Antibiotic-loaded bone cement is associated with a reduction of the risk of revision of total knee arthroplasty: Analysis of the Catalan Arthroplasty Register.

PURPOSE: The purpose of this study was to analyse the impact on peri-prosthetic joint infection (PJI) rate and prosthetic survival using antibiotic-loaded bone cement (ALBC) versus plain cement during total knee arthroplasty (TKA). METHODS: A retrospective cohort study was conducted. The main data source was the Catalan Arthroplasty Register (RACat). TKAs with surgery date between 1 January 2011 and 31 December 2020 were analysed and followed up until 31 December 2023. The main variable of interest was the type of cement (ALBC vs. plain cement), and several endpoints (septic revision, aseptic revision, and all-cause revision) were considered. The analysed outcomes were revision rates, survival rates and risk factors' hazard ratios (HR). RESULTS: A total of 22,781 TKAs were analysed, 13,125 (57.6%) of them with plain cement and 9656 (42.4%) with ALBC. The septic revision rate was lower in the ALBC group after 3 months of follow-up (0.52% vs. 0.78%, p value = 0.04). Prosthetic survival with respect to the aseptic revision endpoint was also higher for the ALBC group during the whole follow-up period (~158 months). Regarding risk factors for infection, ALBC showed a protective effect, HR: 0.53 (0.44, 0.63), while sex (being male) and the analysed comorbidities increased the risk. CONCLUSIONS: ALBC is associated with a reduction in both the septic revision and the aseptic revision rate after TKA, and thus with higher prosthetic survival. LEVEL OF EVIDENCE: Level III, Therapeutic, retrospective.

An umbrella review of the diagnostic value of next-generation sequencing in infectious diseases.

BACKGROUND: An increasing number of systematic reviews (SRs) have evaluated the diagnostic values of next-generation sequencing (NGS) in infectious diseases (IDs). AIM: This umbrella analysis aimed to assess the potential risk of bias in existing SRs and to summarize the published diagnostic values of NGS in different IDs. METHOD: We searched PubMed, Embase, and the Cochrane Library until September 2023 for SRs assessing the diagnostic validity of NGS for IDs. Two investigators independently determined review eligibility, extracted data, and evaluated reporting quality, risk of bias, methodological quality, and evidence certainty in the included SRs. RESULTS: Eleven SRs were analyzed. Most SRs exhibited a moderate level of reporting quality, while a serious risk of bias was observed in all SRs. The diagnostic performance of NGS in detecting pneumocystis pneumonia and periprosthetic/prosthetic joint infection was notably robust, showing excellent sensitivity (pneumocystis pneumonia: 0.96, 95% CI 0.90-0.99, very low certainty; periprosthetic/prosthetic joint infection: 0.93, 95% CI 0.83-0.97, very low certainty) and specificity (pneumocystis pneumonia: 0.96, 95% CI 0.92-0.98, very low certainty; periprosthetic/prosthetic joint infection: 0.95, 95% CI 0.92-0.97, very low certainty). NGS exhibited high specificity for central nervous system infection, bacterial meningoencephalitis, and tuberculous meningitis. The sensitivity to these infectious diseases was moderate. NGS demonstrated moderate sensitivity and specificity for multiple infections and pulmonary infections. CONCLUSION: This umbrella analysis indicates that NGS is a promising technique for diagnosing pneumocystis pneumonia and periprosthetic/prosthetic joint infection with excellent sensitivity and specificity. More high-quality original research and SRs are needed to verify the current findings.

Differences Between Patients With Diabetes Mellitus and Obese Patients in Occurrence of Peri-Prosthetic Joint Infection: A Systemic Review and Meta-Analysis.

Background: To understand the differences between patients with diabetes mellitus and obese patients with respect to the occurrence of peri-prosthetic joint infection (PJI) after lower-extremity joint arthroplasty as well as to identify differences in PJI occurrence at different time periods. Patients and Methods: The Cochrane Library, CINAHL, MEDLINE, and PubMed were searched for literature published between January 2000 and July 2022. Our targets were studies involving patients with PJI who had already been diagnosed as having diabetes mellitus or being obese before receiving lower-extremity joint arthroplasty. Analysis was performed using Comprehensive Meta-Analysis Software (CMA) Version 3 (Biostat, Inc., Englewood, NJ, USA). Results: A total of 53,522 patients with diabetes mellitus and 360,018 obese patients were included. The forest plot for patients with and without diabetes mellitus indicated that patients with diabetes mellitus were more likely to contract PJIs than were patients without diabetes mellitus (odds ratio, 1.84; 95% confidence interval [CI], 1.56-2.16) and that no differences existed among early, delayed, and late PJI occurrence in patients with diabetes mellitus. The forest plot for obese and non-obese patients indicated that obese patients were more likely to contract PJIs than were non-obese patients (odds ratio, 1.86; 95% CI, 1.53-2.14) and that among obese patients, early PJI occurrence was higher than was late PJI occurrence. In addition, the mixed model indicated that obese patients were more likely to develop early PJIs than were patients with diabetes mellitus. Conclusions: Patients with diabetes mellitus and obese patients were more likely to develop PJIs than were patients without diabetes mellitus and non-obese patients, and that obese patients were more likely to develop early PJIs than late PJIs. Also, obese patients were more likely to develop early PJIs than patients with diabetes mellitus.

An Uncommon Case of Prosthetic Elbow Joint Infection Caused by Staphylococcus intermedius.

Staphylococcus intermedius is known to cause a wide variety of infectious processes in animals and is well described in the veterinary literature. However, the incidence of human infections from this organism has increased in recent years, which highlights the zoonotic potential of this pathogen. Here, we present a case of a S. intermedius prosthetic joint infection potentially resulting from exposure to a pet dog.

Combining bacteriophage and vancomycin is efficacious against MRSA biofilm-like aggregates formed in synovial fluid.

Background: Biofilm formation is a major clinical challenge contributing to treatment failure of periprosthetic joint infection (PJI). Lytic bacteriophages (phages) can target biofilm associated bacteria at localized sites of infection. The aim of this study is to investigate whether combination therapy of phage and vancomycin is capable of clearing Staphylococcus aureus biofilm-like aggregates formed in human synovial fluid. Methods: In this study, S. aureus BP043, a PJI clinical isolate was utilized. This strain is a methicillin-resistant S. aureus (MRSA) biofilm-former. Phage Remus, known to infect S. aureus, was selected for the treatment protocol. BP043 was grown as aggregates in human synovial fluid. The characterization of S. aureus aggregates was assessed for structure and size using scanning electron microscopy (SEM) and flow cytometry, respectively. Moreover, the formed aggregates were subsequently treated in vitro with: (a) phage Remus [∼108 plaque-forming units (PFU)/ml], (b) vancomycin (500 µg/ml), or (c) phage Remus (∼108 PFU/ml) followed by vancomycin (500 µg/ml), for 48 h. Bacterial survival was quantified by enumeration [colony-forming units (CFU)/ml]. The efficacy of phage and vancomycin against BP043 aggregates was assessed in vivo as individual treatments and in combination. The in vivo model utilized Galleria mellonella larvae which were infected with BP043 aggregates pre-formed in synovial fluid. Results: Scanning electron microscopy (SEM) images and flow cytometry data demonstrated the ability of human synovial fluid to promote formation of S. aureus aggregates. Treatment with Remus resulted in significant reduction in viable S. aureus residing within the synovial fluid aggregates compared to the aggregates that did not receive Remus (p < 0.0001). Remus was more efficient in eliminating viable bacteria within the aggregates compared to vancomycin (p < 0.0001). Combination treatment of Remus followed by vancomycin was more efficacious in reducing bacterial load compared to using either Remus or vancomycin alone (p = 0.0023, p < 0.0001, respectively). When tested in vivo, this combination treatment also resulted in the highest survival rate (37%) 96 h post-treatment, compared to untreated larvae (3%; p < 0.0001). Conclusion: We demonstrate that combining phage Remus and vancomycin led to synergistic interaction against MRSA biofilm-like aggregates in vitro and in vivo.

Bacterial Burden, Not Local Immune Response, Differs Between Acute and Chronic Peri-Prosthetic Joint Infections.

Background: Conducting gram stains in peri-prosthetic joint infections (PJI) is known to have poor sensitivity. However, the aims of this study were to use gram stain results of acute and chronic PJI to determine differences with respect to bacterial burden and levels of local innate immunologic response. Patients and Methods: Patients with acute and chronic PJI from January 1, 2016 and December 31, 2020 were identified by use of Current Procedural Terminology codes. Manual review of medical records for infecting organisms and gram stain results for stained bacteria and for local tissue inflammation (amount of polymorphonuclear leukocytes seen on high powered microscopic fields) were recorded. Statistical comparisons between acute (n = 70) and chronic (n = 134) PJI were analyzed with respect to gram stain sensitivity and amount of local tissue inflammation. Results: The ability to identify stained bacteria was statistically significantly higher in the acute cohort (61.4%) than the chronic cohort (9.7%; p < 0.0001). Interestingly, the amount of local inflammation was similar for acute and chronic PJI except in the subgroup analysis with chronic polymicrobial (p = 0.0229) and chronic culture negative (p = 0.0001) PJI. Conclusions: This study shows that both acute and chronic PJI had similar levels of local inflammation seen on gram stains, despite higher bacterial burdens in acute infections. This suggests that innate immune responses, and thus likelihood of infection eradication, is not solely dependent on bacterial burden. These findings should spearhead further research evaluating the different immunologic responses that occur in acute and chronic PJI to improve diagnostics, therapeutics, and infection-free implant survival.

The First Case of a Drug-Resistant Pasteurella multocida Prosthetic Knee Infection Successfully Treated With Debridement, Antibiotics, and Implant Retention.

Pasteurella multocida, a zoonotic infectious organism, has most often been described in patients after an animal bite. It can cause a variety of infections ranging from superficial skin infections to more serious systemic infections, such as sepsis and meningitis. P. multocida is a rare but well-recognized cause of prosthetic joint infections. Here, we report the first implant-associated infection caused by drug-resistant (penicillin, ampicillin, amoxicillin/clavulanic acid) P. multocida, which was cured with targeted antimicrobial treatment and debridement, exchange of mobile parts, and retention of the prosthesis. Patients undergoing arthroplasty should be informed of the risks of close contact with pets, especially in light of the worrying phenomena of drug resistance spreading among animals due to the addition of antibiotics in animal feed.

Effect of Hypothyroidism on Complications in Patients Undergoing TKA in Indian Population.

Background: The number of hypothyroidism patients undergoing total knee replacement (TKA) in India is increasing. It is assumed that patients with hypothyroidism are more prone to complications following surgery. The aim of this study is to evaluate the impact of hypothyroidism on the complications following TKA. Methods: This is a case-control analysis of patients who underwent primary total knee replacement in our hospital from 2017 to 2019. A total of 600 patients were included in the study, of which 300 patients were with hypothyroidism. We compared with a matched cohort of another 300 patients without hypothyroidism as control group. Results: A total of 600 patients were analyzed (Hypothyroid group n = 300, Control group n = 300). The medical complications were found to be 6.2% in the hypothyroid group compared to 4% in control group (p = 1.66, odds ratio 0.61). Surgical complications in the hypothyroid group were 3% compared to 0.6% in control group (p = 4.53, odds ratio = 0.21), overall complication rates were not significant statistically when compared between hypothyroid and control group (p = 5.01, odds ratio 0.47). Subgroup analysis of complications of hypothyroid patients with euthyroid status versus uncontrolled hypothyroidism was done and we found no statistical difference in complications. Conclusion: The conclusion can be that the rate of hospital stay, surgical site infections and complications were higher in hypothyroid group when compared with control group though statistically not significant.

High Risk for Persistent Peri-Prosthetic Infection and Amputation in Mega-Prosthesis Reconstruction.

A peri-prosthetic joint infection is a feared complication after mega-prosthesis reconstruction of large bone defects. The current study investigates how patients operated with a mega-prosthesis due to sarcoma, metastasis, or trauma, are affected by a deep infection focusing on re-operations, risk for persistent infection, arthrodesis, or subsequent amputation. Time to infection, causative bacterial strains, mode of treatment and length of hospital stay are also reported. A total of 114 patients with 116 prostheses were evaluated, a median of 7.6 years (range 3.8-13.7) after surgery, of which 35 (30%) were re-operated due to a peri-prosthetic infection. Of the infected patients, the prosthesis was still in place in 51%, 37% were amputated, and 9% had an arthrodesis. The infection was persistent in 26% of the infected patients at follow-up. The mean total length of hospital stay was 68 (median 60) days and the mean number of reoperations was 8.9 (median 6.0). The mean length of antibiotic treatment was 340 days (median 183). Coagulase-negative staphylococci and Staphylococcus aureus were the most frequent bacterial agents isolated in deep cultures. No MRSA- or ESBL-producing Enterobacterales were found but vancomycin-resistant Enterococcus faecium was isolated in one patient. In summary, there is a high risk for peri-prosthetic infection in mega-prostheses, resulting in persistent infection or amputation relatively often.

Globulin and Albumin/Globulin Ratios as Potential Biomarkers for the Diagnosis of Acute and Chronic Peri-Prosthetic Joint Infections: A Retrospective Study.

Background: Peri-prosthetic joint infection (PJI) is the most serious complication after prosthetic joint replacement. However, the diagnosis of PJI remains challenging for clinicians because of the lack of a gold standard. The purpose of this study was to investigate the diagnostic significance of serum globulin, albumin/globulin, and other biomarkers in acute and chronic periprosthetic infections. Patients and Methods: A retrospective study of 162 patients with PJI and aseptic loosening between January 2016 and March 2021 at our institution was performed in three groups. There were 20 patients with acute infection in group A, 36 patients with chronic infection in group B, and 106 patients with aseptic loosening in group C. Globulin, albumin/globulin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count (PLT), mean platelet volume (MPV), d-dimer, and platelet count/mean platelet volume ratio (PMR) levels were recorded. The area under the curve (AUC) was used to measure the diagnostic value of globulin and albumin/globulin with other biomarkers for PJI. Results: Compared with the aseptic loosening group, the acute and chronic PJI group had higher levels of CRP, ESR, d-dimer, globulin, PLT, and PMR (p < 0.01) and lower levels of albumin/globulin and MPV (p < 0.01). The optimal cutoff, AUC, sensitivity, and specificity of CRP, albumin/globulin, ESR, and globulin were: CRP, 8.3 mg/L, 0.903, 78.57%, and 88.68%; albumin/globulin, 1.31, 0.899, 91.07%, and 73.58%; ESR, 32 mm/h, 0.888, 75.%, and 85.85%; globulin, 29.5 g/L, 0.880, 91.07%, and 72.64%. Conclusions: Globulin and albumin/globulin have excellent diagnostic value for acute and chronic PJI and are promising potential biomarkers for the diagnosis of PJI. The diagnostic performance of albumin/globulin is superior to that of ESR and similar to that of CRP.

Biofilms-What Should the Orthopedic Surgeon know?

Background: Musculoskeletal infections are a major source of morbidity for orthopedic and trauma patients, are associated with prolonged treatment times, and, unfortunately, suffer from poor functional outcomes. Further complicating the issue, antimicrobial resistance (AMR) is increasingly impacting the treatment of musculoskeletal infections with a diminishing repertoire of effective antibiotic agents for some highly resistant pathogens. Most orthopedic surgical procedures involve implants, and the formation of bacterial biofilms on these implants is now recognized as a major factor contributing to the failure of antibiotic therapy in orthopedic surgery. Methods: This review presents an overview of the types, structure, formation, and pathogenesis of biofilms as they pertain to musculoskeletal infections. Furthermore, it describes the key concepts in the management of biofilms and future perspectives for the better treatment of patients with biofilm-related musculoskeletal infections. Results: A bacterial biofilm is a dynamic, living conglomerate of bacteria encased in an extracapsular polysaccharide matrix (EPS). Biofilms are a natural mode of survival for virtually all bacterial species, including both Grampositive and Gram-negative bacteria, as well as fungi. The biofilm model of growth confers resistance by several well-defined mechanisms regardless of the species of the microorganism. In most cases, biofilm management often necessitates radical measures to ensure eradication including both surgical and medical interventions. Conclusions: Orthopedic surgeons should be aware of the key concepts pertaining to biofilms, and the impact that these can have on clinical practice.

Presepsin as a diagnostic biomarker of peri-prosthetic joint infection: a review of the literature.

INTRODUCTION: While presepsin has shown promise as a sepsis biomarker, it has only recently been considered in the field of orthopedic surgery. Therefore, the present review evaluates the role of presepsin in total joint arthroplasty (TJA) as well as its diagnostic and prognostic value in diagnosing PJI. METHODS: Utilizing 4 online databases, we thoroughly searched the literature for articles evaluating the role of presepsin in TJA as well as its prognostic and diagnostic value for PJI. RESULTS: Studies evaluating perioperative presepsin trends in primary TJA demonstrated that its natural course is similar to C-Reactive Protein (CRP). The area under (AUC) the receiver operating characteristic curves values for serum presepsin ranged from 0.86 to 0.926. These values were higher than the AUCs for CRP in each of their respective studies. However, synovial presepsin demonstrated a lower AUC (0.41). Prognostically, presepsin demonstrated potential in terms of infection monitoring following revision TJA for PJI. CONCLUSION: Although the data remains limited, presepsin may serve as a potential biomarker to evaluate the natural inflammatory response following TJA as well as to help diagnose PJI. The present review serves to set the foundation for future study into serum presepsin in larger patient cohorts. Further study is needed to evaluate how this biomarker compares to other laboratory values traditionally used for PJI diagnosis.

Peri-Prosthetic Joint Infection in Patients Prescribed Suppressive Antibiotic Therapy Undergoing Primary Total Joint Arthroplasty: A 1:4 Case Control Matched Study.

Background: Oral suppressive antibiotic therapy (SAT) has emerged as a potential means to increase rates of infection-free survival in many complex peri-prosthetic joint infection (PJI) cases after total joint arthroplasty (TJA). The purpose of the present study is to evaluate the risk of PJI of a new primary TJA in patients on oral SAT. Patients and Methods: A retrospective matched cohort study from five hospitals in a 20-year period within a large hospital network was performed. Inclusion criteria consisted of patients over age 18 undergoing primary TJA, with any order for oral long-term (>6 months duration) SAT, and minimum of one-year clinical follow-up. Patients were matched 1:4 on age, gender, body mass index (BMI), hip or knee surgery, diabetes mellitus, smoking status, and indication for primary TJA. Student t-test, Fisher exact, and χ2 tests were utilized for group comparisons. Our study was powered to detect a 10.5% increase in PJI incidence compared with a 1% baseline rate of PJI. Results: We identified 45 TJA in 33 patients receiving SAT, which were matched to 180 control cases. There was no difference in the rate of development of PJI at any time point within follow-up between the SAT cohort and control group (2.22% vs. 1.11%; p = 0.561). Conclusions: We found a 2.22% rate of PJI in a cohort of patients receiving SAT identified over a 20-year period. As the clinical scenario of primary TJA while on SAT is rare but likely to become more prevalent, future large-scale studies can be performed to better clarify rates and risk of PJI in this population.

Prosthetic Knee Joint Infection by Brucella melitensis.

Prosthetic joint infection following arthroplasty is a serious complication associated with high morbidity and prolonged hospitalization. Treatment consists of a combination of surgical intervention and long-acting antibiotic therapy targeted to the responsible microorganism(s). Brucella species-related prosthetic joint infections are uncommon. Diagnosis can be challenging, especially in non-endemic countries, and is confirmed by serological studies and joint aspiration results. We present a rare case of a 78-year-old man with Brucella melitensis infection in a prosthetic right knee joint, seven years after the primary procedure. The patient was treated with a two-stage surgical intervention and a four-month period of antibiotic therapy. After a follow-up period of 12 months, no clinical or laboratory findings of infection were present and the patient was able to return to his everyday activities.

Culture-negative Peri-prosthetic Joint Infection after Total Hip Arthroplasty Treatment Protocol and Outcomes in Acute and Chronic Cases.

The treatment of culture-negative periprosthetic joint infections (CN PJI) of the hip represents complex entities. We, as a result of this, report on 12 cases. Irrigation and debridement (I&D) with implant retention were performed in acute cases and two-stage revisions in chronic infections. Combined antibiotic therapy was administered in all cases for 12 weeks. Infection control was achieved in all patients with an infection-free rate of 100% at 7.5 years of average follow-up.

Is Fibrinogen a Reliable Biomarker in the Diagnosis of Peri-Prosthetic Joint Infection? A Systematic Review and Meta-Analysis.

Background: In recent years, several studies have identified closed correlations between the coagulation cascade and inflammatory mechanisms in infective diseases. Fibrinogen (PF) is emerging as promising biomarker for the diagnosis of peri-prosthetic joint infection (PJI). This study aims to investigate the diagnostic value of PF in diagnosing PJI and to explore potential causes influencing the diagnostic value of PF. Materials and Methods: PubMed, Embase, and Cochrane Library were searched regarding the role of fibrinogen as a biomarker in the diagnosis of PJI. Studies in English were included in the meta-analysis if they determined the diagnostic value of fibrinogen for PJI detection after hip or knee arthroplasty, applying the recognized diagnostic criteria for PJI. A quality evaluation of the studies included was performed. The pooled sensitivity, specificity, likelihood ratios and diagnostic odds ratio (DOR) and the area under the receiver operating characteristic curve (AUROC) were obtained using the statistical software STATA, version 17 (StataCorp, College Station, TX). Results: Ten studies (9 retrospective) were included in the study. Low publication bias was detected, but with high heterogeneity among them. Plasma fibrinogen showed a good diagnostic accuracy and clinical utility in PJI (sensitivity, 0.81 [95% confidence interval {CI}, 0.75-0.86]; specificity, 0.82 [95% CI, 0.76-0.86]; AUROC, 0.88 [95% CI, 0.85-0.91]; DOR, 19 [95% CI, 14-26]). Conclusions: The attempt to find an "ideal" biomarker is crucial to improve the sensitivity and specificity of the current diagnostic algorithms for PJI. The analysis performed in the current study indicates that plasma fibrinogen test is a valid biomarker for PJI diagnosis.

Impact of Coronavirus Disease-2019 Protocols on Primary and Revision Total Knee Arthroplasty.

Background: Surgical site infection (SSI) after total knee arthroplasty (TKA) is associated with increased morbidity and healthcare expenditures. During the coronavirus disease-2019 (COVID-19) pandemic, our institution intensified hygiene standards, including greater glove, personal protective equipment (PPE), and mask use. We assessed the effect of these changes on SSI rates in primary total knee arthroplasty (pTKA) and revision total knee arthroplasty (rTKA). Patients and Methods: A retrospective review was performed identifying TKA from January 2019 to June 2021 at a single institution. Baseline characteristics and outcomes were compared before (January 2019 to February 2020) and during (May 2020 to June 2021) the COVID-19 pandemic when no restriction on operative services was in place and were further analyzed during the first (May 2020 to November 2020) and second (December 2020 to June 2021) periods after full operative services were restored. Results: A total of 3,398 pTKA (pre-pandemic: 1,943 [57.2%]; pandemic: 1,455 [42.8%]) and 454 rTKA (pre-pandemic: 229 [50.4%]; pandemic: 225 [49.6%]) were included. For primary cases, superficial and deep SSI rates were similar before and during COVID-19; however, for revision TKA, the incidence of all (-0.32%, p = 0.035) and superficial (-0.32%, p = 0.035) SSIs decreased during COVID-19. Primary TKA had longer operative times (p < 0.001) and shorter length of stay (LOS; p < 0.001) during COVID-19. Both pTKA (p < 0.001) and rTKA (p = 0.003) were discharged to skilled nursing facilities less frequently during COVID-19 as well. Conclusions: After our hospital implemented COVID-19-motivated hygienic protocols, superficial SSI rates decreased in rTKA but not in pTKA. During COVID-19, patients were less likely to be discharged to skilled nursing facilities, and pTKA operative times increased. Although these changes occurred during intensified hygiene protocols, further research is needed to determine how these factors contributed to the observed changes.

Pre-Admission Use of Chlorhexidine-Impregnated Gauze for Skin Preparation Reduces the Incidence of Peri-Prosthetic Joint Infection after Primary Total Knee Arthroplasty: A Prospective Cohort with Retrospective Controls.

Background: Peri-prosthetic joint infection (PJI) has long been a devastating complication after total knee arthroplasty (TKA), with native skin flora always identified as the causative agents. The aim of this study was to investigate the efficacy of pre-admission use of chlorhexidine-impregnated gauze for pre-operative skin preparation on infection rates after primary TKA surgeries. Patients and Methods: Patients undergoing TKAs performed from January 2017 until January 2021 were prospectively recruited. The experimental group included patients who used chlorhexidine-impregnated gauze the evening before surgery for skin preparation. These patients were compared with a retrospective cohort of TKAs performed during the previous four years without this step as control group. During a one-year follow-up, complications including PJI and superficial infections were collected as the primary outcomes for analysis. Results: A total of 1,218 TKAs in the experimental group and 1,033 TKAs in the control group were included in the study. A total of seven (0.6%) cases of PJI were identified in the experimental group, whereas 16 (1.5%) cases were diagnosed in the control group; a significant difference was detected (χ2 = 5.245; p = 0.022). Eighteen (1.5%) cases of superficial infection were identified in the experimental group, and 28 (2.7%) cases were observed in the control group; a significant difference was found between groups (χ2 = 4.243; p = 0.039). No significant differences were found on other wound-related complications. Conclusions: Pre-admission use of chlorhexidine-impregnated gauze for skin preparation was found to be an effective practice in reducing the incidence of PJI after TKA procedures, which has the potential of being utilized for patients undergoing TKA surgeries.

Reduction in Operating Room Airborne Particle Burden and Time-Dependent Contamination of Sterile Instrument Trays With the Use of a Novel Air Filtration System.

Introduction Postoperative infections represent a substantial burden to patients and healthcare systems. To improve patient care and reduce healthcare expenditures, interventions to reduce surgical infections must be employed. The crystalline C-band ultraviolet (UV-C) air filtration technology (Aerobiotix Inc., Miamisburg, OH, USA) has been designed to reduce airborne bioburden through high-quality filtration and germicidal irradiation. The purpose of this study was to assess the ability of a novel UV-C air filtration device to reduce airborne particle counts and contamination of surgical instrument trays in an operating room (OR) setting. Materials and methods Thirty sterile instrument trays were opened in a positive-air-flow OR. The trays were randomly assigned to one of two groups (UV-C or control, n=15 per group). In the UV-C group, the UV-C filtration device was used and in the control, it was not. All trays were opened with the use of a sterile technique and left exposed in the OR for four hours. Air was sampled by a particle counter to measure the numbers of 5µm and 10µm particles. Culture specimens were obtained from the trays to assess for bacterial contamination. Outcome data were collected at 30-minute intervals for the duration of the four-hour study period. Results Use of the UV-C device resulted in statistically significant reductions in the numbers of 5µm (average of 64.9% reduction when compared with the control, p<0.001) and 10µm (average of 65.7% reduction when compared with the control, p<0.001)-sized particles detectable in the OR. There was no significant difference in the overall rates of contamination (33.3% in the control group vs. 26.7% in the UV-C group, p=1.0) or the time to contamination (mean survival of 114 minutes in the control group vs. 105 minutes in the UV-C group, p=0.72) of surgical instrument trays with the use of the UV-C device. Conclusions The results demonstrate that the UV-C filtration device can successfully reduce airborne bioburden in standard ORs, suggesting that it may have the potential to reduce the risk for wound and hardware infections. Further clinical trials are necessary to better determine the effect of this air filtration system on postoperative infection rates.

Effects of Hypercarbia on Lower Extremity Primary Total Joint Replacement Infections.

INTRODUCTION: Prosthetic joint infection (PJI) is a serious complication after total joint replacement (TJR). Adequate wound oxygenation is critical for wound healing and infection prevention. As carbon dioxide (CO2) is exchanged for oxygen (O2) in the lungs, serum bicarbonate (HCO3 -) may be used as a marker for predicting relative serum O2 levels, and therefore, healing potential. No currently published literature explores the relationship between serum bicarbonate levels and PJI in TJR patients. METHODS: We performed this retrospective review of lower extremity TJR patients to determine whether the risk of PJI and wound complications within one year was correlated with hypercarbia, which was defined as a preoperative serum bicarbonate level >30 mEq/L. RESULTS: Out of 1,690 TJR procedures, 1.6% (N=27) had a PJI or superficial wound infection within one year postoperatively. The average preoperative serum bicarbonate was 26.9 (SD 2.6) among patients without PJI and 27.2 (SD 2.1) among patients with PJI (p=0.46). Hypercarbia was present in 9.2% of non-PJI patients and in 7.4% of PJI patients. The relative risk of PJI and wound complications did not differ for patients with vs without hypercarbia (RR = 0.79, 95% CI = 0.19-3.31, p=0.75). CONCLUSION: The results of this study provide preliminary evidence that preoperative hypercarbia may not be correlated with an increase in the risk of PJI or wound complications. However, due to the rarity of both PJI and hypercarbia, a larger patient population is needed to ensure adequate power to detect clinically meaningful effect sizes.