346 research outputs found

    Biofilm formation in total hip arthroplasty: Prevention and treatment

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    Biomaterials science is a very active area of research, which has allowed the successful use of implants in the orthopaedic field for over a century. However, implant infection remains a clinical concern as it is associated with extensive patient morbidity and a high economic burden, which is predicted to increase due to an ageing population. Bacteria are able to adhere, colonise and develop into biofilms on the surface of biomaterials making associated infections physiologically different to other post-surgical infections. Unfortunately, biofilms exert increased protection from the host immune system and an increased resistance to antibiotic therapy in comparison to their planktonic counterparts. The aim of this review is to assess the current knowledge on treatments, pathogenesis and the prevention of infections associated with orthopaedic implants, with a focus on total hip arthroplasty

    Infection in prosthetic material

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    Surgical site infection (SSI) occurs when a wound created as part of a surgical procedure becomes infected. SSI is one of the most common healthcare-associated infections and occurs in approximately 5% of patients undergoing a surgical procedure. SSI may lead to patients suffering considerable morbidity or mortality and have significant cost implications. The aetiology involves the interplay of host, environmental and pathogen factors all of which should be addressed in seeking to reduce the risk of developing an infection. The presence of prosthetic material reduces the number of bacteria necessary for an infection to develop and can give rise to treatment and diagnostic difficulties. The responsible organisms are most commonly Staphylococcus aureus and S. epidermidis. Diagnosis is frequently problematic and antibiotic treatment alone is often ineffective due to biofilm formation necessitating removal of prosthesis in many cases. Prevention of infection is by far the most important aspect of prosthetic implant surgery. Patient optimization is equally important as the cutting edge research into biological prostheses in reducing the incidence of prosthetic infection in future practice

    Biopolymer Local Delivery Device Loaded with Rifampin and Ciprofloxacin to Inhibit Biofilm Formation

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    Increases in patients\u27 costs, multiple surgeries, and difficult treatment solutions are resultants of musculoskeletal infections. The presence of biofilm-forming or antibiotic resistant bacteria exponentially increase the complexity and complications in treatment of those musculoskeletal infections. During this study, the combination of ciprofloxacin and rifampin loaded in and released from chitosan-based local delivery systems was evaluated as an adjuvant therapy for prompt reduction of biofilm-forming bacteria in the wound when locally delivered. Primary assessments included antibiotic release, sponge eluate in vitro activity, in vitro synergy assays, effect on chitosan sponge pore structure, and an in vivo implant associated biofilm functional model. Antibiotic activity was present through seven days against S. aureus and P. aeruginosa. Ciprofloxacin had a therapeutic elution profile that lasted, at least, seven days while rifampin\u27s lasted three days. Additive effects were present against P. aeruginosa during the in vitro synergy assay with inconclusive results against S. aureus. No unexpected or adverse effects on chitosan sponge pore structure were seen after sponges were loaded with the antibiotic cocktail. Complete clearance of biofilm-forming S. aureus and E. coli with no noticeable adverse effects were achieved in the functional infected pin murine model. The results of this study support the potential use of ciprofloxacin and rifampin in chitosan-based local deiivery devices, as local adjunctive therapy, for prevention of musculoskeletal and surgical site infections

    Development and Evaluation of an Injectable Chitosan-Mannitol Paste as an antimicrobial delivery system for the inhibition and eradication of biofilm

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    Implanted materials can increase the risk of osteomyelitis, leading S. aureus to develop a biofilm not only on the materials, but also in bone and soft tissue surrounding the joint. Biofilm is intrinsically less susceptible to antibiotic therapy than free-floating planktonic microorganisms due to decrease metabolic rates of persister cells. Mannitol has been shown to active persister cell metabolism, priming mircroorganisms for the uptake of antibiotics and subsequent eradication. Blends of mannitol and chitosan were evaluated in elution and activity studies to determine the efficacy against biofilm with additional injectability, degradation, and biofilm eradication evaluations Results indicate the mannitol/chitosan blend is capable of eluting antibiotics for up to 7 days and antimicrobial activity up to 7 days. Clincially this paste could serve as a biodegradable local antibiotic delivery system at the time of surgery to prevent infection, during periprosthetic joint surgeries, or complex musculoskeletal trauam to prevent and treat infection

    Highly Adherent Antimicrobial Coatings for Orthopedic Implants

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    Fracture-related infections (FRIs) are the most devasting sort of complications associated with fracture fixation devices, as they lead to patients’ morbidity, prolonged hospitalization, amputations, and even death.External fixators additionally suffer from pin site infections (PSIs), which initiate at the skin entry points of the skin-metallic pin interface present in the external fixation of the damaged bones, often causing deep tissue infection and osteomyelitis. Small percutaneous pins, commonly known as Kirschner wires (K-wires), are used to treat complex fractures and deformities.They are drilled inside the diseased bone for the healing period and are left protruding outside the skin for fixation adjustments and easy removal. Metal surface of the K-wires, however, provides an anchor for the pathogens to adhere and migrate underneath the skin toward the bone, where they can form biofilms and become resistant to oral and intravenous antibiotics. While the incidence rate of PSIs has been reported to reach 100%, there is still limited literature regarding the prevention of PSIs and the overall lack of pin site-specific research.Despite the significant improvements in post-surgical aseptic technique, there is no consensus on either optimal antimicrobial dressing for the post-operative period or burying K-wires under the closed skin wound. Drug-releasing surface coatings of the implants is the recently emerged trend to address clinicallyimportant issues such as prophylaxis of microbial infections and reduction of inflammatory response. Some orthopedic implants, however, are subjected to large shear forces, which remove or damage any weakly adhered physiosorbed coatings. Hence, little progress has been made on drug-releasing coatings for those implants. Our research, therefore, aims to fill that gap on the drug-eluting orthopedic implants and the modeling of their abrasion-resistance properties. In this study, we have developed two types of highly adhesive drug-releasing coating: the synthetic Poly(glycidyl methacrylate) (PGMA)-based polymeric brush and the natural chitosan coatings. Derived from the shells of crustaceans, chitosan is a linear polysaccharide molecule that is generally recognized as safe by FDA and is currently pending approval for drug delivery applications. Furthermore, chitosan has been shown to possess antimicrobial activity against a wide variety of microorganisms, produce films with good mechanical properties, and stimulate new bone formation.The synthetic (PGMA)-based copolymer, on the other hand, is a branched molecule that consists of three individual monomers: glycidyl methacrylate (GMA) - a cross-linkable monomer with epoxy group which can form stable permanent network; a hydrophilic oligoethylene glycol methacrylate (OEGMA), which provides compatibilization with water; and a hydrophobiclauryl methacrylate (LMA), which provides amphiphilic balance to the resulting macromolecule. We hypothesized that our developed drug-loaded coatings would retain antimicrobial properties after drilling into compact bone or its mimetic and would be superior to the plain drug and the drug-loaded commercial Poly(DL-lactide) (PLA) coatings. The objective of this study was to validate this platform technology for drug-eluting orthopedic implants with specific focus on K-wires because of the high incidence of infections for these devices. In the first part of the dissertation, we prepared and characterized two types of coatings, chitosan-based and PGMA-based. By varying matrix composition parameters of the polymer and drug loading we identified the optimal formulations capable of resisting shear forces during K-wire drilling in vitro. In the second part of the dissertation, we characterized antimicrobial efficacy of the best-performing coatings before and after the drilling. The findings of this aim helped us to choose the optimal coating for the pilot in vivo study. We conducted the animal study which confirmed the effectiveness of the applied highly adherent antimicrobial coating

    Surface Modification Strategies for Antimicrobial Titanium Implant Materials with Enhanced Osseointegration

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    The use of exogenous materials to replace or repair dysfunctional tissues and organs has seen dramatic improvements since the time of the ‘physician-hero’. The past three decades have heralded the advancement of various materials and technologies for medical implant devices to repair, replace or regenerate irreversibly damaged tissues. Improvement in health outcomes, evident in life expectancy increase, has brought in its wake the increased need to replace or repair tissues, particularly weight-bearing bone tissues. Titanium (Ti), a non-magnetic, corrosion resistant, osseo-integrating metal, with a higher strength-to-weight ratio than the traditional stainless steel, has emerged as the material of choice for replacing bone and other support tissues. However, the quest for improved performance (osseointegration) and reduction in implant related infection resulting in the need for resection surgeries, has necessitated the need to improve the titanium-tissue interface mediated osseointegration process, and confer antimicrobial properties to the implant material surface. In this work, a simple cost effective physical and chemical modification strategies have been developed, to alter the surface chemistry, increase the surface water wettability and confer a nano topographic characteristic to the Ti surface. These surface parameters have been demonstrated to enhance the osseointegration process. The chemical treatments resulted in oxides containing the following ions: Calcium (Ca), for improvement of osteogenic cell adhesion to Ti surface, Silver (Ag), and Zinc (Zn) for conferring antimicrobial properties to the novel surface, and their composites (CaAg, CaZn and CaZnAg), Scanning electron microscope (SEM) profiles of the modified surface suggest that, ions are chemically bound and not physically deposited onto the Ti surface. Further evidence of this is provided by the release profile of these elements from the modified surface over a 28-day period. We have also demonstrated that, the physically modified Ti surface is better at incorporating our elements of interest than the commercially pure titanium (cpTi) surface. xi The results from a Staphylococcus aureus biofilm formation assay, and U2OS bone cell adhesion and proliferation studies, suggest that, the physical modifications enhanced both the antimicrobial performance and the osteoblast-like cell adhesion and proliferation. The suggestion also is that, the incorporated Ca further enhances the adhesion and proliferation of bone-like cells, whereas Zn and markedly Ag improve the modified Ti surface’s antimicrobial properties. However, Ag alone has been shown to have a toxic effect on the bone cells; a promising combination treatment involving Ca, Zn and Ag appears to have beneficial response in all tests

    Titanium-Based Hip Stems with Drug Delivery Functionality through Additive Manufacturing

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