Prosthetic Joint Infections and Cost Analysis?

The Microbiology of Knee Prosthetic Joint Infection and its Influence on Persistent Infection

Periprosthetic joint infection (PJI) following total knee arthroplasty (TKA) is a severe complication causing a significant burden. The study aims were to establish the epidemiology of microorganisms in TKA PJI, the rate of persistent infection requiring further surgery, and the risk factors for this. Microbiological specimens between June 2002 and March 2017 at five regional hospital sites were identified with revision TKA procedures in the National Joint Replacement Registry. The time between procedures, type of revision strategy, and any subsequent further revision operations were collected. At minimum 2-year follow-up, 174 revision TKA were identified, with a mean patient age of 69 ± 11 years. A broad range of pathogens were identified. Fifty cases (29%) had persistent infection requiring at least one further operative procedure, 13 cases required 3 or more. Coagulase-negative Staphylococcus species (CNS) was seen most with failed surgery, polymicrobial infections also posing a significant risk factor. The best chance of a successful PJI surgical strategy was < 12 months from primary TKA, with the greatest risk between 3 and 5 years (p < 0.05). Younger age significantly increased the risk of further surgery (p < 0.05). Management varied; 103 (59%) debridement, antibiotic therapy and implant retention, with further surgery in 29%; 45 (17%) single-stage revision, with further surgery in 13%; and 26 (15%) two-stage revision, with further surgery in 12%. This study presents the most common causative pathogens for PJI in TKA, and the high rate of persistent infection after initial revision surgery. Risk factors for persistent infection and further revision surgery were polymicrobial and CNS infections, patients who presented between 3 and 5 years following primary TKA, and younger age. This study therefore raises important risk factors and areas for future research to reduce the burden of multiple operations after PJI.

Antibody-Drug Conjugates to Treat Bacterial Biofilms via Targeting and Extracellular Drug Release

The treatment of implant-associated bacterial infections and biofilms is an urgent medical need and a grand challenge because biofilms protect bacteria from the immune system and harbor antibiotic-tolerant persister cells. This need is addressed herein through an engineering of antibody-drug conjugates (ADCs) that contain an anti-neoplastic drug mitomycin C, which is also a potent antimicrobial against biofilms. The ADCs designed herein release the conjugated drug without cell entry, via a novel mechanism of drug release which likely involves an interaction of ADC with the thiols on the bacterial cell surface. ADCs targeted toward bacteria are superior by the afforded antimicrobial effects compared to the non-specific counterpart, in suspension and within biofilms, in vitro, and in an implant-associated murine osteomyelitis model in vivo. The results are important in developing ADC for a new area of application with a significant translational potential, and in addressing an urgent medical need of designing a treatment of bacterial biofilms.

Debridement, Antibiotics and Implant Retention: A Systematic Review of Strategies for Treatment of Early Infections after Revision Total Knee Arthroplasty

GOAL

The purpose of this review is to provide a systematic and comprehensive overview of the available literature on the treatment of an early prosthetic joint infection (PJI) after revision total knee arthroplasty (TKA) and provide treatment guidelines.

METHODS

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search was conducted using the electronic databases of PubMed, Trip, Cochrane, Embase, LILACS and SciElo. After the inclusion of the relevant articles, we extracted the data and results to compose a treatment algorithm for early and acute PJI after revision TKA.

RESULTS

After applying the in- and exclusion criteria, seven articles were included in this systematic review focusing on debridement, antibiotics and implant retention (DAIR) for PJI following revision TKA, of which one was prospective and six were retrospective. All studies were qualified as level IV evidence.

CONCLUSIONS

The current literature suggests that DAIR is a valid treatment option for early infections after revision TKA with success rates of 50-70%. Repeat DAIR shows success rates of around 50%. Further research should be aimed at predicting successful (repeat/two-stage) DAIRs in larger study populations, antibiotic regimes and the cost effectiveness of a second DAIR after revision TKA.

Alteration of m6A-Tagged RNA Profiles in Bone Originated from Periprosthetic Joint Infection

Periprosthetic joint infection (PJI) is a devastating complication. This study aimed to unravel the veil of the N⁶-methyladenine (m⁶A) modification in PJI. Synovium, synovial fluid, sonication fluid and bone samples were collected intraoperatively from Staphylococcus aureus PJI and aseptic failure (AF) patients. The overall m⁶A level was detected by the m⁶A RNA methylation quantification kit, and the expression of m⁶A-related genes was quantified by real-time PCR and Western blot. Finally, an epitranscriptomic microarray and bioinformatics analysis were performed. We showed that there was a significant difference in overall m⁶A level between the PJI group and the AF group (PJI group had a higher overall m⁶A level). The expression level of METTL3 was higher in the PJI group than that in the AF group. There were 2802 differential m⁶A-modified mRNAs. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that differential m⁶A-modified mRNAs were significantly enriched in the NOD-like receptor signaling pathway, Th17 cell differentiation and the IL-17 signaling pathway, which indicates that the m⁶A modification might be involved in the processes of infection and immune response, bone metabolism and programmed cell death in PJI. In summary, the present work demonstrated that m⁶A modification plays a role in PJI and might be a therapeutic target for developing effective treatment strategies.

Intravenous antibiotic duration in the treatment of prosthetic joint infection: systematic review and meta-analysis

Introduction: Long antibiotic courses, including intravenous (IV) and oral administrations, are utilized in prosthetic joint infection (PJI) treatment. This meta-analysis examines the non-inferiority of short courses ( <  4 weeks) of IV antibiotics compared to long courses in treating PJI. Critical review of IV treatment is necessary due to the clinical, physical, and financial burden associated with it and its continued prolonged use in the US without much evidence to support the practice. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), databases were searched using predefined medical subject headings (MeSH). Results: The nine included studies reported 521 total hip arthroplasties (THAs) and 530 total knee arthroplasties (TKAs). There was no significant difference in the overall success rate in short- vs. long-duration IV antibiotics for PJI treatment: odds ratio (OR) of 1.65, 95 % confidence interval (CI) of 0.78-3.46, and p = 0 .18. However, due to the moderate to high heterogeneity (I 2 = 68  %, p   <  0.01) amongst studies, an adjusted success rate was calculated after the exclusion of two studies. This showed a statistically significant difference between both groups (OR of 2.45, 95 % CI of 1.21-4.96, p   <  0.001) favoring a short course of antibiotics and reflecting a more homogenous population (I 2 = 51  %, p = 0 .06). Conclusion: This study highlights the limited data available for evaluating IV antibiotic duration in the setting of PJI. We found that a shorter duration of IV antibiotics was non-inferior to a longer duration, with an improved OR of 2.45 for treatment success, likely shortening inpatient stay as well as lessening side effects and antimicrobial resistance with a lower cost to patients and overall healthcare.

Prevalence of Bacterial Burden on Macroscopic Contaminants of Orthopaedic Surgical Instruments Following Sterilization

BACKGROUND

Macroscopic contamination of orthopaedic instruments with particulates, including cortical bone and polymethyl methacrylate (PMMA) cement, having previously undergone preoperative sterilization, is frequently encountered peri- or intraoperatively, calling into question the sterility of such instruments.

AIM

The purpose of this study is to determine if macroscopic contaminants of orthopaedic surgical instrumentation maintain a bacterial burden following sterile processing. Additionally, this manuscript looks to determine the most commonly contaminated instruments and what the most common contaminants are.

METHODS

At a single tertiary referral centre, we prospectively collected available macroscopic contaminants in orthopaedic instrument trays over a six month period from August 2021 to May 2022. When identified, these specimens were swabbed and plated on sheep blood agar. All specimens were incubated at 37°C for 14 days, and visually inspected for colony formation. When bacterial colony formation was identified, samples were sent for species identification.

RESULTS

A total of 33 contaminants were tested, with only one contaminant growing bacterial colonies which was found to be Corynebacterium. The items most commonly found to have macroscopic contamination were surgical trays (9) and cannulated drills. The identifiable contaminants were bone (10), PMMA bone cement (4), and hair (4). There were 11 macroscopic contaminants that were not identifiable.

CONCLUSION

This study found that 97% of macroscopic orthopaedic surgical instrument contaminants that underwent sterile processing did not possess a bacterial burden. Contaminants discovered during a procedure are likely to be sterile and do not pose a substantially increased risk of infection to a patient.

Local antibiotic treatment with calcium sulfate as carrier material improves the outcome of debridement, antibiotics, and implant retention procedures for periprosthetic joint infections after hip arthroplasty – a retrospective study

Abstract. Purpose: Debridement, antibiotics, and implant retention (DAIR) is an established treatment modality in periprosthetic joint infections (PJIs), but success rates vary. This study compared the success of DAIR for PJIs after a total hip arthroplasty (THA), with or without local antibiotic delivery with CaSO4 as the carrier material. Methods: A retrospective review of DAIR for PJIs after THA performed between 2010 and 2018, including 41 patients is conducted. A total of 27 patients were treated by DAIR with local antibiotics with CaSO4 as the carrier material, and 14 patients were treated by a standard DAIR. The endpoints were treatment failure, defined as the need for a reoperation, either a second DAIR or a prosthesis removal or exchange due to persistent or recurrent infection, the initiation of a long-term suppressive antibiotic treatment, or death related to infection. Results: Considering any reoperation as an outcome, 11 of 14 cases treated without AB-CaSO4 (79 %) and 4 of the 27 cases treated with AB-CaSO4 failed (15 %). Considering revision as an outcome, 9 out of 14 cases treated without AB-CaSO4 (64 %) and 4 of the 27 cases treated with AB-CaSO4 (15 %) failed. A Kaplan–Meier survival analysis showed that local antibiotic delivery with CaSO4 as the carrier material led to a significantly longer infection-free survival, considering any surgical revision (p<0.0001; hazard ratio 8.9 (95 % CI 2.8–28.2)) or revision with component exchange (p=0.0015; hazard ratio 5.6 (95 % CI 1.7–18.2)) as the endpoint. Conclusion: The addition of local antibiotics with CaSO4 as the carrier material to DAIR for PJIs after THA significantly increases success rates, such as infection-free survival, any reoperation, and revision with component exchange in particular.

Synovial calprotectin for the diagnosis of periprosthetic joint infection: a diagnostic meta-analysis

Background

Periprosthetic joint infections (PJI) are a rare but severe complication of total joint arthroplasty (TJA). However, the diagnosis of PJI remains difficult. It is one of the research that focuses about diagnosis for PJI for majority researchers to discover a novel biomarker. This meta-analysis tried to evaluate diagnostic value of synovial calprotectin for PJI.

Methods

This meta-analysis search of the literature was conducted in PubMed, EMBASE, Web of Science, and the Cochrane Library. Literature quality was appraised using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) based on RevMan (version 5.3). The diagnostic value of calprotectin for PJI was evaluated by calculating sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), diagnostic score and area under SROC (AUC) based on the Stata version 14.0 software. We conduct subgroup analysis according to the study design, cutoff values, the country of study, and gold standard.

Results

Seven studies were included in this meta-analysis. The pooled sensitivity of synovial calprotectin for the diagnosis of PJI was 0.94 (95% CI, 0.87–0.98), and the specificity was 0.93 (95% CI, 0.87–0.96). The pooled AUC, PLR, and NLR for synovial calprotectin were 0.98 (95% CI, 0.96–0.99), 13.65 (95% CI, 6.89–27.07), and 0.06 (95% CI, 0.02–0.15), respectively. The pooled diagnostic score and DOR were 5.4 (95% CI, 3.96–6.85) and 222.32 (95% CI, 52.52–941.12), respectively.

Conclusion

In summary, this meta-analysis indicates that synovial calprotectin is a promising biomarker of assistant diagnosis for PJI, as well as recommended test for excluding diagnostic tool.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02746-2.

Long-term antibacterial properties of a nanostructured titanium alloy surface: An in vitro study

The demand for joint replacement and other orthopedic surgeries involving titanium implants is continuously increasing; however, 1%-2% of surgeries result in costly and devastating implant associated infections (IAIs). Pseudomonas aeruginosa and Staphylococcus aureus are two common pathogens known to colonise implants, leading to serious complications. Bioinspired surfaces with spike-like nanotopography have previously been shown to kill bacteria upon contact; however, the longer-term potential of such surfaces to prevent or delay biofilm formation is unclear. Hence, we monitored biofilm formation on control and nanostructured titanium disc surfaces over 21 days following inoculation with Pseudomonas aeruginosa and Staphylococcus aureus. We found a consistent 2-log or higher reduction in live bacteria throughout the time course for both bacteria. The biovolume on nanostructured discs was also significantly lower than control discs at all time points for both bacteria. Analysis of the biovolume revealed that for the nanostructured surface, bacteria was killed not just on the surface, but at locations above the surface. Interestingly, pockets of bacterial regrowth on top of the biomass occurred in both bacterial species, however this was more pronounced for S. aureus cultures after 21 days. We found that the nanostructured surface showed antibacterial properties throughout this longitudinal study. To our knowledge this is the first in vitro study to show reduction in the viability of bacterial colonisation on a nanostructured surface over a clinically relevant time frame, providing potential to reduce the likelihood of implant associated infections.

Nanomedicine to fight infectious disease

The ubiquity and potency of antibiotics may give the false impression that infection is a solved problem. Unfortunately, even bacterial infections, the target of antibiotics, remain a major cause of illness and death. Several major unmet needs persist: biofilms, such as those on implanted hardware, largely resist antibiotics; the inflammatory host response to infection often produces more damage than the infection itself; and systemic antibiotics often decimate the gut microbiome, which can predispose to additional infections and even predispose to non-infectious diseases. Additionally, there is an increasing threat from multi-drug resistant microorganisms, though market forces may continue to inhibit innovation in this realm. These numerous unmet infection-related needs provide attractive goals for innovation of targeted drug delivery technologies, especially those of nanomedicine. Here we review several of those innovations in pre-clinical development, the two such therapies which have made it to clinical use, and the opportunities for further technology development for treating infections.

Debridement, antibiotics, and implant retention combined with direct intra-articular antibiotic infusion in patients with acute hematogenous periprosthetic joint infection of the knee

Background

Debridement, antibiotics, and implant retention (DAIR) is the recommended treatment for acute hematogenous periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). However, DAIR is associated with a high percentage of unsuccessful outcomes. Since 2007, direct intra-articular antibiotic infusion, which can provide a high concentration of intra-articular antibiotic, has been used in combination with DAIR to improve treatment outcomes among patients in our institution. This study aimed to assess the outcomes of DAIR combined with direct intra-articular antibiotic infusion in patients who presented with acute hematogenous PJI after TKA.

Methods

We reviewed the data of all patients diagnosed with acute hematogenous PJI after primary TKA (from 2008 to 2015) who received DAIR combined with direct intra-articular antibiotic infusion.

Results

In total, 15 knees in 12 patients were semi-urgently treated with this method. The mean follow-up time was 93.3 (minimum: 56) months, and the longest follow-up time was 11 years. Two patients (n = 3 knees) had a well-functioning, non-infected prosthesis 6 and 10 years after the procedure. Two patients (n = 2 knees) had re-infection 2 and 5 years after surgery, and they required two-stage revision. None of the patients were lost to follow-up. Finally, 13 (86.6%) of 15 infected knees were successfully treated with this method.

Conclusions

DAIR combined with direct intra-articular antibiotic infusion is an effective treatment for acute hematogenous PJI after TKA.

Assessing the Bioactive Profile of Antifungal-Loaded Calcium Sulfate against Fungal Biofilms

Calcium sulfate (CS) has been used clinically as a bone- or void-filling biomaterial, and its resorptive properties have provided the prospect for its use as a release mechanism for local antibiotics to control biofilms. Here, we aimed to test CS beads loaded with three antifungal drugs against planktonic and sessile fungal species to assess whether these antifungal beads could be harnessed to provide consistent release of antifungals at biofilm-inhibitory doses. A panel of different fungal species (n = 15) were selected for planktonic broth microdilution testing with fluconazole (FLZ), amphotericin B (AMB), and caspofungin (CSP). After establishing planktonic inhibition, antifungal CS beads were introduced to fungal biofilms (n = 5) to assess biofilm formation and cell viability through a combination of standard quantitative and qualitative biofilm assays. Inoculation of a hydrogel substrate, packed with antifungal CS beads, was also used to assess diffusion through a semidry material, to mimic active infection in vivo In general, antifungals released from loaded CS beads were all effective at inhibiting the pathogenic fungi over 7 days within standard MIC ranges for these fungi. We observed a significant reduction of pregrown fungal biofilms across key fungal pathogens following treatment, with visually observable changes in cell morphology and biofilm coverage provided by scanning electron microscopy. Assessment of biofilm inhibition also revealed reductions in total and viable cells across all organisms tested. These data show that antifungal-loaded CS beads produce a sustained antimicrobial effect that inhibits and kills clinically relevant fungal species in vitro as planktonic and biofilm cells.

Economic Study of 2-Stage Exchange in Patients With Knee or Hip Prosthetic Joint Infection Managed in a Referral Center in France: Time to Use Innovative(s) Intervention(s) at the Time of Reimplantation to Reduce the Risk of Superinfection

Objective: Chronic prosthetic joint infections (PJI) are serious complications in arthroplasty leading to prosthesis exchange and potential significant costs for health systems, especially if a subsequent new infection occurs. This study assessed the cost of chronic PJI managed with 2-stage exchange at the Lyon University Hospital, CRIOAc Lyon reference center, France. A threshold analysis was then undertaken to determine the reimbursement tariff of a hypothetical preventive device usable at the time of reimplantation, which possibly enables health insurance to save money according to the risk reduction of subsequent new infection. This analysis was also performed for a potential innovative device already available on the market, a dual antibiotic loaded bone cement used to fix cemented prosthesis that releases high concentrations of gentamicin and vancomycin locally (G+V cement). Method: Patients >18 years, admitted for a hip or knee chronic PJI managed with 2-stage exchange, between January 1, 2013, and December 31, 2015, were retrospectively identified. Following, resource consumption in relation to inpatient hospital stay, hospitalization at home, rehabilitation care, outpatient antibiotic treatments, imaging, laboratory analysis, and consultations were identified and collected from patient records and taken into account in the evaluation. Costs were assessed from the French health insurance perspective over the 2 years following prosthesis reimplantation. Results: The study included 116 patients (median age 67 y; 47% hip prosthesis). Mean cost of chronic PJI was estimated over the 2 years following prosthesis reimplantation at €21,324 for all patients, and at €51,697 and €15,745 for patients with (n = 18) and without (n = 98) a subsequent new infection after reimplantation, respectively. According to the threshold analysis the reimbursement tariff (i) should not exceed €2,820 for a device which can reduce the risk of a new infection by 50% and (ii) was between €2,988 and €3,984 if the G + V cement can reduce the risk of a new infection by 80% (this reduction risk is speculative and has to be confirmed by clinical trials). Conclusion: This study revealed that chronic PJI requiring a 2-stage revision is costly, with significant costs in relation to the reimplantation procedure (about 15 k€). However, following reimplantation the rate of subsequent new infection remained high, and the cost of reimplantation following a new infection is considerable, reaching 50k€ per patient. These first cost estimates of managing chronic PJI with 2-stage exchange in France underline the economic interest of preventing new infections.

Effectiveness of early switching from intravenous to oral antibiotic therapy in Staphylococcus aureus prosthetic bone and joint or orthopedic metalware-associated infections

Background

The optimal duration of intravenous antibiotic therapy in Staphylococcus aureus prosthetic bone and joint infection has not been established. The objective of this study was to compare the effect of early and late intravenous-to-oral antibiotic switch on treatment failure.

Patients and methods

We retrospectively analyzed all adult cases of S. aureus prosthetic bone and joint or orthopedic metalware-associated infection between January 2008 and December 2015 in a French university hospital. The primary outcome was treatment failure defined as the recurrence of S. aureus prosthetic bone and joint or orthopedic metalware-associated infection at any time during or after the first line of medical and surgical treatment within 2 years of follow-up. A Cox model was created to assess risk factors for treatment failure.

Results

Among the 140 patients included, mean age was 60.4 years (SD 20.2), and 66% were male (n = 92). Most infections were due to methicillin-susceptible S. aureus (n = 113, 81%). The mean duration of intravenous antibiotic treatment was 4.1 days (SD 4.6). The majority of patients (119, 85%) had ≤5 days of intravenous therapy. Twelve patients (8.5%) experienced treatment failure. Methicillin-resistant S. aureus infections (HR 11.1; 95% CI 1.5–111.1; p = 0.02), obesity (BMI > 30 kg/m²) (HR 6.9; 95% CI1.4–34.4, p = 0.02) and non-conventional empiric antibiotic therapy (HR 7.1; 95% CI 1.8–25.2; p = 0.005) were significantly associated with treatment failure, whereas duration of intravenous antibiotic therapy (≤ 5 or > 5 days) was not.

Conclusion

There was a low treatment failure rate in patients with S. aureus prosthetic bone and joint or orthopedic metalware-associated infection with early oral switch from intravenous to oral antibiotic therapy.

Chitosan and Hydroxyapatite Based Biomaterials to Circumvent Periprosthetic Joint Infections

Every year, worldwide, millions of people suffering from joint pain undergo joint replacement. For most patients, joint arthroplasty reduces pain and improve function, though a small fraction will experience implant failure. One of the main reasons includes prosthetic joint infection (PJI), involving the prosthesis and adjacent tissues. Few microorganisms (MO) are required to inoculate the implant, resulting in the formation of a biofilm on its surface. Standard treatment includes not only removal of the infected prosthesis but also the elimination of necrotic bone fragments, local and/or systemic administration of antibiotics, and revision arthroplasty with a new prosthesis, immediately after the infection is cleared. Therefore, an alternative to the conventional therapeutics would be the incorporation of natural antimicrobial compounds into the prosthesis. Chitosan (Ch) is a potential valuable biomaterial presenting properties such as biocompatibility, biodegradability, low immunogenicity, wound healing ability, antimicrobial activity, and anti-inflammatory potential. Regarding its antimicrobial activity, Gram-negative and Gram-positive bacteria, as well as fungi are highly susceptible to chitosan. Calcium phosphate (CaP)-based materials are commonly utilized in orthopedic and dentistry for their excellent biocompatibility and bioactivity, particularly in the establishment of cohesive bone bonding that yields effective and rapid osteointegration. At present, the majority of CaP-based materials are synthetic, which conducts to the depletion of the natural resources of phosphorous in the future due to the extensive use of phosphate. CaP in the form of hydroxyapatite (HAp) may be extracted from natural sources as fish bones or scales, which are by-products of the fish food industry. Thus, this review aims to enlighten the fundamental characteristics of Ch and HAp biomaterials which makes them attractive to PJI prevention and bone regeneration, summarizing relevant studies with these biomaterials to the field.

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.

Prevention of infection in primary THA and TKA

Rates of peri-prosthetic joint infection (PJI) in primary total hip and total knee arthroplasty range between 0.3% and 1.9%, and up to 10% in revision cases. Significant morbidity is associated with this devastating complication, the economic burden on our healthcare system is considerable, and the personal cost to the affected patient is immeasurable.

The risk of surgical site infection (SSI) and PJI is related to surgical factors and patient factors such as age, body mass index (BMI), co-morbidities, and lifestyle. Reducing the risk of SSI in primary hip and knee arthroplasty requires a multi-faceted strategy including pre-operative patient bacterial decolonization, screening and avoidance of anaemia, peri-operative patient warming, skin antisepsis, povidone-iodine wound lavage, and anti-bacterial coated sutures.

This article also considers newer concepts such as the influence of bearing surfaces on infection risk, as well as current controversies such as the potential effects of blood transfusion, laminar flow, and protective hoods and suits, on infection risk.

Cite this article: EFORT Open Rev 2020;5:604-613. DOI: 10.1302/2058-5241.5.200004

Severe adverse events during medical and surgical treatment of hip and knee prosthetic joint infections

INTRODUCTION

The management of prosthetic joint infection requires a complex treatment procedure and can be associated with complications. However, the occurrence of severe adverse events during this intervention has been poorly evaluated.

PATIENTS AND METHODS

A 5-year multicentric retrospective study including patients from 3 hospitals in the South-Western France referral center for complex bone and joint infections (Crioac GSO) and treated for hip or knee prosthetic joint infection with 1 or 2-stage implant exchanges. The objective was to describe grade≥3 adverse events, according to the CTCAE classification, occurring within 6 weeks after surgery and to identify their associated factors.

RESULTS

One hundred and eighteen patients were identified. We observed 71 severe events in 50 patients (42.3%; 95% confidence interval [CI95%]: 33.8-51.4%). Sixteen severe events were an evolution of the infection. The remaining 55 others (47 grade 3 and 8 grade 4) occurred in 41 patients (34.7%; CI95%: 26.8-43.7%). They were distributed as follows: 27 (49.1%) medical complications, 21 (38.2%) surgical complications and 7 (12.7%) antibiotic-related complications. The main identified risk factor was a two-stage prosthetic exchange with OR=3.6 (CI95% [1.11-11.94], P=0.032). Obesity was limit of significance with OR=3.3 (CI95% [0.9-12.51], P=0.071). Infection with coagulase negative Staphylococcus was a protective factor with OR=0.3 (CI95% [0.12-0.99], P=0.047).

CONCLUSION

Severe adverse events are frequent following prosthetic exchange for PJI (34.7%) and are related to the high frequency of comorbidities in this population and to the complex surgical procedures required. The risk factor significantly associated with these events was a two-stage exchange.

The application of ceragenins to orthopedic surgery and medicine

Osteomyelitis and infections associated with orthopedic implants represent a significant burden of disease worldwide. Ceragenins (CSAs) are a relatively new class of small-molecule antimicrobials that target a broad range of Gram-positive and Gram-negative bacteria as well as fungi, viruses, and parasites. This review sets the context of the need for new antimicrobial strategies by cataloging the common pathogens associated with orthopedic infection and highlighting the increasing challenges of managing antibiotic-resistant bacterial strains. It then comparatively describes the antimicrobial properties of CSAs with a focus on the CSA-13 family. More recently developed members of this family such as CSA-90 and CSA-131 may have a particular advantage in an orthopedic setting as they possess secondary pro-osteogenic properties. In this context, we consider several new preclinical studies that demonstrate the utility of CSAs in orthopedic models. Emerging evidence suggests that CSAs are effective against antibiotic-resistant Staphylococcus aureus strains and can prevent the formation of biofilms. There remains considerable scope for developing CSA-based treatments, either as coatings for orthopedic implants or as local or systemic antibiotics to prevent bone infection.

Metagenomic next generation sequencing improves diagnosis of prosthetic joint infection by detecting the presence of bacteria in periprosthetic tissues

OBJECTIVES

The purpose of this study was to explore the role of mNGS in the diagnosis of PJI by detecting the presence of bacteria in periprosthetic tissues.

METHODS

Patients who were suspected of PJI and underwent surgery in our center were enrolled. Microbial culture and mNGS were performed on periprosthetic tissues collected intraoperatively. Patient age, body mass index (BMI), laboratory tests, microbial culture and mNGS results were recorded. The diagnostic performance of microbial culture and mNGS in the diagnosis of PJI was compared.

RESULTS

A total of 44 patients were included. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of periprosthetic tissue microbial culture in the diagnosis of PJI were 72.72%, 77.27%, 76.19%, 73.91% and 75%, respectively. The sensitivity, specificity, PPV, NPV and accuracy of periprosthetic tissue mNGS in the diagnosis of PJI were 95.45%, 90.91%, 91.3%, 95.24% and 93.18%, respectively. The sensitivity and specificity of mNGS in the diagnosis of PJI were superior to those of microbial culture.

CONCLUSION

Periprosthetic tissue can be used as an alternative to synovial fluid and sonication fluid, as mNGS can improve the diagnosis of PJI. mNGS of the periprosthetic tissues showed higher sensitivity than microbial culture.

Poor outcome of octogenarians admitted to ICU due to periprosthetic joint infections: a retrospective cohort study

Background

Even though surgical techniques and implants have evolved, periprosthetic joint infection (PJI) remains a serious complication leading to poor postoperative outcome and a high mortality. The literature is lacking in studies reporting the mortality of very elderly patients with periprosthetic joint infections, especially in cases when an intensive care unit (ICU) treatment was necessary. We therefore present the first study analyzing patients with an age 80 and higher suffering from a periprosthetic joint infection who had to be admitted to the ICU.

Methods

All patients aged 80 and higher who suffered from a PJI (acute and chronic) after THR or TKR and who have been admitted to the ICU have been included in this retrospective, observational, single-center study.

Results

A total of 57 patients met the inclusion criteria. The cohort consisted of 24 males and 33 females with a mean age of 84.49 (± 4.0) years. The mean SAPS II score was 27.05 (± 15.7), the mean CCI was 3.35 (± 2.28) and the most patient had an ASA score of 3 or higher. The PJI was located at the hip in 71.9% or at the knee in 24.6%. Two patients (3.5%) suffered from a PJI at both locations. Sixteen patients did not survive the ICU stay. Non-survivors showed significantly higher CCI (4.94 vs. 2.73; p = 0.02), higher SAPS II score (34.06 vs. 24.32; p = 0.03), significant more patients who underwent an invasive ventilation (132.7 vs. 28.1; p = 0.006) and significantly more patients who needed RRT (4.9% vs. 50%; p < 0.001). In multivariate analysis, RRT (odds ratio (OR) 15.4, CI 1.69–140.85; p = 0.015), invasive ventilation (OR 9.6, CI 1.28–71.9; p = 0.028) and CCI (OR 1.5, CI 1.004–2.12; p = 0.048) were independent risk factors for mortality.

Conclusion

Very elderly patients with PJI who needs to be admitted to the ICU are at risk to suffer from a poor outcome. Several risk factors including a chronic infection, high SAPS II Score, high CCI, invasive ventilation and RRT might be associated with a poor outcome.

Preoperative Vitamin D Repletion in Total Knee Arthroplasty: A Cost-Effectiveness Model

BACKGROUND

Recent studies have identified vitamin D deficiency (serum 25-hydroxyvitamin D [25(OH)D] < 20 ng/L) as a potentially modifiable risk factor for prosthetic joint infection (PJI) in arthroplasty. The purpose of this study is to determine whether implementation of preoperative 25(OH)D repletion is cost-effective for reducing PJI following total knee arthroplasty (TKA).

METHODS

A cost estimation predictive model was generated to determine the utility of both selective and nonselective 25(OH)D repletion in primary TKA to prevent PJI. Input data on the incidence of 25(OH)D deficiency, relative complication rates, and costs of serum 25(OH)D repletion and 2-stage revision for PJI were derived from previously published literature identified using systematic review and publicly available data from Medicare reimbursement schedules. Mean, lower, and upper bounds of 1-year cost savings were computed for nonselective and selective repletion relative to no repletion.

RESULTS

Selective preoperative 25(OH)D screening and repletion were projected to result in $1,504,857 (range, $215,084-$4,256,388) in cost savings per 10,000 cases. Nonselective 25(OH)D repletion was projected to result in $1,906,077 (range, $616,304-$4,657,608) in cost savings per 10,000 cases. With univariate adjustment, nonselective repletion is projected to be cost-effective in scenarios where revision for PJI costs ≥$10,636, incidence of deficiency is ≥1.1%, and when repletion has a relative risk reduction ≥4.2%.

CONCLUSION

This predictive model supports the potential role of 25(OH)D repletion as a cost-effective mechanism of reducing PJI risk in TKA. Given the low cost of 25(OH)D repletion relative to serum laboratory testing, nonselective repletion appears to be more cost-effective than selective repletion. Further prospective investigation to assess this modifiable risk factor is warranted.

Serial C-reactive Protein Monitoring in Prosthetic Joint Infection: A Powerful Predictor or Potentially Pointless?

Background Serum C-reactive protein (CRP) is an important test in the initial diagnosis of prosthetic joint infection (PJI). There is no widely accepted algorithm for the resolution of PJI. Surgeons have traditionally used CRP to determine if the infection has resolved. However, this practice is not currently supported by significant data.  Methods A retrospective analysis of our departmental arthroplasty database was conducted to determine mean values of CRP pre and postoperatively for PJI treated with the debridement, antibiotics and implant retention (DAIR) procedure, single-stage revision and two-stage revision. Receiver operating characteristic (ROC) curves were calculated to determine the sensitivity and specificity of CRP testing in diagnosing persistent infection. Results Of the 121 patients who had undergone treatment (75 hip replacements and 48 knee replacements), there were 26 cases of persistent infection. There was no statistical significance in the mean CRP values between successful and unsuccessful treatment groups. The areas under ROCs (AUCs) for CRP values predicting outcomes ranged from 0.46 to 0.73. Conclusion Our study does not support the use of serial CRP monitoring as an indicator of the successful eradication of PJI.

Genotypic and phenotypic changes of Staphylococcus epidermidis during relapse episodes in prosthetic joint infections

Staphylococcus epidermidis is a coagulase-negative bacterium capable of causing recurrent relapses in prosthetic joint infection (PJI). The aim of this study was to determine if Staphylococcus epidermidis isolates from patients with recurrent relapses of prosthetic joint infection (PJI) changed genotypically (pulsed-field gel electrophoresis (PFGE) pattern analysis and genes involved in biofilm formation) and phenotypically (antimicrobial resistance, biofilm formation) during the different episodes. Four patients with PJI recurrent relapses were evaluated clinically and microbiologically. Genotypic and phenotypic characteristics of 31 S. epidermidis isolates were determined. In all cases, PJI was treated with antimicrobial therapy and resection of the prosthesis without reimplantation. Months later, all patients had a relapse episode and treated with rifampin plus vancomycin and surgical debridement. Changes in the antibiotics resistance profile in isolates from patients 1 and 2 were observed in the two episodes. Patient 1 had four clones A, B, C, and D that were distributed differentially in the two episodes. Similarly, patients 2 and 3 had two clones and subclones (E-E1 and F-F1, respectively), and patient 4 had only the clone G in both episodes. The clone F formed small-colony variants (SCVs). High level of biofilm formation was found in all clones, except for clones D and G. Clones/subclones showed a genotypic variation in icaA, sdrF, bap, sesI, and embp genes. The principal coordinate analysis showed that all clones/subclones were different. These results showed that the initial infective clone of S. epidermidis from PJI, changed genotypically and phenotypically after a second relapse as a response to the treatment.

Synergistic Activity of Fosfomycin, Ciprofloxacin, and Gentamicin Against Escherichia coli and Pseudomonas aeruginosa Biofilms

Gram-negative (GN) rods cause about 10% periprosthetic joint infection (PJI) and represent an increasing challenge due to emergence of antimicrobial resistance. Escherichia coli and Pseudomonas aeruginosa are among the most common cause of GN-PJI and ciprofloxacin is the first-line antibiotic. Due to emergence of fluoroquinolone resistance, we evaluated in vitro the activity of fosfomycin, ciprofloxacin, and gentamicin, alone and in combinations, against E. coli and P. aeruginosa biofilms. Conventional microbiological tests and isothermal microcalorimetry were applied to investigate the anti-biofilm activity of the selected antibiotics against standard laboratory strains as well as clinical strains isolated from patients with prosthetic joint associated infections. The biofilm susceptibility to each antibiotic varied widely among strains, while fosfomycin presented a poor anti-biofilm activity against P. aeruginosa. Synergism of two-pair antibiotic combinations was observed against different clinical strains from both species. Highest synergism was found for the fosfomycin/gentamicin combination against the biofilm of E. coli strains (75%), including a gentamicin-resistant but fosfomycin-susceptible strain, whereas the gentamicin/ciprofloxacin combination presented synergism with higher frequency against the biofilm of P. aeruginosa strains (71.4%). A hypothetical bacteriolysis effect of gentamicin could explain why combinations with this antibiotic seem to be particularly effective. Still, the underlying mechanism of the synergistic effect on biofilms is unknown. In conclusion, combinatorial antibiotic application has shown to be more effective against biofilms compared to monotherapy. Further in vivo and clinical studies are essential to define the potential treatment regimen based on our results.

Health Care Costs of Post-traumatic Osteomyelitis in China: Current Situation and Influencing Factors

BACKGROUND

Currently, very limited information is available regarding the economic burdens of patients with extremity post-traumatic osteomyelitis (OM). This study aimed to investigate direct health care costs and utilization for inpatients with extremity post-traumatic OM and analyze its constituent ratios and influencing factors in Southern China.

METHODS

We searched in the electronic medical record system for inpatients who had received surgical interventions at our department between 2013 and 2016 for extremity post-traumatic OM. Data of direct health care costs incurred during their hospitalizations were collected in six main categories (service, diagnosis, treatment, materials, pharmaceuticals, and miscellaneous expenses). In addition, data of total medical costs for contemporaneous inpatients with non-post-traumatic OM were also collected as controls.

RESULTS

A total of 278 post-traumatic OM and 10,420 controls were included. The median cost for the post-traumatic OM inpatients was $10,504 US dollars, 4.8-fold higher than that for those with non-post-traumatic OM ($2189, P < 0.001). The direct cost in the category of materials accounted for the largest proportion (61%), followed by that in pharmaceuticals (12%) and treatment (11%). The median number of hospital admissions for post-traumatic OM patients was 1 time, with a median length-of-stay of 22 d. The most influencing factors for the health care costs of the post-traumatic OM inpatients were use of an external fixator ($16,016 for those who used versus $4956 for those who did not, P < 0.001), external fixator type ($19,563 for ring fixator versus $14,966 for rail fixator, P < 0.001), infection site ($13,755 for tibia, $14,216 for femur and $5673 for calcaneus, P < 0.001), and infection-associated injury type ($12,890 for infection after open fracture versus $8087 for infection after closed fracture, P = 0.001).

CONCLUSIONS

An unexpectedly large proportion of the direct health care costs for inpatients with extremity post-traumatic OM went to cover an external fixator, with expenses for pharmaceuticals and treatment accounting for only a little more than the tenth of the total health care costs. Use of external fixator, external fixator type, infection site, and infection-associated injury type directly influenced the health care costs.

Cost-analysis of inpatient and outpatient parenteral antimicrobial therapy in orthopaedics: A systematic literature review

BACKGROUND

Increasing numbers of total joint arthroplasties and consecutive revision surgery are associated with the risk of periprosthetic joint infections (PPJI). Treatment of PPJI is complex and associated with immense socio-economic burden. One treatment aspect is parenteral antiinfective therapy, which usually requires an inpatient setting [Inpatient parenteral antibiotic therapy (IPAT)]. An alternative is outpatient parenteral treatment [Outpatient parenteral antibiotic therapy (OPAT)]. To conduct a health economic cost-benefit analysis of OPAT, a detailed cost analysis of IPAT and OPAT is required. So far, there is a lack of knowledge on the health economic effects of IPAT and OPAT for PPJI.

AIM

To review an economic comparison of IPAT and OPAT.

METHODS

A systematic literature review was performed through Medline following the PRISMA guidelines.

RESULTS

Of 619 identified studies, 174 included information of interest and 21 studies were included for quantitative analysis of OPAT and IPAT costs. Except for one study, all showed relevant cost savings for OPAT compared to IPAT. Costs for IPAT were between 1.10 to 17.34 times higher than those for OPAT.

CONCLUSION

There are only few reports on OPAT for PPJI. Detailed analyses to support economic or clinical guidelines are therefore limited. There is good clinical evidence supporting economic benefits of OPAT, but more high quality studies are needed for PPJI.

The Cost Effectiveness of Dilute Betadine Lavage for Infection Prophylaxis in Total Joint Arthroplasty

BACKGROUND

This article presents a break-even analysis for intraoperative Betadine lavage for the prevention of infection in total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

Protocol costs, baseline infection rates after arthroplasty, and average revision costs were obtained from institutional records and the literature. The break-even analysis determined the absolute risk reduction (ARR) in infection rate required for cost effectiveness.

RESULTS

At our institutional price of $2.54, dilute (0.35%) Betadine lavage would be cost effective if initial infection rates of both TKA (1.10%) and THA (1.63%) have an ARR of 0.01%. At a hypothetical lowest cost of $0.50, the ARR is so low as to be immediately cost effective. At a hypothetical high price of $40.00, Betadine is cost effective with ARRs of 0.16% (TKA) and 0.13% (THA).

CONCLUSION

Intraoperative Betadine lavage, at typical institutional prices, can be highly cost effective in reducing infection after joint arthroplasty.

Does the form of venous thromboembolism prophylaxis following primary total knee arthroplasty alter the rate of early reoperation or revision surgery?

BACKGROUND

Currently there is significant variation in the management of venous thromboembolism prophylaxis following total knee arthroplasty (TKA). Excessive wound ooze and bleeding is thought to increase a patient's risk of haematoma formation and possible infection. We evaluated the rate of unexpected reoperation in the perioperative period in patients who received aspirin, rivaroxaban or enoxaparin following primary TKA.

METHOD

A systematic literature search was conducted in MEDLINE, CENTRAL and Embase to identify patients who underwent primary TKA. Two researchers independently reviewed the references identified in the literature search. The final 11 studies included for review were published between 1996 and 2016.

RESULTS

There was a higher rate of reoperation in patients treated with aspirin following TKA when compared to enoxaparin and rivaroxaban in the perioperative period. Of the 5141 patients treated with enoxaparin, 11 (0.21%) required reoperation; of the 2764 patients treated with rivaroxaban, 12 (0.43%) required reoperation; and of the 228 patients treated with aspirin, seven (3.07%) required reoperation. The average time to follow-up in the 11 studies was 55 days, ranging from 30 to 180 days post-operatively.

CONCLUSION

There was a higher rate of reoperation in patients treated with aspirin following TKA when compared to enoxaparin and rivaroxaban in the perioperative period. While there is extensive data on the safety and efficacy of these medications following joint arthroplasty, improved reporting of surgically relevant outcomes are needed to assist both the surgeon and patient in clinical decision-making.

Association between Allogeneic Blood Transfusion and Wound Infection after Total Hip or Knee Arthroplasty: A Retrospective Case-Control Study

Background: To assess using a retrospective case control study, whether patients undergoing primary, elective total hip or knee arthroplasty who receive blood transfusion have a higher rate of post-operative infection compared to those who do not.

Materials and Methods: Data on elective primary total hip or knee arthroplasty patients, including patient characteristics, co-morbidities, type and duration of surgery, blood transfusion, deep and superficial infection was extracted from the Alberta Bone and Joint Health Institute (ABJHI). Logistic regression analysis was used to compare deep infection and superficial infection in blood-transfused and non-transfused cohorts.

Results: Of the 27892 patients identified, 3098 (11.1%) received blood transfusion (TKA 9.7%; THA 13.1%). Overall, the rate of superficial infection (SI) was 0.5% and deep infection (DI) was 1.1%. The infection rates in the transfused cohort were SI 1.0% and DI 1.6%, and in the non-transfused cohort were SI 0.5% and DI 1.0%. The transfused cohort had an increased risk of superficial infection (adjusted odds ratio (OR) 1.9 [95% CI 1.2-2.9, p-value 0.005]) as well as deep infection (adjusted OR 1.6 [95% CI 1.1-2.2, p-value 0.008]).

Conclusion: The odds of superficial and deep wound infection are significantly increased in primary, elective total hip and knee arthroplasty patients who receive blood transfusion compared to those who did not. This study can potentially help in reducing periprosthetic hip or knee infections.

Tailored antimicrobial activity and long-term cytocompatibility of plasma polymer silver nanocomposites

The deposition of coatings enabling antibacterial properties in combination with cytocompatibility remains a challenge for biomaterial applications, such as in medical devices. Silver is one of the most utilized antibacterial surface components, due to its efficacy and extensive applicability. In this work, silver-containing plasma polymer nanocomposites (single layer and multilayers) were developed and tested, with a focus on cytotoxicity and bactericidal function, on the NIH3T3 mammalian cell line as well as Gram-negative ( Pseudomonas aeruginosa) and Gram-positive ( Staphylococcus aureus) bacterial strains. The data demonstrate that a tuneable Ag⁺ release is required, allowing sufficient antimicrobial activity while retaining appropriate cytocompatibility over the entire testing period of up to eight days.

Intrawound vancomycin in primary hip and knee arthroplasty: a safe and cost-effective means to decrease early periprosthetic joint infection

Background

Periprosthetic joint infection (PJI) is a devastating complication after hip and knee arthroplasty. Intrawound vancomycin has been described extensively in the spine literature; however, information regarding use in arthroplasty is limited. We investigate the efficacy and safety of intrawound vancomycin in arthroplasty surgery.

Methods

All primary total hip and knee arthroplasty cases (n = 460) performed by a single surgeon from April 2016 to October 2017 were reviewed. Starting in October 2016, intrawound vancomycin was used in all total joints. Baseline characteristics, infection rates, 90-day readmission, and other complications were compared between untreated subjects and those who received intrawound vancomycin. In addition, cost data were considered. Mean follow-up durations for the control and vancomycin groups were 11.3 and 7.7 months, respectively.

Results

Baseline characteristics and comorbidities were similar for the control (n = 112) and vancomycin groups (n = 348). The vancomycin cohort demonstrated decreased both overall infection rate (0.57% vs 2.7%; P = .031) and PJI rate (0.29% vs 2.7%; P = .009) compared with the untreated group. There was no statistical difference in incidence of ototoxicity or acute kidney injury. Although there was no difference in overall 90-day readmission rate, the vancomycin subset demonstrated lower readmission rate due to infection (0.57% vs 2.7%; P = .031). Based on the cost of vancomycin powder and calculated number needed to treat (NNT = 47.5), the cost to prevent 1 infection with the addition of intrawound vancomycin was $816.

Conclusions

These findings suggest that intrawound vancomycin may be a safe, cost-effective means that shows promise in reducing PJI in early follow-up. Future prospective studies are warranted.

Feasibility of the Atlas Unicompartmental Knee System Load Absorber in Improving Pain Relief and Function in Patients Needing Unloading of the Medial Compartment of the Knee: 1-Year Follow-Up of a Prospective, Multicenter, Single-Arm Pilot Study (PHANTOM High Flex Trial)

In young patients with medial knee osteoarthritis (OA), surgical intervention may not be desirable due to preferences to avoid bone cutting procedures, return to high activity levels, and prolong implant survival. The Atlas Knee System was designed to fill the gap between ineffective conservative treatments and invasive surgery. This single-arm study included 26 patients, aged 25 to 65 years, who completed 12 months of follow-up. All dimensions of the Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Society Score significantly improved from baseline to 12 months. About 96.2% and 92.3% of patients experienced a ⩾20% improvement in their KOOS pain and WOMAC pain scores, respectively, at 12 months. This study highlights the potential benefit of a joint unloading device in the management of young patients with medial knee OA. The trial is still ongoing and another analysis is planned at 24 months.