Silver carboxylate-TiO2/polydimethyl siloxane is a safe and effective antimicrobial with significant wound care potential.

Introduction: With the rise in antibiotic resistance, new methodologies are needed to combat musculoskeletal infections. Silver is an antimicrobial that can be synthesized in different forms, but its pharmacokinetics are difficult to control. This study details the antibacterial efficacy and cellular cytotoxicity of a formulation consisting of silver carboxylate (AgCar) released through a titanium dioxide/polydimethylsiloxane matrix with a predictable release profile on Pseudomonas aeruginosa, Acinetobacterium baumannii, and human-derived primary osteoblasts. Methods: Through an Institutional Animal Care and Use Committee and IRB-approved protocol, AgCar was applied to live Yucatan porcine skin and histologically analyzed for skin penetration. Graphite Furnace Atomic Absorption Spectroscopy (GFAAS) was used to measure elution of AgCar. Dose-response curves were generated through optical density to assess potency. Finally, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to quantify the cellular cytotoxicity of the novel formulation. The results were subject to statistical analysis using analysis of variance and post hoc Tukey tests. Results: The silver carboxylate coating demonstrated deep penetration into the epithelium at the level of the deep pilosebaceous glands in animal models. GFAAS testing demonstrated the extended elution profile of silver carboxylate over 96 hours, while 100% silver with no titanium dioxide-polydimethylsiloxane matrix fully eluted within 48 hours. 10x silver carboxylate demonstrated superior antimicrobial activity to antibiotics and other silver formulations and showed minimal cytotoxicity compared with other silver formulations. Discussion/Clinical Relevance: Current antimicrobial therapies in wound care and surgical antisepsis, such as chlorhexidine gluconate, have pitfalls including poor skin penetration and short duration of efficacy. The broad antimicrobial activity, extended elution, and deep skin penetration of this AgCar formulation show great promise for surgical site infection and wound care treatment. Novel technology to fight the growing threat of microbial resistance should be at the forefront of orthopaedic surgical site infection prevention and treatment.

The Immediate Impact of Total Knee Arthroplasty Removal From the Medicare Inpatient-Only List on Patient Derived Functional Outcomes and Hospital Satisfaction.

BACKGROUND: Total knee arthroplasty (TKA) is the standard of treatment for end-stage knee osteoarthritis. On January 1, 2018, the Centers for Medicare and Medicaid (CMS) officially removed TKA from their inpatient-only list. The clinical impact of this change is not fully understood yet. METHODS: Electronic records were retrospectively reviewed for patients who underwent TKA between January 1 to June 30, 2017, or January 1 to June 30, 2018. Patients completed Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement surveys which assessed patient reported outcomes prior to and following TKA. Hospital statistics for the 2 time points were determined and compared. This was a single institution study resulting in 351 patients in the pre-CMS change group and 350 patients in the post-CMS change group. RESULTS: Analysis of the pre-CMS and post-CMS transition cohorts indicated no significant difference in activities of daily living (ADLs), pain, or pain catastrophizing scale preoperatively or 12-months postoperatively. Additionally, there was no difference in the median change between preoperative and postoperative ADL scores (P = .866), yet pain scores approached significance with a P value of .054. The pre-CMS transition group stayed significantly longer in the hospital postoperatively and was more commonly discharged to a skilled nursing facility. No difference was seen in 30-day readmission rates (P = .253). CONCLUSIONS: Results showed that patients had similar scores for ADL, quality of life, pain, and pain catastrophizing 12-months following their TKA. Movement of TKA from the Medicare inpatient only list did not have an immediate negative impact for patient reported outcomes and 30-day readmissions at our institution in the 6-month transition period.

Mechanically stable rifampin antibiotic cement inhibits Pseudomonas aeruginosa biofilm surface growth.

Rifampin has been proven to be effective in the treatment of prosthetic infections due to its ability to intercalate into biofilms. The use of rifampin in antibiotic spacers is not well described, which would be especially important in the local periprosthetic environment where parenteral doses have poor penetration. The null hypothesis tests if rifampin use in polymethyl methacrylate (PMMA) cement will show no clinically significant impact on mechanical strength at antibiotic concentrations that remain bactericidal. Test antibiotic cement samples supplemented with 0, 30, 50, 100, 150, or 200 mg of rifampin into a standard 40 g bag were tested for compression to failure using published ASTM standards. The samples were then inoculated with Pseudomonas aeruginosa and either evaluated for lipopolysaccharide (LPS) presence as a marker of biofilm or tested by elution as the Kirby Bauer assay. Rifampin concentrations of 30 and 50 mg, showed no statistically different mechanical characteristics from control PMMA (p > 0.05). The 100-mg sample fell within the acceptable range of compressive strength and had significantly less LPS and bacterial presence compared to the control at 12 and 24 h. The ability of PMMA with 100 mg of rifampin to maintain its structural integrity and have significant bacterial inhibition at 12 and 24 h makes it a great candidate as an antibiotic bone cement additive. PMMA loaded with up to 100 mg of rifampin shows promise in the treatment and prevention of periprosthetic joint infection for total knee and total hip arthroplasty.

The Effect of Surgical Approach on the Outcomes of Same-Day Discharge Outpatient Total Hip Arthroplasty at a Single Ambulatory Surgery Center.

BACKGROUND: Primary total hip arthroplasty (THA) is increasingly being performed in the outpatient setting. However, there is little known regarding the differences in same-day discharge (SDD) rates and complications of operative approach in same-day total hip arthroplasty in the ambulatory surgery center (ASC) setting. METHODS: A retrospective chart review was performed between July 2019 and October 2021 for all patients who underwent primary THA in a single freestanding ASC. Successful SDDs, surgical approaches, lengths of surgery, estimated blood losses (EBL), complications, and readmission events were recorded for each patient. Complications were compared using Pearson Chi-Squares, while EBL and surgery lengths were compared with 1-way analysis of variances (ANOVA) (alpha = 0.5). There were 17 total complications in 326 total hip arthroplasties (5.2%), including direct admissions to the emergency department, 30-day and 90-day readmissions, wound complications, instability, infection, and revision surgery. Among all complications, there were 5 direct admissions, making the successful SDD rate 98.5%. RESULTS: Complications and direct admissions were not associated with approach. The 30-day readmission rates were associated with approach, with no readmissions in the direct anterior approach (DAA) or the antero-lateral approach (AL) cohorts and 3 (4.3%) in the posterior approach (PA) cohort. CONCLUSIONS: In the ASC setting, patients undergoing THA regardless of approach showed no difference in successful SDDs or complications aside from 30-day readmissions. Same-day THA can be safely performed in the DAA, AL, and PA to the hip.

Chronic obstructive pulmonary disease is an independent risk factor for increased opioid use in total hip arthroplasty: A retrospective PearlDiver study.

Background: Total hip arthroplasty (THA) has become an incredibly common procedure due to its' predictability and high success rate. The success of surgery is related to strict indications and careful optimization of medical comorbidities to decrease risk and improve outcomes. Chronic obstructive pulmonary disease (COPD) has been associated with increased medical and surgical complications. A regulatory focus on opioid utilization does not usually consider COPD as a risk factor, but limited research exists on the impact of COPD on outcomes and risks after THA. Methods: Retrospective all-inclusive database analysis of Medicare patients who had undergone THA between 2007 and 2017 included in the PearlDiver Database were studied. Postoperative opioid usage was examined at 1-, 3-, 6-, and 12 months, along with surgical infection, implant complications, and revisions. Post-operative complications within 30 days, either medical or implant related, were identified. Controlling for comorbidities, age, and sex, odds ratios were calculated using multivariable logistic regression with a significant α value of 0.05. Results: COPD patients had significantly higher rates of opioid usage postoperatively. COPD patients also had an increased rate of readmissions, medical/implant complications, and revision surgeries. Discussion: This is the only study raising concern regarding opioid use in COPD patients after total hip arthroplasty, which may be critical considering the associated respiratory depression further exacerbating the COPD. Considering the evidence of poor outcomes associated with COPD in arthroplasty, appropriately screening for COPD and counseling or planning for post-operative pain control and complications is paramount.

Medial Calcar Restoration Using Femoral Head Autograft in Conversion Hip Arthroplasty for Failed Fixation after an Unstable Intertrochanteric Hip Fracture: A Case Report and Technique Description.

Introduction: The calcar femorale helps manage compressive loads on the femoral head and is an essential component in determining intertrochanteric (IT) femur fracture stability. Fracture fixation can be complicated when primary fixation techniques, such as cephalomedullary nailing fail. Unstable IT femur fractures involving disruption of the medial calcar present additional fixation challenges. Case Report: This case reports a patient with unstable IT fracture due to medial calcar disruption that experienced failure of a short cephalomedullary nail. Secondary fixation involved total hip arthroplasty (THA) with medical calcar reconstruction using femoral head autograft. Outcomes were good at 2-year follow-up with a full return to baseline activities. Conclusion: The results indicate that femoral head autografting can be a viable option, with good outcomes, for medial calcar reconstruction in cases of failed IT fracture fixations without calcar support, converted to THA.

Staphylococcal biofilm: penetration and bioavailability of vancomycin with or without rifampin.

We measured antibiotic penetration and bioavailability in staphylococcus biofilms using simulated humanized concentrations of fluorescent vancomycin plus or minus rifampin. Vancomycin percent recovery across biofilm layers was:upper = 46%, middle = 40%, and lower = 33%. Vancomycin plus rifampin was not significantly different (P = 0.65). Addition of rifampin did not improve vancomycin penetration across biofilm layers.

Local anesthetic with monitored anesthesia care in cephalomedullary nailing of proximal femur fractures.

INTRODUCTION: Proximal femur fractures have high rates of morbidity, mortality, and perioperative complications. Limiting anesthesia, especially in the elderly population, is a priority from a medical perspective. The goal of the current study is to present a technique of using local anesthetic with monitored anesthesia care (MAC) for the fixation of intertrochanteric (IT) femur fractures with cephalomedullary nailing (CMN), provide early clinical results in a small series of patients, and evaluate the safety, efficiency, and anesthetic efficacy of our technique. HYPOTHESIS: The use of only local anesthetic with MAC for the fixation of IT fractures is safe and leads to decreased operative times when compared to spinal and general anesthesia. MATERIALS AND METHODS: Patients undergoing cephalomedullary nailing (CMN) with a long nail for IT femur fractures by a single surgeon from January 2020 to June 2021 were identified retrospectively from a prospectively-collected patient registry. Patient demographics, operative time, length of hospital stay, perioperative medication use, and complications were collected. Analysis of variance, Chi2, linear regression, and two-sampled T-tests were performed to analyze potential differences between the local anesthesia group and the general or spinal anesthesia group. RESULTS: Thirty-seven patients were identified. Eleven patients underwent CMN using local anesthesia with MAC, 11 using spinal anesthesia, and 15 using general anesthesia. The local anesthesia group demonstrated significantly lower operating room times and anesthesia induction to incision time compared to other anesthesia techniques. The local anesthesia group also trended towards less need for vasopressors during surgery and less postoperative delirium. No differences were identified in intraoperative narcotic use, complications, patient mortality, or hospital readmissions. CONCLUSIONS: Local anesthesia with MAC for the treatment of IT fractures with CMN was associated with decreased operating room times and had similar complication rates including blood transfusions, readmissions, and mortalities, when compared to spinal and general anesthesia. LEVEL OF EVIDENCE: III, therapeutic.

Chronic Obstructive Pulmonary Disease Associated with Prolonged Opiate Use, Increased Short-Term Complications, and the Need for Revision Surgery following Total Knee Arthroplasty.

Chronic obstructive pulmonary disease (COPD) is a condition which causes a substantial burden to patients, physicians, and the health care system at large. Medical comorbidities are commonly associated with adverse health outcomes in the postoperative period. Here, we present a large database review of patients undergoing total knee arthroplasty (TKA) to determine the effect of COPD on patient outcomes. The PearlDiver database was queried for all patients who underwent TKA between 2007 and the first quarter of 2017. Medical complications, surgical complications, 30-day readmission rates, revision rates, and opioid utilization were assessed at various intervals following TKA among patients with and without COPD. Multivariable regression was used to calculate adjusted odds ratios controlling for age, sex, and medical comorbidities. A total of 46,769 TKA patients with COPD and 120,177 TKA patients without COPD were studied. TKA patients with COPD experienced increased risk of 30-day readmission (40.8% vs. 32.2%, p < 0.0001), 30-day total medical complications (10.2% vs. 7.0%, p < 0.0001), prosthesis explanation at 6 months (0.4% vs. 0.2, p = 0.0130), 1 year (0.6% vs. 0.3%, p = 0.0005), and 2 years (0.8% vs. 0.5%, p = 0.0003), as well as an increased rate of revision (p < 0.0046) compared to TKA patients without COPD. Opioid utilization of TKA patients with COPD was greater significantly than that of TKA patients without COPD at 3, 6, and 12 months. Patients with COPD have an increased risk for medical and surgical complications, readmission, and prolonged opioid use following TKA.

The Effect of Early versus Late Manipulation Under Anesthesia on Opioid Use, Surgical Complications, and Revision Following Total Knee Arthroplasty.

Previous studies of early versus late manipulation under anesthesia (MUA) do not report on postoperative opioid utilization or revisions and focused on small single-institution retrospective cohorts. The PearlDiver Research Program (www.pearldiverinc.com), which uses an all-inclusive insurance database, was used to identify patients undergoing primary total knee arthroplasty (TKA) who received (1) late MUA (>12 weeks), (2) early MUA (≤12 weeks), or (3) TKA only. To develop the control group cohort of TKA-only patients, 3:1 matching was conducted using 11 risk factor variables deemed significant by chi-squared analysis. Complications and opioid utilization were compared through multivariate regression analysis, controlling for age, gender, and Charlson Comorbidity Index. The risk of TKA revision was assessed through Cox-proportional hazards modeling and Kaplan-Meier survival analysis with log-rank test. Between 2011 and 2017, 2,062 TKA patients with early MUA, 1,112 TKA patients with late MUA, and a control cohort of 8,327 TKA-only patients were identified in the database. The percent of patients registering opioid use decreased from 54.6% 1 month pre-MUA to 4.6% (p < 0.0001) 1 month post-MUA following early MUA, whereas only from 32.6 to 10.4% (p < 0.0001) following late MUA. Late MUA was associated with higher risk of repeat MUA at 6 months (adjusted odds ratio [aOR] = 2.74, p < 0.0001), 1 year (aOR = 2.66, p < 0.0001), and 2 years (aOR = 2.63, p < 0.0001) following index MUA. Hazards modeling and survival analysis showed increased risk of TKA revision following late MUA (adjusted hazard ratio [aHR] = 3.50, 95% confidence interval [CI]: 2.77-4.43, p < 0.0001) compared to early MUA (aHR = 2.15, 95% CI: 1.72-2.70, p < 0.0001), with significant differences in survival to revision curves (p < 0.0001). When compared to early MUA at 1 year, late MUA was associated with a significantly increased risk of prosthesis explantation (aOR = 2.89, p = 0.0026 vs. aOR = 0.93, p = 0.8563). MUA within 12 weeks after index TKA had improved pain resolution and significant curtailing of opioid use. Furthermore, late MUA was associated with prolonged opioid use, increased risks of revision, as well as prosthesis explantation, supporting screening and early intervention in cases of slow progression and stiffness. The level of evidence of this study is III.

Comparison of periprosthetic joint infection rates in the direct anterior approach and non-anterior approaches to primary total hip arthroplasty: a systematic review and meta-analysis.

BACKGROUND: Periprosthetic joint infection is a serious complication and devastating mode of failure of total hip arthroplasty. Various surgical approaches exist for total hip arthroplasty, including the increasingly popularised direct anterior approach. There is no clear consensus on which approach is least associated with periprosthetic joint infection. The objective of this meta-analysis was to compare the rate of periprosthetic joint infection between surgical approaches to primary total hip arthroplasty for osteoarthritis. METHODS: A search of 3 electronic databases (PubMed/MEDLINE, Embase, and Cochrane Library) was conducted for relevant studies up to June 2020 with a defined list of inclusion and exclusion criteria. Randomised controlled trials and longitudinal studies reporting periprosthetic joint infection rates after primary total hip arthroplasty for osteoarthritis were included based on surgical approach. Data extraction was completed, and a meta-analysis was then performed using OpenMeta[Analyst] software. RESULTS: A total of 24,407 hips were included for meta-analysis with an overall PJI incidence of 0.57%. The incidence rate for periprosthetic joint infection was 0.77% in the direct anterior approach group and 0.44% in the non-anterior approach group. The use of an anterior approach for a total hip arthroplasty was associated with an increased risk for periprosthetic joint infection (odds ratio = 1.404; 95% confidence interval, 0.711-2.771; p = 0.03). CONCLUSIONS: The direct anterior approach to total hip arthroplasty may be associated with a significantly increased risk for periprosthetic joint infection compared to non-anterior approaches, even though the overall rate was still small. This should be considered by orthopedic surgeons when choosing the surgical approach.

Does fusion length matter? Total hip arthroplasty dislocation after extension of lumbosacral fusion: a case report.

CASE: Hip-spine syndrome is a complex challenge for orthopedic surgeons. We present a 60-year-old female with a history of spinal fusion and total hip arthroplasty. The patient underwent extension of the previous fusion with sacropelvic fixation, and 5 months later she presented with left posterior prosthetic hip dislocation which required sedation and closed reduction. CONCLUSION: Even with no change in lumbar lordosis or pelvic tilt and adequate acetabular cup position, extension of the fusion construct may predispose patients to dislocation. This may be the result of an increased lever arm acting at the hip joint, thereby leading to instability.

Silver Carboxylate-Eluting Titanium-Dioxide Polydimethylsiloxane Coating Inhibits Multi-Drug-Resistant Acinetobacterium baumannii and Vancomycin-Resistant Enterococcus faecalis Adherence and Proliferation on Orthopedic Trauma Fixation and Spinal Fusion Materials.

Background: Vancomycin-resistant Enterococcus faecalis and multi-drug-resistant (MDR) Acinetobacter baumannii are rising contributors to spinal fusion and fracture-associated infections (FAI), respectively. These MDR bacteria can form protective biofilms, complicating traditional antibiotic treatment. This study explores the effects of the antibiotic-independent antimicrobial silver carboxylate (AgCar)-doped coating on the adherence sand proliferation of these pathogens on orthopedic implant materials utilized in spinal fusion and orthopedic trauma fixation. Methods: Multi-drug-resistant Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis were inoculated on five common implant materials: cobalt chromium, titanium, titanium alloy, polyether ether ketone, and stainless steel. Dose response curves were generated to assess antimicrobial potency. Scanning electron microscopy and confocal laser scanning microscopy were utilized to characterize and quantify growth and adherence on each material. Results: The optimal AgCar concentration was a 95% titanium dioxide (TiO2)-5% polydimethylsiloxane (PDMS) matrix combined with 10 × silver carboxylate, which inhibited bacterial proliferation by 89.40% (p = 0.001) for MDR Acinetobacter baumannii and 84.02% (p = 0.001) for vancomycin-resistant Enterococcus faecalis compared with uncoated implants. A 95% TiO2-5% PDMS matrix combined with 10 × AgCar was equally effective at inhibiting bacterial proliferation across all implant materials for MDR Acinetobacter baumannii (p = 0.19) and vancomycin-resistant Enterococcus faecalis (p = 0.07). A 95% TiO2-5% PDMS matrix with 10 × AgCar is effective at decreasing bacterial adherence of both MDR Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis on implant materials. Conclusions: Application of this antibiotic-independent coating for surgery in which these implant materials might be used may prevent adherence, biofilm formation, spinal infections, and FAI by MDR Acinetobacter baumannii and vancomycin-resistant Enterococcus faecalis.

The Case of Disappearing Tibia in Rheumatoid Knee Tenosynovitis.

Introduction: Knee pain and osteoarthritis are frequent patient complaints, with a rapidly increasing prevalence. By comparison, the prevalence of rheumatoid arthritis (RA) is significantly lower at around 1%. Inflammatory arthropathies, like RA, are difficult to differentiate from infection, crystal arthropathies, or malignancy. In addition, radiography and roentgenograms are often inconclusive or non-specific, making it much more difficult to evaluate, diagnose, and manage this condition. The current case is unique due to its location in the knee joint, rather than more common presentations in the upper extremities, and use of MRI imaging for diagnosis of RA with tenosynovitis. Case Report: In a Caucasian 70-year-old female with sudden debilitating knee pain and a large atraumatic defect over tibial plateau, MRI showed a large fluid collection within the left gracilis muscle. Gram stain and culture of the aspirate remained negative. The only significant history involved a possible diagnosis of RA. Conclusion: While rheumatoid tenosynovitis is common in the upper extremities, lower extremity features have not been well reported before. We diagnosed the patient with progressive RA and rheumatoid tenosynovitis. This unique presentation and rare usage of MRI imaging may be contributing to an underreporting of this diagnosis in the lower extremities.

Silver as an Antibiotic-Independent Antimicrobial: Review of Current Formulations and Clinical Relevance.

Background: The increase of multi-drug-resistant organisms has revived the use of silver as an alternative antibiotic-independent antimicrobial. Although silver's multimodal mechanism of action provides low risk for bacterial resistance, high local and uncontrolled concentrations have shown toxicity. This has resulted in efforts to develop novel silver formulations that are safer and more predictable in their application. Optimization of silver as an antimicrobial is crucial given the growing resistance profile against antibiotics. This article reviews formulations of silver used as antimicrobials, focusing on the mechanisms of action, potential for toxicity, and clinical applications. Methods: A search of four electronic databases (PubMed, Embase, MEDLINE, and Cochrane Library) was conducted for relevant studies up to January 2022. Searches were conducted for the following types of silver: ionic, nanoparticles, colloidal, silver nitrate, silver sulfadiazine, silver oxide, silver carboxylate, and AQUACEL® (ConvaTec, Berkshire, UK). Sources were compiled based on title and abstract and screened for inclusion based on relevance and study design. Results: A review of the antimicrobial activity and uses of ionic silver, silver nanoparticles, colloidal silver, silver nitrate, silver sulfadiazine, silver oxide, Aquacel, and silver carboxylate was conducted. The mechanisms of action, clinical uses, and potential for toxicity were studied, and general trends between earlier and more advanced formulations noted. Conclusions: Early forms of silver have more limited utility because of their uncontrolled release of silver ions and potential for systemic toxicity. Multiple new formulations show promise; however, there is a need for more prospective in vivo studies to validate the clinical potential of these formulations.

Understanding Health Economics in Joint Replacement Surgery.

The number of arthroplasty procedures has been rising at a significant rate, contributing to a notable portion of the nation's health care spending. This growth has contributed to an increase in the number of health care economic studies in the field of adult reconstruction surgery. Although these articles are filled with important information, they can be difficult to understand without a background in business or economics. The goal of this review is to define the common terminology used in health care economic studies, assess their value and benefit in the context of total joint arthroplasty, and highlight shortcomings in the current literature. [Orthopedics. 2022;45(4):e174-e182.].

Synergistic Effects of Silver Carboxylate and Chlorhexidine Gluconate for Wound Care and Prevention of Surgical Site Infections by Cutibacterium acnes and Methicillin-Resistant Staphylococcus aureus.

Background: This study presents the effectiveness of a combined silver carboxylate (AgCar) and chlorohexidine gluconate (AgCar:CHG) chemistry assessed against two commonly encountered nosocomial pathogens, Methicillin-resistant Staphylococcus aureus (MRSA) and Cutibacterium acnes, within the context of surgical antisepsis and wound care. Methods: Through an Institutional Review Board- and Institutional Animal Care and Use Committee (IACUC)-approved protocol, AgCar:CHG was applied to live Yucatan porcine skin and visualized by fast red and green staining to assess level of skin penetration. Dose response curves for Cutibacterium acnes and MRSA were generated to determine the optimal therapeutic ratio of AgCar to CHG. Coatings were applied to two different clinically available sutures and antimicrobial efficacy was evaluated at 24-hour intervals using Kirby-Bauer (KB) assays. Graphite furnace atomic absorption spectroscopy was used to measure AgCar elution from sutures over time. Results: Synergistic application of AgCar:CHG demonstrated deep pilosebaceous gland penetration on Yucatan pig skin. The therapeutic concentration range of AgCar was determined to be between 120 × -150 × and 30 × -60 × dopage for MRSA and Cutibacterium acnes, respectively. A 1:1 therapeutic ratio of AgCar to CHG was found to have 100% bactericidal activity against both pathogens. Sutures coated with AgCar:CHG showed sustained antimicrobial activity against MRSA and Cutibacterium acnes, and were significantly more efficacious than antimicrobial sutures over the three- to four-day period (p < 0.01). Conclusions: This AgCar:CHG chemistry demonstrates deep skin penetration, extended elution, and broad-spectrum antimicrobial activity compared with commercially available options. This chemistry shows promise as an additional tool for the prophylaxis of surgical site infections.

Silver Carboxylate as an Antibiotic-Independent Antimicrobial: A Review of Current Formulations, in vitro Efficacy, and Clinical Relevance.

The increasing prevalence of multi-drug resistant pathogens has led to a renewed focus on the use of silver as an antibiotic-independent antimicrobial. Unfortunately, the use of many silver formulations may be limited by an uncontrolled release of silver with the potential for significant cytotoxic effects. Silver carboxylate (AgCar) has emerged as an alternative formulation of silver with the potential to mitigate these concerns while still displaying significant bactericidal activity. This article reviews the efficacy of silver carboxylate formulations as a promising novel antibiotic-independent antimicrobial. This study was conducted through a search of five electronic databases (PubMed, Embase, MEDLINE, Cochrane Library, and Web of Science) for relevant studies up to September 2022. Searches were conducted for types of "silver carboxylate" formulations. Sources were compiled based on title and abstract and screened for inclusion based on relevance and study design. A review of the antimicrobial activity and cytotoxicity of silver carboxylate was compiled based on this search. Current body of data suggests that silver carboxylate shows promise as an emerging antibiotic-independent antimicrobial, with significant bactericidal effects while minimizing cytotoxicity. Silver carboxylate addresses several of the limitations of more primitive formulations, including controlled dosing and fewer negative effects on eukaryotic cell lines. These factors are concentration-dependent and largely rely on the vehicle system used to deliver it. Although several silver carboxylate-based formulations like titanium dioxide/polydimethylsiloxane (TiO2/PDMS) matrix-eluting AgCar have shown promising results in vitro, and could potentially be utilized independently or in conjunction with current and future antimicrobial therapies, there is a need for further in vivo studies to validate their overall safety and efficacy profile.

Silver carboxylate-doped titanium dioxide-polydimethylsiloxane coating decreases Cutibacterium acnes adherence and biofilm formation on polyether ether ketone.

BACKGROUND CONTEXT: Cutibacterium acnes (C. acnes) is a gram-positive facultative anaerobe found in the deep sebaceous follicles of the skin on the shoulder and back. C. acnes has been increasingly recognized as a pathogen in spinal surgical site infection (SSI) especially in the presence of instrumentation. PURPOSE: This study assesses whether a silver carboxylate-doped titanium dioxide-polydimethylsiloxane (TiO2-PDMS) coating can decrease C. acnes adherence and biofilm formation on PEEK and four other commonly used spinal implant materials, stainless steel, cobalt chromium, titanium, and titanium alloy. STUDY DESIGN: We compared the adherence of C. acnes over 24 hours between uncoated, 95:5 TiO2 to PDMS ratio with 10× silver carboxylate coating and a 100% silver carboxylate coating on each implant material, which were uniformly saw cut and sterilized. Implants were then subjected to scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). METHODS: Samples were coated using 95:5 TiO2-PDMS 10× silver carboxylate, 100% silver carboxylate, or left uncoated. C. acnes was applied onto the samples and allowed to adhere for periods of 4, 8, 12, 16, or 20 hours. Nonadherent bacteria were then washed from the samples. These samples were then allowed to continue incubating for a total of 24 hours. SEM and confocal laser scanning microscope were used to visualize all samples for the presence of biofilm and quantification of C. acnes adherence at each time point. RESULTS: The 95:5 TiO2-PDMS 10× silver carboxylate coating was able to significantly decrease C. acnes adherence on PEEK after 8, 12, 16, and 20 hours of adherence. No statistical difference was found between the 95:5 TiO2-PDMS 10× silver carboxylate coating and the 100% silver carboxylate positive control. We previously observed extensive C. acnes biofilm formation on uncoated PEEK, but none on PEEK coated with either the 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating . Furthermore, no biofilm formation was observed on stainless steel, cobalt chromium, titanium, and titanium alloy coated with 95:5 TiO2-PDMS 10× silver carboxylate or 100% Ag coating. CONCLUSION: A 95:5 TiO2-PDMS 10× silver carboxylate coating decreases C. acnes adhesion and prevents biofilm formation on PEEK and other common orthopedic implant materials. CLINICAL SIGNIFICANCE: A 95:5 TiO2-PDMS 10× silver carboxylate coating may help decrease spinal SSI due to C. acnes, especially in procedures with instrumentation.

In vitro visualization and quantitative characterization of Pseudomonas aeruginosa biofilm growth dynamics on polyether ether ketone.

Prevention and treatment of orthopedic device-related infection (ODRI) is complicated by the formation of bacterial biofilms. Biofilm formation involves dynamic production of macromolecules that contribute to the structure of the biofilm over time. Limitations to clinically relevant and translational biofilm visualization and measurement hamper advances in this area of research. In this paper, we present a multimodal methodology for improved characterization of Pseudomonas aeruginosa grown on polyether ether ketone (PEEK) as a model for ODRI. PEEK discs were inoculated with P. aeruginosa, incubated for 4-48 h time intervals, and fixed with 10% neutral-buffered formalin. Samples were stained with fluorescent dyes to measure biofilm components, imaged with confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM), and quantified. We were able to visualize and quantify P. aeruginosa biofilm growth on PEEK implants over 48 h. Based on imaging data, we propose a generalized growth cycle that can inform orthopedic diagnostic and treatment for this pathogen on PEEK. These results demonstrate the potential of using a combined CLSM and SEM approach for determining biofilm structure, composition, post-adherence development on orthopedic materials. This model may be used for quantitative biofilm analysis for other pathogens and other materials of orthopedic relevance for translational study of ODRI.