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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_19 | Pages 52 - 52
22 Nov 2024
Schulze M Nonhoff M Hasselmann J Fobker M Gosheger G Moriarty F Zeiter S Tapia-Dean J Kuntze A Puetzler J
Full Access

Aim

The utilization of silver as an anti-infective agent is a subject of debate within the scientific community, with recurring discussions surrounding its biocompatibility. Presently, galvanic silver coating finds widespread clinical application in mitigating infection risks associated with large joint arthroplasties. While some instances have linked this coating to sporadic cases of localized argyria, these occurrences have not exhibited systematic or functional limitations. To address concerns regarding biocompatibility, a novel approach has been devised for anti-infective implant coatings: encapsulating silver nitrate within a biopolymer reservoir for non-articulating surfaces. This poly-L-lactic acid layer releases silver ions gradually, thereby circumventing biocompatibility concerns.

Method

Female C57BL/6 mice were utilized as an experimental model, with 6x2 mm Ti6Al4V discs, coated with or without the biopolymer-protected silver coating, implanted subcutaneously on both sides of the vertebrae. Daily blood samples were collected, and serum was analyzed for C-reactive protein (CRP) and silver concentration. After three days, histopathological analyses were conducted on the surrounding soft tissue pouch.


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_2 | Pages 72 - 72
2 Jan 2024
Agnes C Murshed M Willie B Tabrizian M
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Critical size bone defects deriving from large bone loss are an unmet clinical challenge1. To account for disadvantages with clinical treatments, researchers focus on designing biological substitutes, which mimic endogenous healing through osteogenic differentiation promotion. Some studies have however suggested that this notion fails to consider the full complexity of native bone with respect to the interplay between osteoclast and osteoblasts, thus leading to the regeneration of less functional tissue2. The objective of this research is to assess the ability of our laboratory's previously developed 6-Bromoindirubin-3’-Oxime (BIO) incorporated guanosine diphosphate crosslinked chitosan scaffold in promoting multilineage differentiation of myoblastic C2C12 cells and monocytes into osteoblasts and osteoclasts1, 3, 4. BIO addition has been previously demonstrated to promote osteogenic differentiation in cell cultures5, but implementation of a co-culture model here is expected to encourage crosstalk thus further supporting differentiation, as well as the secretion of regulatory molecules and cytokines2. Biocompatibility testing of both cell types is performed using AlamarBlue for metabolic activity, and nucleic acid staining for distribution. Osteoblastic differentiation is assessed through quantification of ALP and osteopontin secretion, as well as osteocalcin and mineralization staining. Differentiation into osteoclasts is verified using SEM and TEM, qPCR, and TRAP staining. Cellular viability of C2C12 cells and monocytes was maintained when cultured separately in scaffolds with and without BIO for 21 days. Both scaffold variations showed a characteristic increase in ALP secretion from day 1 to 7, indicating early differentiation but BIO-incorporated sponges yielded higher values compared to controls. SEM and TEM imaging confirmed initial aggregation and fusion of monocytes on the scaffold's surface, but BIO addition appeared to result in smoother cell surfaces indicating a change in morphology. Late-stage differentiation assessment and co-culture work in the scaffold are ongoing, but initial results show promise in the material's ability to support multilineage differentiation. Acknowledgements: The authors would like to acknowledge the financial support of the Collaborative Health Research Program (CHRP) through CIHR and NSERC, as well as Canada Research Chair – Tier 1 in Regenerative Medicine and Nanomedicine, and the FRQ-S


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_14 | Pages 15 - 15
1 Dec 2022
Graziani G Ghezzi D Sartori M Fini M Perut F Montesissa M Boi M Cappelletti M Sassoni E Di Pompo G Giusto E Avnet S Monopoli D Baldini N
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Infection in orthopedics is a challenge, since it has high incidence (rates can be up to 15-20%, also depending on the surgical procedure and on comorbidities), interferes with osseointegration and brings severe complications to the patients and high societal burden. In particular, infection rates are high in oncologic surgery, when biomedical devices are used to fill bone gaps created to remove tumors. To increase osseointegration, calcium phosphates coatings are used. To prevent infection, metal- and mainly silver-based coatings are the most diffused option. However, traditional techniques present some drawbacks, including scarce adhesion to the substrate, detachments, and/or poor control over metal ions release, all leading to cytotoxicity and/or interfering with osteointegration. Since important cross-relations exist among infection, osseointegration and tumors, solutions capable of addressing all would be a breakthrough innovation in the field and could improve clinical practice. Here, for the first time, we propose the use antimicrobial silver-based nanostructured thin films to simultaneously discourage infection and bone metastases. Coatings are obtained by Ionized Jet Deposition, a plasma-assisted technique that permits to manufacture films of submicrometric thickness having a nanostructured surface texture. These characteristics, in turn, allow tuning silver release and avoid delamination, thus preventing toxicity. In addition, to mitigate interference with osseointegration, here silver composites with bone apatite are explored. Indeed, capability of bone apatite coatings to promote osseointegration had been previously demonstrated in vitro and in vivo. Here, antibacterial efficacy and biocompatibility of silver-based films are tested in vitro and in vivo. Finally, for the first time, a proof-of-concept of antitumor efficacy of the silver-based films is shown in vitro. Coatings are obtained by silver and silver-bone apatite composite targets. Both standard and custom-made (porous) vertebral titanium alloy prostheses are used as substrates. Films composition and morphology depending on the deposition parameters are investigated and optimized. Antibacterial efficacy of silver films is tested in vitro against gram+ and gram- species (E. coli, P. aeruginosa, S. aureus, E. faecalis), to determine the optimal coatings characteristics, by assessing reduction of bacterial viability, adhesion to substrate and biofilm formation. Biocompatibility is tested in vitro on fibroblasts and MSCs and, in vivo on rat models. Efficacy is also tested in an in vivo rabbit model, using a multidrug resistant strain of S. aureus (MRSA, S. aureus USA 300). Absence of nanotoxicity is assessed in vivo by measuring possible presence of Ag in the blood or in target organs (ICP-MS). Then, possible antitumor effect of the films is preliminary assessed in vitro using MDA-MB-231 cells, live/dead assay and scanning electron microscopy (FEG-SEM). Statistical analysis is performed and data are reported as Mean ± standard Deviation at a significance level of p <0.05. Silver and silver-bone apatite films show high efficacy in vitro against all the tested strains (complete inhibition of planktonic growth, reduction of biofilm formation > 50%), without causing cytotoxicity. Biocompatibility is also confirmed in vivo. In vivo, Ag and Ag-bone apatite films can inhibit the MRSA strain (>99% and >86% reduction against ctr, respectively). Residual antibacterial activity is retained after explant (at 1 month). These studies indicate that IJD films are highly tunable and can be a promising route to overcome the main challenges in orthopedic prostheses


Bone & Joint Research
Vol. 11, Issue 10 | Pages 700 - 714
4 Oct 2022
Li J Cheung W Chow SK Ip M Leung SYS Wong RMY

Aims

Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models.

Methods

Literature research was performed on PubMed and Embase databases. Keywords used for search criteria were “bone AND biofilm”. Information on the species of the animal model, bacterial strain, evaluation of biofilm and bone infection, complications, key findings on observations, prevention, and treatment of biofilm were extracted.


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_5 | Pages 24 - 24
1 Apr 2022
Giotikas D Guryel E
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Introduction

Stryde® lengthening nail has been recently withdrawn because of concerns about osteolysis and other bone lesions that have been observed early after implantation. The present study analyses the incidence and features of these bone lesions in our patients.

Materials and Methods

This is a retrospective review of a series of patients from two centres specializing in limb reconstruction. Inclusion criteria was a history of surgery with Stryde® lengthening nail with more than one year follow-up available.

All postoperative x-rays were and clinical notes were reviewed.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_16 | Pages 69 - 69
1 Dec 2021
MacLeod A Taylor R Casonato A Gill H
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Abstract

Objectives

Additive manufacturing has led to numerous innovations in orthopaedic surgery: surgical guides; surface coatings/textures; and custom implants. Most contemporary implants are made from titanium alloy (Ti-6Al-4V). Despite being widely available industrially and clinically, there is little published information on the performance of this 3D printed material for orthopaedic devices with respect to regulatory approval. The aim of this study was to document the mechanical, chemical and biological properties of selective laser sintering (SLS) manufactured specimens following medical device (TOKA®, 3D Metal Printing LTD, UK) submission and review by the UK Medicines and Healthcare Products Regulatory Agency (MHRA).

Methods

All specimens were additively manufactured in Ti-6Al-4V ELI (Renishaw plc, UK). Mechanical tests were performed according to ISO6892-1, ISO9585 and ISO12107 for tensile (n=10), bending (n=3) and fatigue (n=16) respectively (University of Bath, UK). Appropriate chemical characterisation and biological tests were selected according to recommendations in ISO10993 and conducted by external laboratories (Wickham Labs, UK; Lucideon, UK; Edwards Analytical, UK) in adherence with Good Lab Practise guidelines. A toxicological review was conducted on the findings (Bibra, UK).


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_13 | Pages 13 - 13
1 Nov 2021
Dubus M Rammal H Scomazzon L Baldit A Braux J Mauprivez C Kerdjoudj H
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Introduction and Objective. Alveolar bone resorption following tooth extraction or periodontal disease compromises the bone volume required to ensure the stability of an implant. Guided bone regeneration (GBR) is one of the most attractive technique for restoring oral bone defects, where an occlusive membrane is positioned over the bone graft material, providing space maintenance required to seclude soft tissue infiltration and to promote bone regeneration. However, bone regeneration is in many cases impeded by a lack of an adequate tissue vascularization and/or by bacterial contamination. Using simultaneous spray coating of interacting species (SSCIS) process, a bone inspired coating made of calcium phosphate-chitosan-hyaluronic acid was built on one side of a nanofibrous GBR collagen membrane in order to improve its biological properties. Materials and Methods. First, the physicochemical characterizations of the resulting hybrid coating were performed by scanning electron microscopy, X-ray photoelectron, infrared spectroscopies and high-resolution transmission electron microscopy. Then human mesenchymal stem cells (MSCs) and human monocytes were cultured on those membranes. Biocompatibility and bioactivity of the hybrid coated membrane were respectively evaluated through MSCs proliferation (WST-1 and DNA quantification) and visualization; and cytokine release by MSCs and monocytes (ELISA and endothelial cells recruitment). Antibacterial properties of the hybrid coating were then tested against S. aureus and P. aeruginosa, and through MSCs/bacteria interactions. Finally, a preclinical in vivo study was conducted on rat calvaria bone defect. The newly formed bone was characterized 8 weeks post implantation through μCT reconstructions, histological characterizations (Masson's Trichrome and Von Kossa stain), immunohistochemistry analysis and second harmonic generation. Biomechanical features of newly formed bone were determined. Results. The resulting hybrid coating of about 1 μm in thickness is composed of amorphous calcium phosphate and carbonated poorly crystalline hydroxyapatite, wrapped within chitosan/hyaluronic acid polysaccharide complex. Hybrid coated membrane possesses excellent bioactivity and capability of inducing an overwhelmingly positive response of MSCs and monocytes in favor of bone regeneration. Furthermore, the antibacterial experiments showed that the hybrid coating provides contact-killing properties by disturbing the cell wall integrity of Gram-positive and Gram-negative bacteria. Its combination with MSCs, able to release antibacterial agents and mediators of the innate immune response, constitutes an excellent strategy for fighting bacteria. A preclinical in vivo study was therefore conducted in rat calvaria bone defect. μCT reconstructions showed that hybrid coated membrane favored bone regeneration, as we observed a two-fold increase in bone volume / total volume ratios vs. uncoated membrane. The histological characterizations revealed the presence of mineralized collagen (Masson's Trichrome and Von Kossa stain), and immunohistochemistry analysis highlighted a bone vascularization at 8 weeks post-implantation. However, second harmonic generation analysis showed that the newly formed collagen was not fully organized. Despite a significant increase in the elastic modulus of the newly formed bone with hybrid coated membrane (vs. uncoated membrane), the obtained values were lower than those for native bone (approximately 3 times less). Conclusions. These significant data shed light on the regenerative potential of such bioinspired hybrid coating, providing a suitable environment for bone regeneration and vascularization, as well as an ideal strategy to prevent bone implant-associated infections


Bone & Joint Research
Vol. 10, Issue 7 | Pages 411 - 424
14 Jul 2021
Zhao D Ren B Wang H Zhang X Yu M Cheng L Sang Y Cao S Thieringer FM Zhang D Wan Y Liu C

Aims

The use of 3D-printed titanium implant (DT) can effectively guide bone regeneration. DT triggers a continuous host immune reaction, including macrophage type 1 polarization, that resists osseointegration. Interleukin 4 (IL4) is a specific cytokine modulating osteogenic capability that switches macrophage polarization type 1 to type 2, and this switch favours bone regeneration.

Methods

IL4 at concentrations of 0, 30, and 100 ng/ml was used at day 3 to create a biomimetic environment for bone marrow mesenchymal stromal cell (BMMSC) osteogenesis and macrophage polarization on the DT. The osteogenic and immune responses of BMMSCs and macrophages were evaluated respectively.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_4 | Pages 112 - 112
1 Mar 2021
Pavanram P Li Y Lietaert K Yilmaz A Pouran B Weinans H Mol J Zhou J Zadpoor A Jahr H
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Direct metal printed (DMP) porous iron implants possess promising mechanical and corrosion properties for various clinical application. Nevertheless, there is a requirement for better co-relation between in vitro and in vivo corrosion and biocompatibility behaviour of such biomaterials. Our present study evaluates absorption of porous iron implants under both static and dynamic conditions. Furthermore, this study characterizes their cytocompatibility using fibroblastic, osteogenic, endothelial and macrophagic cell types. In vitro degradation was performed statically and dynamically in a custom-built set-up placed under cell culture conditions (37 °C, 5% CO2 and 20% O2) for 28 days. The morphology and composition of the degradation products were analysed by scanning electron microscopy (SEM, JSM-IT100, JEOL). Iron implants before and after immersion were imaged by μCT (Quantum FX, Perkin Elmer, USA). Biocompatibility was also evaluated under static and dynamic in vitro culture conditions using L929, MG-63, HUVEC and RAW 264.7 cell lines. According to ISO 10993, cytocompatibility was evaluated directly using live/dead staining (Live and Dead Cell Assay kit, Abcam) in dual channel fluorescent optical imaging (FOI) and additionally quantified by flow cytometry. Furthermore, cytotoxicity was indirectly quantified using ISO conform extracts in proliferation assays. Strut size of DMP porous iron implants was 420 microns, with a porosity of 64% ± 0.2% as measured by micro-CT. After 28 days of physiological degradation in vitro, dynamically tested samples were covered with brownish degradation products. They revealed a 5.7- fold higher weight loss than statically tested samples, without significant changes in medium pH. Mechanical properties (E = 1600–1800 MPa) of these additively manufactured implants were still within the range of the values reported for trabecular bone, even after 28 days of biodegradation. Less than 25% cytotoxicity at 85% of the investigated time points was measured with L929 cells, while MG-63 and HUVEC cells showed 75% and 60% viability, respectively, after 24 h, with a decreasing trend with longer incubations. Cytotoxicity was analysed by two-way ANOVA and post-hoc Tukey's multiple comparisons test. Under dynamic culture conditions, live-dead staining and flow cytometric quantification showed a 2.8-fold and 5.7-fold increase in L929 and MG-63 cell survival rates, respectively, as compared to static conditions. Therefore, rationally designed and properly coated iron-based implants hold potential as a new generation of absorbable Orthopaedic implants


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_11 | Pages 73 - 73
1 Dec 2020
Turemis C Gunes OC Baysan G Perpelek M Albayrak AZ Havitcioglu H
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Bone fractures are highly observed clinical situation in orthopaedic treatments. In some cases, there might be non-union problems. Therefore, recent studies have focused on tissue engineering applications as alternative methods to replace surgical procedures. Various biopolymer based scaffolds are produced using different fabrication techniques for bone tissue engineering applications.

In this study, hydroxyapatite (HAp) and loofah containing carboxymethyl chitosan (CMC) scaffolds were prepared. In this regard, first 4 ml of CMC solution, 0.02 g of hydroxyapatite (HAP) and 0.06 g of poly (ethylene glycol) diglycidyl ether (PEGDE) were mixed in an ultrasonic bath until the HAp powders were suspended. Next, 0.04 g of loofah was added to the suspension and with the help of PEGDE as the cross-linking agent, then, the mixture was allowed to cross-link at 40oC overnight. Finally, the three-dimensional, porous and sponge-like scaffolds were obtained after lyophilization (TELSTAR - LyoQuest −85) at 0.1 mbar and −25°C for 2 days.

Morphologies, chemical structures and thermal properties of the scaffolds were characterized by scanning electron microscopy (SEM), Fourier Transform infrared spectroscopy (FT-IR) and thermogravimetric differential thermal analysis (TGA/DTA), respectively. In addition, swelling behavior and mechanical properties of the scaffolds under compression loading were determined.

In order to investigate biocompatibility of the scaffolds, WST-1 colorimetric assay at days 0, 1, 3, 5 and 7 was conducted by using human dermal fibroblast. Also, histological and morphological analysis were performed for cell attachment at day 7.

In conclusion, the produced scaffolds showed no cytotoxic effect. Therefore, they can be considered as a candidate scaffold for bone tissue regeneration. Further studies will be performed by using bone marrow and periosteum derived mesenchymal stem cells with these scaffolds.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_6 | Pages 31 - 31
1 Jul 2020
Jahr H Pavanram P Li Y Lietaert K Kubo Y Weinans H Zhou J Pufe T Zadpoor A
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Biodegradable metals as orthopaedic implant materials receive substantial scientific and clinical interest. Marketed cardiovascular products confirm good biocompatibility of iron. Solid iron biodegrades slowly in vivo and has got supra-physiological mechanical properties as compared to bone and porous implants can be optimized for specific orthopaedic applications. We used Direct Metal Printing (DMP)3 to additively manufacture (AM) scaffolds of pure iron with fine-tuned bone-mimetic mechanical properties and improved degradation behavior to characterize their biocompatibility under static and dynamic 3D culture conditions using a spectrum of different cell types. Atomized iron powder was used to manufacture scaffolds with a repetitive diamond unit cell design on a ProX DMP 320 (Layerwise/3D Systems, Belgium). Mechanical characterization (Instron machine with a 10kN load cell, ISO 13314: 2011), degradation behavior under static and dynamic conditions (37ºC, 5% CO2 and 20% O2) for up of 28 days, with μCT as well as SEM/energy-dispersive X-ray spectroscopy (EDS) (SEM, JSM-IT100, JEOL) monitoring under in vivo-like conditions. Biocompatibility was comprehensively evaluated using a broader spectrum of human cells according to ISO 10993 guidelines, with topographically identical titanium (Ti-6Al-4V, Ti64) specimen as reference. Cytotoxicity was analyzed by two-way ANOVA and post-hoc Tukey's multiple comparisons test (α = 0.05). By μCT, as-built strut size (420 ± 4 μm) and porosity of 64% ± 0.2% were compared to design values (400 μm and 67%, respectively). After 28 days of biodegradation scaffolds showed a 3.1% weight reduction after cleaning, while pH-values of simulated body fluids (r-SBF) increased from 7.4 to 7.8. Mechanical properties of scaffolds (E = 1600–1800 MPa) were still within the range for trabecular bone, then. At all tested time points, close to 100% biocompatibility was shown with identically designed titanium (Ti64) controls (level 0 cytotoxicity). Iron scaffolds revealed a similar cytotoxicity with L929 cells throughout the study, but MG-63 or HUVEC cells revealed a reduced viability of 75% and 60%, respectively, already after 24h and a further decreased survival rate of 50% and 35% after 72h. Static and dynamic cultures revealed different and cell type-specific cytotoxicity profiles. Quantitative assays were confirmed by semi-quantitative cell staining in direct contact to iron and morphological differences were evident in comparison to Ti64 controls. This first report confirms that DMP allows accurate control of interconnectivity and topology of iron scaffold structures. While microstructure and chemical composition influence degradation behavior - so does topology and environmental in vitro conditions during degradation. While porous magnesium corrodes too fast to keep pace with bone remodeling rates, our porous and micro-structured design just holds tremendous potential to optimize the degradation speed of iron for application-specific orthopaedic implants. Surprisingly, the biological evaluation of pure iron scaffolds appears to largely depend on the culture model and cell type. Pure iron may not yet be an ideal surface for osteoblast- or endothelial-like cells in static cultures. We are currently studying appropriate coatings and in vivo-like dynamic culture systems to better predict in vivo biocompatibility


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_14 | Pages 79 - 79
1 Dec 2019
Arens D Zeiter S Paulin T Ranjan N Alt V
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Aim

Silver is known for its excellent antimicrobial activity, including activity against multiresistant strains. The aim of the current study was to analyze the biocompatibility and potential influence on the fracture healing process a silver-coating technology for locking plates compared to silver-free locking plates in a rabbit model.

Methods

The implants used in this study were 7-hole titanium locking plates, and plasma electrolytic oxidation (PEO) silver coated equivalents. A total of 24 rabbits were used in this study (12 coated, 12 non-coated). An osteotomy of the midshaft of the humerus was created with an oscillating saw and the humerus stabilized with the 7 hole locking plates with a total of 6 screws. X-rays were taken on day 0, week 2, 4, 6, 8, and 10 for continuous radiographical evaluation of the fracture healing. All animals were euthanized after 10 weeks and further assessment was performed using X-rays, micro-CT, non-destructive four-point bending biomechanical testing and histology. Furthermore, silver concentration was measured in the kidney, liver, spleen and brain.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_2 | Pages 42 - 42
1 Jan 2019
Lal S Hall R Tipper JL
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Since 2010, there has been a sharp decline in the use of metal-on-metal joint replacement devices due to adverse responses associated with the release of metal wear particles and ions in patients. Surface engineered coatings offer an innovative solution to this problem by covering metal implant surfaces with biocompatible and wear resistant materials. The present study tests the hypothesis whether surface engineered coatings can reduce the overall biological impact of a device by investigating recently introduced silicon nitride coatings for joint replacements. Biological responses of peripheral blood mononuclear cells (PBMNCs) to Si3N4 model particles, SiNx coating wear particles and CoCr wear particles were evaluated by testing cytotoxicity, inflammatory cytokine release, oxidative stress and genotoxicity.

Clinically relevant wear particles were generated from SiNx-on-SiNx and CoCr-on-CoCr bearing combinations using a multidirectional pin-on-plate tribometer. All particles were heat treated at 180°C for 4 h to destroy endotoxin contamination. Whole peripheral blood was collected from healthy donors (ethics approval BIOSCI 10–108, University of Leeds). The PBMNCs were isolated using Lymphoprep (Stemcell) and incubated with particles at various volumetric concentrations (0.5 to 100 µm3 particles/cell) for 24 h in 5% (v/v) CO2 at 37°C. After incubation, cell viability was measured using the ATPlite assay (Perkin Elmer); TNF-alpha release was measured by ELISA (Invitrogen); oxidative stress was measured using H2DCFDA (Abcam); and DNA damage was measured by comet assay (Tevigen). The results were expressed as mean ± 95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis.

No evidence of cytotoxicity, oxidative stress, TNF-alpha release, or DNA damage was observed for the silicon nitride particles at any of the doses. However, CoCr wear particles caused cytotoxicity, oxidative stress, TNF-alpha release and DNA damage in PBMNCs at high doses (50 µm3 particles per cell). This study has demonstrated the in-vitro biocompatibility of SiNx coatings with primary human monocytic cells. Therefore, surface engineered coatings have potential to significantly reduce the biological impact of metal components in future orthopaedic devices.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_16 | Pages 42 - 42
1 Nov 2018
Dubus M Entz L Aubert L Alem H Quilès F Reffuveille F Mauprivez C Gangloff SC Kerdjoudj H Rammal H
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Bone regenerative medicine aims at designing biomimetic biomaterials able to guide stem cells fate towards osteoblast lineage and prevent orthopaedic common pathogen adhesion. Owing to bone inorganic/organic composition, we herein report, using a versatile process based on simultaneous spray coating of interacting species, a calcium phosphate (CaP) / chitosan (CHI) / hyaluronic acid (HA) functionalized collagen membrane as a new strategy for bone regenerative medicine. Physicochemical characterizations of CaP-CHI-HA coating were performed by scanning electron microscopy, X-ray photoelectron and infrared spectroscopies and high-resolution transmission electron microscopy, revealing the formation of a thin coating mainly composed of non-stoichiometric crystalline hydroxyapatite dispersed into polymorphic organic film. Biocompatibility of CaP-CHI-HA coated membrane, evaluated after 7 days in contact with human mesenchymal stem cells (MSCs), showed spread, elongated and aligned cells. Metabolic activity and DNA quantification studies showed an increase in MSCs proliferation on coated membrane compared to uncoated membrane over the study time. Similarly, cytokines (IL-6, IL-8, osteoprotegerin) and growth factors (VEGF, bFGF) release in supernatant, as well as endothelial cells recruitment, were significantly increased in presence of CaP-CHI-HA coated membrane. Thus, CaP-CHI-HA coated membrane provides a suitable environment for MSCs to induce bone healing. Moreover, pro-inflammatory cytokines (IL-1β and TNF-α) secretion by human monocytes was significantly reduced on CaP-CHI-HA coating compared to LPS stimulation. CaP-CHI-HA coating also reduced significantly Staphylococcus aureus and Pseudomonas aeruginosa adhesion on the membrane, conferring a bacterial anti-adhesive surface. Based on our results, CaP-CHI-HA functionalized collagen membrane provides an interesting material for bone regeneration


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 96 - 96
1 Apr 2018
Loenen A Arts C Boelen E
Full Access

Introduction

Because of its high strength and allowance for bone integration, Ti-6Al-4V is the most commonly used material for load bearing bone implants. Compared to conventional production methods, 3D printing Ti-6Al-4V introduces advantages as (near-) net-shape manufacturing of complex geometries, and optimization of utilization rate of the material. However, as result of the additively production procedure, microstructure and surface properties differ from those manufactured using conventional techniques. Therefore, the resulting mechanical properties and biocompatibility of the 3D printed Ti-6Al-4V are investigated in this study. First, it was aimed to reveal the tensile properties of the material and verify if these depend on build orientation. Second, it was determined which post process method provides the best osteoconductivity.

Materials and methods

Tensile specimens were designed and 3D printed using Selective Laser Melting (SLM) technique. Subsequently, specimens were heat treated and tensile properties were determined as described in ASTM E 8M-04. Cell culture discs were manufactured using the same production method. The influence of two different surface treatments (sand-blasting versus polishing) on osteoconductivity was analysed by a 30 day in vitro 2D culture of bovine Bone Marrow Stromal Cells (bBMSCs). Cultures were checked for morphology, collagen production was monitored, ALP activity was revealed, and matrix mineralization was quantified.


Bone & Joint Research
Vol. 7, Issue 1 | Pages 46 - 57
1 Jan 2018
Zhou J Zhou XG Wang JW Zhou H Dong J

Objective

In the present study, we aimed to assess whether gelatin/β-tricalcium phosphate (β-TCP) composite porous scaffolds could be used as a local controlled release system for vancomycin. We also investigated the efficiency of the scaffolds in eliminating infections and repairing osteomyelitis defects in rabbits.

Methods

The gelatin scaffolds containing differing amounts of of β-TCP (0%, 10%, 30% and 50%) were prepared for controlled release of vancomycin and were labelled G-TCP0, G-TCP1, G-TCP3 and G-TCP5, respectively. The Kirby-Bauer method was used to examine the release profile. Chronic osteomyelitis models of rabbits were established. After thorough debridement, the osteomyelitis defects were implanted with the scaffolds. Radiographs and histological examinations were carried out to investigate the efficiency of eliminating infections and repairing bone defects.


Bone & Joint Research
Vol. 6, Issue 4 | Pages 208 - 215
1 Apr 2017
Decambron A Manassero M Bensidhoum M Lecuelle B Logeart-Avramoglou D Petite H Viateau V

Objectives

To compare the therapeutic potential of tissue-engineered constructs (TECs) combining mesenchymal stem cells (MSCs) and coral granules from either Acropora or Porites to repair large bone defects.

Materials and Methods

Bone marrow-derived, autologous MSCs were seeded on Acropora or Porites coral granules in a perfusion bioreactor. Acropora-TECs (n = 7), Porites-TECs (n = 6) and bone autografts (n = 2) were then implanted into 25 mm long metatarsal diaphyseal defects in sheep. Bimonthly radiographic follow-up was completed until killing four months post-operatively. Explants were subsequently processed for microCT and histology to assess bone formation and coral bioresorption. Statistical analyses comprised Mann-Whitney, t-test and Kruskal–Wallis tests. Data were expressed as mean and standard deviation.


Bone & Joint Research
Vol. 6, Issue 3 | Pages 162 - 171
1 Mar 2017
Walker JA Ewald TJ Lewallen E Van Wijnen A Hanssen AD Morrey BF Morrey ME Abdel MP Sanchez-Sotelo J

Objectives

Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated in vivo animal model of knee arthrofibrosis.

Materials and Methods

A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 43 - 43
1 Feb 2017
Muratoglu O Bichara D O'Brien C Doshi B Oral E
Full Access

Introduction

We have previously demonstrated that peroxide crosslinked vitamin E-blended UHMWPE maintains its clinically-required wear and mechanical properties [1]. This material can potentially be used as an irradiation-free bearing surface for TJA. However, using organic peroxides in medical devices requires a thorough examination of tissues in contact with the implant. For this study we crosslinked polyethylene using five times the needed concentration of peroxide (2,5-Dimethyl-2,5-di(t-butylperoxy)-hexyne-3 or P130), followed by implantation to determine implant biocompatibility, and pre and post implant peroxide residual contents.

Methods

The study was performed after institutional approval following ISO standard 10993–6. Study groups: not crosslinked (0.2 (1050) VE), crosslinked (0.2 VE (1050)/5% P130) and crosslinked-high temperature melted (HTM) (0.2 VE (1050)/5% P130). Materials were blended and consolidated, machined (2.5 diameter × 2.5 cm height), sterilized and implanted in the dorsum New Zealand white rabbits. Pre and post implantation FTIR was performed. Two samples were implanted in each rabbit; n=6 samples were included for each group. After 4 weeks, samples were explanted, analyzed using FTIR, and subcutaneous tissues processed for histological analysis.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 97 - 97
1 Feb 2017
Lal S Hall R Tipper J
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Introduction. Currently, different techniques to evaluate biocompatibility of orthopaedic materials, including two-dimensional (2D) cell culture for metal and ceramic wear debris and floating 2D surfaces or three-dimensional (3D) agarose gels for UHMWPE wear debris, are used. We have developed a single method using 3D agarose gels that is suitable to test the biocompatibility of all three types of wear debris simultaneously. Moreover, stimulation of the cells by wear particles embedded in a 3D gel better mimics the in vivo environment. Materials and Methods. Clinically relevant sterile UHMWPE and CoCr wear particles were generated using methodologies described previously [1,2]. Commercially available nanoscale and micron-sized silicon nitride (Si. 3. N. 4. ) particles (<50 nm and <1 μm, Sigma UK) were sterilised by heat treatment for 4h at 180°C. Agarose-particle suspensions were prepared by mixing warm 2% (w/v) low-melting-point agarose solution with the particles dispersed by sonication in DMEM culture media. The suspensions were then allowed to set at room temperature for 10 min in 96 well culture plates. Sub-confluent L929 murine fibroblasts were cultured on the prepared gels for up to 6 days in 5% (v/v) CO. 2. at 37°C. After incubation, the viability of cells was measured using the ATP-lite assay. The results were expressed as mean ± 95% confidence limits and the data was analysed using one-way ANOVA and Tukey-Kramer post-hoc analysis. Results and Discussion. The gels were observed to ensure uniform distribution of particles and migration of cells into the gel. No significant reduction in viability was observed for nanoscale and micron-sized Si. 3. N. 4. particles at low doses (0.5 μm. 3. per cell) and high doses (50 μm. 3. per cell), or for UHMWPE wear debris at high doses (100 μm. 3. per cell) [Figure1]. Moreover, the viability was significantly reduced for high doses of CoCr wear debris (50 μm. 3. per cell) and the positive control, camptothecin (2 μg.ml. −1. ) at day 6 [Figure1]. These results are consistent with the literature [2,3] and therefore validate our 3D agarose cell culture method for comparing cytotoxicity of polymer, metal and ceramic particles in a single assay, simultaneously. Conclusion. Biocompatibility ofpolymer, metal and ceramic wear debris can be tested simultaneously by using 3D particle embedded agarose gels. Acknowledgements. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. GA-310477 LifeLongJoints