Aims

Electromagnetic induction heating has demonstrated in vitro antibacterial efficacy over biofilms on metallic biomaterials, although no in vivo studies have been published. Assessment of side effects, including thermal necrosis of adjacent tissue, would determine transferability into clinical practice. Our goal was to assess bone necrosis and antibacterial efficacy of induction heating on biofilm-infected implants in an in vivo setting.

Aim. Diagnostics of orthopedic implant infection remains challenging and often shows false negative or inadequate results. Several methods have been described to improve diagnostic methods but most of them are expensive (PCR) or not accessible for all hospitals (sonication). Aim of this study was to evaluate the results of incubation of orthopedic explants compared to biopsies and punction fluid using conventional microbiological methods. Method. In this prospective study, we included patients who received septic or aseptic orthopedic implant removal in a single University hospital between July and December 2018. A part of the explant as well as minimum 2 tissue biopsies or additional punction fluid were put in a bouillon and incubated for 11 days. Patient´s records with co-morbidities, use of antibiotics and demographic data were evaluated. The results were analyzed. The study was approved by the ethical committee. Results. 94 patients were included in this study (43 females, 51 males, mean age 54 years). We detected statistically significant more pathogens in the bouillon with explants compared to biopsies (p=0,0059). We found the same results with pedicle screws (n=11, p=0,039) and endoprosthesis (n=56, p=0,019). Patients after osteosynthesis (p=27) showed same results but statistically not significant (p=0,050). Use of antibiotics did not have influence on the diagnostic result as well as co-morbidities. In 38 patients (40,4%), additional bacteria could be detected in explant´s bouillon. Most common pathogens were Staph. aureus, E. faecalis, Staph. epidermidis and Micrococcus luteus, mixed infections could be found in 9%. Conclusions. In this study we could show that incubation of orthopedic implants has advantages in diagnostics of pathogens in infected endoprosthesis, osteosynthesis and spondylodesis. This method is simple compared to PCR or sonication and as cheap as incubation of tissue samples but in 40% of the cases, additional pathogens can be detected. We recommend to incubate removed screws, hip endoprosthetic heads or inlays in bouillon to optimize diagnostics and to detect all pathogens

Purpose: Peri-implant osteolysis after total joint arhtro-plasty (TJA) is a major cause of implant loosening. Cellular responses to wear particles have been reported to play a role in asceptic loosening due to their cytotoxic nature to cellular components. Purpose of this study is to evaluate the effect of orthopedic implant wear particles on immature osteoblasts in an in-vitro setting in order to further understand the mechanisms involved in asceptic loosening of implants. Methods: Stromal cells from femurs of 30 day-old Swiss Webster Mice were isolated, cultured in-vitro, and incubated with Titanium and Ceramic (smooth and angular) particles in the micrometer size range. After 9 days of incubation the cells were assessed for Alkaline phosphatase (ALP) activity or stained for cellular changes consistent with apoptosis. Results: Here we report both a dose-dependent decrease (P< 0.05) in ALP activity and a significant increase in programmed cell death when murine stromal cells were cultured with orthopedic implant wear particles of differing compositions. Ceramic wear particles were consistently less toxic at lower concentrations (1 x 107 to 2 x 107 particles/ml) than were wear particles composed of titanium. However, at high concentrations (4 x 107 particles/ml) all particles regardless of composition were equally toxic. These findings suggest that ceramic particles may be less cytotoxic to bone marrow stromal cells/osteoblasts than are titanium particles. Conclusions: Previous studies have suggested that inflammatory responses to orthopedic wear particles are responsible for the asceptic loosening of orthopedic implants. In the current study however, we found that wear particles may also induce cellular apoptosis of primary bone forming cells. This suggests that the asceptic loosening of orthopedic implants may be independent of inflammatory processes, and that implant material selection should be directed, in part, by its inability to cause programmed cell death

Introduction: In recent years the implementation of sonication in the diagnosis of orthopaedic implant infections has improved the detection of subclinical infections. With the use of sonication of removed orthopaedic material we can detect the presence of biofilm. The method has already shown encouraging results, especially in cases of preoperative antibiotic therapy. Aim: The aim of the study was to detect infections of orthopaedic material using both sonication and standard diagnostic methods, and to compare the obtained results of both methods. For the purpose of the study we sonicated all explanted material at revision surgery and cultured the obtained samples. During revision surgery soft tissue biopsies were collected and analyzed using standard microbiologic methods. The results were compared, analyzed and additional therapy was applied, if an infection of the material was proven. During the period from September 2009 to the end of March 2014 we studied 249 cases (198 patients) of revision surgery (166 cases of revision hip arthroplasty, 53 cases of revision knee arthroplasty, 13 cases of revision foot surgery, 17 cases of revision spine surgery). Of studied cases infection was proven in 20 (8,0%) cases by soft tissue biopsies only, 90 cases (36,1%) were diagnosed both by soft tissue biopsies and sonication, 45 cases (18,1%) were diagnosed only by sonication of explanted prosthetic material and in 94 cases (37,8%) all results were negative. The statistical analysis has shown statistically significant (p<0,05) improvement of infection detection using sonication. According to our experience the implementation of sonication has shown an improvement in the diagnosis of orthopaedic implant infections. Despite certain limitations, sonication should be considered in doubtful cases of revision surgery. The use of sonication should be emphasized in cases of preoperative antibiotic treatment

Aseptic loosening of orthopaedic implants has a major financial impact on the Health Service. The process is thought to be caused by wear particles that are phagocytosed by macrophages and hence stimulate bone resorption via a cytokine response. Previous work suggests that factors inhibiting or enhancing bone resorption act through regulation of the OPG and RANK-L mechanism. The objective of this study was to identify the role of RANK-L and OPG within the cytokine response leading to orthopaedic implant loosening. Ten samples of cellular membrane obtained during revision arthroplasty surgery were analysed with basic histological staining, immunohistology and polymerase chain reaction (PCR). In vitro studies were also carried out using explanted cancellous bone, to which PMMA particles were added and bone resorbing osteoclastic cells were identified by their Tartrate-Resistant Acid Phosphatase (TRAP) activity. PCR identified the presence of OPG in all of the periprosthetic samples, with RANK-L shown in 40% of the specimens. Immunoreactivity was shown for CD3, CD68 and RANK-L. In vitro studies confirm that there is an initial burst of inflammatory cytokine activity that then subsequently plateaus. A balance of RANK-L and OPG regulates bone resorption at the bone/implant interface of implants by stimulating a significant initial inflammatory response which leads to loosening

Background and aim. Implant-associated osteomyelitis is one of the most feared complications following orthopedic surgery. Although the risk is low it is crucial to achieve adequate antibiotic concentrations proximate to the implant for a sufficient amount of time to protect the implant surface and ensure tissue integration. The aim of this study was to assess steady-state piperacillin concentrations in the proximity of an orthopedic implant inserted in cancellous bone. Method. Six female pigs received an intravenous bolus infusion of 4 g/0.5 g piperacillin/tazobactam over 30 min every 6 h. Steady state was assumed achieved in the third dosing interval (12–18 h). Microdialysis catheters were placed in a cannulated screw in the proximal tibial cancellous bone, in cancellous bone next to the screw, and in cancellous bone on the contralateral tibia. Dialysates were collected from time 12 to 18 h and plasma samples were collected as reference. Results. Time above the minimal inhibitory concentration (fT>MIC) was evaluated for MIC of 8 (low target) and 16 μg/mL (high target). For the low piperacillin target (8 μg/mL), comparable mean fT>MIC across all the investigated compartments (mean range: 54–74%) was found. For the high target (16 μg/mL), fT>MIC was shorter inside the cannulated screw (mean: 16%) than in the cancellous bone next to the screw and plasma (mean range: 49–54%), and similar between the two cancellous bone compartments. Conclusions. To reach more aggressive piperacillin fT>MIC targets in relation to the implant, alternative dosing regimens such as continuous infusion may be considered

Background of Study. Identification of the exact make and model of an orthopaedic implant prior to a revision surgery can be challenging depending upon the surgeon's experience and available knowledge base about the available implants. The current identification procedure is manual and time consuming as the surgeon may have to do a comprehensive search within an online database of radiographs of an implant to make a visual match. There is further time lapse in contacting that particular implant manufacturer to confirm the make and model of the implant and then order the whole inventory for the revision surgery. This leads to delay in treatment thus requiring extra hospital bed occupancy. Materials and Methods. We have analysed image recognition techniques currently in use for image recognition to understand the underlying technologies based on an interface commonly known as Application Programming interface (API). These API's specifies how the software components of the proposed application interact with each other. The objective of this study is to leverage one or a combination of API's to design a fully functional application in the initial phase and that can help recognize the implant accurately from a large database of radiographs and then develop a specialized and advanced API/Technology in the implant identification application. Results. Our study takes into account the existent technologies such as Facebook, Pictoria, Imagga, Google images. We found that there is an API currently available that can be directly applied to build an implant recognition system. However, commonly known Facebook's image tagging algorithms to store unique information with each image is the starting point to help build an intelligent system that in combination with image processing and development of a custom implant recognition API. Conclusion. There is an urgent need to have a robust and accurate system for identification of orthopaedic implants. Revision surgeries may need to be carried out by hospitals without access to index surgery operating notes. Patients may approach the most convenient not necessarily the same surgeon for a revision surgery. The dependency upon surgeon's experience, hospitals facilities and archiving of records can be avoided with the use of a single application that allows multiple manufacturers to contribute to a database of catalogue of their products

Objectives. Infection of implants is a major problem in elective and trauma surgery. Heating is an effective way to reduce the bacterial load in food preparation, and studies on hyperthermia treatment for cancer have shown that it is possible to heat metal objects with pulsed electromagnetic fields selectively (PEMF), also known as induction heating. We therefore set out to answer the following research question: is non-contact induction heating of metallic implants effective in reducing bacterial load in vitro?. Methods. Titanium alloy cylinders (Ti6Al4V) were exposed to PEMF from an induction heater with maximum 2000 watts at 27 kHz after being contaminated with five different types of micro-organisms: Staphylococcus epidermidis; Staphylococcus aureus; Pseudomonas aeruginosa; spore-forming Bacillus cereus; and yeast Candida albicans. The cylinders were exposed to incremental target temperatures (35°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C) for up to 3.5 minutes. Results. There was an average linear heating rate of 0.39°C per second up to the target temperature, and thereafter the target temperature was maintained until the end of the experiment. At 60°C and higher (duration 3.5 minutes), there was a 6-log reduction or higher for every micro-organism tested. At 60°C, we found that the shortest duration of effective induction heating was 1.5 minutes. This resulted in a 5-log reduction or higher for every micro-organism tested. Conclusion. Non-contact induction heating of a titanium disk is effective in reducing bacterial load in vitro. These promising results can be further explored as a new treatment modality for infections of metal orthopaedic implants. Cite this article: B. G. Pijls, I. M. J. G. Sanders, E. J. Kuijper, R. G. H. H. Nelissen. Non-contact electromagnetic induction heating for eradicating bacteria and yeasts on biomaterials and possible relevance to orthopaedic implant infections: In vitro findings. Bone Joint Res 2017;6:323–330. DOI: 10.1302/2046-3758.65.BJR-2016-0308.R1

Introduction. Metal alloys have been commonly used for surgical applications due to their suitable mechanical characteristics and relatively good biocompatibility. However, direct cellular corrosion of orthopaedic implants remains a controversial topic and is still not fully understood. This study aims to examine a possible aspect of this corrosion mechanism by determining if macrophages can attach and directly affect the surfaces of 316L stainless steel, Ti6Al4V, and CoCrMo by releasing components of the alloy oxide layer. Methods. IC-21 ATCC peritoneal macrophages were cultured with growth medium of RPMI 1640 with 10%FBS, L-glutamine, and gentamicin. Interferon Gamma (IFNy) and Lipopolysaccharide (LPS) were used to induce activation of macrophages. Stainless Steel, CoCr, and Titanium disks cut, polished, and placed into a 96 well plate. Stainless steel testing included 6 groups: standard medium, 20,000 cells, 40,000 cells, 20,000 activated cells, 40,000 activated cells. CoCr and Ti testing included the following: medium, 40,000 cells, 20,000 activated cells, cells, no disk + 20,000 cells, no disk + 40,000 cells. After cells were attached to the surface, culture media was replaced and collected every 24 hours for stainless steel and every 12 hours for Ti and CoCr. ICP-MS, conducted at Brooks Applied Labs (Bothell, WA), was used to determine metal concentrations found in the supernatant. Results. A Kurskal-Wallis test and Tukey test were used to compare the groups in Table 2 (medium only, IFNy/LPS 20K, medium 20K cells, medium 40K cells). On stainless steel, both non-activated and activated cell groups were shown to have a statistically significant increase in metal ion release for Cr, Fe, and Ni (p<0.05) compared to medium only. On Ti, there was a significant increase in Al (<0.001) and decrease in V (p=0.003) among all groups compared to medium. No differences were seen among disk groups on CoCr. No difference was seen among activated and non-activated cells placed on all three types of disks. Discussion. This study was successful in showing that macrophages are capable of affecting the oxide layer of stainless steel and Ti by releasing more components of the oxide surface within 30 days. A significant increase in Cr, Fe, and Ni ion release was realized when cells were cultured on the surface of stainless steel disks for 30 days. A previous study, also involving 316L stainless steel, has shown that osteoclasts cause a greater increase in Cr compared to Ni under similar conditions. Our results show that macrophages lead to a greater increase of Ni ions compared to Cr. This suggest that various cell types may effectively change metal ion release profiles in different ways. Surprisingly, V content decreased when cells were attached to Ti disks, possibly indicating uptake of the V particles into the cells instead of release into the supernatant. No differences where seen among CoCr disk groups, therefore we cannot determine if corrosion is occurring during the 30 period. To get a more accurate representation a longer testing time may be necessary. For any tables or figures, please contact the authors directly

To evaluate the mechanism by which orthopedic implant wear particles induce apoptosis in immature osteoblasts in an in-vitro setting. Stromal cells from femurs of thirty day-old Swiss Webster Mice were isolated, cultured in-vitro, and incubated with orthopedic wear particles in the micrometer size range. After incubation with wear-particles, the cells were assessed for Caspase three expression and activity in the presence or absence of specific inhibitor(s) in order to delineate potential mechanism for cellular changes previously reported. Here we report the induction of caspase three protein expression and activity with incubation of stromal cells with titanium wear particles. Caspase three activity however was not demonstrated to be up regulated in a time dependent manner or at lower concentration of particles (2 x 107 particles/ml). However, there was a significant (P< 0.05) increase in caspase three activity with titanium particle at higher concentration (4 x 107 particles/ml) that was not reversible when the extrinsic arm of the apoptotic pathway was blocked with anti-TNFƒa antibodies. Our previous studies have suggested that aseptic loosening of orthopedic implants may be independent of inflammatory processes, and may be associated with induction of programmed cell death. Our current results would strengthen this idea by demonstrating induction of expression and activity of caspase three involved in apoptosis in cells incubated with wear particles. In addition, titanium wear particles may induce apoptosis through direct cellular effects rather than through the extrinsic TNFƒa pathway. Delineating the mechanism by which wear particles induce apoptosis in immature osteoblasts will allow for the selection and/or development of inhibitors to the process of asceptic loosening by targeting a specific pathway

Infection of orthopaedic implants is a significant problem, with increased antibiotic resistance of adherent ‘biofilm’ bacteria causing difficulties in treatment. We have investigated the in vitro effect of a pulsed electromagnetic field (PEMF) on the efficacy of antibiotics in the treatment of infection of implants. Five-day biofilms of Staphylococcus epidermidis were grown on the tips of stainless-steel pegs. They were exposed for 12 hours to varying concentrations of gentamicin or vancomycin in microtitre trays at 37°C and 5% CO. 2. The test group were exposed to a PEMF. The control tray was not exposed to a PEMF. After exposure to antibiotic the pegs were incubated overnight, before standard plating onto blood agar for colony counting. Exposure to a PEMF increased the effectiveness of gentamicin against the five-day biofilms of Staphylococcus epidermidis. In three of five experiments there was reduction of at least 50% in the minimum biofilm inhibitory concentration. In a fourth experiment there was a two-log difference in colony count at 160 mg/l of gentamicin. Analysis of variance (ANOVA) confirmed an effect by a PEMF on the efficacy of gentamicin which was significant at p < 0.05. There was no significant effect with vancomycin

Many orthopaedic procedures require implants to be trialled before definitive implantation. Where this is required, the trials are provided in a set with the instrumentation. The most common scenario this is seen in during elective joint replacements. In Scotland (2007) the Scottish Executive (. http://www.sehd.scot.nhs.uk/cmo/CMO(2006)13.pdf. ) recommended and implemented individually packed orthopaedic implants for all orthopaedic sets. The premise for this was to reduce the risk of CJD contamination and fatigue of implants due to constant reprocessing from corrosion. During many trauma procedures determining the correct length of plate or size of implant can be challenging. Trials of trauma implants is no longer common place. Many implants are stored in closed and sealed boxes, preventing the surgeon looking at the implant prior to opening and contaminating the device. As a result many implants are incorrectly opened and either need reprocessed or destroyed due to infection control policy, thus implicating a cost to the NHS. With even the simplest implants costing several hundreds of pounds, this cost is a very significant waste in resources that could be deployed else where. My project was to develop a method to produce in department accurate, cheap and disposable trials for implants often used in trauma, where the original manufacturer do not offer the option of a trial off the shelf. The process had to not involve contaminating or destroying the original implant in the production of a trial. Several implants which are commonly used within Glasgow Royal Infirmary and do not have trials were identified. These implants were then CT scanned within their sealed and sterile packaging without contamination. Digital 3D surface renders of the models were created using free open source software (OsiriX, MeshLab, NetFabb). These models were then processed in to a suitable format for 3D printing using laser sintering via a cloud 3D printing bureau (. Shapeways.com. ). The implants were produced in polyamide PA220 material or in 316L stainless steel. These materials could be serialized using gamma irradiation or ethylene oxide gas. The steel models were suitable for autoclaving in the local CSSU. The implants produced were accurate facsimiles of the original implant with dimensions within 0.7mm. The implants were cost effective, an example being a rim mesh was reproduced in polyamide PA220 plastic for £3.50 and in 316L stainless steel for £15. The models were produced within 10 days of scanning. The stainless steel trials were durable and suitable for reprocessing and resterilisation. The production of durable, low cost and functional implant trials all completed in department was successful. The cost of production of each implant is so low that it would be offset if just one incorrect implant was opened during a single procedure. With some of the implants tested, the trials would have paid for themselves 100 times. This is a simple and cost saving technique that would help reduce department funding and aid patient care

Summary. Staphylococcus aureus isolates from Fracture fixation device related infections contained fewer isolates that form a strong biofilm in comparison with isolates from Prosthetic joint infections. Both orthopaedic implant related infection groups possessed fnbB and sdrE more frequently than the non-implant related infection groups. Introduction. One of the most common pathogen causing musculoskeletal infections is Staphylococcus aureus. The aim was to characterise S. aureus isolated from these infections and to look for differences between the isolates from orthopaedic implant related infections (OIRI) and those in non-implant related infections (NIRI). The OIRI are further differentiated in those associated with fracture fixation (FFI) devices and those found in prosthetic joint infections (PJI). Methods. Three-hundred and five S. aureus isolates were collected from different Swiss and French hospitals (FFI, n=112; PJI, n=105; NIRI, n=88). The cases of NIRI were composed of 27 osteomyelitis (OM), 23 diabetic foot infections (DFI), 27 soft tissue infections (STI) and 11 postoperative spinal infections (SI). Isolates were tested for their ability to form a biofilm. They were typed by agr (accessory gene regulator) group and genes coding for the 13 most relevant MSCRAMMs, Panton-Valentine leukocidin (PVL), PIA (polysaccharide intercellular adhesin), γ-haemolysin, the five most relevant Staphylococcal enterotoxins (SEA-SEE), exfoliative toxins A and B (ETA and ETB) and toxic shock protein (TST) were screened for by PCR. Results. The majority of the S. aureus isolates were methicillin susceptible (MSSA) with 83.4% for the OIRI and 93.2% for the NIRI. All isolates were able to produce a biofilm. A strong biofilm was produced in 13.8% of the OIRI isolates compared to 10.2% of the NIRI isolates. The difference between the isolates of the PJI versus the FFI was statistically significant (20% vs 8%; p=0.011). All four agr types were present in all groups. agrI predominated in the OIRI (42.4%) as well as in the NIRI (44.4%). Comparing OIRI with NIRI, agrII was present in a higher prevalence in OIRI (30.9% vs 14.8%) and agrIII in a lower incidence (21.2% vs 30.7%). Genes cna, clfA and bbp were exhibited predominantly by isolates from the NIRI, while the fnbB and the sdrE gene were more frequently observed among OIRI. Conclusions. Methicillin susceptible S. aureus (MSSA) was more prevalent than methicillin resistant S. aureus (MRSA) in this collection. Possible trends for the orthopaedic device associated infection groups FFI and PJI could be observed whereby isolates from PJI produced stronger biofilm than isolates from the FFI group. The agr type agrII, the fnbB gene and sdrE gene were more prevalent present in the OIRI compared to the NIRI. In contrast, agrIII, and the bbp gene were more prevalent in the NIRI than in the OIRI

Many orthopaedic procedures require implants to be trialled before definitive implantation. Where this is required, the trials are provided in a set with the instrumentation. The most common scenario this is seen in during elective joint replacements. In Scotland (2007) the Scottish Executive (. http://www.sehd.scot.nhs.uk/cmo/CMO(2006)13.pdf. ) recommended and implemented individually packed orthopaedic implants for all orthopaedic sets. The premise for this was to reduce the risk of CJD contamination and fatigue of implants due to constant reprocessing from corrosion. During many trauma procedures determining the correct length of plate or size of implant can be challenging. Trials of trauma implants is no longer common place. Many implants are stored in closed and sealed boxes, preventing the surgeon looking at the implant prior to opening and contaminating the device. As a result many implants are incorrectly opened and either need reprocessed or destroyed due to infection control policy, thus implicating a cost to the NHS. With even the simplest implants costing several hundreds of pounds, this cost is a very significant waste in resources that could be deployed else where. My project was to develop a method to produce in department accurate, cheap and disposable trials for implants often used in trauma, where the original manufacturer do not offer the option of a trial off the shelf. The process had to not involve contaminating or destroying the original implant in the production of a trial. Several implants which are commonly used within Glasgow Royal Infirmary and do not have trials were identified. These implants were then CT scanned within their sealed and sterile packaging without contamination. Digital 3D surface renders of the models were created using free open source software (OsiriX, MeshLab, NetFabb). These models were then processed in to a suitable format for 3D printing using laser sintering via a cloud 3D printing bureau (. Shapeways.com. ). The implants were produced in polyamide PA220 material or in 316L stainless steel. These materials could be serialized using gamma irradiation or ethylene oxide gas. The steel models were suitable for autoclaving in the local CSSU. The implants produced were accurate facsimiles of the original implant with dimensions within 0.7mm. The implants were cost effective, an example being a rim mesh was reproduced in polyamide PA220 plastic for £3.50 and in 316L stainless steel for £15. The models were produced within 10 days of scanning. The stainless steel trials were durable and suitable for reprocessing and resterilisation. The production of durable, low cost and functional implant trials all completed in department was successful. The cost of production of each implant is so low that it would be offset if just one incorrect implant was opened during a single procedure. With some of the implants tested, the trials would have paid for themselves 100 times. This is a simple and cost saving technique that would help reduce department funding and aid patient care

Device-associated bacterial infections are a major and costly clinical challenge. This project aimed to develop a smart new biomaterial for implants that helps to protect against infection and inflammation, promote bone growth, and is biodegradable. Gallium (Ga) doped strontium-phosphate was coated on pure Magnesium (Mg) through a chemical conversion process. Mg was distributed in a graduated manner throughout the strontium-phosphate coating GaSrPO4, with a compact structure and a Ga-rich surface. We tested this sample for its biocompatibility, effects on bone remodeling and antibacterial activities including Staphylococcus aureus, S. epidermidis and E. coli - key strains causing infection and early failure of the surgical implantations in orthopaedics and trauma. Ga was distributed in a gradient way throughout the entire strontium-phosphate coating with a compact structure and a gallium-rich surface. The GaSrPO4 coating protected the underlying Mg from substantial degradation in minimal essential media at physiological conditions over 9 days. The liberated Ga ions from the coatings upon Mg specimens inhibited the growth of bacterial tested. The Ga dopants showed minimal interferences with the SrPO4 based coating, which boosted osteoblasts and undermined osteoclasts in in vitro co-cultures model. The results evidenced this new material may be further translated to preclinical trial in large animal model and towards clinical trial. Acknowledgements: Authors are grateful to the financial support from the Australian Research Council through the Linkage Scheme (ARC LP150100343). The authors acknowledge the facilities, and the scientific and technical assistance of the RMIT University and John Curtin School of Medical Research, Australian National University

By modifying only the nanofeatures on material surfaces without changing surface chemistry, it is possible to increase tissue growth of any human tissue by controlling the endogenous adsorption of adhesive proteins onto the material surface. In addition, our group has shown that these same nanofeatures and nano-modifications can reduce bacterial growth without using antibiotics, which may further accelerate the growth of antibiotic resistant microbes. Inflammation can also be decreased through the use of nanomaterials. Finally, nanomedicine has been shown to stimulate the growth and differentiation of stem cells, which may someday be used to treat incurable disorders, such as neural damage. This strategy also accelerates FDA approval and commercialization efforts since new chemistries are not proposed, rather chemistries already approved by the FDA with altered nanoscale features. This invited talk will highlight some of the advancements and emphasize current ceramic nanomaterials approved by the FDA for human implantation. It will also emphasize the future of nanomaterials in medicine, such as their use in personalized medicine as internal sensors to detect and fight alterations in health.

Aims

This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys.

The aim of this study was to evaluate whether coating titanium discs with selenium in the form of sodium selenite decreased bacterial adhesion of Staphylococcus aureus and Staph. epidermidis and impeded osteoblastic cell growth.

In order to evaluate bacterial adhesion, sterile titanium discs were coated with increasing concentrations of selenium and incubated with bacterial solutions of Staph. aureus (ATCC 29213) and Staph. epidermidis (DSM 3269) and stained with Safranin-O. The effect of selenium on osteoblastic cell growth was also observed. The adherence of MG-63 cells on the coated discs was detected by staining with Safranin-O. The proportion of covered area was calculated with imaging software.

The tested Staph. aureus strain showed a significantly reduced attachment on titanium discs with 0.5% (p = 0.011) and 0.2% (p = 0.02) selenium coating. Our test strain from Staph. epidermidis showed a highly significant reduction in bacterial adherence on discs coated with 0.5% (p = 0.0099) and 0.2% (p = 0.002) selenium solution. There was no inhibitory effect of the selenium coating on the osteoblastic cell growth.

Selenium coating is a promising method to reduce bacterial attachment on prosthetic material.

Cite this article: Bone Joint J 2013;95-B:678–82.

The development and pre-clinical evaluation of nano-texturised, biomimetic, surfaces of titanium (Ti) implants treated with titanium dioxide (TiO₂) nanotube arrays is reviewed. In vitro and in vivo evaluations show that TiO₂ nanotubes on Ti surfaces positively affect the osseointegration, cell differentiation, mineralisation, and anti-microbial properties. This surface treatment can be superimposed onto existing macro and micro porous Ti implants creating a surface texture that also interacts with cells at the nano level. Histology and mechanical pull-out testing of specimens in rabbits indicate that TiO₂ nanotubes improves bone bonding nine-fold (p = 0.008). The rate of mineralisation associated with TiO₂ nanotube surfaces is about three times that of non-treated Ti surfaces. In addition to improved osseointegration properties, TiO₂ nanotubes reduce the initial adhesion and colonisation of Staphylococcus epidermidis. Collectively, the properties of Ti implant surfaces enhanced with TiO₂ nanotubes show great promise.

Cite this article: Bone Joint J 2018;100-B(1 Supple A):9–16.