Scalable Functional Bone Substitutes: Strategic Integration of Key Structural Elements of Bone in Synthetic Biomaterials

Summary: Introduces recent advances in the evolvement of non-metallic orthopedic biomaterials in the design of organic-inorganic composite bone substitutes

Findings From an Accelerated _In Vivo_ Corrosion Model of Magnesium

In this article, we are presenting some findings of magnesium corrosion in an _in vivo_ model. While there is consensus that subcutaneous bubbles will occur, it was found in our corrosion-accelerated model that magnesium corrosion is more severe in areas under the gas bubbles. This finding may bring insights to novel methods in reducing the uneven corrosion

Synthesis Of -Tcp Powder Via Wet Precipitation And Hydrothermal Methods

Matlamat kajian ini adalah untuk mensintesis β-TCP [β-Ca3(PO4)2] menggunakan Ca(OH)2 dan H3PO4 sebagai bahan mula. The purpose of this study is to synthesize β-TCP [β-Ca3(PO4)2] using Ca(OH)2 and H3PO4 as the starting material

Predicting Corrosion Damage in the Human Body Using Artificial Intelligence: In Vitro Progress and Future Applications Applications

Artificial intelligence (AI) is used in the clinic to improve patient care. While the successes illustrate the impact AI can have, few studies have led to improved clinical outcomes. A gap in translational studies, beginning at the basic science level, exists. In this review, we focus on how AI models implemented in non-orthopedic fields of corrosion science may apply to the study of orthopedic alloys. We first define and introduce fundamental AI concepts and models, as well as physiologically relevant corrosion damage modes. We then systematically review the corrosion/AI literature. Finally, we identify several AI models that may be Preprint implemented to study fretting, crevice, and pitting corrosion of titanium and cobalt chrome alloys

Synthesis Of B-TCP Powder Via Wet Precipitation And Hydrothermal Methods [R857.M3 P534 2007 f rb].

Matlamat kajian ini adalah untuk mensintesis β-TCP [β-Ca3(PO4)2] menggunakan Ca(OH)2 dan H3PO4 sebagai bahan mula. Dua pendekatan telah digunakan dalam kajian ini untuk menghasilkan β-TCP, iaitu kaedah pemendakan basah dan kaedah hidtroterma. The purpose of this study is to synthesize β-TCP [β-Ca3(PO4)2] using Ca(OH)2 and H3PO4 as the starting material. Two approaches were used in this work to produce β-TCP, namely a precipitation method and a hydrothermal method

Micro-Computed Tomography-Based Finite Element Analysis Of The Mechanical Integrity Of In Vivo Biodegradable Magnesium-Alloy Screw And Surrounding Bone

The anterior cruciate ligament (ACL) tear, the most common knee injury, affects 100,000 to 200,000 persons in the US annually. Surgical repair is employed to restore the knee to its full range of motion. In the surgery, an interference screw is used to a secure a soft tissue graft that is used to replace the torn ACL. In 2012, orthopedic devices for knees accounted for the largest share of the $29.2 billion overall revenue for orthopedic devices. Biodegradable implants are expected to lead growth in the orthopedic sector by increasing the quality of life and decreasing recovery time after orthopedic injury for athletes and non-athletes and aging, osteoporotic, osteoarthritic and obese populations. Magnesium-based orthopedic devices, including interference screws, are being investigated because of their ability to provide high strength as a metal, but degrade like a polymer. One objective of this study was to compare the pull-out forces of an unnamed magnesium-alloy against a commercially available copolymer, 82:18 PLLA:PLGA, in woven bone using finite element analysis. The reaction forces in bone and displacement of the screws were used to assess the overall performance of each material in a pull-out test. The second objective of this work was to develop and evaluate micro-computed tomography-based finite element models of in vivo biodegradable screws of the unnamed magnesium-alloy over time in rabbit femurs. Several foundational observations were made about modeling in vivo degrading magnesium devices with a micro-CT to FEA protocol. The results of this work have shown that an unnamed biodegradable magnesium-alloy and a biodegradable 82:18 PLLA:PLGA copolymer performed equally in nodal displacement and that the Mg-based device only outperformed the copolymer in Emin woven bone

In vitro time-kill kinetics of dalbavancin against Staphylococcus spp. biofilms over prolonged exposure times

Abstract Staphylococcus aureus and Staphylococcus epidermidis are leading pathogens of biofilm-related infections and represent the most common cause of osteomyelitis and biomedical implants infections. Biofilm-related infections usually require long-term antibiotic treatment, often associated to surgical interventions. Dalbavancin is a newer lipoglycopeptide approved for the treatment of acute skin and skin-structure infections caused by Gram-positive pathogens. In addition, dalbavancin has recently been considered as a potential option for the treatment of staphylococcal osteomyelitis and orthopedic implant infections. In this study, time-kill kinetics of dalbavancin against S. aureus and S. epidermidis biofilms were determined over prolonged exposure times (up to 7 days), using both a standardized biofilm susceptibility model and biofilms grown onto relevant orthopedic biomaterials (i.e. titanium and cobalt-chrome disks). Dalbavancin (at concentrations achievable in bone and articular tissue) showed a potent activity against established staphylococcal biofilms in both tested models, and was overall superior to the comparator vancomycin

Respuesta ósea al implante del compuesto beta-fosfato tricálcico-colágeno (ß-ftc-c). Estudio «in vivo» en conejos

Se ha estudiado la correlación entre los hallazgos histológicos y las imágenes radiológicas de un compuesto de beta-fosfato tricálcico y colágeno (ß-FTC-C) después de su implantación en defectos óseos creados experimentalmente en 21 conejos de 4 Kg de peso medio. Bajo anestesia general los defectos óseos creados en ambos fémures se rellenaron con un cilindro de 4,5 x 6 mm del compuesto. Los animales fueron sacrificados a la semana y 1, 2, 4 y 12 meses del postoperatorio. Las muestras obtenidas fueron sometidas a estudio radiográfico e histológico. Microscópicamente se comprobó que el compuesto a lo largo del período de implantación sufrió un proceso de reabsorción progresiva mediado por células de estirpe macrofágica y que se correspondió con una disminución de la densidad radiológica y cambios en su morfología. A los doce meses del postoperatorio se observaron escasos restos del material, hecho que se corresponde con la desaparición del implante en la placa radiográfica.The correlation between histologic and radiological findings was studied after implantation of a composite (ß-FTC-C) into osseus defects which were experimentally induced in 21 rabbits. Under general anaesthetic osseus defects were made in both femurs and filled in with a 4,5 x 6 mm composite cylinder. The animals were killed at the first week and, one, two, four and twelve months after surgery. X-ray study and microscopic examination were made in all the specimens. Troughout the implantation period, it was microscopically proven that the composite showed a progressive reabsortion process, mediated by cells of macrophagus lineage. A decrease in radiologic density and changes in its morphology were also observed. At the end of the study (twelve months), limited traces of the material could be seen, in correlation with the images of the X-ray films which revealed the total absence of the composite implant

Fracture and fatigue behaviour of implants made of Ti alloys

This paper presents an analysis of Ti alloys used in biomedical applications, such as artificial joint implants and fixation plates, from a fracture mechanics perspective, including fatigue crack initiation and propagation phenomenon. Toward this end experimental and numerical research of mechanical behaviour of fixation plate and hip replacement implant is presented. Experimental analysis was based on standard methods for testing mechanical properties and application of Digital Image Correlation (DIC) technique, while the Finite Element Method (FEM) was used for numerical simulation. Comparison of results indicated a good agreement of experimental and numerical results and reasonable explanation of fixation plate failure. Experimental and numerical research of cracked hip replacement implant is also presented, including fatigue crack propagation, simulated by the Extended FEM (XFEM) using MORFEO postprocessing of ABAQUS stress-strain results. Based on static analysis and fracture toughness properties, the critical crack length was calculated and then used as the final crack length for fatigue life estimation. Toward this end, the Paris law has been used, with coefficients C and m obtained experimentally on RUMUL testing device. The number of cycles needed for failure which has been obtained was in a reasonable agreement with data from case study analysed

Fracture and fatigue behaviour of implants made of Ti alloys

This paper presents an analysis of Ti alloys used in biomedical applications, such as artificial joint implants and fixation plates, from a fracture mechanics perspective, including fatigue crack initiation and propagation phenomenon. Toward this end experimental and numerical research of mechanical behaviour of fixation plate and hip replacement implant is presented. Experimental analysis was based on standard methods for testing mechanical properties and application of Digital Image Correlation (DIC) technique, while the Finite Element Method (FEM) was used for numerical simulation. Comparison of results indicated a good agreement of experimental and numerical results and reasonable explanation of fixation plate failure. Experimental and numerical research of cracked hip replacement implant is also presented, including fatigue crack propagation, simulated by the Extended FEM (XFEM) using MORFEO postprocessing of ABAQUS stress-strain results. Based on static analysis and fracture toughness properties, the critical crack length was calculated and then used as the final crack length for fatigue life estimation. Toward this end, the Paris law has been used, with coefficients C and m obtained experimentally on RUMUL testing device. The number of cycles needed for failure which has been obtained was in a reasonable agreement with data from case study analysed