Selfprotective smart orthopedic implants

Industry 5.0 in Orthopaedics

Background

Industrial revolutions play a major role in the development of technologies in various fields. Currently, the world is marching towards softwarization and digitalization. There is an emerging need for conversion of Industry 4.0 to Industry 5.0 for technological development and implementation of the same in the digital era. In health care, digitalization emerged in Industry 4.0 revolution. To enhance patient care and quality of life, Industry 5.0 plays a major role in providing patient-centric care and customization and personalization of products. The integration of human intelligence with artificial intelligence provides a precise diagnosis and enhances the recovery and functional outcome of the patients.

Materials and methods

In this manuscript, the domains and limitations of Industry 5.0 and further research on Industry 6.0 were elaborated on to bring out technologies in better health care.

Results

Industry 5.0 lessens the work of medical professionals and integrates software-based diagnosis and management. It provides cost-effective manufacturing solutions with limited resources compared to Industry 4.0. Industry 5.0 focuses on SMART and additive manufacturing of implants, and the development of bio-scaffolds, prosthetics, and instruments. In this manuscript, the domains and limitations of Industry 5.0 and further research on Industry 6.0 were elaborated on to bring out technologies in better health care.

Conclusion

'The personalization and customization of products' are the hallmarks of this evolving Industry 5.0 revolution. The major uplifts in various domains of industry 5.0 such as advanced automation, digitalization, collaborative robots, and personalization bring this an inevitable mechano-scientific technological revolution in this current medical era.

Antibacterial Effects of Sodium Borate and Calcium Borate Based Polymeric Coatings for Orthopedic Implants

Introduction

Implants used in orthopedic surgery can be colonized by bacteria that form biofilm layers complicating treatment. We aimed to determine titanium implants' antibacterial and biofilm-degrading properties when coated with sodium borate (NaB) and calcium borate (CaB) minerals.

Methods

We analyzed twenty-four different implants. Three implants were not coated, three were coated with only a carrier polymer (alginate), and eighteen were coated with either CaB or NaB at different concentrations. The implants were incubated with Staphylococcus aureus, and then the bacterial colonies were enumerated.

Results

The highest microbial load was observed on the implant coated with alginate (1000 colony-forming units [CFU]/mL). The implant without coating contained a microbial load of 420 CFU/mL. The microbial loads of the implants coated with 0.75 mg/mL CaB or 0.25, 0.5, and 0.75 mg/mL NaB (100, 200, 0, and 0 CFU/mL, respectively) were lower than that of the implant without coating. No biofilm formation was observed on implant surfaces coated with 0.5 mg/mL NaB, 0.75 mg/mL NaB, or 0.75 mg/mL CaB; biofilm formation was observed on the implant without coating and alginate-coated implants surfaces.

Conclusion

At high concentrations, borate minerals (NaB and CaB) have a potent antibacterial effect on colonization and biofilm formation on the implant surface. These elements may be used in implant coating in the future because of their potential antibacterial effects.

Antimicrobial Peptides in the Battle against Orthopedic Implant-Related Infections: A Review

Prevention of orthopedic implant-related infections is a major medical challenge, particularly due to the involvement of biofilm-encased and multidrug-resistant bacteria. Current therapies, based on antibiotic administration, have proven to be insufficient, and infection prevalence may rise due to the dissemination of antibiotic resistance. Antimicrobial peptides (AMPs) have attracted attention as promising substitutes of conventional antibiotics, owing to their broad-spectrum of activity, high efficacy at very low concentrations, and, importantly, low propensity for inducing resistance. The aim of this review is to offer an updated perspective of the development of AMPs-based preventive strategies for orthopedic and dental implant-related infections. In this regard, two major research strategies are herein addressed, namely (i) AMP-releasing systems from titanium-modified surfaces and from bone cements or beads; and (ii) AMP immobilization strategies used to graft AMPs onto titanium or other model surfaces with potential translation as coatings. In overview, releasing strategies have evolved to guarantee higher loadings, prolonged and targeted delivery periods upon infection. In addition, avant-garde self-assembling strategies or polymer brushes allowed higher immobilized peptide surface densities, overcoming bioavailability issues. Future research efforts should focus on the regulatory demands for pre-clinical and clinical validation towards clinical translation.

Smart sensor implant technology in total knee arthroplasty

Innovations in computer technology and implant design have paved the way for the development of smart instruments and intelligent implants in trauma and orthopaedics to improve patient-related functional outcomes. Sensor technology uses embedded devices that detect physical, chemical and biological signals and provide a way for these signals to be measured and recorded. Sensor technology applications have been introduced in various fields of medicine in the diagnosis, treatment and monitoring of diseases. Intelligent 'Smart' implants are devices that can provide diagnostic capabilities along with therapeutic benefits. In trauma and orthopaedics, applications of sensors is increasing because of the advances in microchip technologies for implant devices and research designs. It offers real-time monitoring from the signals transmitted by the embedded sensors and thus provides early management solutions. Smart orthopaedic implants have applications in total knee arthroplasty, hip arthroplasty, spine surgery, fracture healing, early detection of infection and implant loosening. Here we have explored the role of Smart sensor implant technology in total knee arthroplasty. Smart sensor assisted can be used intraoperatively to provide objective assessment of ligament and soft tissue balancing whilst maintaining the sagittal and coronal alignment to achieve desired kinematic targets following total knee arthroplasty. It can also provide post-implantation data to monitor implant performance in natural conditions and patient's clinical recovery during rehabilitation. The use of Smart Sensor implant technology in total knee arthroplasty appears to provide superior patient satisfaction rates and improved functional outcomes.

Coating Technologies for Copper Based Antimicrobial Active Surfaces: A Perspective Review

Microbial contamination of medical devices and treatment rooms leads to several detrimental hospital and device-associated infections. Antimicrobial copper coatings are a new approach to control healthcare-associated infections (HAI’s). This review paper focuses on the efficient methods for depositing highly adherent copper-based antimicrobial coatings onto a variety of metal surfaces. Antimicrobial properties of the copper coatings produced by various deposition methods including thermal spray technique, electrodeposition, electroless plating, chemical vapor deposition (CVD), physical vapor deposition (PVD), and sputtering techniques are compared. The coating produced using different processes did not produce similar properties. Also, process parameters often could be varied for any given coating process to impart a change in structure, topography, wettability, hardness, surface roughness, and adhesion strength. In turn, all of them affect antimicrobial activity. Fundamental concepts of the coating process are described in detail by highlighting the influence of process parameters to increase antimicrobial activity. The strategies for developing antimicrobial surfaces could help in understanding the mechanism of killing the microbes.

Strategies for antimicrobial peptide coatings on medical devices: a review and regulatory science perspective

Indwelling and implanted medical devices are subject to contamination by microbial pathogens during surgery, insertion or injection, and ongoing use, often resulting in severe nosocomial infections. Antimicrobial peptides (AMPs) offer a promising alternative to conventional antibiotics to reduce the incidence of such infections, as they exhibit broad-spectrum antimicrobial activity against Gram-negative and Gram-positive bacteria, microbial biofilms, fungi, and viruses. In this review-perspective, we first provide an overview of the progress made in this field over the past decade with an emphasis on the local release of AMPs from implant surfaces and immobilization strategies for incorporating these agents into a wide range of medical device materials. We then provide a regulatory science perspective addressing the characterization and testing of AMP coatings based on the type of immobilization strategy used with a focus on the US market regulatory niche. Our goal is to help narrow the gulf between academic studies and preclinical testing, as well as to support a future literature base in order to develop the regulatory science of antimicrobial coatings.

Plasma treatments of dressings for wound healing: a review

This review covers the use of plasma technology relevant to the preparation of dressings for wound healing. The current state of knowledge of plasma treatments that have potential to provide enhanced functional surfaces for rapid and effective healing is summarized. Dressings that are specialized to the needs of individual cases of chronic wounds such as diabetic ulcers are a special focus. A summary of the biology of wound healing and a discussion of the various types of plasmas that are suitable for the customizing of wound dressings are given. Plasma treatment allows the surface energy and air permeability of the dressing to be controlled, to ensure optimum interaction with the wound. Plasmas also provide control over the surface chemistry and in cases where the plasma creates energetic ion bombardment, activation with long-lived radicals that can bind therapeutic molecules covalently to the surface of the dressing. Therapeutic innovations enabled by plasma treatment include the attachment of microRNA or antimicrobial peptides. Bioactive molecules that promote subsequent cell adhesion and proliferation can also be bound, leading to the recruitment of cells to the dressing that may be stem cells or patient-derived cells. The presence of a communicating cell population expressing factors promotes healing.

Silver Nanocoating Technology in the Prevention of Prosthetic Joint Infection

Prosthetic joint infection (PJI) is a feared complication of total joint arthroplasty associated with increased morbidity and mortality. There is a growing body of evidence that bacterial colonization and biofilm formation are critical pathogenic events in PJI. Thus, the choice of biomaterials for implanted prostheses and their surface modifications may significantly influence the development of PJI. Currently, silver nanoparticle (AgNP) technology is receiving much interest in the field of orthopaedics for its antimicrobial properties and a strong anti-biofilm potential. The great advantage of AgNP surface modification is a minimal release of active substances into the surrounding tissue and a long period of effectiveness. As a result, a controlled release of AgNPs could ensure antibacterial protection throughout the life of the implant. Moreover, the antibacterial effect of AgNPs may be strengthened in combination with conventional antibiotics and other antimicrobial agents. Here, our main attention is devoted to general guidelines for the design of antibacterial biomaterials protected by AgNPs, its benefits, side effects and future perspectives in PJI prevention.

Intraoperative intra-articular injection of gentamicin: will it decrease the risk of infection in total shoulder arthroplasty?

BACKGROUND

Deep infection is a debilitating complication after shoulder arthroplasty. Intra-articular injection of antibiotic can give a higher concentration compared with intravenous administration. We hypothesized that a group of patients given an intra-articular, intraoperative injection of gentamicin would report a lower infection rate than a group without local antibiotics.

METHODS

Between 2005 and 2011, the senior author performed 507 shoulder arthroplasties. We retrospectively reviewed all of those cases. All patients were administered systemic prophylactic antibiotics. Beginning in June 2007, patients were also injected with 160 mg of gentamicin in the glenohumeral joint at the end of their surgery. Patient records were examined for preexisting medical conditions, type of surgery, and presence of infection. Patients receiving surgery before 2007 were compared with those after to determine the effect of prophylactic gentamicin administration in preventing deep infection associated with surgery. All patients were observed for a minimum of 1 year.

RESULTS

Of the 507 surgeries, 164 were performed before 2007 (without intra-articular injection of gentamicin; group A) and 343 were performed with addition of gentamicin (group B). In group A, 5 patients presented with infection (3.0%) compared with 1 in group B (0.29%). The gender, mean age, mean body mass index, and prevalence of comorbidities were similar between the groups.

CONCLUSIONS

The data from this study support the conclusion that intra-articular intraoperative gentamicin administration may reduce postoperative infection.

Antibacterial surface treatment for orthopaedic implants. Int J Mol Sci. 2014;15:13849-13880. [PMID: 25116685 PMCID: PMC4159828 DOI: 10.3390/ijms150813849]

It is expected that the projected increased usage of implantable devices in medicine will result in a natural rise in the number of infections related to these cases. Some patients are unable to autonomously prevent formation of biofilm on implant surfaces. Suppression of the local peri-implant immune response is an important contributory factor. Substantial avascular scar tissue encountered during revision joint replacement surgery places these cases at an especially high risk of periprosthetic joint infection. A critical pathogenic event in the process of biofilm formation is bacterial adhesion. Prevention of biomaterial-associated infections should be concurrently focused on at least two targets: inhibition of biofilm formation and minimizing local immune response suppression. Current knowledge of antimicrobial surface treatments suitable for prevention of prosthetic joint infection is reviewed. Several surface treatment modalities have been proposed. Minimizing bacterial adhesion, biofilm formation inhibition, and bactericidal approaches are discussed. The ultimate anti-infective surface should be “smart” and responsive to even the lowest bacterial load. While research in this field is promising, there appears to be a great discrepancy between proposed and clinically implemented strategies, and there is urgent need for translational science focusing on this topic.

Instrumented hip implants: electric supply systems

Instrumented hip implants were proposed as a method to monitor and predict the biomechanical and thermal environment surrounding such implants. Nowadays, they are being developed as active implants with the ability to prevent failures by loosening. The generation of electric energy to power active mechanisms of instrumented hip implants remains a question. Instrumented implants cannot be implemented without effective electric power systems. This paper surveys the power supply systems of seventeen implant architectures already implanted in-vivo, namely from instrumented hip joint replacements and instrumented fracture stabilizers. Only inductive power links and batteries were used in-vivo to power the implants. The energy harvesting systems, which were already designed to power instrumented hip implants, were also analyzed focusing their potential to overcome the disadvantages of both inductive-based and battery-based power supply systems. From comparative and critical analyses of the methods to power instrumented implants, one can conclude that: inductive powering and batteries constrain the full operation of instrumented implants; motion-driven electromagnetic energy harvesting is a promising method to power instrumented passive and active hip implants.

Osteoblast, fibroblast and in vivo biological response to poly(vinylidene fluoride) based composite materials

Electroactive materials can be taken to advantage for the development of sensors and actuators as well as for novel tissue engineering strategies. Composites based on poly(vinylidene fluoride), PVDF, have been evaluated with respect to their biological response. Cell viability and proliferation were performed in vitro both with Mesenchymal Stem Cells differentiated to osteoblasts and Human Fibroblast Foreskin 1. In vivo tests were also performed using 6-week-old C57Bl/6 mice. It was concluded that zeolite and clay composites are biocompatible materials promoting cell response and not showing in vivo pro-inflammatory effects which renders both of them attractive for biological applications and tissue engineering, opening interesting perspectives to development of scaffolds from these composites. Ferrite and silver nanoparticle composites decrease osteoblast cell viability and carbon nanotubes decrease fibroblast viability. Further, carbon nanotube composites result in a significant increase in local vascularization accompanied an increase of inflammatory markers after implantation.

Controlled delivery systems: from pharmaceuticals to cells and genes

During the last few decades, a fair amount of scientific investigation has focused on developing novel and efficient drug delivery systems. According to different clinical needs, specific biopharmaceutical carriers have been proposed. Micro- and nanoparticulated systems, membranes and films, gels and even microelectronic chips have been successfully applied in order to deliver biopharmaceuticals via different anatomical routes. The ultimate goal is to deliver the potential drugs to target tissues, where regeneration or therapies (chemotherapy, antibiotics, and analgesics) are needed. Thereby, the bioactive molecule should be protected against environmental degradation. Delivery should be achieved in a dose- and time-correct manner. Drug delivery systems (DDS) have been conceived to provide improvements in drug administration such as ability to enhance the stability, absorption and therapeutic concentration of the molecules in combination with a long-term and controlled release of the drug. Moreover, the adverse effects related with some drugs can be reduced, and patient compliance could be improved. Recent advances in biotechnology, pharmaceutical sciences, molecular biology, polymer chemistry and nanotechnology are now opening up exciting possibilities in the field of DDS. However, it is also recognized that there are several key obstacles to overcome in bringing such approaches into routine clinical use. This review describes the present state-of-the-art DDS, with examples of current clinical applications, and the promises and challenges for the future in this innovative field.

Efficacy of colistin-impregnated beads to prevent multidrug-resistant A. baumannii implant-associated osteomyelitis

Osteomyelitis (OM) from multidrug-resistant (MDR) Acinetobacter has emerged in >30% of combat-related injuries in Iraq and Afghanistan. While most of these strains are sensitive to colistin, the drug is not available in bone void fillers for local high-dose delivery. To address this, we developed a mouse model with MDR strains isolated from wounded military personnel. In contrast to S. aureus OM, which is osteolytic and characterized by biofilm in necrotic bone, A. baumannii OM results in blastic lesions that do not contain apparent biofilm. We also found that mice mount a specific IgG response against three proteins (40, 47, and 56 kDa) regardless of the strain used, suggesting that these may be immuno-dominant antigens. PCR for the A. baumannii-specific parC gene confirmed a 100% infection rate with 75% of the MDR strains, and in vitro testing confirmed that all strains were sensitive to colistin. We also developed a real-time quantitative PCR (RTQ-PCR) assay that could detect as few as 10 copies of parC in a sample. To demonstrate the efficacy of colistin prophylaxis in this model, mice were treated with either parenteral colistin (0.2 mg colistinmethate i.m. for 7 days), local colistin (PMMA bead impregnated with 1.0 mg colistin sulfate), or an unloaded PMMA bead control. While the parenteral colistin failed to demonstrate any significant effects versus the placebo, the colistin PMMA bead significantly reduced the infection rate such that only 29.2% of the mice had detectable levels of parC at 19 days (p < 0.05 vs. i.m. colistin and placebo).

Quantitative mouse model of implant-associated osteomyelitis and the kinetics of microbial growth, osteolysis, and humoral immunity

Although osteomyelitis (OM) remains a serious problem in orthopedics, progress has been limited by the absence of an in vivo model that can quantify the bacterial load, metabolic activity of the bacteria over time, immunity, and osteolysis. To overcome these obstacles, we developed a murine model of implant-associated OM in which a stainless steel pin is coated with Staphylococcus aureus and implanted transcortically through the tibial metaphysis. X-ray and micro-CT demonstrated concomitant osteolysis and reactive bone formation, which was evident by day 7. Histology confirmed all the hallmarks of implant-associated OM, namely: osteolysis, sequestrum formation, and involucrum of Gram-positive bacteria inside a biofilm within necrotic bone. Serology revealed that mice mount a protective humoral response that commences with an IgM response after 1 week, and converts to a specific IgG2b response against specific S. aureus proteins by day 11 postinfection. Real-time quantitative PCR (RTQ-PCR) for the S. aureus specific nuc gene determined that the peak bacterial load occurs 11 days postinfection. This coincidence of decreasing bacterial load with the generation of specific antibodies is suggestive of protective humoral immunity. Longitudinal in vivo bioluminescent imaging (BLI) of luxA-E transformed S. aureus (Xen29) combined with nuc RTQ-PCR demonstrated the exponential growth phase of the bacteria immediately following infection that peaks on day 4, and is followed by the biofilm growth phase at a significantly lower metabolic rate (p < 0.05). Collectively, these studies demonstrate the first quantitative model of implant-associated OM that defines the kinetics of microbial growth, osteolysis, and humoral immunity following infection.

Vancomycin bound to Ti rods reduces periprosthetic infection: preliminary study

A major challenge in treating periprosthetic infection is the predilection of certain bacteria to colonize implants, form biofilms, and resist treatment. We engineered an innovative self-protective implant with covalently bound antibiotics that prevents bacterial colonization and remains stable for extended periods of time. To test this surface in vivo, we developed a rat periprosthetic infection model with an intramedullary implant in S. aureus-infected femora. Using the model, we then evaluated the effect of vancomycin-modified titanium rods on the clinical presentation of bone infection. Finally, assuming delayed and chronic periprosthetic infections originate from biofilms atop contaminated implants, the numbers of surface adherent bacteria were measured to assess the capability of the implant to prevent biofilms. S. aureus (1.5 x 10(3) colony forming units) with no known resistance were injected into the femoral canal of Wistar rats, followed by the implant. Signs of infection were assessed weekly by direct clinical observation of the animals, radiograph, and microCT, and counts of bacteria adherent to the implant. Vancomycin-modified implants showed superior inhibition of bacterial attachment and proliferation compared to control titanium surfaces.