their design and operation. Orthopedic implants must be successful and long-lasting to ensure biocompatibility, promote osseointegration (osteointegration), avoid biofilm development, and consider the patient's biological environment. This paper discusses biocompatibility in orthopedic implants, its advancements, and challenges. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the in vivo behavior of orthopedic implants covered with thin films obtained by matrix-assisted pulsed laser evaporation and containing bioactive glass, a polymer, and natural plant extract was evaluated. In vivo testing was performed by carrying out a study on guinea pigs who had coated metallic screws inserted in them and also controls, following the regulations of European laws regarding the use of animals in scientific studies. After 26 weeks from implantation, the guinea pigs were subjected to X-ray analyses to observe the evolution of osteointegration over time; the guinea pigs' blood was collected for the detection of enzymatic activity and to measure values for urea, creatinine, blood glucose, alkaline phosphatase, pancreatic amylase, total protein, and glutamate pyruvate transaminase to see the extent to which the body was affected by the introduction of the implant. Moreover, a histopathological assessment of the following vital organs was carried out: heart, brain, liver, and spleen. We also assessed implanted bone with adjacent tissue. Our studies did not find significant variations in biochemical and histological results compared to the control group or significant adverse effects caused by the implant coating in terms of tissue compatibility, inflammatory reactions, and systemic effects. [ABSTRACT FROM AUTHOR]

The alternative Ti-6Al-7Nb alloy has gained extensive progression due to its ability to eliminate the cytotoxicity of vanadium (V) in Ti-6Al-4V alloy for orthopedic implants. The production of titanium alloys by centrifugal casting shows significant potential to reduce costs. Heat treatment and aging can tailor the microstructure and improve the corrosion resistance of titanium alloys. This study examines the effects of various ageing times on the microstructure and corrosion resistance of a centrifugal cast Ti-6Al-7Nb alloy that has previously been heated and treated at a temperature of 1050 °C, and subsequently cooled to room temperature in argon atmosphere gas. Ageing was carried out at a temperature of 550 °C with variable times of 0, 4, 6, and 8 hours. The surface morphology, metal phase changes, and electrochemical characterization were tested using an optical microscope (OM), X-ray diffraction (XRD), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The basket-weave microstructure is formed where globularization occurs in some phases as ageing time increases. Increasing the FWHM α value is correlated with increasing the amount of α′ martensite phase. As an ageing time enhances, the temperature might offer a greater driving constrain for the nucleation and expansion of the lamellar phase (α). Ageing of 8 hours has the lowest corrosion rate, 0.0023 mpy and highest corrosion resistance, 90457 Ω∙cm², due to the partially bimodal structure and grain refinement with a smallest grain size of 327.87 µm. Tafel polarization results show that all passivated samples are stable in the Solution Body Fluid (SBF). This work can be used as a starting point for developing microstructural evolution in titanium alloys [ABSTRACT FROM AUTHOR]

Magnesium composites stay relevant for the applications of biodegradable implant as they are harmless and possess characteristics such as density and elastic modulus analogous to the cortical bone in humans. But corrosion is one major issue associated with magnesium when the biomedical applications are contemplated. Moreover, load bearing abilities are also required in case of an orthopedic implant. In this study, to achieve the desired implant characteristics, hybrid nanocomposites (HNCs) of Mg–2.5Zn binary alloys such as metal matrix, hydroxyapatite (HAp), and reduced graphene oxide (rGO) as reinforcements were fabricated via the vacuum-assisted stir casting method. The overall weight percentage of the reinforcements was fixed at 3% and both the reinforcements varied in compositions by weight to prepare the samples S0 (Pure Magnesium), S1 (Mg–2.5Zn–0.5HAp–2.5rGO), S2 (Mg–2.5Zn–1.0HAp–2.0rGO), S3 (Mg–2.5Zn–1.5HAp–1.5rGO), S4 (Mg–2.5Zn–2.0HAp–1.0rGO), and S5 (Mg–2.5Zn–2.5HAp–0.5rGO), respectively. The influence of mechanical characteristics such as tensile strength, compressive strength, and microhardness as well as the corrosion over the surface of the nanocomposite in simulated body fluid (SBF) have been assessed for their suitability as biodegradable orthopedic implants. Results suggest that the fabricated nanocomposites exhibit superior characteristics in comparison to pure magnesium. Increasing the HAp from 0.5 wt.% to 2.5 wt.% enhanced the compressive strength and reduced the corrosion rate. On the other hand, increasing the rGO from 0.5 wt.% to 1.5 wt.% increased the tensile strength. The formation of apatite layer over the composites is observed in the SBF solution. Among all the fabricated hybrid nanocomposite samples, the sample S3 (Mg–2.5Zn–1.5HAp–1.5rGO) with equal wt.% of HAp and rGO exhibited 209.60 MPa of ultimate tensile strength, 300.1 MPa of ultimate compressive strength, and a corrosion rate of 0.91 mm/year thus making it the best suited and a prospective material for biodegradable implant application. [ABSTRACT FROM AUTHOR]

Graft fixation during cruciate ligament reconstruction using interference screws is a common and frequently used surgical technique. These interference screws are usually made of metal or bioabsorbable materials. This paper describes the development of an allograft interference screw from cortical human bone. During the design of the screw, particular attention was paid to the choice of the screw drive and the screw shape, as well as the thread shape. Based on these parameters, a prototype was designed and manufactured. Subsequently, the first biomechanical tests using a bovine model were performed. The test procedure comprised a torsion test to determine the ultimate failure torque of the screw and the insertion torque during graft fixation, as well as a pull-out test to asses the ultimate failure load of the graft fixation. The results of the biomechanical analysis showed that the mean value of the ultimate failure torque was 2633 N m m , whereas the mean occurring insertion torque during graft fixation was only 1125 N m m. The mean ultimate failure load of the graft fixation was approximately 235 N. The results of this work show a good overall performance of the allograft screw compared to conventional screws, and should serve as a starting point for further detailed investigations and studies. [ABSTRACT FROM AUTHOR]

As societal aging intensifies, senile osteoporosis has become a global public health concern. Bone microdamage is mainly caused by processes such as enhancing osteoclast activity or reducing bone formation by osteoblast-lineage cells. Compared with young individuals, extracellular vesicles derived from senescent bone marrow mesenchymal stem cells(BMSCs) increase the transient differentiation of bone marrow monocytes (BMMs) to osteoclasts, ultimately leading to osteoporosis and metal implant failure. To address this daunting problem, an exosome-targeted orthopedic implant composed of a nutrient coating was developed. A high-zinc atmosphere used as a local microenvironmental cue not only could inhibit the bone resorption by inhibiting osteoclasts but also could induce the reprogramming of senile osteogenesis and osteoclast dialogue by exosome modification. Bidirectional regulation of intercellular communication via cargoes, including microRNAs carried by exosomes, was detected. Loss- and gain-of-function experiments demonstrated that the key regulator miR-146b-5p regulates the protein kinase B/mammalian target of rapamycin pathway by targeting the catalytic subunit gene of PI3K–PIK3CB. In vivo evaluation using a naturally-aged osteoporotic rat femoral defect model further confirmed that a nutrient coating substantially augments cancellous bone remodeling and osseointegration by regulating local BMMs differentiation. Altogether, this study not only reveals the close link between senescent stem cell communication and age-related osteoporosis but also provides a novel orthopedic implant for elderly patients with exosome modulation capability. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Featured Application: Prediction of orthopedic implant stability, particularly pedicle screws, as an index comparable to insertion torque. To prevent pedicle screw implant failure, a diagnostic technique that allows surgeons to evaluate implant stability easily, quickly, and quantitatively in clinical orthopedic situations is required. This study aimed to predict the insertion torque equivalent to laboratory-level evaluation accuracy. This serves as an index of the implant stability of pedicle screws placed in cadaveric bone, which relies on laser resonance frequency analyses (L-RFA) when irradiating with two types of lasers. The machine learning analysis was optimized using a dataset with artificial bone as teaching data. In this analysis, many explanatory variables extracted from the laser-induced vibration spectra obtained during an analysis/RFA evaluation were predicted by selecting important variables using the least absolute shrinkage and selection operator and performing a non-linear approximation using support vector regression. It was found that combining both artificial and cadaveric bone data with the bone densities as teaching data dramatically improved the determination coefficient from R2 = −0.144 to R2 = 0.858 as the prediction accuracy and reduced the influence of differences between artificial and cadaveric bones. This technology will contribute to the development of preventive diagnostic technologies that can be used during surgery, which is necessary in order to further advance treatment technologies. [ABSTRACT FROM AUTHOR]

Calcium phosphate/Bioglass composite coatings on AISI 316L were investigated with regard to their potential role as a beneficial coating for orthopedic implants. These coatings were realized by the galvanic co-deposition of calcium phosphate compounds and Bioglass particles. A different amount of Bioglass 45S5 was used to study its effect on the performance of the composite coatings. The morphology and chemical composition of the coatings were investigated before and after their aging in simulated body fluid. The coatings uniformly covered the AISI 316L substrate and consisted of a brushite and hydroxyapatite mixture. Both phases were detected using X-ray diffraction and Raman spectroscopy. Additionally, both analyses revealed that brushite is the primary phase. The presence of Bioglass was verified through energy-dispersive X-ray spectroscopy, which showed the presence of a silicon peak. During aging in simulated body fluid, the coating was subject to a dynamic equilibrium of dissolution/reprecipitation with total conversion in only the hydroxyapatite phase. Corrosion tests performed in simulated body fluid at different aging times revealed that the coatings made with 1 g/L of Bioglass performed best. These samples have a corrosion potential of −0.068V vs. Ag/AgCl and a corrosion current density of 8.87 × 10−7 A/cm2. These values are better than those measured for bare AISI 316L (−0.187 V vs. Ag/AgCl and 2.52 × 10−6 A/cm2, respectively) and remained superior to pure steel for all 21 days of aging. This behavior indicated the good protection of the coating against corrosion phenomena, which was further confirmed by the very low concentration of Ni ions (0.076 ppm) released in the aging solution after 21 days of immersion. Furthermore, the absence of cytotoxicity, verified through cell viability assays with MC3T3-E1 osteoblastic cells, proves the biocompatibility of the coatings. [ABSTRACT FROM AUTHOR]

Titanium (Ti) is a popular biomaterial for orthopedic implant applications due to its superior mechanical properties such as corrosion resistance and low modulus of elasticity. However, around 10% of these implants fail annually due to bacterial infection and poor osseointegration, resulting in severe pain and suffering for the patients. To improve their performance, nanoscale surface modification approaches and doping of trace elements on the surfaces can be utilized which may help in improving cell adhesion for better osseointegration while reducing bacterial infection. In this work, at first, titania (TiO2) nanotube arrays (NT) were fabricated on commercially available pure Ti surfaces via anodization. Then zinc (Zn) doping was conducted following two distinct methods: hydrothermal and alkaline heat treatment. Scanning electron microscopic (SEM) images of the prepared surfaces revealed unique surface morphologies, while energy dispersive X-ray spectroscopy (EDS) revealed Zn distribution on the surfaces. Contact angle measurements indicated that NT surfaces were superhydrophilic. X-ray photoelectron spectroscopy (XPS) provided the relative amount of Zn on the surfaces and indicated that hydrothermally treated surfaces had more Zn compared to the alkaline heat-treated surfaces. X-ray crystallography (XRD) and nanoindentation techniques provided the crystal structure and mechanical properties of the surfaces. While testing with adipose-derived stem cells (ADSC), the surfaces showed no apparent cytotoxicity to the cells. Finally, bacteria adhesion and morphology were evaluated on the surfaces after 6 h and 24 h of incubation. From the results, it was confirmed that NT surfaces doped with Zn drastically reduced bacteria adhesion compared to the Ti control. Zn-doped NT surfaces thus offer a potential platform for orthopedic implant application. [ABSTRACT FROM AUTHOR]

The High Speed High Pressure Torsion (HSHPT) is the severe plastic deformation method (SPD) designed for the grain refinement of hard-to-deform alloys, and it is able to produce large, rotationally complex shells. In this paper, the new bulk nanostructured Ti-Nb-Zr-Ta-Fe-O Gum metal was investigated using HSHPT. The biomaterial in the as-cast state was simultaneously compressed up to 1 GPa and torsion was applied with friction at a temperature that rose as a pulse in less than 15 s. The interaction between the compression, the torsion, and the intense friction that generates heat requires accurate 3D finite element simulation. Simufact Forming was employed to simulate severe plastic deformation of a shell blank for orthopedic implants using the advancing Patran Tetra elements and adaptable global meshing. The simulation was conducted by applying to the lower anvil a displacement of 4.2 mm in the z-direction and applying a rotational speed of 900 rpm to the upper anvil. The calculations show that the HSHPT accumulated a large plastic deformation strain in a very short time, leading to the desired shape and grain refinement. [ABSTRACT FROM AUTHOR]

Objectives: Orthopedic implants have improved the quality of life in aging society but also induces several kinds of tissue reactions, referred to as orthopedic implant hypersensitivity (OIH). The aim of our study is to report the clinical characteristics of OIH and the effects of photobiomodulation therapy (PBMT) on these groups of patients. Materials and Methods: We collected cases that complained of skin rashes with pruritus after orthopedic implants from January 2017 to June 2022 at the Dermatology clinic in Hualien Tzu Chi Hospital. We recorded the sites and material of orthopedic implants, skin lesions onset time, symptoms, location after implantation, and the disease duration. Laboratory tests were measured, including complete blood count, differential count, serum immunoglobulin E (IgE) level, as well as inflammatory and autoimmune markers. PBMT, including UVB311 nm or low-level laser therapy 808 nm, was performed. Dose, duration, and response were documented. Results: Fourteen patients were diagnosed with OIH; twelve presented with localized eczema at the implant sites, and two with generalized eczema. Eleven patients (78.6%) had either elevated eosinophils percentage (>6%) or IgE level (>200 U/mL) or both. Seven patients (50%) had favorable outcome after PBMT and successfully withdrew from systemic steroid. Conclusion: In our case series, localized eczema at implant sites was a common cutaneous presentation in OIH. Hence, a surgical scar at the eczema site or long-term waxing and waning generalized eczema should prompt physicians on the possibility of OIH. Blood eosinophils percentage and serum IgE level can be reference biomarkers for OIH. PBMT provides a noninvasive and effective treatment strategy for immune regulation and tissue regeneration. [ABSTRACT FROM AUTHOR]

Polymers, in general, and Poly (Ether-Ether-Ketone) (PEEK) have emerged as potential alternatives to conventional osseous implant biomaterials. Due to its distinct advantages over metallic implants, PEEK has been gaining increasing attention as a prime candidate for orthopaedic and dental implants. However, PEEK has a highly hydrophobic and bioinert surface that attenuates the differentiation and proliferation of osteoblasts and leads to implant failure. Several improvements have been made to the osseointegration potential of PEEK, which can be classified into three main categories: (1) surface functionalization with bioactive agents by physical or chemical means; (2) incorporation of bioactive materials either as surface coatings or as composites; and (3) construction of three-dimensionally porous structures on its surfaces. The physical treatments, such as plasma treatments of various elements, accelerated neutron beams, or conventional techniques like sandblasting and laser or ultraviolet radiation, change the micro-geometry of the implant surface. The chemical treatments change the surface composition of PEEK and should be titrated at the time of exposure. The implant surface can be incorporated with a bioactive material that should be selected following the desired use, loading condition, and antimicrobial load around the implant. For optimal results, a combination of the methods above is utilized to compensate for the limitations of individual methods. This review summarizes these methods and their combinations for optimizing the surface of PEEK for utilization as an implanted biomaterial. [ABSTRACT FROM AUTHOR]

Subchondroplasty is a new minimally invasive surgical technique developed to treat bone marrow lesions (BML) and early osteoarthritis (OA). During the procedure, engineered calcium phosphate compound (CPC) is injected. It is claimed by the manufacturer that during the healing process, the CPC is replaced with new bone. The purpose of this study was to verify the replacement of CPC with new bone after subchondroplasty for the first time in humans. A 76-year old woman was referred for resistant medial knee pain. Standing radiographs showed varus knee OA and magnetic resonance imaging (MRI) revealed BML. She was treated with subchondroplasty of medial femoral condyle. Excellent relief of pain was achieved after procedure. Afterwards, the pain worsened, the radiographs confirmed the OA progression and the patient was treated with a total knee arthroplasty (TKA) 4 years after primary procedure. The resected bone was examined histologically and with micro-computed tomography (CT). Histologically, bone trabeculae of subcortical bone were embedded in the amorphous mass. However, no signs of CPC resorption and/or bone replacement have been found with micro-CT. In short term, excellent pain relief could be expected after the subchondroplasty procedure. However, there was no replacement of CPC with bone and the technique probably did not influence the natural process of knee OA. [ABSTRACT FROM AUTHOR]

Background: Total joint replacements are an established treatment for patients suffering from reduced mobility and pain due to severe joint damage. Aseptic loosening due to stress shielding is currently one of the main reasons for revision surgery. As this phenomenon is related to a mismatch in mechanical properties between implant and bone, stiffness reduction of implants has been of major interest in new implant designs. Facilitated by modern additive manufacturing technologies, the introduction of porosity into implant materials has been shown to enable significant stiffness reduction; however, whether these devices mitigate stress-shielding associated complications or device failure remains poorly understood. Methods: In this systematic review, a broad literature search was conducted in six databases (Scopus, Web of Science, Medline, Embase, Compendex, and Inspec) aiming to identify current design approaches to target stress shielding through controlled porous structures. The search keywords included ‘lattice,’ ‘implant,’ ‘additive manufacturing,’ and ‘stress shielding.’ Results: After the screening of 2530 articles, a total of 46 studies were included in this review. Studies focusing on hip, knee, and shoulder replacements were found. Three porous design strategies were identified, specifically uniform, graded, and optimized designs. The latter included personalized design approaches targeting stress shielding based on patient-specific data. All studies reported a reduction of stress shielding achieved by the presented design. Conclusion: Not all studies used quantitative measures to describe the improvements, and the main stress shielding measures chosen varied between studies. However, due to the nature of the optimization approaches, optimized designs were found to be the most promising. Besides the stiffness reduction, other factors such as mechanical strength can be considered in the design on a patient-specific level. While it was found that controlled porous designs are overall promising to reduce stress shielding, further research and clinical evidence are needed to determine the most superior design approach for total joint replacement implants. [ABSTRACT FROM AUTHOR]

Statistical data of many national registers and medical societies show that aseptic instability of the hip joint prosthesis is one of the main obstacles in the path to application of orthopedic implants. One of the causes for aseptic instability is manifestation of stress shielding effect, which is due to mismatch of the moduli of elasticity of the implant and bone tissue. Methods are considered, which allow lowering the modulus of elasticity of the metal implant, bringing it closer to the respective modulus of elasticity of bone tissue. It is found that reaching the posed goal by replacement of the traditional metals, which are used for implant manufacture, by alloys with much lower modulus of elasticity, is a task, which has not been solved technologically in their mass production. the currently most common methods of lowering the modulus of elasticity of orthopedic implants were analyzed, and their advantages and short-comings are indicated. The most serious problem in mass application of advanced additive technologies in implant manufacture is their labour- and material consumption. It is found that application of surface modification technologies, in particular plasma methods of porous coating deposition is the most affordable and effective method of lowering the modulus of elasticity of the implant surface, contacting the bone, with a high probability of reduction of the stress shielding effect manifestation. [ABSTRACT FROM AUTHOR]

The biodegradation behavior of newly developed orthopedic implant materials provides essential insight into the potential degradation products and their ability to match the rate of bone healing prior to complete degradation. Ironically, biodegradation performance is not only influenced by alloy design or advanced surface treatment on the alloy, but also it is dominantly controlled by the specific inorganic species and their concentration in the corrosion media as well as their pH level. In this study, the biodegradation behavior of commercially pure magnesium (CP Mg) and a Mg-1.0Ca-0.5Sr alloy was evaluated in 27 mM HCO 3 − - Simulated Body Fluid (r-SBF) due to its identical ionic species and concentrations with human blood plasma via immersion test, including (i) hydrogen evolution test (H2), (ii) pH trend, and (iii) weight-loss measurement. To simulate the pH regulation by the physiological homeostatic response, the pseudo-physiological solution was treated with two treatments: through a (i) a 24 h corrosion media renewal routine and through the use of (ii) a TRIS-HCL buffer reagent. The Mg-1.0Ca-0.5Sr alloy is shown to have superior corrosion resistance due to grain refinement and unique secondary phases, whereas the daily renewal routine imparts a better emulation of in vivo corrosion control. [ABSTRACT FROM AUTHOR]

Statistical data of many national registers and medical societies show that aseptic instability of the hip joint prosthesis is one of the main obstacles in the path to application of orthopedic implants. One of the causes for aseptic instability is manifestation of stress shielding effect, which is due to mismatch of the moduli of elasticity of the implant and bone tissue. Methods are considered, which allow lowering the modulus of elasticity of the metal implant, bringing it closer to the respective modulus of elasticity of bone tissue. It is found that reaching the posed goal by replacement of the traditional metals, which are used for implant manufacture, by alloys with much lower modulus of elasticity, is a task, which has not been solved technologically in their mass production. The currently most common methods of lowering the modulus of elasticity of orthopedic implants were analyzed, and their advantages and short-comings are indicated. The most serious problem in mass application of advanced additive technologies in implant manufacture is their labour- and material consumption. It is found that application of surface modification technologies, in particular plasma methods of porous coating deposition is the most affordable and effective method of lowering the modulus of elasticity of the implant surface, contacting the bone, with a high probability of reduction of the stress shielding effect manifestation. 53 Ref., 8 Fig. [ABSTRACT FROM AUTHOR]

Traditional inert materials used in internal fixation have caused many complications and generally require removal with secondary surgeries. Biodegradable materials, such as magnesium (Mg)-, iron (Fe)- and zinc (Zn)-based alloys, open up a new pathway to address those issues. During the last decades, Mg-based alloys have attracted much attention by researchers. However, the issues with an over-fast degradation rate and release of hydrogen still need to be overcome. Zn alloys have comparable mechanical properties with traditional metal materials, e.g., titanium (Ti), and have a moderate degradation rate, potentially serving as a good candidate for internal fixation materials, especially at load-bearing sites of the skeleton. Emerging Zn-based alloys and composites have been developed in recent years and in vitro and in vivo studies have been performed to explore their biodegradability, mechanical property, and biocompatibility in order to move towards the ultimate goal of clinical application in fracture fixation. This article seeks to offer a review of related research progress on Zn-based biodegradable materials, which may provide a useful reference for future studies on Zn-based biodegradable materials targeting applications in orthopedic internal fixation. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Prevention and treatment of orthopedic device‐related infection (ODRI) is complicated by the formation of bacterial biofilms. Biofilm formation involves dynamic production of macromolecules that contribute to the structure of the biofilm over time. Limitations to clinically relevant and translational biofilm visualization and measurement hamper advances in this area of research. In this paper, we present a multimodal methodology for improved characterization of Pseudomonas aeruginosa grown on polyether ether ketone (PEEK) as a model for ODRI. PEEK discs were inoculated with P. aeruginosa, incubated for 4−48 h time intervals, and fixed with 10% neutral‐buffered formalin. Samples were stained with fluorescent dyes to measure biofilm components, imaged with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and quantified. We were able to visualize and quantify P. aeruginosa biofilm growth on PEEK implants over 48 h. Based on imaging data, we propose a generalized growth cycle that can inform orthopedic diagnostic and treatment for this pathogen on PEEK. These results demonstrate the potential of using a combined CLSM and SEM approach for determining biofilm structure, composition, post‐adherence development on orthopedic materials. This model may be used for quantitative biofilm analysis for other pathogens and other materials of orthopedic relevance for translational study of ODRI. [ABSTRACT FROM AUTHOR]

In this work, composite coatings of chitosan and silver nanoparticles were presented as an antibacterial coating for orthopedic implants. Coatings were deposited on AISI 304L using the galvanic deposition method. In galvanic deposition, the difference of the electrochemical redox potential between two metals (the substrate and a sacrificial anode) has the pivotal role in the process. In the coupling of these two metals a spontaneous redox reaction occurs and thus no external power supply is necessary. Using this process, a uniform deposition on the exposed area and a good adherence of the composite coating on the metallic substrate were achieved. Physical-chemical characterizations were carried out to evaluate morphology, chemical composition, and the presence of silver nanoparticles. These characterizations have shown the deposition of coatings with homogenous and porous surface structures with silver nanoparticles incorporated and distributed into the polymeric matrix. Corrosion tests were also carried out in a simulated body fluid at 37 °C in order to simulate the same physiological conditions. Corrosion potential and corrosion current density were obtained from the polarization curves by Tafel extrapolation. The results show an improvement in protection against corrosion phenomena compared to bare AISI 304L. Furthermore, the ability of the coating to release the Ag+ was evaluated in the simulated body fluid at 37 °C and it was found that the release mechanism switches from anomalous to diffusion controlled after 3 h. [ABSTRACT FROM AUTHOR]

Titanium (Ti) alloys are the most used material in biomedical applications as orthopedic and dental implants. However, the poor tribological properties and low abrasion resistance of Ti alloys in biological environments are problematic. In the present study, the electron-beam physical vapor deposition (EB-PVD) method was used to coat the tantalum carbide (Ta2C) layer on the Ti-6Al-4V surface (Ti-Ta2C) to improve the corrosion resistance and surface properties. Moreover, a multiwalled carbon nanotubes (MWCNTs) layer was deposited on the Ti/Ta2C sample to decrease the release of harmful ions from the coated alloy and improve the tribological properties of Ti-Ta2C substrate. The corrosion current density of MWCNTs-coated Ti-Ta2C sample (Ti-Ta2C/MWCNT) decreased from 1.5 µA/cm2 to 0.05 µA/cm2 compared to the Ti-Ta2C sample. Evaluation of the Ti-Ta2C/MWCNT surface showed an increase in the surface hardness and corrosion resistance and a reduction in the amount of harmful ions released. Furthermore, the nanoindentation experiment showed that the hardness and elastic modulus of Ti-Ta2C/MWCNT sample were more than that of the Ti-Ta2C sample. After coating Ti-6Al-4V with the Ta2C/MWCNT, the load–displacement curve shifted to the left and the final depth decreased due to a 4.8-fold increase in the nanohardness of Ti-Ta2C/MWCNT sample compared to the Ti-6Al-4V sample. Additionally, the Ta2C/MWCNT coating layer improved the tribological properties, the resistance to plastic deformation, and the fracture toughness of Ti-6Al-4V sample. According to the results of nanoindentation measurements, the wear volume loss of samples reduced after coating with the MWCNTs. Also, the roughness of Ti-Ta2C/MWCNT increased from 0.6 μm to 4.4 μm compared to the Ti-Ta2C sample. MG-63 cell adhesion and cell proliferation on the surface of samples were evaluated via MTT assay, and it was found that the high roughness of MWCNTs on the surface of Ti-Ta2C sample increased cell growth and adhesion. In conclusion, our findings demonstrated that the Ti-Ta2C/MWCNT implants can provide an excellent construct with improved tribological properties and high corrosion resistance for orthopedic and dental implants. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: There is increasing use of open‐bore vertical MR systems that consist of two planar RF coils. A recent study showed that the RF‐induced heating of a neuromodulation device was much lower in the open‐bore system at the brain and the chest imaging landmarks. This study focused on the hip and knee implants and compared the specific absorption rate (SAR) distribution in human models in a 1.2T open‐bore coil with that of a 1.5T conventional birdcage coil. Methods: Computational modeling results were compared against the measurement values using a saline phantom. The differences in RF exposure were examined between a 1.2T open‐bore coil and a 1.5T conventional birdcage coil using SAR in an anatomical human model. Results: Modeling setups were validated. The body placed closed to the coil elements led to high SAR values in the birdcage system compared with the open‐bore system. Conclusion: Our computational modeling showed that the 1.2T planar system demonstrated a lower intensity of SAR distribution adjacent to hip and knee implants compared with the 1.5T conventional birdcage system. [ABSTRACT FROM AUTHOR]

Fretting corrosion in modular orthopedic implants is a well‐documented process that may be associated with adverse local tissue reactions, pain, and revisions. Engineering modular junction interfaces to withstand applied fretting motion without surface abrasion could prevent implant degradation and surface damage. Previous work on geometrically modified Ti‐6Al‐4V/CoCrMo interfaces with increased compliance showed reduced fretting currents and surface damage during short term, variable‐load in vitro testing. This study assesses the same interfaces under long‐term conditions using an in vitro pin‐on‐disk fretting corrosion test apparatus. Preliminary variable‐load frequency testing of typical control pin geometries showed a frequency‐dependent current response, with underlying contact conditions of metal–metal interfaces that remained unchanged. One‐million‐cycle testing showed diminished fretting currents in all groups by 5 × 105 cycles, but consistently lower currents in the high‐compliance group. Corresponding fretting currents and work of fretting measurements of high‐compliance pins confirmed that minimal fretting was experienced at the interface, with elastic bending of the pin accounting for almost all applied displacement. Debris generated during testing were composed of titanium and chromium oxides, small amounts of cobalt and molybdenum oxides, and sodium and phosphate originating from the surrounding test solution. Post‐test analyses of sample surfaces revealed substantially more surface damage on CoCrMo disks than Ti‐6Al‐4V pins, thought to be a result of adhesive wear of mixed oxide debris on the pin and abrasion of the disk by the oxide debris layer. Surface damage to high‐compliance pins suggests some abrasion is unavoidable with geometric modifications. [ABSTRACT FROM AUTHOR]

Fretting corrosion in modular orthopedic implants is a well‐documented process that may be associated with adverse local tissue reactions, pain, and revisions. Engineering modular junction interfaces to withstand applied fretting motion without surface abrasion could prevent implant degradation and surface damage. Previous work on geometrically modified Ti‐6Al‐4V/CoCrMo interfaces with increased compliance showed reduced fretting currents and surface damage during short term, variable‐load in vitro testing. This study assesses the same interfaces under long‐term conditions using an in vitro pin‐on‐disk fretting corrosion test apparatus. Preliminary variable‐load frequency testing of typical control pin geometries showed a frequency‐dependent current response, with underlying contact conditions of metal–metal interfaces that remained unchanged. One‐million‐cycle testing showed diminished fretting currents in all groups by 5 × 105 cycles, but consistently lower currents in the high‐compliance group. Corresponding fretting currents and work of fretting measurements of high‐compliance pins confirmed that minimal fretting was experienced at the interface, with elastic bending of the pin accounting for almost all applied displacement. Debris generated during testing were composed of titanium and chromium oxides, small amounts of cobalt and molybdenum oxides, and sodium and phosphate originating from the surrounding test solution. Post‐test analyses of sample surfaces revealed substantially more surface damage on CoCrMo disks than Ti‐6Al‐4V pins, thought to be a result of adhesive wear of mixed oxide debris on the pin and abrasion of the disk by the oxide debris layer. Surface damage to high‐compliance pins suggests some abrasion is unavoidable with geometric modifications. [ABSTRACT FROM AUTHOR]

Organ printing is a branch of medicinal regeneration. Here, we try to illustrate to reduce the death rate of patients, who die at the right time only because of defective human organs. The research concerns the concept of organ printing, technological forms, materials and methods, advantages and challenges, projected marketing rate and how it can be applied. The most important advances in 3DPrinting have taken place in external prosthetics, cranial or orthopedic implants and custom airway stents. But it has also proved to be helpful in surgical planning and has been used in complex open planning and has been used in complex open heart surgery, and also the complete face transplant of Cleveland clinic. Human tissue printing talks suggested that transplants of organs would one day be obsolete. [ABSTRACT FROM AUTHOR]