Prosthetic joint infection

Bone and Joint Infection Involving Corynebacterium spp.: From Clinical Features to Pathophysiological Pathways

Introduction: Corynebacteria represent often-neglected etiological agents of post-traumatic and/or post-operative bone and joint infection (BJI). We describe here clinical characteristics and bacteriological determinants of this condition. Methods: A retrospective cohort study described characteristics, outcome and determinants of treatment failure of all patients with proven Corynebacterium spp. BJI (i.e., ≥2 culture-positive gold-standard samples). Available strains were further characterized regarding their antibiotic susceptibilies, abilities to form early (BioFilm Ring Test®) and mature (crystal violet staining method) biofilms and to invade osteoblasts (gentamicin protection assay). Results: The 51 included BJI were mostly chronic (88.2%), orthopedic device-related (74.5%) and polymicrobial (78.4%). After a follow-up of 60.7 weeks (IQR, 30.1-115.1), 20 (39.2%) treatment failures were observed, including 4 Corynebacterium-documented relapses, mostly associated with non-optimal surgical management (OR 7.291; p = 0.039). Internalization rate within MG63 human osteoblasts was higher for strains isolated from delayed (>3 months) BJI (p < 0.001). Infection of murine osteoblasts deleted for the β1-integrin resulted in a drastic reduction in the internalization rate. No difference was observed regarding biofilm formation. Conclusions: Surgical management plays a crucial role in outcome of BJI involving corynebacteria, as often chronic and device-associated infections. Sanctuarisation within osteoblasts, implicating the β1 cellular integrin, may represent a pivotal virulence factor associated with BJI chronicity.

The EBJIS definition of periprosthetic joint infection

Aims

The diagnosis of periprosthetic joint infection (PJI) can be difficult. All current diagnostic tests have problems with accuracy and interpretation of results. Many new tests have been proposed, but there is no consensus on the place of many of these in the diagnostic pathway. Previous attempts to develop a definition of PJI have not been universally accepted and there remains no reference standard definition.

Methods

This paper reports the outcome of a project developed by the European Bone and Joint Infection Society (EBJIS), and supported by the Musculoskeletal Infection Society (MSIS) and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Implant-Associated Infections (ESGIAI). It comprised a comprehensive review of the literature, open discussion with Society members and conference delegates, and an expert panel assessment of the results to produce the final guidance.

Results

This process evolved a three-level approach to the diagnostic continuum, resulting in a definition set and guidance, which has been fully endorsed by EBJIS, MSIS, and ESGIAI.

Conclusion

The definition presents a novel three-level approach to diagnosis, based on the most robust evidence, which will be useful to clinicians in daily practice.

Cite this article: Bone Joint J 2021;103-B(1):18–25.

Rifampin, Rifapentine, and Rifabutin Are Active against Intracellular Periprosthetic Joint Infection-Associated Staphylococcus epidermidis

Staphylococcus epidermidis is a major cause of periprosthetic joint infection (PJI); its intracellular persistence within osteoblasts may compromise therapy if that therapy is not intracellularly active. The intracellular activity of rifampin, rifapentine, and rifabutin was assessed against five rifampin-susceptible and two rifampin-resistant S. epidermidis isolates. Compared to no treatment, treatment resulted in a ≥2-fold log₁₀ reduction of intracellular rifampin-susceptible, but not rifampin-resistant, S. epidermidis These findings show activity of rifampin, rifapentine, and rifabutin against intraosteoblast PJI-associated S. epidermidis.

Incisionless Synovium and Bone Biopsy of a Painful Total Knee Arthroplasty

Knee arthroscopy has evolved greatly from its inception in the 20th century. Arthroscopic synovectomy is performed in the case of infection or significant synovitis. We continue to develop more minimally invasive procedures, and the NanoScope (Arthrex, Naples, FL) has provided a new generation of possibilities. The system does not require the use of a standard incision or portal, and using the GraftNet (Arthrex), we can harvest tissue with a standard shaver for further evaluation. This technique provides an option to perform a synovial and bone biopsy in a painful total knee arthroplasty without the use of standard arthroscopy portals through an incisionless approach. This technique provides distinct advantages over a more open approach in the setting of a prosthetic joint. Specifically, this technique is useful for a difficult-to-diagnose painful total knee arthroplasty.

Microbiological pattern of prosthetic hip and knee infections: a high-volume, single-centre experience in China

Introduction. Prosthetic joint infection (PJI) is a serious complication after arthroplasty, which results in high morbidity, prolonged treatment and considerable healthcare expenses in the absence of accurate diagnosis. In China, microbiological data on PJIs are still scarce.Hypothesis/Gap Statement. The incidence of PJI is increasing year by year, and the proportion of drug-resistant bacteria infection is nicreasing, which brings severe challenges to the treatment of infection.Aim. This study aimed to identify the pathogens in PJIs, multi-drug resistance, and evaluate the effect of the treatment regimen in patients with PJI.Methodology. A total of 366 consecutive cases of PJI in the hip or knee joint were admitted at the Orthopedic Surgery Center in Zhengzhou, China from January 2012 to December 2018. Infections were confirmed in accordance with the Infectious Diseases Society of America and the Musculoskeletal Infection Society (MSIS) criteria. Concurrently, patient demographic data, incidence and antibiotic resistance were investigated. Statistical differences were analysed using Fisher's exact test or chi-square test.Results. Altogether, 318 PJI cases satisfying the inclusion criteria were enrolled in this study, including 148 with hip PJIs and 170 with knee PJIs. The average age of patients with hip PJIs was lesser than that of patients with knee PJIs (56.4 vs. 68.6 years). Meanwhile, coagulase-negative staphylococcus (CNS, n=81, 25.5 %) was the predominant causative pathogen, followed by Staphylococcus aureus (n=67, 21.1 %). Methicillin-resistant Staphylococcus (MRS) was identified in 28.9 % of PJI patients. In addition, fungus accounted for 4.8 % (n=15), non-tuberculosis mycobacterium accounted for 1.6 % (n=5), polymicrobial pathogens accounted for 21.7 % (n=69), and Gram-negative bacteria accounted for 7.9 % (n=25) of the total infections. The results of antibiotic susceptibility testing showed that gentamicin and clindamycin β-lactam antibiotics were poorly susceptible to Gram-positive isolates, but they were sensitive to rifampicin, linezolid and vancomycin. While antibiotics such as amikacin and imipenem were effective against Gram-negative bacteria, there was a high resistance rate of other pathogens to gentamicin, clindamycin and some quinolone antibacterial drugs. Empirical antibiotic treatment should combine vancomycin and cephalosporin, levofloxacin or clindamycin. When the pathogen is confirmed, the treatment should be individualized.Conclusions. The prevalence of culture-negative PJIs is still very high. Gram-positive bacteria are still the main type of pathogens that cause PJIs. Attention should be paid to the high incidence of MRS, such as MRSA and MR-CNS, among PJI patients. Empirical antibiotic treatment should cover Gram-positive isolates, especially Staphylococcus.

Comparison of two fluorescent probes in preclinical non-invasive imaging and image-guided debridement surgery of Staphylococcal biofilm implant infections

Implant-associated infections are challenging to diagnose and treat. Fluorescent probes have been heralded as a technologic advancement that can improve our ability to non-invasively identify infecting organisms, as well as guide the inexact procedure of surgical debridement. This study’s purpose was to compare two fluorescent probes for their ability to localize Staphylococcus aureus biofilm infections on spinal implants utilizing noninvasive optical imaging, then assessing the broader applicability of the more successful probe in other infection animal models. This was followed by real-time, fluorescence image-guided surgery to facilitate debridement of infected tissue. The two probe candidates, a labelled antibiotic that targets peptidoglycan (Vanco-800CW), and the other, a labelled antibody targeting the immunodominant Staphylococcal antigen A (1D9-680), were injected into mice with spine implant infections. Mice were then imaged noninvasively with near infrared fluorescent imaging at wavelengths corresponding to the two probe candidates. Both probes localized to the infection, with the 1D9-680 probe showing greater fidelity over time. The 1D9-680 probe was then tested in mouse models of shoulder implant and allograft infection, demonstrating its broader applicability. Finally, an image-guided surgery system which superimposes fluorescent signals over analog, real-time, tissue images was employed to facilitate debridement of fluorescent-labelled bacteria.

Bacteriological and mechanical impact of the Sterrad sterilization method on personalized 3D printed guides for mandibular reconstruction

Surgical cutting guides are increasingly used for maxillofacial reconstruction. They are usually provided by laboratories. In recent years, surgical teams have published studies on the possibility of manufacturing their own cutting guides thanks to 3D printers. The object of this study is to analyze the impact of the sterilization on the surface of those personalized models and to assess the effectiveness of sterilization. Using the data from high-resolution CT scan of patient, 3D models were generated through computerized assisted design and fabricated with a 3D printer using Acrylonitrile Butadiene Styrene (ABS). For the sterilization, a Sterrad method was used. In order to evaluate the effectiveness of sterilization, 3D models were artificially contaminated with several bacterial reference strains, sterilized and finally cultured. The surfaces and mechanical modifications were analyzed before and after sterilization with infrared spectrometry, surface contact angle, extensometer, scanning electron microscopy and atomic force microscopy. Ten models of different shapes and 24 samples were fabricated, sterilized and analyzed. The 3D models were designed in 48 h, printed in an average of 122 min and underwent a 47 min cycle of sterilization. All experimentally contaminated 3D models were negative in culture, with at least, a six log reduction of the initial inoculum. The hydrophobicity and roughness of the surface suffered few changes. The reproducibility of this procedure was proved by identical results in the three sterilization rounds. Using Sterrad process for the sterilization of ABS printed material doesn’t represent a bacterial risk for the patient. It is a feasible and safe innovative reconstructive method that can save time particularly for oncological cases.

Sampling challenges in diagnosis of chronic bacterial infections

In recent decades there has been an increase in knowledge of the distribution, species diversity and growth patterns of bacteria in human chronic infections. This has challenged standard diagnostic methods, which have undergone a development to both increase the accuracy of testing as well as to decrease the occurrence of contamination. In particular, the introduction of new technologies based on molecular techniques into the clinical diagnostic process has increased detection and identification of infectious pathogens. Sampling is the first step in the diagnostic process, making it crucial for obtaining a successful outcome. However, sampling methods have not developed at the same speed as molecular identification. The heterogeneous distribution and potentially small number of pathogenic bacterial cells in chronic infected tissue makes sampling a complicated task, and samples must be collected judiciously and handled with care. Clinical sampling is a step in the diagnostic process that may benefit from innovative methods based on current knowledge of bacteria present in chronic infections. In the present review, we describe and discuss different aspects that complicate sampling of chronic infections. The purpose is to survey representative scientific work investigating the presence and distribution of bacteria in chronic infections in relation to various clinical sampling methods.

Combined Techniques of Non-invasive 99mTc-Besilesomab/99mTc-Sulfur Colloid with Hybrid SPECT/CT Imaging in Characterising Cellulitis from Symptomatic Perimegaprosthetic Infection: A Case Report

Megaprosthesis is used to restore the form and function of massive skeletal defects, but it is accompanied by risks of failure, mainly due to perimegaprosthetic infection (PMI). In practice, the diagnosis of infected megaprosthesis among patients with a high index of clinical suspicion, elevated serological markers, and multiple negative or inconclusive imaging can be very challenging and poses a diagnostic conundrum to many orthopaedic surgeons. We present the case of a symptomatic 26-year-old female with large B-cell lymphoma who developed cellulitis with suspected complication of PMI 15 months post-implantation. The combination of advanced nuclear medicine imaging strategies, i.e., ^99mTc-besilesomab/^99mTc-sulfur colloid scintigraphy with hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) scanning helps to characterise and delineate both infections. Invasive procedures such as joint aspiration and biopsy were avoided, and the patient was successfully treated with antibiotics. Hence, we report a case where advanced imaging modalities were decisive in the investigation of PMI.

Nanotheranostics: A Possible Solution for Drug-Resistant Staphylococcus aureus and their Biofilms?

Staphylococcus aureus is a notorious pathogen that colonizes implants (orthopedic and breast implants) and wounds with a vicious resistance to antibiotic therapy. Methicillin-resistant S. aureus (MRSA) is a catastrophe mainly restricted to hospitals and emerged to community reservoirs, acquiring resistance and forming biofilms. Treating biofilms is problematic except via implant removal or wound debridement. Nanoparticles (NPs) and nanofibers could combat superbugs and biofilms and rapidly diagnose MRSA. Nanotheranostics combine diagnostics and therapeutics into a single agent. This comprehensive review is interpretative, utilizing mainly recent literature (since 2016) besides the older remarkable studies sourced via Google Scholar and PubMed. We unravel the molecular S. aureus resistance and complex biofilm. The diagnostic properties and detailed antibacterial and antibiofilm NP mechanisms are elucidated in exciting stories. We highlight the challenges of bacterial infections nanotheranostics. Finally, we discuss the literature and provide "three action appraisals". (i) The first appraisal consists of preventive actions (two wings), avoiding unnecessary hospital visits, hand hygiene, and legislations against over-the-counter antibiotics as the general preventive wing. Our second recommended preventive wing includes preventing the adverse side effects of the NPs from resistance and toxicity by establishing standard testing procedures. These standard procedures should provide breakpoints of bacteria's susceptibility to NPs and a thorough toxicological examination of every single batch of synthesized NPs. (ii) The second appraisal includes theranostic actions, using nanotheranostics to diagnose and treat MRSA, such as what we call "multifunctional theranostic nanofibers. (iii) The third action appraisal consists of collaborative actions.

New developments in anti-biofilm intervention towards effective management of orthopedic device related infections (ODRI's)

Orthopedic device related infections (ODRI's) represent a difficult to treat situation owing to their biofilm based nature. Biofilm infections once established are difficult to eradicate even with an aggressive treatment regimen due to their recalcitrance towards antibiotics and immune attack. The involvement of antibiotic resistant pathogens as the etiological agent further worsens the overall clinical picture, pressing on the need to look into alternative treatment strategies. The present review highlightes the microbiological challenges associated with treatment of ODRI's due to biofilm formation on the implant surface. Further, it details the newer anti-infective modalities that work either by preventing biofilm formation and/or through effective disruption of the mature biofilms formed on the medical implant. The study, therefore aims to provide a comprehensive insight into the newer anti-biofilm interventions (non-antibiotic approaches) and a better understanding of their mechanism of action essential for improved management of orthopedic implant infections.

Gout in primary total knee arthroplasty: Prevalent but not independently associated with complications

BACKGROUND

Gout is a common synovial pathology, but its prevalence in patients undergoing total knee arthroplasty (TKA) and potential association with complications such as periprosthetic infection (PJI) and revision are unknown.

METHODS

Medicare data from 2009 to 2013 was retrospectively reviewed using PearlDiver. All patients 65 years of age or older and undergoing primary TKA with at least 3 years of pre-TKA records were included. The prevalence of gout was based on ICD-9 codes. Univariable associations of gout with PJI and revision at 1 year were assessed using odds ratios with 95% confidence intrervals (C.I.). To control for potential confounding, patients with a history of gout were matched on age, gender, smoking history, and Elixhauser Comorbidity Index (ECI) to patients without gout and associations reassessed.

RESULTS

The prevalence of gout in Medicare patients undergoing primary TKA was 5.7%. On univariable analysis, patients with a history of gout were more likely to develop PJI (O.R., 1.58; 95% C.I., 1.45-1.72) and undergo revision (O.R., 1.33; 95% C.I., 1.25-1.41) at 1 year. After matching for confounders, a history of gout was no longer associated with developing PJI (O.R., 0.98; 95% C.I., 0.90-1.06) or undergoing revision (O.R., 0.94; 95% C.I., 0.89-1.00) at 1 year.

CONCLUSIONS

Gout is a relatively common pathology in patients undergoing TKA. While gout is associated with increased complications, this appears to be driven by confounding through its association with other medical comorbidities. Gout does not appear to be an independent risk factor for complications following TKA.

The AO trauma CPP bone infection registry: Epidemiology and outcomes of Staphylococcus aureus bone infection

Bone infection represents a serious complication of orthopedic surgery and Staphylococcus aureus is the most common pathogen. To improve the understanding of host-pathogen interaction, we developed a biospecimen registry (AO Trauma CPP Bone Infection Registry) to collect clinical data, bacterial isolates, and serum from patients with S. aureus bone infection. A prospective multinational registry with a 12-month follow-up was created to include adult patients (18 years or older) with culture-confirmed S. aureus infection in long bones after fracture fixation or arthroplasty. Baseline patient attributes and details on infections and treatments were recorded. Blood and serum samples were obtained at baseline, 6, and 12 months. Patient-reported outcomes were collected at 1, 6, and 12 months. Clinical outcomes were recorded. Two hundred and ninety-two patients with fracture-related infection (n = 157, 53.8%), prosthetic joint infection (n = 86, 29.5%), and osteomyelitis (n = 49, 16.8%) were enrolled. Methicillin-resistant S. aureus was detected in 82 patients (28.4%), with the highest proportion found among patients from North American sites (n = 39, 48.8%) and the lowest from Central European sites (n = 18, 12.2%). Patient outcomes improved at 6 and 12 months in comparison to baseline. The SF-36 physical component summary mean (95% confidence interval) score, however, did not reach 50 at 12 months. The cure rate at the end of the study period was 62.1%. Although patients improved with treatment, less than two-thirds were cured in 1 year. At 12-month follow-up, patient-reported outcome scores were worse for patients with methicillin-resistant S. aureus infections.

Vancomycin prophylaxis for revision hip arthroplasty in penicillin and cephalosporin sensitive patients: Is dose adjustment necessary in accordance with blood loss and fluid replacement?

OBJECTIVE

The aims of this study were (1) to investigate the changes in the serum concentration of prophylactically administrated vancomycin in the perioperative period of revision hip arthroplasty in penicillin/cephalosporin-allergic patients, (2) to assess whether the postoperative re-administration of vancomycin is needed, and (3) to determine the relationships of vancomycin serum concentration with blood loss, body weight, and fluid replacement in such patients.

METHODS

This study consisted of 29 patients (20 females, 9 males; mean age=63.3 years; age range=45-79 years) with a history of penicillin/cephalosporin allergy undergoing revision hip arthroplasty secondary to aseptic loosening or periprosthetic fractures. Serum vancomycin levels were measured (1) before administration of vancomycin, (2) at the time of skin incision, (3) every 1,5 hours thereafter until the end of the operation, (4) during the skin closure, and (5) after three and 12 hours from the initial dosage. Data regarding body weight, amounts of intraoperative blood loss, fluid and blood replacements and postoperative wound drainage were recorded.

RESULTS

The average blood loss, fluid replacement, and drain volume were 1280.3±575.8 (500-2700) mL, 2922.6±768.8 (1700-4600) mL, and 480.2±163.7 (200-850) mL, respectively. The mean levels of serum vancomycin were 46.3±21.8 (14.1-80.7) mg/L at the time of skin incision, 17.9±4.7 (9.4-30.9) and 9.8±2.2 (4.3-13.8) mg/L after 1.5 and 3 hours from the beginning of the surgery and 5.1±1.1 (2.9-6.8)mg/L after 12th hour postoperatively. The measured vancomycin levels were below the effective serum concentrations (< 5 mg/L) for 18 patients at 12 hours the administration of the first dose. A moderate level negative correlation between the blood loss/body weight ratio and vancomycin levels was found (p=0.004, r=-0.493). Predictive ROC curve analysis resulted in determining a blood loss volume higher than 1150 ml and a blood loss/body weight ratio higher than 18,5 is significant to estimate the vancomycin level below the minimum effective serum level at 12th hour postoperatively (AUC=0.793±0.16, p=0.009, AUC=0.753) 26±0.12, p=0.025, respectively).

CONCLUSION

Evidence from this study has indicated vancomycin concentration at 12th hour is below the effective level in most patients. Thus, earlier repetitive infusion of vancomycin seems to be necessary in penicillin/cephalosporin-allergic patients undergoing revision hip arthroplasty, especially in those with high blood loss.

LEVEL OF EVIDENCE

Level III, Therapeutic Study.

Higher age, female gender, osteoarthritis and blood transfusion protect against periprosthetic joint infection in total hip or knee arthroplasties: a systematic review and meta-analysis

PURPOSE

The goal of this systematic review and meta-analysis was to identify the main risk factors for periprosthetic joint infection (PJI) in patients undergoing total hip or knee arthroplasties.

METHODS

A systematic review was conducted of the potential risk factors for PJI in total hip or total knee arthroplasty. Risk factors were compared and grouped according to demographics, comorbidities, behavior, infections, native joint diseases and other patient-related and procedure-related factors. Meta-analysis (random-effects models) was conducted using odds ratio (OR) and mean difference (MD). Risk of bias (ROBBINS-I) and strength of the evidence (GRADE) were assessed.

RESULTS

The study included 37 studies (2,470,827 patients). Older age was a protective factor (MD = - 1.18). Male gender (OR 1.34), coagulopathy (3.05), congestive heart failure (2.36), diabetes mellitus (1.80), obesity (1.61), systemic neoplasia (1.57), chronic lung disease (1.52), and hypertension (1.21) increased the risk for PJI. Behavioral risk factors comprised alcohol abuse (2.95), immunosuppressive therapy (2.81), steroid therapies (1.88), and tobacco (1.82). Infectious risk factors included surgical site infections (6.14), postoperative urinary tract infections (2.85), and prior joint infections (2.15). Rheumatoid arthritis, posttraumatic native joint disease, high National Nosocomial Infections Surveillance (NNIS) system surgical patient index score, prior joint operation, American Society of Anesthesiologists score ≥ 3 and obesity were also significantly associated with higher risk of PJI. Osteoarthritis and blood transfusion were protective factors.

CONCLUSIONS

The main risk factors for PJI in each category were male gender, coagulopathy, alcohol abuse, surgical site infection (highest score) and high NNIS system surgical patient index score. Protective factors were age, female gender in TKA, osteoarthritis and blood transfusion. Optimization of modifiable risk factors for PJI should be attempted in clinical practice.

LEVEL OF EVIDENCE

II.

Controlling Antibiotic Release from Polymethylmethacrylate Bone Cement

Bone cement is used as a mortar for securing bone implants, as bone void fillers or as spacers in orthopaedic surgery. Antibiotic-loaded bone cements (ALBCs) have been used to prevent and treat prosthetic joint infections by providing a high antibiotic concentration around the implanted prosthesis. High antibiotic concentrations are, on the other hand, often associated with tissue toxicity. Controlling antibiotic release from ALBCS is key to achieving effective infection control and promoting prosthesis integration with the surrounding bone tissue. However, current ALBCs still need significant improvement in regulating antibiotic release. In this review, we first provide a brief introduction to prosthetic joint infections, and the background concepts of therapeutic efficacy and toxicity in antibiotics. We then review the current state of ALBCs and their release characteristics before focusing on the research and development in controlling the antibiotic release and osteo-conductivity/inductivity. We then conclude by a discussion on the need for better in vitro experiment designs such that the release results can be extrapolated to predict better the local antibiotic concentrations in vivo.

The Cost-Effectiveness of Vancomycin Powder in Lumbar Laminectomy

STUDY DESIGN

Break-even cost analysis.

OBJECTIVE

The goal of this study is to examine the cost-effectiveness of vancomycin powder for preventing infection following lumbar laminectomy.

METHODS

The product cost of vancomycin powder was obtained from our institution's purchasing records. Infection rates and revision costs for lumbar laminectomy and lumbar laminectomy with fusion were obtained from the literature. A break-even analysis was then performed to determine the absolute risk reduction (ARR) in infection rate to make prophylactic application of vancomycin powder cost-effective. Analysis of lumbar laminectomy with fusion was performed for comparison.

RESULTS

Costing $3.06 per gram at our institution, vancomycin powder was determined to be cost-effective in lumbar laminectomy if the infection rate of 4.2% decreased by an ARR of 0.015%. Laminectomy with fusion was also determined to be cost-effective at the same cost of vancomycin powder if the infection rate of 8.5% decreased by an ARR of 0.0034%. The current highest cost reported in the literature, $44.00 per gram of vancomycin powder, remained cost-effective with ARRs of 0.21% and 0.048% for laminectomy and laminectomy with fusion, respectively. Varying the baseline infection rate did not influence the ARR for either procedure when the analysis was performed using the product cost of vancomycin at our institution.

CONCLUSIONS

This break-even analysis demonstrates that prophylactic vancomycin powder can be highly cost-effective for lumbar laminectomy. At our institution, vancomycin powder is economically justified if it prevents at least one infection out of 6700 lumbar laminectomy surgeries.

The prospects of antimicrobial coated medical implants

The implants are increasingly being a part of modern medicine in various surgical procedures for functional or cosmetic purposes. The progressive use of implants is associated with increased infectious complications and prevention of such infections always remains precedence in the clinical settings. The preventive approaches include the systemic administration of antimicrobial agents before and after the surgical procedures as well as the local application of antibiotics. The relevant literature and existing clinical practices have highlighted the role of antimicrobial coating approaches in the prevention of implants associated infections, although the applications of these strategies are not yet standardized, and the clinical efficacy is not much clear. The adequate data from the randomized control trials is challenging because of the unavailability of a large sample size although it is compulsory in this context to assess the clinical efficacy of preemptive practices. This review compares the efficacy of preventive approaches and the prospects of antimicrobial-coated implants in preventing implant-related infections.

Successful Two-Stage Exchange Arthroplasty for Periprosthetic Infection Following Total Knee Arthroplasty: The Impact of Timing on Eradication of Infection

Background: Periprosthetic joint infection (PJI) represents a serious complication following total knee arthroplasty. In the setting of chronic infections, the two-staged approach has traditionally been the preferred treatment method. The aim of this study was to determine the optimal period of rest between the first and second stage. Furthermore, we analyzed potentially outcome-relevant parameters, such as general and local conditions and the presence of difficult-to-treat or unidentified microorganisms, with regard to their impact on successful treatment of PJI. Patients and Methods: We performed a retrospective analysis of prospectively collected data for all patients treated for PJI at our institution. Seventy-seven patients who had undergone two-stage revision arthroplasty for PJI of the knee were included into the study. Antibiotic-loaded cement spacers were used for all patients. Results: After a median follow-up time of 24.5 months, infection had reoccurred in 14 (18.7%) patients. A prolonged spacer-retention period of more than 83 days was related to a significantly higher proportion of reinfections. Furthermore, significant compromising local conditions of the prosthetic tissue and surrounding skin, as well as repeated spacer-exchanges between first- and second-stage surgery, negatively influenced the outcome. Neither the patients' age nor gender exerted a significant influence on the outcome regarding reinfection rates for patients' age or gender. Conclusions: We observed the best outcome regarding infection control in patients who had undergone second-stage surgery within 12 weeks after first-stage surgery. Nearly 90% of these patients stayed free from infection until the final follow-up. An increased number of performed spacer-exchanges and a bad local extremity grade also had a negative impact on the outcome.

Intraoperative Bacterial Contamination and Activity of Different Antimicrobial Prophylaxis Regimens in Primary Knee and Hip Replacement

Surgical antimicrobial prophylaxis (SAP) is important for the prevention of prosthetic joint infections (PJIs) and must be effective against the microorganisms most likely to contaminate the surgical site. Our aim was to compare different SAP regimens (cefazolin, cefuroxime, or vancomycin, alone or combined with gentamicin) in patients undergoing total knee (TKA) and hip (THA) arthroplasty. In this preclinical exploratory analysis, we analyzed the results of intraoperative sample cultures, the ratio of plasma antibiotic levels to the minimum inhibitory concentrations (MICs) for bacteria isolated at the surgical wound and ATCC strains, and serum bactericidal titers (SBT) against the same microorganisms. A total of 132 surgical procedures (68 TKA, 64 THA) in 128 patients were included. Cultures were positive in 57 (43.2%) procedures (mostly for coagulase-negative staphylococci and Cutibacterium spp.); the rate was lower in the group of patients receiving combination SAP (adjusted OR 0.475, CI95% 0.229-0.987). The SAP regimens evaluated achieved plasma levels above the MICs in almost all of intraoperative isolates (93/94, 98.9%) and showed bactericidal activity against all of them (SBT range 1:8-1:1024), although SBTs were higher in patients receiving cefazolin and gentamicin-containing regimens. The potential clinical relevance of these findings in the prevention of PJIs remains to be determined.

Clinical and Health-Care Cost Analysis of Negative Pressure Dressing in Primary and RevisionTotal Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Negative pressure wound therapy (NPWT) has been used because of its perceived advantages in reducing surgical site infections, wound complications, and the need for further surgery. The purpose of this study was to assess the infection rates, wound complications, length of stay, and financial burden associated with NPWT use in primary and revision total knee arthroplasty (TKA).

METHODS

We performed a PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) systematic review of the existing literature on using NPWT in primary and revision TKA. PubMed, Embase, Science Direct, and the Cochrane Library were utilized. The risk of bias was evaluated using the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool, and the quality of evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria.

RESULTS

Twelve articles that evaluated 1,403 primary TKAs and 279 revision TKAs were reviewed. NPWT significantly reduced complication rates in revision TKA. However, there was no significant difference in infection rates between NPWT and regular dressings in primary or revision TKA. NPWT use in primary TKA significantly increased the risk of blistering, although no increase in reoperations was noted. The analysis showed a possible reduction in length of stay associated with NPWT use for both primary and revision TKA, with overall health-care cost savings.

CONCLUSIONS

Based on a meta-analysis of the existing literature, we do not recommend the routine use of NPWT. However, in high-risk revision TKA and selected primary TKA cases, NPWT reduced wound complications and may have health-care cost savings.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The Rationale for Using Bacteriophage to Treat and Prevent Periprosthetic Joint Infections

Prosthetic joint infection (PJI) is a devastating complication after a joint replacement. PJI and its treatment have a high monetary cost, morbidity, and mortality. The lack of success treating PJI with conventional antibiotics alone is related to the presence of bacterial biofilm on medical implants. Consequently, surgical removal of the implant and prolonged intravenous antibiotics to eradicate the infection are necessary prior to re-implanting a new prosthetic joint. Growing clinical data shows that bacterial predators, called bacteriophages (phages), could be an alternative treatment strategy or prophylactic approach for PJI. Phages could further be exploited to degrade biofilms, making bacteria more susceptible to antibiotics and enabling potential combinatorial therapies. Emerging research suggests that phages may also directly interact with the innate immune response. Phage therapy may play an important, and currently understudied, role in the clearance of PJI, and has the potential to treat thousands of patients who would either have to undergo revision surgery to attempt to clear an infections, take antibiotics for a prolonged period to try and suppress the re-emerging infection, or potentially risk losing a limb.

A Rare Case of Joint Infection due to Raoultella planticola

Raoultella planticola , a gram-negative bacterium, first emerged in late 1900s as Klebsiella planticola . It was later classified as Raoultella genus in 2001. This nonmotile rod is usually found in soil and aquatic environment. There are two known species of Raoultella : R. planticola and R. ornithinolytica . They are responsible for numerous yet rare infections including cystitis, pneumonia, and bacteremia. To date, only one case of joint or bone infection due to R. planticola has been reported. The infection is eradicated after arthroscopic lavage and antibiotic therapy with fluoroquinolones. We present the first case of septic arthritis due to R. planticola involving a native knee joint following synovectomy during arthroscopy.

The utility of dithiothreitol treatment of periprosthetic tissues and explanted implants in the diagnosis of prosthetic joint infection

PURPOSE

The methods used for the processing of periprosthetic tissues and explanted implants to improve culture outcome especially in biofilm mediated prosthetic joint infections (PJIs) are still debated upon. Studies have reported that Dithiothreitol (DTT) pretreatment of infected devices gives similar results as sonication. However, none of them evaluated the DTT treatment of periprosthetic tissues and explanted implants in the same cohort. We evaluated the diagnostic utility of DTT treatment of periprosthetic tissue and explanted implants, as compared to the normal saline treatment of periprosthetic tissues and sonication of explanted implants for the diagnosis of PJI.

METHODS

Seventy-three revision arthroplasty cases were prospectively included in this study. Three to five tissue specimens and the explanted implants were collected from each patient. Periprosthetic tissue samples were processed by both normal saline and DTT treatments. Explanted implants were subjected to both DTT treatment and sonication. Musculoskeletal Infection Society (MSIS) PJI criteria was used as the reference standard for the diagnosis of PJI.

RESULTS

Of the 73 cases enrolled, 34 had PJI and 39 were aseptic failures. The sensitivity of DTT treated periprosthetic tissue culture (PTC) and saline treated PTC was similar (66.6% vs 58.8%, P = 0.25). The specificity of both was 100%. Sonication and DTT treatment of explanted implants showed comparable sensitivity (85.3% vs 82.4%) and specificity (100% vs 97.4%), P > 0.99. Compared to DTT treated PTC, culture of DTT treated explanted implants significantly improved the diagnosis of PJI (P = 0.03).

CONCLUSIONS

We could verify that DTT can be used to improve culture outcome in laboratories where biofilm detaching sonication techniques are not available for infected implants. In addition, we showed that it is possible to use DTT for treating tissue biopsies, but larger studies are required to confirm our findings.

A Case Illustrating the Practical Application of the AAOS Clinical Practice Guideline: Diagnosis and Prevention of Periprosthetic Joint Infection

The American Academy of Orthopaedic Surgeons Clinical Practice Guideline "Diagnosis and Prevention of Periprosthetic Joint Infections (PJI)" is a summary of the available literature designed to help guide surgeons and other qualified physicians in the management of PJI. Obesity and intra-articular joint injections are associated with an increased risk of PJI according to this Clinical Practice Guideline. Serum erythrocyte sedimentation rate, C-reactive protein, and/or interleukin-6 should be obtained when diagnosing PJI. Synovial fluid leukocyte count, neutrophil percentage, aerobic and anaerobic bacterial cultures, leukocyte esterase, alpha-defensin, C-reactive protein, and nucleic acid amplification testing may assist with the diagnosis of PJI. Antibiotics should be held for 2 weeks before obtaining samples. Intraoperatively, Gram stains do not help with PJI diagnosis, whereas histopathology samples are helpful. These guidelines may help clinicians with the prevention and diagnosis of PJI.

Alteration of Bacterial Communities in Anterior Nares and Skin Sites of Patients Undergoing Arthroplasty Surgery: Analysis by 16S rRNA and Staphylococcal-Specific tuf Gene Sequencing

The aim was to study alterations of bacterial communities in patients undergoing hip or knee arthroplasty to assess the impact of chlorhexidine gluconate soap decolonisation and systemic antibiotic prophylaxis. A Swedish multicentre, prospective collection of samples obtained from elective arthroplasty patients (n = 83) by swabbing anterior nares, skin sites in the groin and the site of planned surgery, before and after arthroplasty surgery, was analysed by 16S rRNA (V3-V4) gene sequencing and a complementary targeted tuf gene sequencing approach to comprehensively characterise alterations in staphylococcal communities. Significant reductions in alpha diversity was detected for both bacterial (p = 0.04) and staphylococcal (p = 0.03) groin communities after arthroplasty surgery with significant reductions in relative Corynebacterium (p = 0.001) abundance and Staphylococcus hominis (p = 0.01) relative staphylococcal abundance. In nares, significant reductions occurred for Staphylococcus hominis (p = 0.02), Staphylococcus haemolyticus (p = 0.02), and Staphylococcus pasteuri (p = 0.003) relative to other staphylococci. Staphylococcus aureus colonised 35% of anterior nares before and 26% after arthroplasty surgery. Staphylococcus epidermidis was the most abundant staphylococcal species at all sampling sites. No bacterial genus or staphylococcal species increased significantly after arthroplasty surgery. Application of a targeted tuf gene sequencing approach provided auxiliary staphylococcal community profiles and allowed species-level characterisation directly from low biomass clinical samples.

Risk factors affect success rate of debridement, antibiotics and implant retention (DAIR) in periprosthetic joint infection

Background

Periprosthetic joint infection (PJI) is the most devastating complication of joint replacement that seriously affects the quality of life and causes a heavy burden to the families and society. Due to shorter hospital stays, lower costs, improved joint function and less morbidity, a process of debridement, antibiotics and implant retention (DAIR) is recommended as the preferred treatment for acute periprosthetic joint infection. However, the factors that impact the success rate of DAIR remain controversial. This article evaluates the influential factors of DAIR and provides insights for orthopaedics surgeons to make optimal decisions to improve the success rate of DAIR.

Conclusion

The poor general condition of patients, high preoperative C-reactive protein (CRP) level, repeated joint surgeries, and Methicillin-resistant Staphylococcus aureus (MRSA) infections may be associated with lower DAIR success rate. To the contrary, early surgery, radical debridement, exchange of removable components, washing with iodine and vacuum sealing drainage (VSD) may improve the success rate of DAIR. A sinus tract may not be absolutely contraindicated, but surgeons should treat it with caution. As there is no consensus on many issues, more high-quality research is required.

Synovial fluid interleukin-6 is not superior to cell count and differential in the detection of periprosthetic joint infection

Aims

Synovial fluid white blood cell (WBC) count and percentage of polymorphonuclear cells (%PMN) are elevated at periprosthetic joint infection (PJI). Leucocytes produce different interleukins (IL), including IL-6, so we hypothesized that synovial fluid IL-6 could be a more accurate predictor of PJI than synovial fluid WBC count and %PMN. The main aim of our study was to compare the predictive performance of all three diagnostic tests in the detection of PJI.

Methods

Patients undergoing total hip or knee revision surgery were included. In the perioperative assessment phase, synovial fluid WBC count, %PMN, and IL-6 concentration were measured. Patients were labeled as positive or negative according to the predefined cut-off values for IL-6 and WBC count with %PMN. Intraoperative samples for microbiological and histopathological analysis were obtained. PJI was defined as the presence of sinus tract, inflammation in histopathological samples, and growth of the same microorganism in a minimum of two or more samples out of at least four taken.

Results

In total, 49 joints in 48 patients (mean age 68 years (SD 10; 26 females (54%), 25 knees (51%)) were included. Of these 11 joints (22%) were infected. The synovial fluid WBC count and %PMN predicted PJI with sensitivity, specificity, accuracy, PPV, and NPV of 82%, 97%, 94%, 90%, and 95%, respectively. Synovial fluid IL-6 predicted PJI with sensitivity, specificity, accuracy, PPV, and NPV of 73%, 95%, 90%, 80%, and 92%, respectively. A comparison of predictive performance indicated a strong agreement between tests.

Conclusions

Synovial fluid IL-6 is not superior to synovial fluid WBC count and %PMN in detecting PJI.

Level of Evidence: Therapeutic Level II

Cite this article: Bone Jt Open 2020;1-12:737–742.

Systematic Review and Meta-Analysis of Tobacco Use as a Risk Factor for Prosthetic Joint Infection After Total Hip Replacement

Background

A prosthetic joint infection (PJI) is one of the possible complications after total hip arthroplasty (THA). Several studies, but not all, have reported smoking as a risk factor of PJIs in orthopaedic surgery. This study summarizes the most recent evidence using a systematic review of whether tobacco use (not only tobacco smoking) is a risk factor in developing PJIs, specifically after THA.

Methods

Ovid Medline, EMBASE, Scopus, Web of Science, and Cochrane databases were searched from inception to July 2019 to identify case-control studies that examined the PJI risk in tobacco users and tobacco nonusers undergoing THA. Publication bias was also assessed through funnel plots.

Results

Searches identified 2689 articles, and 10 of these, involving a total of 20,640 patients, met the inclusion criteria. The overall odds ratio (pooled odds ratio) to develop either a superficial infection, a deep infection, or an infection requiring revision surgery for tobacco users vs nonusers was 1.54 (95% confidence interval: 1.25-1.91) when a fixed-effect model was used and 1.56 (95% confidence interval: 1.10-2.21) when a random-effect model was used. No publication bias was observed among the identified studies.

Conclusions

The findings of the study indicated that tobacco use is associated with a higher risk of PJIs in patients undergoing THA.

Do Prosthetic Joint Infections Worsen the Functional Ambulatory Outcome of Patients with Joint Replacements? A Retrospective Matched Cohort Study

OBJECTIVES

To assess the effect on the functional ambulatory outcome of postoperative joint infection (PJI) cured at the first treatment attempt versus not developing PJI in patients with hip and knee prostheses.

METHODS

In a single-hospital retrospectively matched cohort study, each patient with PJI between 2007 and 2016 was matched on age, sex, type of prosthesis and year of implantation with two other patients with uninfected arthroplasties. The definition of a PJI cure included infection eradication, no further surgical procedures, no PJI-related mortality and no suppressive antibiotics. Functional ambulatory status evaluated one year after the last surgery was classified into four simple categories: able to walk without assistance, able to walk with one crutch, able to walk with two crutches, and unable to walk. Patients with total hip arthroplasties (THA), total knee arthroplasties (TKA) and partial hip arthroplasty (PHA) were analysed separately.

RESULTS

A total of 109 PJI patients (38 TKA, 41 THA, 30 PHA) and 218 non-PJI patients were included. In a model adjusted for clinically relevant variables, PJI was associated with a higher risk of needing an assistive device for ambulation (vs. walking without aid) among THA (adjusted odds ratio (OR) 3.10, 95% confidence interval (95% CI) 1.26-7.57; p = 0.014) and TKA patients (OR 5.40, 95% CI 2.12-13.67; p < 0.001), and with requiring two crutches to walk or being unable to walk (vs. walking unaided or with one crutch) among PHA patients (OR 3.05, 95% CI 1.01-9.20; p = 0.047).

CONCLUSIONS

Ambulatory outcome in patients with hip and knee prostheses with postoperative PJI is worse than in patients who do not have PJI.

Antibiotic resistance and persistence-Implications for human health and treatment perspectives

Antimicrobial resistance (AMR) and persistence are associated with an elevated risk of treatment failure and relapsing infections. They are thus important drivers of increased morbidity and mortality rates resulting in growing healthcare costs. Antibiotic resistance is readily identifiable with standard microbiological assays, and the threat imposed by antibiotic resistance has been well recognized. Measures aiming to reduce resistance development and spreading of resistant bacteria are being enforced. However, the phenomenon of bacteria surviving antibiotic exposure despite being fully susceptible, so-called antibiotic persistence, is still largely underestimated. In contrast to antibiotic resistance, antibiotic persistence is difficult to measure and therefore often missed, potentially leading to treatment failures. In this review, we focus on bacterial mechanisms allowing evasion of antibiotic killing and discuss their implications on human health. We describe the relationship between antibiotic persistence and bacterial heterogeneity and discuss recent studies that link bacterial persistence and tolerance with the evolution of antibiotic resistance. Finally, we review persister detection methods, novel strategies aiming at eradicating bacterial persisters and the latest advances in the development of new antibiotics.

Measurement of Serum Anti-staphylococcal Antibodies Increases Positive Predictive Value of Preoperative Aspiration for Hip Prosthetic Joint Infection

BACKGROUND

Preoperative synovial fluid culture is pivotal in the early diagnosis of prosthetic joint infection (PJI) but may yield false-positive and false-negative results. We evaluated the predictive value of synovial fluid culture results combined with the measurement of serum anti-staphylococcal antibodies (SASA).

QUESTIONS/PURPOSES

(1) For hip and knee PJI, does combining positive SASA results with preoperative synovial culture results improve the positive predictive value (PPV) of preoperative synovial fluid culture alone? (2) Does combining preoperative synovial fluid culture results with a positive cell count and differential result increase the PPV of preoperative synovial fluid culture alone? (3) What proportion of isolated organisms exhibit concordance in antibiotic susceptibility: preoperative aspiration versus intraoperative isolates?

METHODS

A prospective study was conducted at two French reference centers that manage bone and joint infections and included 481 adult patients who had a revision or resection arthroplasty between June 25, 2012 and June 23, 2014. Exclusion criteria including no serum sample available for immunoassay, the lack of microbiological documentation, and the absence of preoperative aspiration reduced the patient number to 353. Seven patients with an undetermined SASA result were excluded from the analysis. We also excluded patients with PJI involving more than one Staphylococcus species (polystaphylococcal infection) and those in whom more than one Staphylococcus species was recovered from the preoperative synovial fluid culture (polystaphylococcal synovial fluid culture). In total, 340 patients were included in the analysis (no infection, 67% [226 of 340]; staphylococcal infection, 21% [71 of 340]; other infection, 13% [43 of 340]). The preoperative synovial fluid analysis included a cell count and differential and bacterial culture. SASAs were measured using a multiplex immunoassay. The diagnosis of PJI was determined using the Infectious Diseases Society of America (IDSA) criteria [] and intraoperative tissue culture at the time of revision surgery was used as the gold standard (at least one positive intraoperative sample for a "virulent" organism (such as S. aureus) or two positive samples for a "non-virulent" (for example S. epidermidis).

RESULTS

SASA increased the PPV compared with synovial fluid culture alone (92% [95% CI 82 to 97] versus 79% [95% CI 68 to 87]; p = 0.04); when stratified by site, an increase in PPV was seen in hip infections (100% [95% CI 89 to 100] versus 77% [95% CI 63 to 88]; p = 0.01) but not in knee infections (84% [95% CI 66 to 95] versus 80% [95% CI 64 to 91]; p = 0.75). A positive cell count and differential result increased the PPV of staphylococcal synovial fluid cultures compared with synovial fluid culture alone (86% [95% CI 70 to 95] versus 79% [95% CI 68 to 87]; p = 0.36); when stratified by site, no difference in hip and knee infections was observed (86% [95% CI 67 to 96] versus 77% [95% CI 63 to 88]; p = 0.42) and 86% [95% CI 70 to 95] versus 80% [95% CI 64 to 91]; p = 0.74).

CONCLUSION

SASA measurement improves the predictive value of synovial fluid cultures of the hip for all staphylococcal organisms, including coagulase-negative staphylococci, but the PPV of SASA plus synovial fluid culture it is not superior to the PPV of synovial fluid cell count/differential plus synovial culture for the knee.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Clinical Characteristics and Causative Pathogens of Infective Arthritis and Risk Factors for Gram-Negative Bacterial Infections

BACKGROUND

The aim of this study was to describe the clinical and microbiological characteristics of infective arthritis and to analyze risk factors for Gram-negative bacterial infections that cause infective arthritis.

MATERIALS AND METHODS

Patients admitted between 2009 - 2018 with infective arthritis in a single-tertiary hospital were evaluated retrospectively.

RESULTS

A total of 181 patients were enrolled in this study. Of them, 135 were native joint infection patients and 46 were prosthetic joint infection patients. The most common site of infective arthritis was the knee (63.6%), followed by the shoulder (17.7%), and the hip (9.9%). The most frequently identified microorganisms were Staphylococcus aureus (51.1%), followed by Streptococci sp. (21.1%), Enterobacteriaceae (8.4%), and coagulase-negative-Staphylococci (CNS; 8.4%). Infections due to Gram-negative bacteria and fungi made up 13.7% and 3.2% of all cases, respectively. Additionally, 20% and 4.2% of the cases involved methicillin-resistant S. aureus (MRSA) and MRCNS. We found that bacteriuria, infective arthritis in the hip, and steroid use at admission are independent risk factors for Gram-negative bacterial infections.

CONCLUSION

Infective arthritis with methicillin-resistant microorganisms reached up to about 25% in a single-tertiary hospital in Korea. In case of suspected urinary tract infection, infective arthritis of the hip joint, or steroid use at admission time among infective arthritis patients, empirical treatment covering Gram-negative microorganisms can be considered.

Cost-effectiveness of dental antibiotic prophylaxis in total knee arthroplasty recipients with type II diabetes mellitus

Objective

Type II diabetes mellitus (T2DM) is prevalent in knee osteoarthritis (OA) patients undergoing total knee arthroplasty (TKA) and increases risk for prosthetic joint infection (PJI). We examined the cost-effectiveness of antibiotic prophylaxis (AP) before dental procedures to reduce PJI in TKA recipients with T2DM.

Design

We used the Osteoarthritis Policy Model, a validated computer simulation of knee OA, to compare two strategies among TKA recipients with T2DM (mean age 68 years, mean BMI 35.4 kg/m2): 1) AP before dental procedures and 2) no AP. Outcomes included quality-adjusted life expectancy (QALE) and lifetime medical costs. We used published efficacy of AP. We report incremental cost-effectiveness ratios (ICERs) and considered strategies with ICERs below well-accepted willingness-to-pay (WTP) thresholds cost-effective. We conducted sensitivity analyses to examine the robustness of findings to uncertainty in model input parameters. We used a lifetime horizon and healthcare sector perspective.

Results

We found that AP added 1.0 quality-adjusted life-year (QALY) and $66,000 for every 1000 TKA recipients with T2DM, resulting in an ICER of $66,000/QALY. In sensitivity analyses, reduction of the probability of PJI, T2DM-associated risk of infection, or attribution of infections to dental procedures by 50% resulted in ICERs exceeding $100,000/QALY. Probabilistic sensitivity analyses showed that AP was cost-effective in 32% and 58% of scenarios at WTP of $50,000/QALY and $100,000/QALY, respectively.

Conclusions

AP prior to dental procedures is cost-effective for TKA recipients with T2DM. However, the cost-effectiveness of AP depends on the risk of PJI and efficacy of AP in this population.

Implications for diagnosis and treatment of peri-spinal implant infections from experiences in periprosthetic joint infections-a literature comparison and review

Both, periprosthetic joint infection (PJI) and peri-spinal implant infection (PSII) are serious complications occurring in arthroplasty and spine instrumentation with absolute numbers expected to rise in the next years. The currently existing literature data describing the characteristics of PSII are limited when compared to PJI studies. However, both PJI and PSII exhibit similarities concerning pathogenesis, symptoms, diagnosis, treatment and prognosis. This literature review aims at comparing PJI and PSII and to develop implications for diagnosis and treatment of PSII from existing studies about PJI. The review was performed on the basis of a structured PubMed, Cochrane Library, and Medline analysis and existing guidelines, with 99 references being included. The results indicate that specific terms like re-infection should be defined in the context of PSII based on existing definitions of PJI, that in vitro biofilm studies and studies analyzing different prosthesis surfaces in arthroplasty could be used for PSII, and that histopathology as an additional standard tool in PSII diagnosis might be helpful. In addition, the development of a standardized algorithm-based treatment system with antibiotic protocols, including long term suppression, for PSII similar to the ones existing for PJI is necessary.

Perioperative Venous Thromboembolism Prophylaxis

Venous thromboembolism (VTE) is a preventable cause of postoperative morbidity and mortality; however, audits suggest that the use of thromboprophylaxis is underused. In this review, we describe our approach to prevention of postoperative VTE and provide guidance on how to formulate an optimal VTE prophylaxis plan. We recommend that all patients undergo thrombosis- and bleeding-risk assessment as part of their preoperative evaluation. The risk of thrombosis can be estimated based on patient- and procedure-specific factors, using validated risk-assessment models such as the Caprini score. There are no validated models to predict perioperative bleeding; however, several risk factors have been proposed. Patients should ambulate early and frequently after surgery. We recommend no additional prophylaxis in patients at very low risk of VTE (Caprini score 0). Patients at low risk of VTE (Caprini 1 to 2) are recommended to receive either mechanical or pharmacological prophylaxis. Patients at moderate (Caprini 3 to 4) to high risk of VTE (Caprini ≥5) are recommended pharmacological prophylaxis either alone or combined with mechanical prophylaxis. Patients at high risk of bleeding should receive mechanical prophylaxis until their risk of bleeding is reduced and pharmacological prophylaxis can be reconsidered. Populations for which the Caprini score has not been validated (such as orthopedic surgery) are recommended prophylaxis based on individual and procedure-specific risk factors. Prophylaxis is typically continued until the patient is ambulatory or until hospital dismissal; however, longer durations can be considered in certain circumstances (high-risk patients undergoing malignant abdominopelvic operations, bariatric operations, and certain orthopedic operations).

Direct antimicrobial activity of cationic amphipathic peptide WLBU2 against Staphylococcus aureus biofilms is enhanced in physiologic buffered saline

Periprosthetic joint infection of total knee arthroplasties represents a major challenge to the field of orthopedic surgery. These infections are commonly associated with antibiotic-tolerant Staphylococcus aureus biofilms. Engineered cationic amphipathic peptide WLBU2 has shown the ability to kill antibiotic-resistant pathogens and drug-tolerant bacterial biofilms. The novelty of using WLBU2 during the direct irrigation and debridement of periprosthetic joint infections led our group to investigate the optimal washout conditions for treatment of S. aureus biofilms. S. aureus mature biofilms were grown on metal implant material and treated with WLBU2 dissolved in differing irrigation solvents. Mature biofilms were treated both in vitro as well as in a periprosthetic joint infection murine model. WLBU2 activity against S. aureus biofilms was increased when dissolved in diphosphate-buffered saline (dPBS) with pH of 7.0 compared with normal saline with pH of 5.5. WLBU2 activity was decreased in acidic dPBS and increased in alkaline dPBS. WLBU2 activity could be decreased in hypertonic dPBS and increased in hypotonic dPBS. WLBU2 dissolved in less acidic dPBS displayed increased efficacy in treating periprosthetic joint infection (PJI) implants ex vivo. WLBU2 demonstrated the ability to eliminate PJI associated S. aureus biofilms on arthroplasty material. The efficacy of engineered cationic amphipathic peptide WLBU2 for intraoperative elimination of S. aureus biofilms can be further optimized when kept in a less acidic and more physiologic pH adjusted saline. Understanding optimal physical washout conditions are vital for the success of WLBU2 in treating S. aureus biofilms in PJI clinical trials going forward.

Investigation and management of prosthetic joint infection in knee replacement: A BASK Surgical Practice Guideline

BACKGROUND

The burden of knee replacement prosthetic joint infection (KR PJI) is increasing. KR PJI is difficult to treat, outcomes can be poor and it is financially expensive and limited evidence is available to guide treatment decisions.

AIM

To provide guidelines for surgeons and units treating KR PJI.

METHODS

Guideline formation by consensus process undertaken by BASK's Revision Knee Working Group, supported by outputs from UK-PJI meetings.

RESULTS

Improved outcomes should be achieved through provision of care by revision centres in a network model. Treatment of KR PJI should only be undertaken at specialist units with the required infrastructure and a regular infection MDT. This document outlines practice guidelines for units providing a KR PJI service and sets out: CONCLUSIONS: KR PJI patients treated within the NHS should be provided the best care possible. This report sets out guidance and support for surgeons and units to achieve this.

The evolution from the two stage to the one stage procedure for biofilm based periprosthetic joint infections (PJI)

A definitive consensus on the optimal limb salvage protocol for infected total joints does not currently exist. Popular, is the two-stage revision which calls for the use of an antibiotic loaded spacer followed by a delayed exchange. Our question is whether single-stage revisions for biofilm based infected arthroplasties results in comparable or possibly better patient outcomes as compared to those reported for two-stage revisions. We retrospectively reviewed 500 cases of one-stage revisions for periprosthetic joint infections (PJI) using dual setup with radical debridement, definitive reconstruction with antibiotic loaded cement and implantation of antibiotic calcium sulfate pellets between the years 2005-2017. The revisions included 351 total knees, 122 hips, 2 hip-femur-knees, 13 shoulders, 10 elbows, and 2 shoulder-humerus-elbows. The patient population had a mean follow-up of 60 months (range: 24 months-14 years) and mean patient age of 61 years old, consisting of 250 males and 250 females. Patient comorbidities were reviewed, classified using McPherson's staging for PJIs, and compared to the Cierny & Mader classification system. Successful treatment was defined as a joint without recurrence of infection, for a minimum of 2 years, and limb preservation. Based on our findings, one-stage revision of PJIs demonstrates at least as good an infection eradication rate as two-stage revision: 88% vs 85% respectively.

THE CROATIAN HEALTH INSURANCE FUND DOES NOT RECOGNIZE DIFFERENCES IN THE COST OF DIFFERENT TREATMENTS FOR REVISION TOTAL HIP ARTHROPLASTY

In recent years, there has been increased interest in the cost of treatment for revision interventions for hip and knee prostheses. In all publications so far, the authors note the high cost of treatment for revision interventions, especially if infection is present. The aim of this study was to compare the cost of treatment and health insurance reimbursements between revision total hip arthroplasty (THA) for infection and revision for aseptic indications (aseptic instability and periprosthetic fracture). Hospital data on 168 patients having undergone revision THA between 2010 and 2018 at the Department of Traumatology, Sestre milosrdnice University Hospital Centre from Zagreb were analyzed. Financial data were collected from the Hospital Information System. Financial analysis included total cost per patient, Croatian Health Insurance Fund reimbursements, cost of implants, and length of hospital stay. The difference between the mean total cost per patient and the mean Croatian Health Insurance Fund reimbursements was -262.83 € (-6.08%) for aseptic instability, -1694.94 € (-17.25%) for infection and -916.49 € (-17.33%) for periprosthetic fracture. The Croatian Health Insurance Fund does not recognize differences in the cost of revision THA for aseptic instability, infection and periprosthetic fracture. Health insurance reimbursement is inadequate for centers that offer revision hip surgery.

A novel antimicrobial coating to prevent periprosthetic joint infection

Aims

Periprosthetic joint infection (PJI) is a debilitating condition with a substantial socioeconomic burden. A novel autologous blood glue (ABG) has been developed, which can be prepared during surgery and sprayed onto prostheses at the time of implantation. The ABG can potentially provide an antimicrobial coating which will be effective in preventing PJI, not only by providing a physical barrier but also by eluting a well-known antibiotic. Hence, this study aimed to assess the antimicrobial effectiveness of ABG when impregnated with gentamicin and stem cells.

Methods

Gentamicin elution from the ABG matrix was analyzed and quantified in a time-dependent manner. The combined efficiency of gentamicin and ABG as an anti-biofilm coating was investigated on titanium disks.

Results

ABG-gentamicin was bactericidal from 10 μg/ml and could release bactericidal concentrations over seven days, preventing biofilm formation. A concentration of 75 μg/ml of gentamicin in ABG showed the highest bactericidal effect up to day 7. On titanium disks, a significant bacterial reduction on ABG-gentamicin coated disks was observed when compared to both uncoated (mean 2-log reduction) and ABG-coated (mean 3-log reduction) disks, at days 3 and 7. ABG alone exhibited no antimicrobial or anti-biofilm properties. However, a concentration of 75 μg/ml gentamicin in ABG sustains release over seven days and significantly reduced biofilm formation. Its use as an implant coating in patients with a high risk of infection may prevent bacterial adhesion perioperatively and in the early postoperative period.

Conclusion

ABG’s use as a carrier for stem cells was effective, as it supported cell growth. It has the potential to co-deliver compatible cells, drugs, and growth factors. However, ABG-gentamicin’s potential needs to be further justified using in vivo studies.

Cite this article: Bone Joint Res 2020;9(12):848–856.

Efficacy of universal preoperative decolonization with Polyhexanide in primary joint arthroplasty on surgical site infections. A multicenter before-and after-study

Background

Surgical site infections (SSI) are rare but severe complications after total joint arthroplasty (TJA). Decolonization measures prior to elective orthopedic surgeries have shown to reduce the risk of SSI with Staphylococcus aureus (S. aureus).

Objective

To determine the efficacy of universal decolonization with Polyhexanide on SSI rates with a focus on Staphylococcus aureus in patients with TJA.

Methods

Patients scheduled for elective hip or knee TJA in 5 participating certified orthopedic centers were included between 2015 and 2018 into this before and after study. Data on patients, surgeries and infections were prospectively collected. CDC-criteria were used to define and categorize Infections within 90 days after surgery. From January 2017 on, patients received decolonization sets containing Polyhexanide. Patients performed a 5 day decolonization regimen starting 4 days prior to surgery which included wipes, nasal decontamination and oral solution.

Results

Thirteen thousand, three hundred fifteen patients received TJA. During intervention 4437 decolonization sets were distributed among 7175 patients.

Overall SSI rates increased from 0.68 /100 surgeries to 0.91/ 100 surgeries after implementation of the intervention (IRR 1.32; 95% CI 0.90–1.96). Time series analysis identified an increasing trend of SSI prior to the intervention. After implementation overall SSI rates plateaued. Regression analysis revealed surgery during intervention period to be an independent risk factor for developing a SSI (OR 1.34; 95%CI 1.18–1.53).

Initial SSI rates due to S. aureus were 0.24/100 surgeries and decreased to 0.14/100 surgeries (IRR 0.57; 95% CI 0.25–1.22) after introduction of decolonization. Regression analysis revealed surgery during intervention period to be an independent protective factor for developing a SSI with S. aureus (OR 0.57, 95% CI: 0.33–0.99).

Overall deep S. aureus SSI decreased significantly from 0.22/100 surgeries to 0.00/100 surgeries in patients adherent to protocol (IRR 0.00, 95% CI 0.00–.85).

Conclusion

Universal decolonization with Polyhexanide did not reduce overall surgical site infections, but was effective in reducing Staphylococcus aureus - surgical site infections following elective joint arthroplasty. Polyhexanide could extend the list of alternatives to already established decolonization strategies.

Trial registration

The trial was registered at the German Registry for clinical studies www.drks.de (DRKS00011505).

Preclinical In Vitro Assessment of Submicron-Scale Laser Surface Texturing on Ti6Al4V

Loosening of orthodontic and orthopedic implants is a critical and common clinical problem. To minimize the numbers of revision surgeries due to peri-implant inflammation or insufficient osseointegration, developments of new implant manufacturing strategies are indicated. Ultrafast laser surface texturing is a promising contact-free technology to modify the physicochemical properties of surfaces toward an anti-infectious functionalization. This work aims to texture Ti6Al4V surfaces with ultraviolet (UV) and green (GR) radiation for the manufacturing of laser-induced periodic surface structures (LIPSS). The assessment of these surface modifications addresses key aspects of topography, morphology and chemical composition. Human primary mesenchymal stromal cells (hMSCs) were cultured on laser-textured and polished Ti6Al4V to characterize the surfaces in terms of their in vitro biocompatibility, cytotoxicity, and metal release. The outcomes of the in vitro experiment show the successful culture of hMSCs on textured Ti6Al4V surfaces developed within this work. Cells cultured on LIPSS surfaces were not compromised in terms of their viability if compared to polished surfaces. Yet, the hMSC culture on UV-LIPSS show significantly lower lactate dehydrogenase and titanium release into the supernatant compared to polished. Thus, the presented surface modification can be a promising approach for future applications in orthodontics and orthopedics.

Titanium for Orthopedic Applications: An Overview of Surface Modification to Improve Biocompatibility and Prevent Bacterial Biofilm Formation

Titanium and its alloys have emerged as excellent candidates for use as orthopedic biomaterials. Nevertheless, there are often complications arising after implantation of orthopedic devices, most notably prosthetic joint infection and aseptic loosening. To ensure that implanted devices remain functional in situ, innovation in surface modification has attracted much attention in the effort to develop orthopedic materials with optimal characteristics at the biomaterial-tissue interface. This review will draw together metallurgy, surface engineering, biofilm microbiology, and biomaterial science. It will serve to appreciate why titanium and its alloys are frequently used orthopedic biomaterials and address some of the challenges facing these biomaterials currently, including the significant problem of device-associated infection. Finally, the authors shall consolidate and evaluate surface modification techniques employed to overcome some of these issues by offering a unique perspective as to the direction in which research is headed from a broad, interdisciplinary point of view.

Isolation of clinically significant microorganisms from prosthetic joint tissue using BacT/ALERT paediatric blood culture bottles compared with solid culture media and enrichment broth

The diagnosis of prosthetic joint infections and isolation of causative microorganisms has been found to be challenging in microbiology laboratories due to low sensitivity of microbiological culture. The aim of this study was to compare the use of conventional culture methods with the use of both enrichment broth and BacT/ALERT paediatric blood culture bottles, for the diagnosis of prosthetic joint infections. A total of 121 specimens from 44 patients were processed using three methods of microbiological culture: solid media, enrichment broth and paediatric bottles. The paediatric bottle method had a significantly lower (p<0.0001) time to detection than the standard solid media method, and was significantly more sensitive than solid media when used independently (93.33%, CI 83.27-98.09, vs 60.00%, CI 45.43-73.33). The combination use of solid media with paediatric bottles was found to be superior to the conventional solid media method and combination use with enrichment broth.

Alpha-Defensin versus Leukocyte Esterase in Periprosthetic Joint Infection: An Updated Meta-Analysis

Periprosthetic joint infection (PJI) is a devastating complication after arthroplasty. Prompt establishment of an infection diagnosis is critical but can be very challenging at present. In order to evaluate the diagnostic accuracy of alpha-defensin or leukocyte esterase for PJI, we performed systematic research in PubMed, Embase, and Cochrane Library to retrieve relevant studies. Data extraction and quality assessment were performed by two reviewers independently. A total of thirty-one eligible studies were finally included in the quantitative analysis. The pooled sensitivity and specificity of alpha-defensin (21 studies) for the diagnosis of PJI were 0.89 (95% confidence interval (CI), 0.83 to 0.93) and 0.96 (95% CI, 0.95 to 0.97), respectively. The value of the pooled diagnostic odds ratios (DOR) of alpha-defensin for PJI was 209.14 (95% CI, 97.31 to 449.50), and the area under the curve (AUC) was 0.98 (95% CI, 0.96 to 0.99). The pooled sensitivity and specificity of leukocyte esterase (17 studies) for the diagnosis of PJI were 0.90 (95% CI, 0.84 to 0.95) and 0.96 (95% CI, 0.93 to 0.97), respectively. The value of the DOR of leukocyte esterase for PJI was 203.23 (95% CI, 96.14 to 429.61), and the AUC was 0.98 (95% CI, 0.96 to 0.99). Based on the results of our meta-analysis, we can conclude that alpha-defensin and leukocyte esterase are valuable synovial fluid markers for identifying PJI with comparable high diagnostic accuracy.

An Antibiotic-Releasing Bone Void Filling (ABVF) Putty for the Treatment of Osteomyelitis

The number of total joint replacements (TJR) is on the rise with a corresponding increase in the number of infected TJR, which necessitates revision surgeries. Current treatments with either non-biodegradable, antibiotic-releasing polymethylmethacrylate (PMMA) based bone cement, or systemic antibiotic after surgical debridement do not provide effective treatment due to fluctuating antibiotic levels at the site of infection. Here, we report a biodegradable, easy-to-use "press-fitting" antibiotic-releasing bone void filling (ABVF) putty that not only provides efficient antibiotic release kinetics at the site of infection but also allows efficient osseointegration. The ABVF formulation was prepared using poly (D,L-lactide-co-glycolide) (PLGA), polyethylene glycol (PEG), and polycaprolactone (PCL) as the polymer matrix, antibiotic vancomycin, and osseointegrating synthetic bone PRO OSTEON for bone-growth support. ABVF was homogenous, had a porous structure, was moldable, and showed putty-like mechanical properties. The ABVF putty released vancomycin for 6 weeks at therapeutic level. Furthermore, the released vancomycin showed in vitro antibacterial activity against Staphylococcus aureus for 6 weeks. Vancomycin was not toxic to osteoblasts. Finally, ABVF was biodegradable in vivo and showed an effective infection control with the treatment group showing significantly higher bone growth (p < 0.001) compared to the control group. The potential of infection treatment and osseointegration makes the ABVF putty a promising treatment option for osteomyelitis after TJR.

Clinical effects of staged joint replacement in patients with septic arthritic knee

OBJECTIVE

To assess the clinical effect of staged joint replacement for the treatment of septic arthritic knee and the therapeutic differences between antibiotic cement beads and the tibial plateau spacer.

METHODS

Twenty-three patients (24 knee joints) treated with a staged joint replacement for septic arthritis knee were retrospectively reviewed between March 2014 and April 2018. At the first stage, thorough debridement and irrigation with self-made antibiotic cement beads or tibial plateau spacer were performed. After that, systemic antibiotic treatment was followed; when the infection was surely eliminated, the second-stage TKA was performed. Knee mobility (range of motion, abbreviated to ROM) and function (HSS scores system) were evaluated before surgery, in the interval period, and after joint replacement.

RESULTS

All patients finished follow-up, and the mean follow-up time was 27.3 months (12-54 months). Each group has one patient replaced with a homotypic spacer, and all patients eventually cleared the infection. None of the patients had a recurrent infection. The mobility and HSS scores of the two groups were significantly improved postoperation (p < 0.05). And there was no significant difference in the post-surgery ROM (p = 0.153) and the HSS score (p = 0.054) between the two groups.

CONCLUSION

Staged joint replacement is an efficacious way for septic arthritic knees, whether tibial plateau spacer or antibiotic cement beads were used, which can effectively control infection and improve knee function.