Use of Chlorhexidine Preparations in Total Joint Arthroplasty

Incisional surgical site infections by subcutaneous soaking of wound with aqueous 0.05% chlorhexidine gluconate in gastroenterological surgery: A randomized controlled trial

BACKGROUND

Chlorhexidine gluconate solution is superior to povidone-iodine for prevention of surgical site infection. However, the overall efficacy of chlorhexidine gluconate for surgical site infection prevention in various types of gastroenterological surgery, as well as the optimal concentration of chlorhexidine gluconate, remain unclear. The aim of the present study was to clarify whether subcutaneous wound soaking with chlorhexidine gluconate would reduce the incidence of surgical site infection associated with gastroenterological surgery in patients with wound classes Ⅱ to Ⅳ.

METHODS

Patients were randomly assigned (1:1) to either wound soaking with chlorhexidine gluconate (chlorhexidine gluconate group) or no chlorhexidine gluconate soaking (control group). After closure of the abdominal fascia, gentle subcutaneous soaking of the wound was performed using gauze fully soaked in aqueous 0.05% chlorhexidine gluconate before skin closure. Incisional surgical site infection was diagnosed using the Centers for Disease Control and Prevention criteria. The primary end point was the occurrence of incisional surgical site infection.

RESULTS

Among 363 patients, 245 (67%) underwent laparoscopic surgery. All 363 patients were included-181 in the chlorhexidine gluconate group (49.9%) and 182 (50.1%) in the control group. There were no significant inter-group differences in patient background, the type of procedure, or wound classification. The incidence proportion of incisional surgical site infection was significantly lower in the chlorhexidine gluconate group than in the control group (9.4% vs 19.2%; P = .008).

CONCLUSION

Subcutaneous wound soaking with chlorhexidine gluconate reduces the incidence of incisional surgical site infection in patients undergoing gastroenterological surgery.

Effect of amoxicillin and clindamycin on the gene expression of markers involved in osteoblast physiology

Background/purpose

Amoxicillin and clindamycin are the most effective decontaminants for intraoral bone grafts before their application in bone regeneration without cytotoxic effects on osteoblasts, but their effects on the gene expression of markers involved in osteoblast growth and differentiation remain unclear. The study objective was to determine the effects of amoxicillin and clindamycin on the gene expression of markers involved in osteoblast growth and differentiation.

Materials and methods

Real-time polymerase chain reaction (RT-PCR) was performed to explore the effect of 150 μg/mL clindamycin or 400 μg/mL amoxicillin on the gene expression by primary human osteoblasts (HOBs) of runt-related transcription factor 2 (Runx-2), osterix (OSX), alkaline phosphatase (ALP), osteocalcin (OSC), osteoprotegerin (OPG), receptor activator for nuclear factor κ B ligand (RANKL), type I collagen (Col-I), bone morphogenetic proteins 2 and 7 (BMP-2 and BMP-7), TGF-β1 and TGF-β receptors (TGF-βR1, TGF-βR2, and TGF-βR3), and vascular endothelial growth factor (VEGF).

Results

Treatment with 150 μg/mL clindamycin significantly increased the gene expression of TFG-β1, TGF-βR1, TGF-βR2, TGF-βR3, RUNX-2, Col-1, OSX, OSC, BMP-2, BMP-7, ALP, VEGF, and RANKL by HOBs. Treatment with 400 μg/mL amoxicillin significantly increased the gene expression of TGF-β R1, Col-I, OSC, RANKL, and OPG alone.

Conclusion

These findings suggest that 150 μg/mL clindamycin is the decontaminant of choice to treat intraoral bone grafts before their application in bone regeneration. The osteogenic and antibacterial properties of clindamycin can favor and accelerate the integration of bone grafts in the oral cavity.

Biofilm and How It Relates to Prosthetic Joint Infection

Prosthetic joint infection following total joint arthroplasty is a devastating complication, resulting in increased morbidity and mortality for the patient. The formation of a biofilm on implanted hardware contributes to the difficulty in successful identification and eradication of the infection. Antibiotic therapy and surgical intervention are necessary for addressing this condition; we present a discussion on different treatment options, including those that are not yet routinely utilized in the clinical setting or are under investigation, to highlight the present and future of PJI management.

Effect of Commercially Available Wound Irrigation Solutions on Uninfected Host Tissue in a Murine Model

Background

Commercially available irrigation solutions are used to reduce bacterial contamination and prevent surgical site infections. However, the effect of these solutions on the healing capacity of tissue has not been well-established. The purpose of this study was to investigate the effects of 5 commercially available irrigation solutions on host tissue in a murine model.

Methods

There were 5 treatment groups: bacitracin, Clorpactin, Irrisept, Prontosan, Bactisure, and normal saline control. The irrigation solutions were applied to the wound for 30 seconds or 1 minute, as per the manufacturer's instructions, and then washed with normal saline. Mice were sacrificed at 3 days and 10 days. The tissue was examined histologically for inflammation, edema, granulation tissue formation, and re-epithelialization. Granulation tissue formation and re-epithelialization were surrogates for effective wound healing.

Results

All of the irrigation solutions had negative effects on host tissue in the acute phase. The inflammation and edema were improved in the later phase (10 days). Recovery and healing of the open wounds were observed for all groups at 10 days. The antiseptic irrigation solutions had similar cytotoxic effects on host tissue at 3 days and did not have delayed or compromised wound healing at 10 days when compared to normal saline control.

Conclusions

Single short-duration use of these commercially available antiseptic irrigation solutions appears to be safe in an uninfected wound. Data from this study will provide surgeons with useful information regarding the safety of using antiseptic wound irrigation solutions intraoperatively for prevention of surgical site infections.

Functional Outcome of Above-Knee Amputation After Infected Total Knee Arthroplasty

Background

Periprosthetic joint infection is a serious complication of total knee arthroplasty (TKA). Management usually involves irrigation and debridement, polyethylene liner exchange, one-stage revision, two-stage revision, knee arthrodesis, or ultimately above-knee amputation (AKA). We present our experience with 21 patients who underwent AKA as a sequela of unresolved infected TKA, highlighting their etiology and functional outcomes.

Methods

A retrospective chart review was performed for all cases of infected TKA treated with AKA at 1 institute from January 2007 to December 2020, with a minimum follow-up of 1 year. Patient demographics, Charlson comorbidity index, culture results, ambulation status, prosthesis fitting, and functional outcomes were collected. Short Form-36 and activities of daily living questionnaires were used for functional outcome assessment.

Results

Twenty-one patients were identified, 7 of whom were male (33.3%). Mean ± standard deviation follow-up was 5.7 ± 3.1 years (range, 1-11 years). Mean ± standard deviation age was 57.9 ± 10.7 years (range, 38-87 years), and the mean body mass index was 33.5 ± 6.4 kg/m2 (range, 25.4-46 kg/m2). Gram-positive organisms were identified in 15 cases (66.7%). Prosthesis fitting was successful in 17 patients (81%). Post-AKA ambulation was achieved in 12 patients (57.1%). The ambulating group showed higher Short Form-36 and activities of daily living scores when compared with patients who did not ambulate (60.2 vs 43.3, P = .041, and 67.2 vs 52.7, P = .029, respectively).

Conclusions

AKA should be considered solely as the final recourse for infected TKA. Despite the low-to-moderate patient-reported postoperative outcomes, prosthesis fitting and maintaining ambulation can improve postoperative functional outcomes.

Stability analysis of tranexamic acid in the presence of various antiseptic solutions

Tranexamic acid (TXA) effectively reduces blood loss and transfusion risk during total joint arthroplasty. Additionally, intraoperative irrigation with various antiseptic solutions is often utilized for the management and prevention of surgical site infection. However, interactions between various antiseptic solutions and TXA have not been investigated. The purpose of this in vitro study is to evaluate the stability of TXA in the presence of common orthopedic antiseptic solutions. Five antiseptic solutions-0.1% chlorhexidine (CHX) gluconate, 10% povidone-iodine (BTD), 0.5% sodium hypochlorite (Dakin's), 3% hydrogen peroxide (H₂ O₂ ), and 1.5% H₂ O₂ -and a 0.9% normal saline (NS) control were obtained. A stock 100 mg/ml TXA solution was diluted in each antiseptic solution to a concentration of 10.0 mg/ml to generate reference standard and stability samples. TXA stability in each solution was measured using high performance liquid chromatography at t = 0 and t = 120 min and reported as mean percent of theoretical concentration (MPT) with associated relative standard deviation (RSD). All experiments were performed in triplicate at room temperature. At t = 0 min, TXA remained stable when mixed with 0.9% NS, 0.1% CHX, 10% BTD, 3% H₂ O₂ , and 1.5% H₂ O₂ (MPT range: 102.0%-105.0%, RSD range: 0.80%-2.92%). Only 0.5% Dakin's led to significant degradation of TXA at t = 0 min (MPT: 14.3%, RSD:1.28%). At t = 120 min, TXA stability persisted for all compounds except Dakin's 0.5% (MPT: 18.4%, RSD: 28.7%). TXA efficacy may be significantly diminished when 0.5% Dakin's is used as an intraoperative irrigation solution. CHX, BTD, and H₂ O₂ do not degrade TXA.

Evaluation of the role of povidone‑iodine in the prevention of surgical site infections

Background

The occurrence of surgical site infections (SSIs) is associated with increased risk of mortality, development of other infections, and the need for reintervention, posing a significant health burden. The aim of this review was to examine the current data and guidelines around the use of antiseptic povidone‑iodine (PVP-I) for the prevention of SSIs at each stage of surgical intervention.

Methods

A literature search for selected key words was performed using PubMed. Additional papers were identified based on author expertise.

Results

Scientific evidence demonstrates that PVP-I can be used at every stage of surgical intervention: preoperative, intraoperative, and postoperative. PVP-I is one of the most widely used antiseptics on healthy skin and mucous membranes for preoperative surgical site preparation and is associated with a low SSI rate. For intraoperative irrigation, aqueous PVP-I is the recommended agent and has been demonstrated to decrease SSIs in a range of surgical settings, and for postoperative wound healing, there is a growing body of evidence to support the use of PVP-I.

Conclusions

There is a need for more stringent study designs in clinical trials to enable meaningful comparisons between antiseptic agents, particularly for preoperative skin preparation. The use of a single agent (PVP-I) at each stage of surgical intervention could potentially provide advantages, including economic benefits, over agents that can only be used at discrete stages of the surgical procedure.

Key message

Evidence supports the use of PVP-I at all stages of surgical intervention, from preoperative measures (including skin preparation, preoperative washing, and nasal decolonization) to intraoperative irrigation, through to postoperative wound management. However, there is a need for more stringent study designs in clinical trials to enable meaningful comparisons between antiseptic agents, particularly for preoperative skin preparation.

Effective Biofilm Eradication on Orthopedic Implants with Methylene Blue Based Antimicrobial Photodynamic Therapy In Vitro

Periprosthetic joint infections (PJI) are difficult to treat due to biofilm formation on implant surfaces, often requiring removal or exchange of prostheses along with long-lasting antibiotic treatment. This in vitro study investigated the effect of methylene blue photodynamic therapy (MB-PDT) on PJI-causing biofilms on different implant materials. MB-PDT (664 nm LED, 15 J/cm²) was tested on different Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Cutibacterium acnes strains in both planktonic form and grown in early and mature biofilms on prosthetic materials (polyethylene, titanium alloys, cobalt-chrome-based alloys, and bone cement). The minimum bactericidal concentration with 100% killing (MBC_100%) was determined. Chemical and topographical alterations were investigated on the prosthesis surfaces after MB-PDT. Results showed a MBC_100% of 0.5-5 μg/mL for planktonic bacteria and 50-100 μg/mL for bacteria in biofilms-independent of the tested strain, the orthopedic material, or the maturity of the biofilm. Material testing showed no relevant surface modification. MB-PDT effectively eradicated common PJI pathogens on arthroplasty materials without damage to the materials, suggesting that MB-PDT could be used as a novel treatment method, replacing current, more invasive approaches and potentially shortening the antibiotic treatment in PJI. This would improve quality of life and reduce morbidity, mortality, and high health-care costs.

Irrigation Solutions Negatively Affect the Viability and Function of Human Fibroblasts: An in vitro Study

Introduction

Multiple irrigation solutions are used in orthopedic surgeries although there are limited studies on their lasting effects on human tissues. The purpose of this work was to investigate the cytotoxic effects of the irrigation solutions Bacitracin, Clorpactin (sodium oxychlorosene), Irrisept (0.05% chlorhexidine gluconate), and Bactisure (ethanol 1%, acetic acid 0.6%, sodium acetate 0.2%, benzalkonium chloride 0.013%, and water) on 3D cultures of human fibroblasts.

Methods

Two independent experiments with 6 replicates were performed for the following conditions: Control (saline), bacitracin, Clorpactin, Irrisept, and Bactisure. Human fibroblast cell sheets were exposed to these solutions (1 or 2 min), followed by three washes with warm saline. Cell sheets were then cultured for additional 5- and 7-day posttreatment. Cell viability was measured using the alamarBlue (AB) assay. The more cytotoxic the irrigant, the lower the AB reduction.

Results

For 1-min exposure time, significant differences in AB reduction were noted in Clorpactin, Irrisept, and Bactisure groups compared to control at both 5 days (Clorpactin p = 0.0003, Irrisept p = 7.31 × 10^-15, Bactisure p = 6.86 × 10^-14) and 7 days posttreatment (all groups p < 0.0001). The results were similar in the 2-min exposure groups. Bacitracin-treated fibroblasts displayed no significant difference at all measurement times compared to control.

Discussion

Impacts of irrigation solution exposure on cell viability were varied. Irrisept and Bactisure showed the highest cell toxicity even after a brief exposure (1 min), while bacitracin and Clor-pactin exposure showed smaller impacts on cell viability as compared to saline controls. This in vitro study provided insight into the effects of the irrigants on human cells and provides the groundwork essential to move to in vivo studies. Our findings raised the concern that some irrigation solutions may have negative impacts on wound healing and healthy cellular response.

Do patients need advice and information to prevent infections - results of a single centre structured survey

Background

Healthcare-associated infections are a major burden for hospitals, leading to morbidity and mortality and unnecessary medical costs. They can probably be reduced through what is known as patient empowerment. This study aims to address the question of whether patients are interested in receiving infection prevention and control information.

Methods

Patients were asked in structured interviews whether they would like more information on infection prevention and control. Inclusion criteria comprised 2 groups of patients. Group 1 were patients undergoing elective total endoprosthesis (TEP) and Group 2 were patients tested positive for meticillin-resistant Staphylococcus aureus (MRSA).

Results

The response rate was 38.4 % (163/425 patients). Approximately 75 % of the patients were interested in information on infection prevention and control. The topics of interest differed between the two patient groups: MRSA patients had a higher need for infection prevention and control information. TEP patients showed a high acceptance of antiseptic body wash and a willingness to pay for it themselves. Information given to patients should be group-specific and timely.

Conclusion

Our data suggest a lack of information on infection prevention and control among patients and underline the importance of patient empowerment. The willingness of patients to pay personally for antiseptic wash should be assessed further.

Techniques for Decreasing Bacterial Load for Open Shoulder Surgery

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Benzoyl peroxide (BPO) 5% has been shown to reduce Cutibacterium acnes load on the skin. BPO 5% with miconazole nitrate (MN) 2% may be beneficial, whereas BPO 5% with clindamycin cream 1% to 1.2% does not seem to have additive effects when compared with BPO 5% alone. Chlorhexidine gluconate solutions reduce the total bacterial load on the skin, but do not seem to have a significant effect on C. acnes.

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ChloraPrep seems to be the best surgical skin preparation to decrease overall positive skin cultures. Preincisional hydrogen peroxide 3% application has been shown to be a cost-effective practice to inhibit growth of C. acnes. Vancomycin powder before deltopectoral interval closure has antimicrobial effects against C. acnes and is a cost-effective practice. Finally, Bactisure surgical lavage is protective against the formation of biofilms.

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IV cefazolin has been shown to be more effective for shoulder arthroplasty infection prophylaxis than antibiotic alternatives such as vancomycin. Thus, patients with a questionable history of penicillin allergy should undergo additional testing.

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For shoulder surgery infection prophylaxis, we recommend the use of BPO 5% cream for 5 days preoperatively with chlorhexidine wipes the night before and the morning of surgery. IV cefazolin should be administered perioperatively, and patients with a questionable history of penicillin allergy should be tested. Surgeons should consider preincisional application of hydrogen peroxide 3% for 5 minutes, followed by standard ChloraPrep preparation. Normal saline should be used for preclosure lavage. Finally, application of vancomycin powder deep to the deltopectoral interval closure should be considered.

Common Wound Irrigation Solutions Produce Different Responses in Infected vs Sterile Host Tissue: Murine Air Pouch Infection Model

Background

Despite desirable microbicidal actions of irrigation solutions in surgical site infection treatment, several studies demonstrate potential cytotoxic effects. This study investigated tissue damage caused by irrigation solutions in the presence or absence of infection.

Methods

Air pouches were created in 60 mice and evenly divided into 2 groups as infected with Staphylococcus aureus and control. Groups were then subdivided both by type of solution and by timing after irrigation. Solutions included control (0.9% saline), bacitracin (33 IU/ml), 0.2% sodium oxychlorosene, 0.05% chlorhexidine gluconate, and 0.013% benzalkonium chloride.

Results

Inflammation decreased in infected pouches compared to the sterile ones for all solutions except bacitracin on day 0 and for all on day 7. On day 0, infected pouches had increased necrosis with bacitracin (P = .006), chlorhexidine gluconate (P = .18), and benzalkonium chloride (P = .07); on day 7, there was decreased necrosis in infected pouches for all solutions (P < .05) except for sodium oxychlorosene (P = .18). Edema decreased in infected pouches on day 0 for all solutions. On day 7, infected pouches had decreased edema with 0.9% saline, bacitracin, and benzalkonium chloride (P < .05) and increased edema with chlorhexidine gluconate (P < .05) and sodium oxychlorosene (P = .069). Bacitracin allowed for more bacteria growth than sodium oxychlorosene (P = .024), chlorhexidine gluconate (P = .025), and benzalkonium chloride (P = .025).

Conclusions

The presence of bacteria led to less immediate tissue inflammation and edema, while tissue necrosis varied over time. The current study may guide surgeons on which solution to use and whether to irrigate a possibly sterile wound or joint.

Ex Vivo Toxicity of Commonly Used Topical Antiseptics and Antibiotics on Human Chondrocytes

Topical povidone-iodine, chlorhexidine, bacitracin, and vancomycin are commonly used antiseptic and antimicrobial agents to reduce risk and treat surgical site infections in numerous orthopedic procedures. Chondrocytes potentially may be exposed to these agents during operative procedures. The impact of these topical agents on chondrocyte viability is unclear. The goal of this study is to determine human chondrocyte viability ex vivo after exposure to commonly used concentrations of these topical antiseptic and antimicrobial agents. Human osteochondral plugs were harvested from the knee joint of a human decedent within 36 hours of death. Individual human osteochondral plugs were exposed to normal saline as a control; a range of concentrations of povidone-iodine (0.25%, 0.5%, and 1%), chlorhexidine (0.01% and 0.5%), and bacitracin (10,000 units/L, 50,000 units/L, and 100,000 units/L) for 1-minute lavage; or a 48-hour soak in vancomycin (0.16 mg/mL, 0.4 mg/mL, and 1.0 mg/mL) with nutrient media. Chondrocyte viability was evaluated with a live/dead viability assay at 0, 2, 4, and 6 days after exposure to bacitracin at 0, 3, and 6 days). Control subjects showed greater than 70% viability at all time points. Povidone-iodine, 0.5% chlorhexidine, and vancomycin showed significant cytotoxicity, with viability dropping to less than 40% by day 6. Chondrocytes exposed to 0.01% chlorhexidine maintained viability. Chondrocytes exposed to bacitracin showed viability until day 3, when there was a large drop in viability. Commonly used topical concentrations of povidone-iodine, vancomycin, and bacitracin are toxic to human chondrocytes ex vivo. A low concentration of chlorhexidine appears safe. Caution should be used when articular cartilage may be exposed to these agents during surgery. [Orthopedics. 2022;45(5):e263-e268.].

Prevention of Orthopedic Prosthetic Infections Using Evidence-Based Surgical Site Infection Care Bundles: A Narrative Review

Background: The number of primary/revision total joint replacements (TJR) are expected to increase substantially with an aging population and increasing prevalence of comorbid conditions. The 30-day re-admission rate, in all orthopedic specialties, is 5.4% (range, 4.8%-6.0%). A recent publication has documented that the surgical site infection (SSI) infection rate associated with revision total knee (rTKR, 15.6%) and revision total hip (rTHR, 8.6%) arthroplasties are four to seven times the rate of the primary procedures (2.1%-2.2%). These orthopedic infections prolong hospital stays, double re-admissions, and increase healthcare costs by a factor of 300%. Methods: A search of PubMed/MEDLINE, EMBASE and the Cochrane Library publications, which reported the infection risk after TKR and THR, was undertaken (January 1, 1995 to December 31, 2021). The search also included documentation of evidence-based practices that lead to improved post-operative outcomes. Results: The evidence-based approach to reducing the risk of SSI was grouped into pre-operative, peri-operative, and post-operative periods. Surgical care bundles have existed within other surgical disciplines for more than 20 years, although their use is relatively new in peri-operative orthopedic surgical care. Pre-admission chlorhexidine gluconate (CHG) showers/cleansing, staphylococcal decolonization, maintenance of normothermia, wound irrigation, antimicrobial suture wound closure, and post-operative wound care has been shown to improve clinical outcome in randomized controlled studies and meta-analyses. Conclusions: Evidence-based infection prevention care bundles have improved clinical outcomes in all surgical disciplines. The significant post-operative morbidity, mortality, and healthcare cost, associated with SSIs after TJR can be reduced by introduction of evidence-based pre-operative, intra-operative, and post-operative interventions.

Irrigation Solutions and Antibiotic Powders: Should I Use Them in Primary and Revision Total Joint Arthroplasty?

BACKGROUND

The prevention and treatment of periprosthetic joint infection is of utmost importance to orthopedic surgeons. Irrigation solutions have become a popular additive to the prevention and treatment armamentarium.

METHODS

This symposium summarizes the mechanism of action, basic science, and clinical research to date on the use of irrigation solutions. The four most commonly used irrigation solutions, povidone iodine, chlorhexidine, hydrogen peroxide, and acetic acid, are discussed. In addition, the role of antibiotic powers is reviewed.

RESULTS

Each solution has its risks and benefits that must be weighed by the surgeon. There is no clear irrigation solution that is superior. The role of additive antibiotic powder (vancomycin) remains controversial.

CONCLUSION

More rigorous prospective clinical trials are needed to determine the optimal irrigation solution for the prevention and treatment of periprosthetic joint infection.

Chlorhexidine gluconate lavage during total joint arthroplasty may improve wound healing compared to dilute betadine

PURPOSE

Intraoperative wound irrigation prior to closure during total joint arthroplasty (TJA) is an essential component of preventing infections and limiting health care system costs. While studies have shown the efficacy of dilute betadine in reducing infection risk, there remains concerns over its safety profile and theoretical inactivation by blood and serum. This study aims to compare infection and wound complications between chlorhexidine gluconate (CHG) and betadine lavage during TJA.

METHODS

All primary TJA between 2019-2021 were analyzed at a single institution, and periprosthetic joint infection (PJI), wound drainage, 30 and 90-day emergency room (ER) readmission due to wound complications, aseptic loosening, and revision surgery rate were compared between patients undergoing intraoperative CHG versus betadine lavage prior to closure. Baseline demographics were controlled, and multivariate logistic regression was performed to compare complication rates.

RESULTS

A total of 410 TJA, including 160 hip and 250 knee arthroplasties were included. Compared to the dilute betadine cohort, all TJA patients undergoing CHG lavage had a statistically significant lower 30 and 90-day emergency room readmission rate due to wound complications. Both hip and knee arthroplasty patients with CHG had a statistically significant lower rate of postoperative superficial drainage and dressing saturation at clinic follow-up, but only knee arthroplasty patients had significant decreased readmission rate for incisional wound vacuum placement and close inpatient monitoring of wound healing. Among all TJA, there was no significant association in the rate of PJI requiring return to the OR between groups.

CONCLUSIONS

Although betadine is cost-effective and has been shown to reduce PJI rates, there remains concerns in the literature over soft tissue toxicity and wound healing. This study suggests CHG may be as efficacious as dilute betadine in preventing PJI while also decreasing the risk of superficial drainage and wound complications needing unplanned ER visits during the acute postoperative period.

A novel activated-zinc antiseptic solution effective against MRSA and Pseudomonas aeruginosa: a pig model

OBJECTIVE

The purpose of this study was to investigate the antimicrobial efficacy of a novel activated zinc solution against meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa after one hour, and to evaluate any untoward effect of the solution on local wound tissue at 24 hours after solution exposure in a pig wound model.

METHOD

A pathogen-free, commercially raised, Yorkshire-cross female pig was acquired 12 days prior to the procedure. Within one week prior to the procedure, a small loopful of test bacteria, Pseudomonas aeruginosa (pig-isolate) and MRSA (ATCC-6538), were streaked and cultured on a non-selective agar. Full-thickness wounds (n=24) were created and evenly divided into three groups: control wounds (exposed to bacteria but untreated, n=8); wounds treated with Compound 1 (n=8), and wounds treated with Compound 2 (n=8). All wounds were dressed and monitored for one hour and 24 hours.

RESULTS

After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable total bacteria of 2.8 log colony forming units (CFUs) and 3.5 logCFUs, respectively. After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable MRSA of 2.3 logCFUs and 1.6 logCFUs, respectively (p=0.009). After one hour, the wounds treated with Compound 1 and Compound 2 had a mean recoverable Pseudomonas aeruginosa of 0.3 logCFUs and 0.0 logCFUs, respectively (p=0.000). After 24 hours of exposure to Compound 1 and Compound 2, there was no statistically significant increased necrosis (p=0.12, p=0.31, respectively) or neutrophilic infiltrate (Compound 2, p=0.12) when compared with control wounds.

CONCLUSION

The novel activated-zinc compound used in this study demonstrated a 99.5-99.9% reduction in total bacteria, a 99.9-99.98% reduction in MRSA, and 100% eradication of Pseudomonas aeruginosa one hour after exposure. This novel solution may provide another significant tool to treat and/or prevent wound infections.

Current Trends in Revision Hip Arthroplasty: Indications and Types of Components Revised

BACKGROUND

The materials and techniques for both primary and revision total hip arthroplasty (THA) have changed over time. This study evaluated if the indications for revision THA, rates of components utilized (femoral or acetabulum, both, or head/liner exchange), length of stay (LOS), and payments to surgeons and facilities have also changed.

METHODS

A retrospective study, utilizing the PearlDiver database, of 38,377 revision THA patients from January 2010 through December 2018 was performed. Data included the indication for revision, components revised (femoral or acetabulum, both, or head/liner exchange), LOS, and payments. Indications and components were analyzed by logistic regression (Dunnett's post hoc test). Revision totals were analyzed with a linear regression model. Analysis of variance assessed changes in LOS and payments.

RESULTS

Patients' median age was 67 years (Q1-Q3: 59-74), and 58.7% were female. Revisions for dislocation decreased between 2010 and 2018 (odds ratio [OR] 0.82, 95% confidence interval [CI] 0.68-0.98). Revisions for component loosening increased (OR 1.54, 95% CI 1.25-1.91). Dislocation remained the most common indication (19.3%), followed by PJI (17.3%) and loosening (17.1%). Both-component (OR:1.45; 95% CI:1.25-1.67) and femoral component only revisions increased; acetabular component only and head/liner exchanges decreased. Acetabular (OR 0.57, 95% CI 0.47-0.70) and head/liner exchange (OR 0.29, 95% CI 0.20-0.43) revisions decreased, while both component exchange (OR 1.45, 95% CI 1.25-1.67) and femoral revisions (OR 1.17, 95% CI 0.99-1.37) increased. Average LOS (-0.68 days; P < .001) and surgeon payments decreased (-$261.8; P < .001) while facility payments increased ($4,211; P < .001).

CONCLUSION

Indications for revision THA in this database study changed over time, with revision for dislocation decreasing and revision for loosening increasing over time. Both component and femoral revisions increased, and acetabular component and head/liner exchanges decreased. It is possible that these associations could be attributed to a number of details, the method of femoral fixation, surgical approach, and cementing, all of which require additional study.

Current treatments for biofilm-associated periprosthetic joint infection and new potential strategies

Periprosthetic joint infection (PJI) remains a devastating complication after total joint arthroplasty. Bacteria involved in these infections are notorious for adhering to foreign implanted surfaces and generating a biofilm matrix. These biofilms protect the bacteria from antibiotic treatment and the immune system making eradication difficult. Current treatment strategies including debridement, antibiotics, and implant retention, and one- and two-stage revisions still present a relatively high overall failure rate. One of the main shortcomings that has been associated with this high failure rate is the lack of a robust approach to treating bacterial biofilm. Therefore, in this review, we will highlight new strategies that have the potential to combat PJI by targeting biofilm integrity, therefore giving antibiotics and the immune system access to the internal network of the biofilm structure. This combination antibiofilm/antibiotic therapy may be a new strategy for PJI treatment while promoting implant retention.

Are multiple-use bottles of chlorhexidine solutions at risk of contamination in joint replacement surgery?

INTRODUCTION

Chlorhexidine gluconate 2% w/v in isopropanol 70% solutions in multiple-use bottles is commonly used in surgery as a cost-effective method for skin disinfection. However, multiple-use bottles risk contamination. This study aims to test whether bacterial contamination of multiple-use bottles or their solutions occurs once open and on use between different patients.

METHODS

Consecutive samples were taken each time a chlorhexidine bottle was used over a 7-day study period. Samples were tested using blood culture, agar plate and mass spectrometry.

RESULTS

No growth was observed in 52 samples taken from 18 bottles inoculated into blood culture bottles. Four growths on agar plate culture were determined to be contaminants from the sampling process.

CONCLUSIONS

This study supports the use of multiple-use bottled chlorhexidine solutions as safe and cost-effective in surgical practice.

Antiseptic Irrigation Solutions Used in Total Joint Arthroplasty: A Critical Analysis Review

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There are limited data that directly compare the efficacy of antiseptic irrigation solutions used for the prevention and treatment of periprosthetic joint infections in orthopaedic procedures; there is a notable lack of prospective data.

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For prevention of periprosthetic joint infections, the strongest evidence supports the use of low-pressure povidone-iodine.

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For the treatment of periprosthetic joint infections, delivering multiple solutions sequentially may be beneficial.

Use of Adjunct Antiseptic Agents in Periprosthetic Joint Infections

Periprosthetic joint infection is a leading cause for failure of contemporary total hip arthroplasty and total knee arthroplasty projected to nearly double in the next decade and reach an economic burden of $1.85 billion in the United Sates by 2030. Although multiple treatments for periprosthetic joint infection have been described, a thorough débridement and joint lavage to decrease bacterial bioburden and to remove biofilm remains a critical component of treatment. Various adjunct antiseptic agents such as chlorhexidine, povidone-iodine, hydrogen peroxide, acetic acid, and chlorine compounds are currently in off-label use in this capacity. Each antiseptic agent, however, has a distinct mechanism of action and targets different organisms, and some combinations of agents may lead to tissue toxicity. In this review, currently available adjunct antiseptic washes will be described in detail based on their mechanism of action and the evidence for their use will be reviewed. Furthermore, this review puts forward an evidence-based treatment algorithm based on the specific causative organism.

Post-Mastectomy Surgical Pocket Irrigation With Triple Antibiotic Solution vs Chlorhexidine Gluconate: A Randomized Controlled Trial Assessing Surgical Site Infections in Immediate Tissue Expander Breast Reconstruction

BACKGROUND

Post-mastectomy pocket irrigation solution choice is debated and primarily surgeon dependent. We compare triple antibiotic solution (TAS) with 0.05% chlorhexidine gluconate (CHG).

OBJECTIVES

The purpose of this study was to determine surgical site infection (SSI) rates after utilizing TAS vs CHG for breast pocket irrigation in immediate tissue expander (TE) breast reconstruction.

METHODS

A prospective, blinded, randomized controlled trial was performed in patients (18-81 years old) who underwent bilateral mastectomy with TE reconstruction. In each patient, 1 mastectomy pocket was randomized to TAS and the other to CHG. Both the TE and the pocket were irrigated in the respective solution. The primary outcome was the incidence of SSI. Secondary outcomes were rates of mastectomy flap necrosis, hematoma, and seroma.

RESULTS

A total of 88 patients who underwent bilateral immediate breast reconstruction were enrolled. Demographic and operative characteristics were equivalent because each patient served as their own control. Between the TAS and CHG groups, the incidence of SSI did not differ (5 [4.5%] vs 7 [8.0%], P = 0.35), including minor infections (2 [2.3%] vs 1 [1.1%], P = 0.56), major infections (2 [2.3%] vs 6 [6.8%], P = 0.15), and those resulting in explantation (2 [2.3%] vs 5 [4.5%], P = 0.25). Necrosis, hematoma, or seroma formation also did not differ. No patients who developed SSI received radiation.

CONCLUSIONS

This study does not demonstrate a statistically significant difference in SSI between TAS and CHG irrigation, though TAS approached statistical significance for lower rates of infectious complications.

LEVEL OF EVIDENCE: 2

Review of Pre-Operative Skin Preparation Options Based on Surgical Site in Orthopedic Surgery

Background: Surgical site infections (SSIs) are a primary contributor to surgical morbidity and mortality, causing a substantial financial burden on the healthcare system. Specifically, Cutibacterium acnes contributes greatly to infections in the shoulder and spine regions. Prevention of infection is crucial to improve patient outcomes and reduce costs. This article reviews current surgical skin preparation solutions, the unique distribution of organisms at common orthopedic surgical sites, and recommends solutions based on surgical location. Methods: A search of electronic databases (PubMed, MEDLINE, and Embase) was conducted for relevant literature until December 2020. Sources were compiled based on title and abstract, then full texts were read for possible inclusion. This review summarizes the most recent publications in the field of SSIs and preparation solutions. Results: The mechanism and efficacy of alcohol-, iodine-, and chlorhexidine-based preparations were reviewed, along with experimental preparations. This article identifies common colonization patterns for the shoulder, elbow, hip, knee, spine, foot, and ankle, and discusses recommendations for preparations based on current evidence. Recommendations: For shoulder and elbow operations, we recommend ChloraPrep™ (CareFusion, BD, El Paso, TX), DuraPrep™ (3M Health Care, St. Paul, MN), or Betadine^® applied with 4 × 4 gauze sponge, three-day pre-operative benzyl peroxide, and application of 3% hydrogen peroxide before skin preparation. For the hip and knee, we recommend application of 2% chlorhexidine gluconate (CHG) cloth the night before and morning of surgery and either DuraPrep or iodine-alcohol skin prep prior to surgery. For spine surgeries, we recommended ChloraPrep. For foot and ankle, our recommendations are: ChloraPrep or DuraPrep, submersion of foot in 70% ethanol/10% isopropyl alcohol for five minutes prior to procedure, application with a bristled brush, and a second vigorous scrub with 4 × 4 soaked gauze. Conclusions: The current surgical skin preparations have both benefits and drawbacks. We recommend that orthopedic surgeons choose a skin preparation based on surgical site and prevalence of unique skin flora there.

Health care-associated infections: Controlled delivery of cationic antiseptics from polymeric excipients

Nowadays, the treatment of health care-associated infections represents a serious issue, due to the increasing number of bacterial strains resistant to traditional antibiotics. The use of antiseptics like quaternary ammonium salts and biguanides is a viable alternative to face these life-threatening infections. However, their inherent toxicity as well as the necessity of providing a sustained release to avoid the formation of pathogen biofilms are compelling obstacles towards their assessment in the hospitals. Within this framework, the role of polymeric drug delivery systems is fundamental to overcome the aforementioned problems. Biocompatibility, biodegradability and excipient-drug interactions are crucial properties determining the efficacy of the formulation. In this work, we provide an in-depth analysis of the polymer drug delivery systems that have been developed or are under development for the sustained release of positively charged antiseptics, highlighting the crucial characteristics that allowed to achieve the most relevant therapeutic effects. We reported and compared natural occurring polymers and synthetic carriers to show their pros and cons and applicability in the treatment of health care-associated infections. Then, the discussion is focused on a particularly relevant class of materials adopted for the scope, represented by polyesters, which gave rise, due to their biodegradability, to the field of resorbable drug delivery devices. Finally, a specific analysis on the effect of the polymer functionalization over the formulation performances for the different types of polymeric carriers is presented.

Pursuit of the ideal antiseptic irrigation solution in the management of periprosthetic joint infections

Irrigation and debridement in the treatment of periprosthetic joint infection (PJI) serve an integral role in the eradication of bacterial burden and subsequent re-infection rates. Identifying the optimal irrigation agent, however, remains challenging, as there is limited data on superiority. Direct comparison of different irrigation solutions remains difficult because of variability in treatment protocols. While basic science studies assist in the selection of irrigation fluids, in vitro results do not directly translate into clinical significance once implemented in vivo. Dilute povidone iodine, hydrogen peroxide, chlorhexidine gluconate, acetic acid, sodium hypochlorite, hypochlorous acid, and preformed combination solutions all have potential against a broad spectrum of PJI pathogens with their own unique advantages and disadvantages. Future clinical studies are needed to identify ideal irrigation solutions with optimal bactericidal properties and low cytotoxicity for PJI treatment.

The Prevention of Periprosthetic Joint Infection in Primary Total Hip Arthroplasty Using Pre-Operative Chlorhexidine Bathing

Periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is a devastating complication. The aim of this study was to investigate whether preoperative bathing using chlorhexidine gluconate (CHG) before THA can effectively reduce the postoperative PJI rate. A total of 933 primary THA patients, with the majority being female (54.4%) were included in the study. Primary THA patients who performed preoperative chlorhexidine bathing were assigned to the CHG group (190 subjects), and those who did not have preoperative chlorhexidine bathing were in the control group (743 subjects). The effects of chlorhexidine bathing on the prevention of PJI incidence rates were investigated. Differences in age, sex, and the operated side between the two groups were not statistically significant. Postoperative PJI occurred in four subjects, indicating an infection rate of 0.43% (4/933). All four infected subjects belonged to the control group. Although the PJI cases were significantly more in the control group than in the CHG group, statistical analysis revealed no statistical significance in the risk of PJI occurrence between the two groups (p = 0.588). Preoperative skin preparation by bathing with a 2% chlorhexidine gluconate cleanser did not produce significant effects on the prevention of postoperative PJI in primary THA.

The Effect of Different Irrigation Solutions on the Cytotoxicity and Recovery Potential of Human Osteoblast Cells In Vitro

Background

Surgeons use various irrigation solutions to minimize the risk of prosthetic joint infection after total joint arthroplasty. The toxicity of these solutions is an important consideration in their use. This study investigates the effect of irrigation solutions Bacitracin, Clorpactin (sodium oxychlorosene), and Irrisept (chlorhexidine) on osteoblast cytotoxicity and proliferation.

Methods

Four replicates of 6 conditions at 3 time points (1, 2, and 4 min) were tested: control (normal saline), Bacitracin (33 IU/ml), Clorpactin (0.05%, 0.1%, 0.2%), and Irrisept (0.05% chlorhexidine gluconate). Human osteoblasts were cultured at 37°C and 5% CO₂ until confluent monolayers were obtained. The treatment solution was applied, and cells were washed 3x with warm phosphate-buffered saline and then supplemented with a fresh medium. Phase-contrast images were taken before and after treatment. The cytotoxicity and proliferation of the treated cells was measured for all conditions on day 3 and day 5 after treatment using the alamarBlue assay.

Results

All test conditions showed morphological changes to cells after treatment; controls did not. Cells demonstrated curling and detachment. This effect was the worst and permanent with Irrisept, whereas other treatments showed a return to normal morphology after 1 week. All treatments showed increased %alamarBlue reduction after 5 days except Irrisept, which showed decreased reduction. There was no statistically significant time or dose dependence with Clorpactin treatment.

Conclusions

Clorpactin and Bacitracin are damaging to human osteoblast cells in vitro as compared with normal saline. This damage is at least partially reversible as shown by morphology and cell viability assay. Irrisept caused more damage than either Clorpactin or Bacitracin, and the damage was not reversible.

Polyvinyl alcohol/chitosan wound dressings loaded with antiseptics

Wound care remains a challenge in healthcare. This work aimed to develop a new polyvinyl alcohol (PVA)/chitosan (Ch) based wound dressing able to ensure protection, hydration and a controlled release of antiseptics, as alternative to actual treatments. Two distinct formulations (1:1 and 3:1, w/w) were prepared, sterilized by autoclaving and characterized concerning surface morphology, degradation over the time, mechanical properties and hydrophilicity. Both dressings revealed adequate properties for the intended purpose. The dressings were loaded with chlorhexidine (CHX) and polyhexanide (PHMB) and the drug release profiles were determined using Franz diffusion cells. The release of PHMB was more sustained than CHX, lasting for 2 days. As the amounts of drugs released by PVA/Ch 1:1 were greater, the biological tests were done only with this formulation. The drug loaded dressings revealed antibacterial activity against S. aureus and S. epidermidis, but only the ones loaded with PHMB showed adequate properties in terms of cytotoxicity and irritability. The application of this elastic dressing in the treatment of wounds in a dog led to faster recovery than conventional treatment, suggesting that the material can be a promising alternative in wound care.

Effect of Exposure to Chlorhexidine Residues at "During Use" Concentrations on Antimicrobial Susceptibility Profile, Efflux, Conjugative Plasmid Transfer, and Metabolism of Escherichia coli

There is no standardized protocol to predict the concentration levels of microbicides that are left on surfaces as a result of the use of these products, and there is no standardized method to predict the potential risk that such levels pose to emerging antibacterial resistance. The ability to distinguish between selection and adaption processes for antimicrobial resistance in bacteria and the impact of different concentrations of microbicide exposure have not been fully investigated to date. This study considers the effect of exposure to a low concentration of chlorhexidine digluconate (CHX) on selected phenotypes of Escherichia coli and relates the findings to the risk of emerging antimicrobial resistance. A concentration of 0.006 mg/ml CHX is a realistic "during use" exposure concentration measured on surfaces. At this concentration, it was possible for CHX-susceptible bacteria to survive, adapt through metabolic alterations, exhibit a transient decrease in antimicrobial susceptibility, and express stable clinical cross-resistance to front-line antibiotics. Efflux activity was present naturally in tested isolates, and it increased in the presence of 0.00005 mg/ml CHX but ceased with 0.002 mg/ml CHX. Phenotypic microarray assays highlighted a difference in metabolic regulation at 0.00005 mg/ml and 0.002 mg/ml CHX; more changes occurred after growth with the latter concentration. Metabolic phenotype changes were observed for substrates involved with the metabolism of some amino acids, cofactors, and secondary metabolites. It was possible for one isolate to continue transferring ampicillin resistance in the presence of 0.00005 mg/ml CHX, whilst 0.002 mg/ml CHX prevented conjugative transfer. In conclusion, E. coli phenotype responses to CHX exposure are concentration dependent, with realistic residual CHX concentrations resulting in stable clinical cross-resistance to antibiotics.

Prevention of Prosthetic Joint Infection: From Traditional Approaches towards Quality Improvement and Data Mining

A projected increased use of total joint arthroplasties will naturally result in a related increase in the number of prosthetic joint infections (PJIs). Suppression of the local peri-implant immune response counters efforts to eradicate bacteria, allowing the formation of biofilms and compromising preventive measures taken in the operating room. For these reasons, the prevention of PJI should focus concurrently on the following targets: (i) identifying at-risk patients; (ii) reducing “bacterial load” perioperatively; (iii) creating an antibacterial/antibiofilm environment at the site of surgery; and (iv) stimulating the local immune response. Despite considerable recent progress made in experimental and clinical research, a large discrepancy persists between proposed and clinically implemented preventative strategies. The ultimate anti-infective strategy lies in an optimal combination of all preventative approaches into a single “clinical pack”, applied rigorously in all settings involving prosthetic joint implantation. In addition, “anti-infective” implants might be a choice in patients who have an increased risk for PJI. However, further progress in the prevention of PJI is not imaginable without a close commitment to using quality improvement tools in combination with continual data mining, reflecting the efficacy of the preventative strategy in a particular clinical setting.

Long acting anti-infection constructs on titanium

Peri-prosthetic joint infections (PJI) are a serious adverse event following joint replacement surgeries; antibiotics are usually added to bone cement to prevent infection offset. For uncemented prosthesis, alternative antimicrobial approaches are necessary in order to prevent PJI; however, despite elution of drug from the surface of the device being shown one of the most promising approach, no effective antimicrobial eluting uncemented device is currently available on the market. Consequently, there is a clinical need for non-antibiotic antimicrobial uncemented prosthesis as these devices present numerous benefits, particularly for young patients, over cemented artificial joints. Moreover, non-antibiotic approaches are driven by the need to address the growing threat posed by antibiotic resistance. We developed a multilayers functional coating on titanium surfaces releasing chlorhexidine, a well-known antimicrobial agent used in mouthwash products and antiseptic creams, embedding the drug between alginate and poly-beta-amino-esters. Chlorhexidine release was sustained for almost 2 months and the material efficacy and safety was proven both in vitro and in vivo. The coatings did not negatively impact osteoblast and fibroblast cells growth and were capable of reducing bacterial load and accelerating wound healing in an excisional wound model. As PJI can develop weeks and months after the initial surgery, these materials could provide a viable solution to prevent infections after arthroplasty in uncemented prosthetic devices and, simultaneously, help the fight against antibiotic resistance.

The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions

INTRODUCTION

The Mulcahy salvage fundamentally altered the management of penile prosthesis infections (PPI). Central to this procedure is a sequence of antiseptic irrigations that aims to remove and eradicate pathogenic microflora from the infected field, thus preparing for immediate reimplantation. The antiseptic solutions and their respective concentrations, however, have never been evaluated for efficacy.

AIM

This review critically examines 3 commonly used antiseptic irrigation solutions (povidone-iodine [PVI], hydrogen peroxide [H₂O₂], and chlorhexidine gluconate [CHG]) in terms of their antimicrobial activity, cytotoxicity, and clinical use.

METHODS

A PubMed literature review was performed on articles published between 2003 and 2018. Both preclinical as well as clinical studies from various surgical disciplines were included in this review.

MAIN OUTCOME MEASURE

The original salvage protocol selected for irrigation solutions at concentrations that are likely detrimental to native tissue.

RESULTS

All 3 agents demonstrate in vitro cytotoxic effects at subclinical concentrations, but H₂O₂ is associated with the most significant deleterious properties. It does not seem to broaden antimicrobial coverage beyond what is covered by PVI. Dilute PVI (0.35-3.5% with exposure time of at least 3 minutes) possesses the most robust clinical evidence as an intraoperative adjunct, reducing the incidence of postoperative infectious complications. chlorhexidine gluconate is a promising new agent but lacks clinical data.

CLINICAL IMPLICATION

Improvements in the salvage protocol are warranted based on current evidence. Careful selection of lavage solution and usage of the lowest necessary concentration will help achieve desired antimicrobial activity while avoiding native tissue cytotoxicity. Strength and limitation: The study is limited by its retrospective nature, and the heterogeneity of literature reviewed precluded a formal meta-analysis. Furthermore, future studies will need to address the roles of normal saline and antibiotic irrigations as intraoperative adjuncts for infection prevention.

CONCLUSION

Diluted PVI (0.35-3.5% for 3 minutes) may be beneficial in the prevention of PPI. Evidence supports its use both in the setting of primary implantation as well as salvage of infected hardware. An improved, evidence-based protocol may increase positive outcomes of urologic prosthetic surgery. Pan S, Rodriguez D, Thirumavalavan N, et al. The Use of Antiseptic Solutions in the Prevention and Management of Penile Prosthesis Infections: A Review of the Cytotoxic and Microbiological Effects of Common Irrigation Solutions. J Sex Med 2019;16:781-790.

Evaluation of Necrotic, Edematous and Inflammatory Changes in Bone Marrow and Soft Tissue After Irrigation with Different Concentrations of NaOCl Solution: An Experimental Study in Rat Tibia

Objective

We aimed to investigate effects of different concentrations (0.5-5%) of Sodium Hypochlorite (NaOCl) solution on healthy tissues, and determine the optimal concentration that does not harm to tissue.

Materials and Methods

30 tibias of 15 male Wistar albino rats were used. The tibias were randomly divided into 5 groups (Salin, 0.5%, 1%, 2.5%, and 5% NaOCl). Tibias were reamed intramedullary, and irrigated with 20 ml of saline or increasing concentrations of (0.5-5%) NaOCl. The tibias were embedded in paraffin and the sections were stained with hematoxylin-eosin. All sections were assessed for edema, acute inflammation, or necrosis according to their density, in bone marrow and soft tissues.

Results

Pairwise comparisons revealed that irrigation of tibia with saline or 0.5% NaOCl solutions was not statistically significant in terms of necrosis in the bone marrows (p=0.320). However, irrigation of rat tibia with saline caused less necrosis in the bone marrows compared to high concentrations (1%, 2.5%, and 5%) of NaOCl (saline and 1% NaOCl, p=0.017; saline and 2.5% NaOCl, p=0.0007; saline and 5% NaOCl, p=0.001).

Conclusion

As an irrigation solution, the effects of 0.5% NaOCl are similar to those of saline in terms of edema, inflammation, and necrosis. There is a need for evaluation of necrosis for extended periods such as one week or one month by immunohistochemical methods and flow cytometry.

Early adherence and biofilm formation of Cutibacterium acnes (formerly Propionibacterium acnes) on spinal implant materials

BACKGROUND

Cutibacterium acnes (C. acnes) is associated with infection following shoulder and spine surgery due to follicular pore concentrations in these anatomic regions. It has been established that it can form biofilms on surgical implant materials, which may contribute to its role in perioperative infection, but its behavior of early colonization on those materials is not yet well understood.

PURPOSE

The purpose of this study was to evaluate the time to adherence and subsequent biofilm formation of C. acnes in the first 24 hours on implant materials commonly used in spinal surgery.

STUDY DESIGN

We compared the colonization and behavior of C. acnes over time when applied to five commonly used spine implant materials - polyether ether ketone (PEEK), cobalt chromium (CC), stainless steel (SS), titanium, and titanium alloy.

METHODS

C. acnes was applied onto the samples of PEEK, CC, SS, titanium, and titanium alloy, and allowed to adhere for periods of 4, 8, 12, 16, and 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total 24 hours. Scanning electron microscopy and confocal laser scanning microscopy were used to visualize all samples for the presence and quantification of C. acnes adherence at each time period. Subsequent transition to biofilm formation on these samples was assessed via scanning electron microscopy at each time period.

RESULTS

The PEEK specimens exhibited the highest amount of surface biological burden in the first 24 hours compared with the other materials, which displayed little or no adherence. Rapid biofilm formation first observed at 8 hours of allowed adhesion on PEEK, whereas no significant biofilm formation was seen on the other materials during the observed time period.

CONCLUSIONS

Although C. acnes is known to have a slow proliferation rate, the results of this investigation demonstrate that it can rapidly adhere to and form a biofilm on PEEK. These data suggest that the use of PEEK implants placed during spinal surgery may facilitate early intraoperative colonization, and subsequent infection, compared with metallic implants.

CLINICAL SIGNIFICANCE

The findings of this study suggest that PEEK may prove to be problematic as a choice of implant material in cases were C. acnes infection is a possibility.

Study of the Relationship Between Chlorhexidine-Grafted Amount and Biological Performances of Micro/Nanoporous Titanium Surfaces

Biomaterial-associated infection and lack of sufficient osseointegration contribute to a large proportion of implant failures. Therefore, antibacterial and osseointegration-accelerating properties are important in implant surface design. In this study, a micro/nanoporous titanium surface was prepared through alkaline and heat treatments, covalently conjugated with aminosilane. Then, varying amounts of chlorhexidine (CHX) were covalently grafted onto the aminosilane-modified surface via glutaraldehyde to obtain different CHX-grafted surfaces. These as-prepared surfaces were evaluated in terms of their surface chemical composition, surface topography, CHX grafting amount, antibacterial activity, and osteoblast compatibility. The results showed that the CHX grafting amount increased with increasing CHX concentrations, leading to better antibacterial activity. CHX (1 mg/mL) resulted in the best antibacterial surface, which still retained good osteoblast compatibility. Meanwhile, competitive bacterial-cell adhesion analysis demonstrated that this surface has great value for osteoblast adhesion at the implant-bone interface even in the presence of bacteria. This effortless, easily performed, and eco-friendly technique holds huge promise for clinical applications.

Antimicrobial Irrigation and Technique during Breast Augmentation: Survey of Current Practice

Breast augmentation is among the most common procedures performed in the United States. Though bacterial contamination of breast prostheses is associated with adverse sequelae, there are no universally accepted guidelines and limited best practice recommendations for antimicrobial breast pocket irrigation. We designed a survey to identify pocket irrigation preferences and antimicrobial techniques during implant-based breast augmentation among American Society of Plastic Surgeons (ASPS) members.

METHODS

In January 2018, a random cohort of 2,488 ASPS members was surveyed. Questions queried breast pocket irrigation methods and surgical techniques including implant placement, incision location, and implant soaking agents. An extensive literature review of breast pocket irrigation practices was completed and used as a basis for the survey.

RESULTS

The survey response rate was above the ASPS average at 16% (n = 407). Respondents preferred an inframammary incision (90%) and submuscular implant placement (92%). Triple antibiotic solution (TAS) and TAS + Betadine ± Bacitracin were preferred by 61% and Betadine variants by 11%. Preferred dwell times stratified to 30 seconds (39%), 1 minute (18%), 2-5 minutes (21%), and >5 minutes (22%). Among those employing a TAS variant, 53% preferred a suboptimal dwell time of ≤1 minute. Prostheses were soaked in TAS (42%), TAS + Betadine ± Bacitracin (15%), a Betadine variant (12%), or other (31%).

CONCLUSIONS

Periprosthetic bacterial contamination leads to comorbidity following breast augmentation. Our results reveal significant variability regarding breast pocket irrigation techniques among ASPS members during cosmetic breast augmentation. These data suggest the need for best practice guidelines regarding breast pocket irrigation and implant soaking agents.

Efficacy of Intraoperative Antiseptic Techniques in the Prevention of Periprosthetic Joint Infection: Superiority of Betadine

BACKGROUND

Povidone-iodine (PI), chlorhexidine gluconate (CHG), and vancomycin (VANC) powder are common intrawound prophylactic agents to prevent periprosthetic joint infection during primary total joint arthroplasty. The aims of this study are (1) to determine the minimal inhibitory concentration (MIC) and time to death for PI, CHG, and VANC against multiple bacteria and (2) to determine time to death against bacteria dried on titanium discs.

METHODS

A standard quantitative suspension assay was performed to determine the MIC for PI, CHG, and VANC against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Haemophilus influenzae, Pseudomonas aeruginosa, Burkholderia cepacia, and Escherichia coli. Time to death assay was performed with time points of 0, 3, 30, and 60 minutes. Concentrations of antiseptic agents for time to death assay were 1% PI, 0.05% CHG, and 5 μg/mL VANC. Dry-phase bacteria on titanium discs were treated in a similar fashion.

RESULTS

The MIC of PI was 0.63%, CHG was 0.0031%, and VANC was 1.56 μg/mL. All 7 bacterial isolates were completely killed by PI at all times tested. CHG failed to kill MRSA and B cepacia at 0- and 3-minute exposures. Vancomycin completely killed MRSA and S epidermidis isolates between 18-20 hours of exposure. All bacterial isolates dried on titanium discs were eliminated by PI exposure on contact. E coli and S epidermidis were incompletely eliminated by CHG at 0 minutes, with all isolates eliminated at 3, 10, and 30 minutes.

CONCLUSION

Our study suggests that PI kills all bacteria tested immediately on contact and that the exposure time is not the key factor.

Proceedings from the 2018 International Consensus Meeting on Orthopedic Infections: prevention of periprosthetic shoulder infection

The Second International Consensus Meeting on Orthopedic Infections was held in Philadelphia, Pennsylvania, in July 2018. Over 800 international experts from all 9 subspecialties of orthopedic surgery and allied fields of infectious disease, microbiology, and epidemiology were assembled to form a consensus workgroup. The following proceedings on the prevention of periprosthetic shoulder infection come from 16 questions evaluated by delegates from the shoulder section.

Standardising intraoperative irrigation with 0.05% chlorhexidine gluconate in caesarean delivery to reduce surgical site infections: A single institution experience

Background

Surgical site infection is a significant cause of morbidity and mortality following caesarean delivery.

Objective

To determine whether standardising intraoperative irrigation with 0.05% chlorhexidine gluconate during caesarean delivery could decrease infection rates.

Methods

This was a process improvement project involving 742 women, 343 of whom received low-pressured 0.05% chlorhexidine gluconate irrigation during caesarean delivery over a one-year period. Infection rates were compared with a standard-of-care control group (399 women) undergoing caesarean delivery the preceding year.

Results

The treatment group infection rate met the study goal by achieving a lower infection rate than the control group, though this was not statistically significant. A significant interaction effect between irrigation with 0.05% chlorhexidine gluconate and antibiotic administration time existed, such that infection occurrence in the treatment group was not dependent on antibiotic timing, as opposed to the control group infection occurrence, which was dependent on antibiotic timing.

Conclusion

Intraoperative irrigation with 0.05% chlorhexidine gluconate during caesarean delivery did not statistically significantly reduce the rate of infections. It did render the impact of antibiotic administration timing irrelevant in prevention of surgical site infection. This suggests a role for 0.05% chlorhexidine gluconate irrigation in mitigating infection risk whether antibiotic prophylaxis timing is suboptimal or ideal.

Delayed Allergic Reaction to ChloraPrepTM in Foot and Ankle Surgery

Chlorhexidine-based skin preparations are frequently used in orthopaedic surgery. We report 2 recent cases of patients suffering significant allergic reactions to ChloraPrep^TM complicating routine foot and ankle surgery. We advise vigilance for this possible issue and recommend thorough removal of all preparation at the end of the procedure.

Etiology of Above-knee Amputations in the United States: Is Periprosthetic Joint Infection an Emerging Cause?

BACKGROUND

Above-knee amputation (AKA) is a morbid procedure and is performed for a number of conditions. Although AKA is usually performed for dysvascular disease, trauma, and malignancy, AKA is also considered in patients who have failed multiple salvage attempts at treating periprosthetic joint infection (PJI) of TKA. Although aggressive measures are being taken to treat PJI, the huge volume of TKAs might result in a large number of AKAs being performed for PJI in the United States. However, the national trends in the incidence of AKAs from different etiologies and the relative contribution of different etiologies to AKA are yet to be studied.

QUESTIONS/PURPOSES

(1) What are the temporal trends in the incidence of AKAs (from all causes) in the US population from 1998 to 2013? (2) What are the temporal trends in the incidence of AKAs by etiology (dysvascular disease, trauma, malignancy, and PJI)? (3) What are the temporal trends in the relative contribution of different etiologies to AKA?

METHODS

Using the Nationwide Inpatient Sample (NIS) from 1998 to 2013, AKAs were identified using International Classification of Diseases, 9 Revision (ICD-9) procedure code 84.17. The NIS database is the largest all-payer database in the United States containing information on approximately 20% of all the hospital admissions in the country. As a result of its sampling design, it allows for estimation of procedural volumes at the national level. All AKAs were grouped into one of the following five etiologies in a sequential manner using ICD-9 diagnosis codes: malignancy, PJI, trauma, dysvascular disease (peripheral vascular disease, diabetic, or a combination), and others. All of the numbers were converted to national estimates using sampling weights provided by the NIS, and the national incidence of AKAs resulting from various etiologies was calculated using the US population as the denominator. Poisson and linear regression analyses were used to analyze the annual trends.

RESULTS

From 1998 to 2013, the incidence of AKAs decreased by 47% from 174 to 92 AKAs per 1 million adults (incidence rate ratio [IRR]; change in the number of AKAs per 1 million adults per year; 0.96; 95% confidence interval [CI], 0.96-0.96; p < 0.001). The incidence of AKAs resulting from PJI increased by 263% (IRR, 1.07; 95% CI, 1.06-1.07; p < 0.001). An increase was also observed for AKAs from malignancy (IRR, 1.01; 95% CI, 1.00-1.02; p = 0.007), although to a smaller extent. AKAs from dysvascular causes (IRR, 0.96; 95% CI, 0.95-0.96; p < 0.001) and other etiologies (IRR, 0.97; 95% CI, 0.96-0.97; p < 0.001) decreased. There was no change in the incidence of AKAs related to trauma (IRR, 1.00; 95% CI, 0.99-1.00; p = 0.088). The proportion of AKAs resulting from PJI increased by 589% from 1998 to 2013 (coefficient = 0.18; 95% CI, 0.15-0.22; p < 0.001). The proportion of AKAs resulting from dysvascular causes decreased (coefficient = 0.18; 95% CI, 0.15-0.22; p < 0.001), whereas that resulting from malignancy (coefficient = 0.04; 95% CI, 0.03-0.05; p < 0.001) and trauma (coefficient = 0.13; 95% CI, 0.09-0.18; p < 0.001) increased.

CONCLUSIONS

The incidence of AKAs has decreased in the United States. AKAs related to dysvascular disease and other etiologies such as trauma and malignancy have either substantially decreased or remained fairly constant, whereas that resulting from PJI more than tripled. Given the increased resource utilization associated with limb loss, the results of this study suggest that national efforts to reduce disability should prioritize PJI. Further studies are required to evaluate the risk factors for AKA from PJI and to formulate better strategies to manage PJI.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Bioelectric Silver-Zinc Dressing Equally Effective to Chlorhexidine in Reducing Skin Bacterial Load in Healthy Volunteers

PURPOSE

The aim of the present study was to evaluate and compare the effectiveness of the silver-zinc bioelectric dressing as compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in reducing the bacterial count on the knee.

METHODS

Three groups consisting of 48 healthy volunteers were included. Age range was 23 to 54 years old and 60% of participants were male. Each subject had 1 knee serve as the test and the contralateral as the control. The test site was prepared with either 2% chlorhexidine, 4% chlorhexidine, or a silver-zinc bioelectric dressing and after 24 hours skin cultures were taken and examined for bacterial growth.

RESULTS

In the 2% chlorhexidine group 23 of 48 unprepped knees had positive cultures, compared with 9 of 48 prepped knees (P = .003; risk reduction, 4.0 times). In the 4% chlorhexidine group 25 of 48 unprepped knees had positive cultures, compared with 14 of 48 prepped knees (P = .027; risk reduction, 2.6 times). In the silver-zinc bioelectric dressing group 29 of 48 unprepped knees had positive cultures, compared with 7 of 48 prepped knees (P < .001; risk reduction, 8.9 times). There was no difference in the positive skin culture rate between the 3 methods.

CONCLUSIONS

Application of the silver-zinc bioelectric dressing was equally effective at reducing skin bacterial load when compared with skin preparation with 2% chlorhexidine or 4% chlorhexidine in healthy volunteers.

LEVEL OF EVIDENCE

Basic Science - Microbiology.

CLINICAL RELEVANCE

The findings of this study indicate that the use of a bioelectric dressing after knee surgery can match the standard of care of preparing the skin with an antiseptic before surgery.

Cytotoxicity evaluation of chlorhexidine gluconate on human fibroblasts, myoblasts, and osteoblasts

Introduction: Chlorhexidine gluconate (CHX) is widely used as a preoperative surgical skin-preparation solution and intra-wound irrigation agent, with excellent efficacy against wide variety of bacteria. The cytotoxic effect of CHX on local proliferating cells following orthopaedic procedures is largely undescribed. Our aim was to investigate the in vitro effects of CHX on primary fibroblasts, myoblasts, and osteoblasts. Methods: Cells were exposed to CHX dilutions (0%, 0.002%, 0.02%, 0.2%, and 2%) for either a 1, 2, or 3-minute duration. Cell survival was measured using a cytotoxicity assay (Cell Counting Kit-8). Cell migration was measured using a scratch assay: a "scratch" was made in a cell monolayer following CHX exposure, and time to closure of the scratch was measured. Results: All cells exposed to CHX dilutions of ≥ 0.02% for any exposure duration had cell survival rates of less than 6% relative to untreated controls (p < 0.001). Cells exposed to CHX dilution of 0.002% all had significantly lower survival rates relative to control (p < 0.01) with the exception of 1-minute exposure to fibroblasts, which showed 96.4% cell survival (p = 0.78). Scratch defect closure was seen in < 24 hours in all control conditions. However, cells exposed to CHX dilutions ≥ 0.02% had scratch defects that remained open indefinitely. Conclusions: The clinically used concentration of CHX (2%) permanently halts cell migration and significantly reduces survival of in vitro fibroblasts, myoblasts, and osteoblasts. Further in vivo studies are required to examine and optimize CHX safety and efficacy when applied near open incisions or intra-wound application.

Preliminary Results of the Use of a Stabilized Hypochlorous Acid Solution in the Management of Ralstonia Pickettii Biofilm on Silicone Breast Implants

BACKGROUND

Ralstonia Pickettii biofilms are associated with pocket infections following breast implant surgeries. Biofilm protects bacteria most topically applied antimicrobial irrigations.

OBJECTIVES

To evaluate the effectiveness of four antimicrobial solutions on the planktonic form and established biofilm of Ralstonia Pickettii grown on 3 different types of silicone breast implants.

METHODS

Time kill assays at clinical concentrations of chlorhexidine gluconate, povidone iodine, triple-antibiotic solution, and a 0.025% hypochlorous acid solution stabilized in amber glass were evaluated. Normal saline was the control. Three types of silicone implants, two with a textured surface and one smooth surface, were selected. Planktonic assays were performed after implants were soaked for one, five, 30, and 120 minute time points. Biofilm assays were performed after 5 and 120 minutes of implant soak time. Both tests evaluated cell-forming units (CFU/mL).

RESULTS

Triple antibiotic solution had no effect on R. pickettii and was dropped from the study. Remaining solutions showed total kill of planktonic bacteria at one minute. Saline control showed no significant effect on biofilm as anticipated. Stabilized hypochlorous acid was the only solution tested capable of eradicating R. pickettii biofilm on all implant surfaces tested within the first five minute soak time.

CONCLUSIONS

Noncytotoxic, 0.025% hypochlorous acid in normal saline, stabilized in amber glass, successfully eradicated Ralstonia pickettii in planktonic and mature biofilm on three types of silicone implants during initial five minute soak time and may be the preferred antimicrobial solution for pocket lavage. This preliminary study requires further investigation. Leaching and implant compatibility testing is currently in progress.

Antiseptics Commonly Used in Total Joint Arthroplasty Interact and May Form Toxic Products

BACKGROUND

Multiple antiseptics have been described for use in total joint arthroplasty infection, and the use of multiple antiseptic solutions during a single operation has been described. Our clinical experience is that chlorhexidine (CHX) and Dakin's solution (NaOCl) interact and form a precipitate. The purpose of this study is to determine whether this reaction could be replicated in a laboratory setting, and to determine if other commonly used antiseptics also visibly react when mixed.

METHODS

Four percent chlorhexidine gluconate (CHX), 0.5% sodium hypochlorite (NaOCl), 3% hydrogen peroxide (H₂O₂), and 10% povidone-iodine (BTD) solutions were obtained and all possible combinations were mixed. Any visible reactions were noted and recorded, and a literature search was performed to characterize the reaction and products.

RESULTS

CHX and NaOCl, CHX and H₂O₂, and CHX and BTD reacted instantly, forming a precipitate. NaOCl and H₂O₂ reacted to produce a gas. NaOCl and BTD reacted and produced a color change. The literature review revealed that at least 2 of the reactions tested (CHX + NaOCl and NaOCl + H₂O₂) could result in byproducts toxic to humans.

CONCLUSION

Surgeons must be aware of these interactions when using antiseptic solutions during procedures. Caution should be used combining or mixing antiseptics, and we recommend against concomitant introduction in a surgical wound.