Iodine-Supported Hip Implants: Short Term Clinical Results

Enhancement of in vitro antibacterial activity and bioactivity of iodine-loaded titanium by micro-scale regulation using mixed-acid treatment

Postoperative infection and subsequent device loss are serious complications in the use of titanium dental implants and plates for jawbone reconstruction. We have previously reported that NaOH-CaCl2 -thermal-ICl3 -treated titanium (NaCaThIo) has a nano-scale surface and exhibits antibacterial activity against Staphylococcus aureus. The present study examined the surface properties of mixed-acid treated and then iodine-treated titanium (MA-NaCaThIo), and evaluated oral antibacterial activity and cytotoxicity compared with the results obtained with NaCaThIo. MA-NaCaThIo formed a surface layer with a nano-scale network structure having microscale irregularities, and both the thickness of the surface layer (1.49 ± 0.16 μm) and the average surface roughness (0.35 ± 0.03 μm) were significantly higher than those of NaCaThIo. Furthermore, MA-NaCaThIo maintained high hydrophilicity with a contact angle of 7.5 ± 1.7° even after 4 weeks, as well as improved apatite formation, iodine ion release, and antibacterial activity against Prevotella intermedia compared to NaCaThIo. Cell culture test revealed that MA-NaCaThIo exhibited no cytotoxicity against MG-63 and Vero cells, while increased cell proliferation, ALP activity and mineralization of MG-63 compared to NaCaThIo. This treated titanium is expected to be useful for the development of next-generation titanium devices having both bone-bonding and antibacterial properties.

Therapeutic efficacy of vancomycin-loaded carbon fiber-reinforced polyetheretherketone hip stem for periprosthetic joint infection: A pilot study

A carbon fiber-reinforced polyetheretherketone (CFR/PEEK) hip stem with a special antibiotic elution mechanism is under development to treat periprosthetic joint infection (PJI). The antibiotic elution characteristics of intramedullary implants were experimentally investigated, and the efficacy of revision surgery using a therapeutic stem in treating ovine PJI was examined. To evaluate elution characteristics, the intramedullary vancomycin-loaded CFR/PEEK cylindrical implants were inserted in the distal femur of nine sheep, and the vancomycin elution rate was measured at 2, 7, and 21 days. To evaluate therapeutic efficacy, the PJI model with staphylococcus aureus was attempted to create for five sheep. Moreover, the therapeutic vancomycin-loaded CFR/PEEK stem was implanted during one-stage revision surgery. Three weeks after revision surgery, the treatment efficacy was evaluated based on bacterial cultures and wound findings. In addition, the vancomycin elution rate from the stem was measured. On average, the cylindrical implants eluted approximately 70% vancomycin in 21 days. Of the five sheep attempting to create a PJI model, three were successfully infected with S. aureus as intended for verification of treatment efficacy. In all three joints, negative bacterial cultures and no purulence were observed 3 weeks after revision surgery. The vancomycin elution rates from the stems were >70%. Efficient elution of vancomycin was confirmed by the experimental implant inserted into the bone marrow and the stem in actual PJI treatment. Using a novel therapeutic stem with an antibiotic elution mechanism in one-stage revision surgery, successful treatment was demonstrated in all S. aureus-induced PJIs.

Potential side effects of antibacterial coatings in orthopaedic implants: A systematic review of clinical studies

Objective: The systematic review aimed to determine the potential side effects of antibacterial coatings in orthopaedic implants. Methods: Publications were searched in the databases of Embase, PubMed, Web of Science and Cochrane Library using predetermined keywords up to 31 October 2022. Clinical studies reporting side effects of the surface or coating materials were included. Results: A total of 23 studies (20 cohort studies and three case reports) reporting the concerns about the side effects of antibacterial coatings were identified. Three types of coating materials, silver, iodine and gentamicin were included. All of studies raised the concerns regarding safety of antibacterial coatings, and the occurrence of adverse events was observed in seven studies. The main side effect of silver coatings was the development of argyria. For iodine coatings, only one anaphylactic case was reported as an adverse event. No systemic or other general side effects were reported for gentamicin. Conclusion: Clinical studies on the side effects of antibacterial coatings were limited. Based on the available outcomes, the most reported side effects of antibacterial coatings in clinical use were argyria with silver coatings. However, researchers should always pay attention to the potential side effects of antibacterial materials, such as systematic or local toxicity and allergy.

Osteocompatibility of Si3N4-coated carbon fiber-reinforced polyetheretherketone (CFRP) and hydroxyapatite-coated CFRP with antibiotics and antithrombotic drugs

This study used a rabbit model to investigate the osteocompatibility of Si₃N₄-coated carbon fiber-reinforced polyetheretherketone (CFRP) and hydroxyapatite (HA)-coated CFRP with antibiotics (vancomycin [VCM]) and antithrombotic drugs (polyvinylpyrrolidone [PVP]). HA-coated cylindrical CFRP implants were used as the controls (HA), and HA-coated implants treated with VCM and PVP were prepared (HA-VP) as the test groups; a cylindrical CFRP coated with Si₃N₄ was also prepared (SiN). Ten implants from each group were randomly inserted into the femoral diaphysis of rabbits. The pull-out test, radiological analysis using micro-computed tomography (µ-CT), and histological analysis were performed. The pull-out strength of the SiN group was lower than that of the HA group. µ-CT analysis revealed that the amount of bone formation around the implant in the SiN group was inferior to that in the HA group. Conversely, the HA-VP group had equivalent pull-out strength and bone formation as analyzed by µ-CT compared to the HA group. In conclusion, the additional surface treatment of the HA-coated CFRP with VCM and PVP provided sufficient bone fixation and formation.

Development of Silver-Containing Hydroxyapatite-Coated Antimicrobial Implants for Orthopaedic and Spinal Surgery

The prevention of surgical site infections is directly related to the minimization of surgical invasiveness, and is in line with the concept of minimally invasive spine therapy (MIST). In recent years, the incidence of postoperative infections has been increasing due to the increased use of spinal implant surgery in patients at high risk of infection, including the elderly and easily infected hosts, the limitations of poor bone marrow transfer of antibiotics, and the potential for contamination of surgical gloves and instruments. Thus, the development of antimicrobial implants in orthopedic and spinal surgery is becoming more and more popular, and implants with proven antimicrobial, safety, and osteoconductive properties (i.e., silver, iodine, antibiotics) in vitro, in vivo, and in clinical trials have become available for clinical use. We have developed silver-containing hydroxyapatite (Ag-HA)-coated implants to prevent post-operative infection, and increase bone fusion capacity, and have successfully commercialized antibacterial implants for hip prostheses and spinal interbody cages. This narrative review overviews the present status of available surface coating technologies and materials; describes how the antimicrobial, safety, and biocompatibility (osteoconductivity) of Ag-HA-coated implants have been demonstrated for commercialization; and reviews the clinical use of antimicrobial implants in orthopedic and spinal surgery, including Ag-HA-coated implants that we have developed.

Megaprosthesis anti-bacterial coatings: A comprehensive translational review

Periprosthetic joint infections (PJI) are catastrophic complications for patients with implanted megaprostheses and pose significant challenges in the management of orthopaedic oncology patients. Despite various preventative strategies, with the increasing rate of implanted orthopaedic prostheses, the number of PJIs may be increasing. PJIs are associated with a high rate of amputation. Therefore, novel strategies to combat bacterial colonization and biofilm formation are required. A promising strategy is the utilization of anti-bacterial coatings on megaprosthetic implants. In this translational review, a brief overview of the mechanism of bacterial colonization of implants and biofilm formation will be provided, followed by a discussion and classification of major anti-bacterial coatings currently in use and development. In addition, current in vitro outcomes, clinical significance, economic importance, evolutionary perspectives, and future directions of anti-bacterial coatings will also be discussed. Megaprosthetic anti-bacterial coating strategies will help reduce infection rates following the implantation of megaprostheses and would positively impact sarcoma care. STATEMENT OF SIGNIFICANCE: This review highlights the clinical challenges and a multitude of potential solutions to combating peri-prosthetic join infections in megaprotheses using anti-bacterial coatings. Reducing infection rates following the implantation of megaprostheses would have a major impact on sarcoma care and major trauma surgeries that require reconstruction of large skeletal defects.

Multifunctional Coatings of Titanium Implants Toward Promoting Osseointegration and Preventing Infection: Recent Developments

Titanium and its alloys are dominant material for orthopedic/dental implants due to their stable chemical properties and good biocompatibility. However, aseptic loosening and peri-implant infection remain problems that may lead to implant removal eventually. The ideal orthopedic implant should possess both osteogenic and antibacterial properties and do proper assistance to in situ inflammatory cells for anti-microbe and tissue repair. Recent advances in surface modification have provided various strategies to procure the harmonious relationship between implant and its microenvironment. In this review, we provide an overview of the latest strategies to endow titanium implants with bio-function and anti-infection properties. We state the methods they use to preparing these efficient surfaces and offer further insight into the interaction between these devices and the local biological environment. Finally, we discuss the unmet needs and current challenges in the development of ideal materials for bone implantation.

A long-term experience with Mutars tumor megaprostheses: analysis of 187 cases

PURPOSE

Modular megaprostheses have widely replaced allografts, as a reconstructive option; however, failures of these devices remain high. Aim of this study was to analyze outcomes, survival of the implants, incidence and types of complications with Mutars modular endoprostheses at long term.

METHODS

Between 2000 and 2019, 187 Mutars prostheses were implanted in two dedicated centers: 72 upper limbs and 115 lower limbs reconstructions. Diagnoses included 107 primary malignant bone or soft tissue tumors, 65 metastases, 8 benign bone tumors and 7 non-oncologic cases. Silver-coated prostheses were used in 118/187 (63%) cases.

RESULTS

At last follow-up, 76.5% of patients had retained their implant. The overall failure rate was 23.5% at a mean of 1.7 years. There were 22 mechanical failures and 22 non-mechanical failures. The overall implant survival to all types of failure was 68% and 52% at 5 and 10 years, respectively. Infection was the most common mode of failure with an incidence of 6.9%. Implant survival to infection was better for silver-coated implants than for standard implants even if with no significant difference (p = 0.56). Functional results were satisfactory in 97% of patients.

CONCLUSIONS

The overall implant survival at long term was satisfactory with Mutars prostheses. The incidence of complications with Mutars prosthesis is in line with the incidence reported in the literature with other types of tumor prosthesis. The most frequent cause of failure was infection with a lower incidence in silver-coated prostheses; silver coating seems to prevent infection in distal femur and proximal tibia. The silver coating seems to be particularly useful in two-stage revisions with a lower incidence of secondary amputation. In higher risk patients, silver-coated prostheses are the preferable choice for the reduction of the reinfection rate. The functional results of Mutars prostheses were excellent or good in most of cases. The current paper is design to enhance the literature on megaprosthesis in tumor surgery, proven that this system is one of the most used all over the word and one of the best performing.

Biomaterials and technologies in the management of periprosthetic infection after total hip arthroplasty: An updated review

Although total hip arthroplasty (THA) is considered one of the most efficacious procedures for managing various hip conditions, failures due to different mechanisms are still being reported. Periprosthetic joint infection (PJI) is one of the devastating causes of failure and revision of THA. PJI carries a burden on the patient, the surgeon, and the health-care system. The diagnosis and management of PJIs carry many morbidities and increased treatment costs. The development of PJI is multifactorial, including issues related to the patient’s general condition, the surgeon’s efficiency, surgical technique, and the implants used. Recent advances in the area of diagnosis and predicting PJI as well as introducing new technologies and biomaterials update for the prevention and treatment of PJI. Local implant coatings, advancement in the bearing surfaces technologies, and new technologies such as immunotherapy and bacteriophage therapy were introduced and suggested as contemporary PJI eradication solutions. In this review, we aimed at discussing some of the newly introduced materials and technologies for the sake of PJI control.

Antibacterial Activity in Iodine-coated Implants Under Conditions of Iodine Loss: Study in a Rat Model Plus In Vitro Analysis

BACKGROUND

We developed iodine-coated titanium implants to suppress microbial activity and prevent periprosthetic joint infection (PJI); their efficacy was demonstrated in animal and in vitro models. The iodine content in iodine-coated implants naturally decreases in vivo. However, to our knowledge, the effect of reduced iodine content on the implant's antimicrobial activity has not been evaluated to date.

QUESTIONS/PURPOSES

(1) How much does the iodine content on the implant surface decrease after 4 and 8 weeks in vivo in a rat model? (2) What effect does the reduced iodine content have on the antimicrobial effect of the implant against multiple bacteria in an in vitro model?

METHODS

This experiment was performed in two parts: an in vivo experiment to determine attenuation of iodine levels over time in rats, and an in vitro experiment in which we sought to assess whether the reduced iodine content observed in the in vivo experiment was still sufficient to deliver antimicrobial activity against common pathogens seen in PJI. For the in vivo experiment, three types of titanium alloy washers were implanted in rats: untreated (Ti), surface-anodized to produce an oxide film (Ti-O), and with an iodine layer on the oxidation film (Ti-I). The attenuation of iodine levels in rats was measured over time using inductively coupled plasma-mass spectrometry. Herein, only the Ti-I washer was used, with five implanted in each rat that were removed after 4 or 8 weeks. For the 4- and 8-week models, two rats and 15 washers were used. For the in vitro study, to determine the antibacterial effect, three types of washers (Ti, Ti-O, and Ti-I) (nine washers in total) were implanted in each rat. Then, the washers were removed and the antibacterial effect of each washer was examined on multiple bacterial species using the spread plate method and fluorescence microscopy. For the spread plate method, six rats were used, and five rats were used for the observation using fluorescence microscopy; further, 4- and 8-week models were made for each method. Thus, a total of 22 rats and 198 washers were used. Live and dead bacteria in the biofilm were stained, and the biofilm coverage percentage for quantitative analysis was determined using fluorescence microscopy in a nonblinded manner. Ti-I was used as the experimental group, and Ti and Ti-O were used as control groups. The total number of rats and washers used throughout this study was 24 and 213, respectively.

RESULTS

Iodine content in rats implanted with Ti-I samples decreased to 72% and 65% after the in vivo period of 4 and 8 weeks, respectively (p = 0.001 and p < 0.001, respectively). In the in vitro experiment, the Ti-I implants demonstrated a stronger antimicrobial activity than Ti and Ti-O implants in the 4- and 8-week models. Both the median number of bacterial colonies and the median biofilm coverage percentage with live bacteria on Ti-I were lower than those on Ti or Ti-O implants for each bacterial species in the 4- and 8-week models. There was no difference in the median biofilm coverage percentage of dead bacteria. In the 8-week model, the antibacterial activity using the spread plate method had median (interquartile range) numbers of bacteria on the Ti, Ti-O, and Ti-I implants of 112 (104 to 165) × 105, 147 (111 to 162) × 105, and 55 (37 to 67) × 105 of methicillin-sensitive Staphylococcus aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.009); 71 (39 to 111) × 105, 50 (44 to 62) × 105, and 26 (9 to 31)× 105 CFU of methicillin-resistant S. aureus (Ti-I versus Ti, p = 0.026; Ti-I versus Ti-O, p = 0.034); and 77 (74 to 83) × 106, 111 (95 to 117) × 106, and 30 (21 to 45) × 106 CFU of Pseudomonas aeruginosa (Ti-I versus Ti, p = 0.004; Ti-I versus Ti-O, p = 0.009). Despite the decrease in the iodine content of Ti-I after 8 weeks, it demonstrated better antibacterial activity against all tested bacteria than the Ti and Ti-O implants.

CONCLUSION

Iodine-coated implants retained their iodine content and antibacterial activity against methicillin-sensitive S. aureus, methicillin-resistant S. aureus, and P. aeruginosa for 8 weeks in vivo in rats. To evaluate the longer-lasting antibacterial efficacy, further research using larger infected animal PJI models with implants in the joints of both males and females is desirable.

CLINICAL RELEVANCE

Iodine-coated titanium implants displayed an antibacterial activity for 8 weeks in rats in vivo. Although the findings in a rat model do not guarantee efficacy in humans, they represent an important step toward clinical application.

The feasibility of iodine-supported processing for titanium with different surfaces

BACKGROUND

The reduction of microbial infections can substantially improve the success of implant surgery. The iodine-supported implants that were developed by us for infection prevention were featured at the recent International Consensus Meeting on Musculoskeletal Infection and were partly incorporated into the consensus guidelines. For future clinical application, we examined (1) whether iodine can be added to metals with different surface roughness, (2) differences in surface roughness before and after processing, and (3) the effect of sterilization on the iodine content.

METHODS

Four Ti-6Al-4V metals were prepared with different surface roughness values by polishing, blasting and plasma spraying. Before and after processing, the surface structure of metals was observed using a scanning electron microscope and stylus instruments. Before and after sterilization, iodine contents were measured by X-ray fluorescence spectroscopy.

RESULTS

After processing, sufficient iodine contents with an antimicrobial effect were detected for each metal. These iodine contents decreased after sterilization but were higher than the lowest content of iodine observed to have an antimicrobial effect in a previous study, indicating that the antimicrobial effect persists even after sterilization. After processing, surface roughness was greater for polishing metal. With general surface processing, iodine processing was possible.

CONCLUSIONS

Our results indicated that surface roughness is affected by the processing method and that the iodine content should be set according to the sterilization method. Considering these factors, iodine processing can be used for clinical applications.

A comparison of bone conductivity on titanium screws inserted into the vertebra using different surface processing

PURPOSE

Antibacterial iodine-supported titanium has an anodized oxide layer; thus, it can be expected to have a higher osteoconductivity than untreated titanium. This study aimed to compare the osteoconductivity between untreated titanium (Ti), anodically oxidized titanium (AO-Ti), and iodine-supported titanium (I-Ti) screws.

METHODS

The screws were inserted into the vertebral bodies of 30 dogs (12 for the biomechanical, and 18 for the histological examination). The vertebral bodies were analyzed at 4 or 8 weeks after screw insertion. Biomechanically, rotational torque of the screw was measured. Histologically, bone formation index (ratio of the length of the part where the bone directly contacts with the length of the screw) and bone volume density (ratio of the area of the bone tissue to the area between the threads of the screw) were measured.

RESULT

At 4 weeks, the torque value was significantly higher in the AO-Ti (0.59 ± 0.16 Nm) and I-Ti (0.72 ± 0.14 Nm) groups than in the Ti group (0.39 ± 0.12 Nm), with the AO-Ti and I-Ti groups showing no significant difference. Bone formation index was significantly higher in the AO-Ti (72.5% ± 0.8%) and I-Ti (73.4% ± 1.5%) groups than in the Ti group (64.6% ±1.7%), with the AO-Ti and I-Ti groups showing no significant difference. Bone volume density did not show a significant difference. At 8 weeks, the results were similar to those at 4 weeks.

CONCLUSIONS

I-Ti had a higher osteoconductivity than Ti, indicating that iodine coating did not adversely affect osteoconductivity.

Antibacterial Activity of Ag-Hydroxyapatite Coating Against Hematogenous Infection by Methicillin-Resistant Staphylococcus aureus in the Rat Femur

Several antibacterial materials have been developed to prevent periprosthetic joint infection and thus prevent serious complications for patients and surgeons. However, no study has addressed the activity of antibacterial materials against hematogenous infection. The present study evaluated the antibacterial activity of a silver-containing hydroxyapatite-coated implant against methicillin-resistant Staphylococcus aureus (MRSA) hematogenous infection. Implants coated with hydroxyapatite and silver-hydroxyapatite were inserted into rats' right and left femurs, respectively, after which the animals were infected with S. aureus via a tail vessel. About 10⁷ colony-forming units was the optimal bacterial number for the establishment of S. aureus hematogenous infection. Bacterial loads and C-reactive protein in the blood were measured to confirm bacteremia and inflammation. Fourteen days after the infection, bacterial loads were statistically lower in the femurs containing silver-hydroxyapatite-coated implants than in those with hydroxyapatite-coated implants (p = 0.022). Thus, silver-hydroxyapatite-coated implants might provide antibacterial activity against MRSA hematogenous infection in the postoperative period. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2655-2660, 2019.

Is surface modification effective to prevent periprosthetic joint infection? A systematic review of preclinical and clinical studies

BACKGROUND

With increasing recognition of the importance of biofilm formation in the pathogenesis of periprosthetic joint infection (PJI), a push towards finding solutions to prevent PJI via surface modification of prostheses is occurring. Unlike the promising in vitro antimicrobial effects of these surface modifications, the preclinical and clinical prophylactic effects vary and are debated. Therefore, we performed this systematic review to answer: (1) what kinds of methods of surface modification are used in preclinical and clinical studies to prevent PJI, (2) whether these modifications are effective to prevent PJI.

METHODS

Electronic searches were performed using PubMed, Embase and the Cochrane library databases up to and including December 2017 with predetermined criteria: (1) in vivo studies with (2) surface modification for prophylactic effects against infection. Both animal studies and clinical trials were included. Data were extracted and presented systematically.

RESULTS

Overall, 21 studies were included. Among these, fourteen were carried out in animal models and seven were clinical studies. In the animal studies, six used antibiotics and six silver modifications, while copper and Cationic Steroidal Antimicrobial-13 were each used for one study. In the seven clinical studies targeting patients with high infection risk, five of them focused on silver-coated prostheses and the remaining two studied iodine-coated implants. In all of the animal studies, when compared with the control group, the surface modified groups had a lower infection risk (RR ranging from 0 to 0.71). Clinical studies using silver-coated prostheses also demonstrated a lower infection risk (RR ranging from 0.24 to 0.70), while iodine-coated implants showed a 0% and 5% incidence of PJI in the two case series included.

DISCUSSION

The results from the publications included in this review indicate that surface modification, especially antibiotic and silver modifications, are helpful preventing PJI in both preclinical animal models and in clinical trials.

LEVEL OF EVIDENCE

III, systematic review of level III retrospective comparative studies and level IV case series and animal experiments.

Bone ongrowth of a cementless silver oxide-containing hydroxyapatite-coated antibacterial acetabular socket

BACKGROUND

The silver oxide-containing hydroxyapatite-coated socket (KYOCERA, Osaka, Japan) is a cementless antibacterial implant that has both the osteoconductivity of the HA and the antibacterial activity of silver. The silver oxide-containing hydroxyapatite coating was shown to have good osteoconductivity and new bone formation in vitro and in vivo. However, the histological bone ongrowth of this implant has not been proven in a clinical study.

METHODS

We analyzed bone ongrowth using two silver oxide-containing hydroxyapatite-coated sockets that were removed in revision total hip arthroplasty for recurrent dislocation. A histomorphometric analysis was performed using a scanning electron microscope (SEM) connected to a CCD camera and an elemental analysis was performed by energy-dispersive elemental spectrometry (EDS).

RESULT

A white structure thought to be osseous tissue was attached to the retrieved socket surface macroscopically, and histological bone ongrowth of the silver oxide-containing hydroxyapatite coating of the socket was confirmed by SEM. In addition, the presence of silver in the silver oxide-containing hydroxyapatite coating was confirmed in an elemental analysis by EDS.

CONCLUSION

Histologically, the silver oxide-containing hydroxyapatite-coated socket presented bone ongrowth in this clinical study.

Antibacterial coating of implants: are we missing something?

Implant-related infection is one of the leading reasons for failure in orthopaedics and trauma, and results in high social and economic costs. Various antibacterial coating technologies have proven to be safe and effective both in preclinical and clinical studies, with post-surgical implant-related infections reduced by 90% in some cases, depending on the type of coating and experimental setup used. Economic assessment may enable the cost-to-benefit profile of any given antibacterial coating to be defined, based on the expected infection rate with and without the coating, the cost of the infection management, and the cost of the coating. After reviewing the latest evidence on the available antibacterial coatings, we quantified the impact caused by delaying their large-scale application. Considering only joint arthroplasties, our calculations indicated that for an antibacterial coating, with a final user's cost price of €600 and able to reduce post-surgical infection by 80%, each year of delay to its large-scale application would cause an estimated 35 200 new cases of post-surgical infection in Europe, equating to additional hospital costs of approximately €440 million per year. An adequate reimbursement policy for antibacterial coatings may benefit patients, healthcare systems, and related research, as could faster and more affordable regulatory pathways for the technologies still in the pipeline. This could significantly reduce the social and economic burden of implant-related infections in orthopaedics and trauma. Cite this article: C. L. Romanò, H. Tsuchiya, I. Morelli, A. G. Battaglia, L. Drago. Antibacterial coating of implants: are we missing something? Bone Joint Res 2019;8:199-206. DOI: 10.1302/2046-3758.85.BJR-2018-0316.

2018 international consensus meeting on musculoskeletal infection: Summary from the biofilm workgroup and consensus on biofilm related musculoskeletal infections

Biofilm-associated implant-related bone and joint infections are clinically important due to the extensive morbidity, cost of care and socioeconomic burden that they cause. Research in the field of biofilms has expanded in the past two decades, however, there is still an immense knowledge gap related to many clinical challenges of these biofilm-associated infections. This subject was assigned to the Biofilm Workgroup during the second International Consensus Meeting on Musculoskeletal Infection held in Philadelphia USA (ICM 2018) (https://icmphilly.com). The main objective of the Biofilm Workgroup was to prepare a consensus document based on a review of the literature, prepared responses, discussion, and vote on thirteen biofilm related questions. The Workgroup commenced discussing and refining responses prepared before the meeting on day one using Delphi methodology, followed by a tally of responses using an anonymized voting system on the second day of ICM 2018. The Working group derived consensus on information about biofilms deemed relevant to clinical practice, pertaining to: (1) surface modifications to prevent/inhibit biofilm formation; (2) therapies to prevent and treat biofilm infections; (3) polymicrobial biofilms; (4) diagnostics to detect active and dormant biofilm in patients; (5) methods to establish minimal biofilm eradication concentration for biofilm bacteria; and (6) novel anti-infectives that are effective against biofilm bacteria. It was also noted that biomedical research funding agencies and the pharmaceutical industry should recognize these areas as priorities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

[Local antibiotic therapy]

The treatment of superficial wound infections with local antibiotics is considered to be problematic as it is accompanied by an increased risk of resistance development and ineffectiveness in deeper regions. On the contrary, the local application of antibiotics is useful in arthroplasty and necessary if implants are utilized. The reason for this is the prevention of a rapid biofilm formation on foreign implants and a resulting infection may remain undiscovered until it becomes chronic. Apart from exogenous material, necrotic tissue (e. g. bone sequestra) provides suitable retreat areas for pathogens in the body. Because of the characteristics of bone and joint infections and an exceptional infection recurrence rate, a combined approach is required. Systemic antibiotic prophylaxis is able to reduce the number of pathogens acquired by perioperative contamination or hematogenic spread from another focus of infection; however, systemically applied antibiotics often fail to form an effective colonization barrier around the implant because their ability to penetrate the bone is relatively low. On the other hand, the high concentration of locally released antibiotics leads to an effective protection of the implant from bacteria in situ. Thus, for the treatment of implant-associated infections, systemic and local application of anti-infective agents is a reliable adjuvant measure that improves the therapeutic success. Polymethylmethacrylate (PMMA) bone cement is the most commonly used local drug carrier. Based on clinical and microbiological results, microbiologists and infectious disease experts together with the surgeon and pharmacist determine which anti-infective agents are indicated for systemic and local, PMMA cement-related application. Because there is no evident concept for the local application, unlike the recommendation for systemic use of anti-infective agents, this review article describes which aspects should be taken into account.

In vitroantibacterial activity of oxide and non-oxide bioceramics for arthroplastic devices: I.In situtime-lapse Raman spectroscopy

Raman spectroscopy proved why the antibacterial response of non-oxide Si₃N₄bioceramic is superior to those of alumina-based oxide bioceramics.