Use of thioglycolate broth as a pre-analytic transport medium in the diagnosis of prosthetic joint infection.

OBJECTIVES: This study aimed to investigate whether adding tissue samples directly into thioglycolate (TG) broth yielded a greater number of anaerobic organisms than freshly sampled tissue in suspected hip and knee prosthetic joint infections (PJIs). PATIENTS AND METHODS: Between January 2017 and December 2020, a total of 90 patients (46 males, 44 females; median age: 71.7 years; range, 50.8 and 87.8 years) who underwent revision hip or knee arthroplasty were included. Intraoperative samples were taken, with five placed in TG broth and five in standard containers (PC) with subsequent aerobic and anaerobic culturing conducted. Demographic and baseline data of the patients were recorded. The primary outcome was positive bacterial growth from a PJI specimen inoculated directly into TG broth at the time of collection or standard PJI specimen processing. Secondary outcomes investigated were the presence of Cutibacterium acnes (C. acnes) and the curative success of revision procedure. RESULTS: A total of 900 samples (450 PC and 450 TG) were taken from 90 revision arthroplasty patients (47 knees and 43 hips). There was no statistically significant difference in the number of positive bacterial growth samples between TG broth and standard processing (p=0.742). This was consistent with subgroup analysis analyzing C. acnes (p=0.666). CONCLUSION: In hip and knee arthroplasty, there is no benefit in substituting or adding TG broth as a culture medium to better identify both general bacterial species and C. acnes infections specifically. However, the use of TG may be useful in confirming a true positive result for infection.

Outcomes in orthopedic device infections due to Streptococcus agalactiae: a retrospective cohort study.

BACKGROUND: Group B streptococci (Streptococcus agalactiae) (GBS) is a rare cause of prosthetic joint infection (PJI) occurring in patients with comorbidities and seems to be associated with a poor outcome. Depiction of GBS PJI is scarce in the literature. METHODS: A retrospective survey in 2 referral centers for bone joint infections was done Patients with a history of PJI associated with GBS between 2014 and 2019 were included. A descriptive analysis of treatment failure was done. Risk factors of treatment failure were assessed. RESULTS: We included 61 patients. Among them, 41 had monomicrobial (67%) infections. The median duration of follow-up was 2 years (interquartile range 2.35) Hypertension, obesity, and diabetes mellitus were the most reported comorbidities (49%, 50%, and 36% respectively). Death was observed in 6 individuals (10%) during the initial management. The rate of success was 63% (26/41). Removal of the material was not associated with remission (p = 0.5). We did not find a specific antibiotic regimen associated with a better outcome. CONCLUSION: The results show that S. agalactiae PJIs are associated with high rates of comorbidities and a high treatment failure rate with no optimal treatment so far.

Positive Culture of Atypical Mycobacterium Avium Following Revision Total Knee Arthroplasty.

CASE: We report a rare case of mycobacterial periprosthetic joint infection (PJI) after primary total knee arthroplasty 14 years earlier. Progressive knee pain over three years with a negative PJI infectious workup led to revision total knee arthroplasty. A surprising result was isolation of Mycobacterium avium from tissue cultures taken at time of revision surgery. After six months of antibiotic treatment, the patient is alive with well- functioning pain-free TKA at over one-year follow-up. CONCLUSION: Periprosthetic joint infection can present acutely or chronically years following total knee arthroplasty. Depending on the infecting organism, patients can present with sepsis, or a more indolent slower course that mimics aseptic loosening. In the absence of positive pre-operative labs and cultures, and based on the Musculoskeletal Infection Society (MSIS) criteria, aseptic loosening is a diagnosis of exclusion. An atypical infectious organism should be considered a possible cause and may require specialized cultures of operative specimens.

The Effect of Slime Factor in the Treatment of Spinal Implant Infections.

AIM: To investigate the effect of the biofilm-forming ability of the bacteria on treatment in rats by using biofilm-forming and nonbiofilm- forming strains of Staphylococcus aureus (S. aureus). MATERIAL AND METHODS: Forty rats were divided into four equal groups as Group 1A, 1B, 2A, and 2B. All rats underwent single distance lumbar laminectomy, and titanium implants were introduced. Group 1 rats were inoculated with Slime factor (-) S. aureus, while Group 2 rats were inoculated with biofilm Slime factor (+) S. aureus. None of the rats were given antibiotics. One week later, the surgical field was reopened and microbiological samples were taken. The implants of rats in Groups 1A and 2A were left in place, while the implants of rats in Groups 1B and 2B were removed. RESULTS: There was no statistically significant difference between the groups inoculated with slime factor (+) S. aureus; although, Groups 1A and 2A showed statistically significant difference. Statistical analysis with respect to bacterial count also showed a statistically significant difference between Groups 1A and 2A. There was a statistically significant difference between Group 1B and 2B. CONCLUSION: The results obtained in the present study reveal that in case of implant-dependent infection, the first sample taken can be checked for slime factor, and if there is infection with slime factor-negative bacterium, treatment without removing the implant may be recommended. S. aureus was used in the study because it is the most common cause of implant-related infection at surgical sites. Further studies using different bacterial species are needed to reach a definitive conclusion.

Absorbable antibiotic beads for treatment of LVAD driveline infections.

BACKGOUND: Infections of the left ventricular assist device (LVAD) driveline are a dreaded complication that results in high mortality and morbidity. METHOD: We retrospectively reviewed five consecutive patients with severe continuous-flow LVAD (HVAD, Heartmate 2, and Heartmate 3) driveline infection. These infections, which developed on an average of 960.4 ± 843.9 days after LVAD placement, were refractory to systemic antibiotics and local wound care. All were treated with extensive surgical debridement, local installation of absorbable antibiotic-loaded calcium sulfate beads (vancomycin and tobramycin), primary wound closure, and 6 weeks of systemic antibiotics after surgery. RESULTS: Four patients had resolution of DLI, and one had a recurrent infection at another part of the driveline 7 months after the complete resolution of the previous site. This patient was successfully treated with debridement and bead placements. Three patients still have their LVADs, while two received orthotopic heart transplants. At the time of the transplant, there was no evidence of gross infection of the LVAD drivelines or pumps. At the average follow-up time of 425.8 ± 151 days, no patients have an active infection. CONCLUSION: Treatment of LVAD driveline infection with absorbable antibiotic beads with primary wound closure is a viable option and merits further investigation.

Cathodic voltage-controlled electrical stimulation and betadine decontaminate nosocomial pathogens from implant surfaces.

Periprosthetic joint infection (PJI) after total joint arthroplasty is a major concern requiring multiple surgeries and antibiotic interventions. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli are the predominant causes of these infections. Due to biofilm formation, antibiotic treatment for patients with PJI can prolong resistance, further complicating the use of current treatments. Previous research has shown that cathodic voltage-controlled electrical stimulation (CVCES) is an effective technique to prevent/treat implant-associated biofilm infections on titanium (Ti) surfaces. This study thus evaluated the efficacy of CVCES via the use of 10% betadine alone and in combination with CVCES to eradicate lab-grown biofilms on cemented and cementless cobalt-chromium (CoCr) and Ti surfaces. CVCES treatment alone for 24 hours demonstrated no detectable CFU for E. coli and P. aeruginosa biofilms on cementless CoCr implants. In the presence of cement, E. coli biofilms had 106 CFUs/implant remaining after CVCES treatment alone; however, P. aeruginosa biofilms on cemented implants were reduced to below detectable limits. The use of 10% betadine treatment for 3 minutes followed by 24-hour CVCES treatment brought CFU levels to below detectable limits in E. coli and P. aeruginosa. The same was true for S. aureus biofilms on cementless patellofemoral implants as well as femoral and tibial implants. These treatment methods were not sufficient for eradication of S. aureus biofilms on cemented implants. These results suggest that CVCES alone and CVCES with 10% betadine are effective approaches to treating biofilms formed by certain bacterial species potentially leading to the treatment of PJI.IMPORTANCEPeriprosthetic joint infections (PJIs) are problematic due to requiring multiple surgeries and antibiotic therapies that are responsible for increased patient morbidity and healthcare costs. These infections become resistant to antibiotic treatment due to the formation of biofilms on the orthopedic surfaces. Cathodic voltage-controlled electrical stimulation (CVCES) has previously been shown to be an effective technique to prevent and treat biofilm infections on different surfaces. This study shows that CVCES can increase the efficacy of 10% betadine irrigation used in debridement, antibiotics, and implant retention by 99.9% and clear infection to below detection limits. PJI treatments are at times limited, and CVCES could be a promising technology to improve patient outcomes.

Articulating Spacers in Total Hip Arthroplasty: Surgical Technique and Outcomes.

Although one-stage exchange arthroplasty is gaining popularity, two-stage exchange arthroplasty remains the gold standard for the treatment of periprosthetic joint infections. Use of an articulating spacer for this procedure offers an avenue for maintaining hip motion and controlled weight-bearing, allowing local antibiotic elution. However, there is no uniform consensus on the optimal surgical protocol for using articulating spacers. This review describes the surgical technique for undertaking a first-stage exchange arthroplasty using an articulating spacer and discusses the pertinent literature on key concepts relating to periprosthetic joint infections in total hip arthroplasty to guide effective surgical decision making in these patients.

Innovations in the Isolation and Treatment of Biofilms in Periprosthetic Joint Infection: A Comprehensive Review of Current and Emerging Therapies in Bone and Joint Infection Management.

Periprosthetic joint infections (PJIs) are a devastating complication of joint arthroplasty surgeries that are often complicated by biofilm formation. The development of biofilms makes PJI treatment challenging as they create a barrier against antibiotics and host immune responses. This review article provides an overview of the current understanding of biofilm formation, factors that contribute to their production, and the most common organisms involved in this process. This article focuses on the identification of biofilms, as well as current methodologies and emerging therapies in the management of biofilms in PJI.

Effect of Antibiotic Spacer Dosing on Treatment Success in Two-Stage Exchange for Periprosthetic Joint Infection.

INTRODUCTION: In two-stage exchange for periprosthetic joint infection (PJI), adding antibiotics to cement spacers is the standard of care; however, little is known about optimal dosage. There is emphasis on using >3.6 g of total antibiotic, including ≥2.0 g of vancomycin, per 40 g of cement, but these recommendations lack clinical evidence. We examined whether recommended antibiotic spacer doses affect treatment success. METHODS: This was a retrospective review of 202 patients who underwent two-stage exchange for PJI from 2004 to 2020 with at least 1-year follow-up. Patients were separated into high (>3.6 g of total antibiotic per 40 g of cement) and low-dose spacer groups. Primary outcomes were overall and infectious failure. RESULTS: High-dose spacers were used in 80% (162/202) of patients. High-dose spacers had a reduced risk of overall (OR, 0.37; P = 0.024) and infectious (OR, 0.35; P = 0.020) failure for infected primary arthroplasties, but not revisions. In multivariate analysis, vancomycin dose ≥2.0 g decreased the risk of infectious failure (OR, 0.31; P = 0.016), although not overall failure (OR, 0.51; P = 0.147). CONCLUSION: During two-stage exchange for PJI, spacers with greater than 3.6 g of total antibiotic may reduce overall and infectious failure for infected primary arthroplasties. Furthermore, using at least 2.0 g of vancomycin could independently decrease the risk of infectious failure.

Biofilm Microenvironment Activated Antibiotic Adjuvant for Implant-Associated Infections by Systematic Iron Metabolism Interference.

Hematoma, a risk factor of implant-associated infections (IAIs), creates a Fe-rich environment following implantation, which proliferates the growth of pathogenic bacteria. Fe metabolism is a major vulnerability for pathogens and is crucial for several fundamental physiological processes. Herein, a deferiprone (DFP)-loaded layered double hydroxide (LDH)-based nanomedicine (DFP@Ga-LDH) that targets the Fe-rich environments of IAIs is reported. In response to acidic changes at the infection site, DFP@Ga-LDH systematically interferes with bacterial Fe metabolism via the substitution of Ga3+ and Fe scavenging by DFP. DFP@Ga-LDH effectively reverses the Fe/Ga ratio in Pseudomonas aeruginosa, causing comprehensive interference in various Fe-associated targets, including transcription and substance metabolism. In addition to its favorable antibacterial properties, DFP@Ga-LDH functions as a nano-adjuvant capable of delaying the emergence of antibiotic resistance. Accordingly, DFP@Ga-LDH is loaded with a siderophore antibiotic (cefiderocol, Cefi) to achieve the antibacterial nanodrug DFP@Ga-LDH-Cefi. Antimicrobial and biosafety efficacies of DFP@Ga-LDH-Cefi are validated using ex vivo human skin and mouse IAI models. The pivotal role of the hematoma-created Fe-rich environment of IAIs is highlighted, and a nanoplatform that efficiently interferes with bacterial Fe metabolism is developed. The findings of the study provide promising guidance for future research on the exploration of nano-adjuvants as antibacterial agents.

Outcomes After Pseudomonas Prosthetic Joint Infections.

BACKGROUND: Pseudomonas species are a less common but devastating pathogen family in prosthetic joint infections (PJIs). Despite advancements in management, Pseudomonas PJIs remain particularly difficult to treat because of limited antibiotic options and robust biofilm formation. This study aimed to evaluate Pseudomonas PJI outcomes at a single institution and review outcomes reported in the current literature. METHODS: All hip or knee PJIs at a single institution with positive Pseudomonas culture were evaluated. Forty-two patients (24 hips, 18 knees) meeting inclusion criteria were identified. The primary outcome of interest was infection clearance at 1 year after surgical treatment, defined as reassuring aspirate without ongoing antibiotic treatment. Monomicrobial and polymicrobial infections were analyzed separately. A focused literature review of infection clearance after Pseudomonas PJIs was performed. RESULTS: One-year infection clearance was 58% (n = 11/19) for monomicrobial PJIs and 35% (n = 8/23) for polymicrobial PJIs. Among monomicrobial infections, the treatment success was 63% for patients treated with DAIR and 55% for patients treated with two-stage exchange. Monotherapy with an oral or intravenous antipseudomonal agent (minimum 6 weeks) displayed the lowest 1-year clearance of 50% (n = 6/12). Resistance to antipseudomonal agents was present in 16% (n = 3/19), and two of eight patients with monomicrobial and polymicrobial PJIs developed resistance to antipseudomonal therapy in a subsequent Pseudomonas PJI. Polymicrobial infections (55%) were more common with a mortality rate of 44% (n = 10/23) at a median follow-up of 3.6 years. CONCLUSION: Pseudomonas infections often present as polymicrobial PJIs but are difficult to eradicate in either polymicrobial or monomicrobial setting. A review of the current literature on Pseudomonas PJI reveals favorable infection clearance rates (63 to 80%) after DAIR while infection clearance rates (33 to 83%) vary widely after two-stage revision.

The outcomes of acute periprosthetic joint infection following unicompartmental knee replacement managed with early debridement, Antibiotics, and implant retention.

BACKGROUND: Periprosthetic joint infection (PJI) following unicompartmental knee replacement (UKR) is an uncommon, yet serious, complication. There is a paucity of evidence regarding the effectiveness of Debridement-Antibiotics-and-Implant-Retention (DAIR) in this setting. The aim of this study is to investigate the effectiveness of DAIR for acute UKR PJI. METHOD: Between 2006 and 2019, 5195 UKR were performed at our institution. Over this period, sixteen patients underwent DAIR for early, acute PJI. All patients met MSIS PJI diagnostic criteria. The median age at DAIR was 67 years (range 40-73) and 12 patients were male (75.0%). The median time to DAIR was 24 days (range 6-60). Patients were followed up for a median of 6.5 years (range1.4-10.5) following DAIR. RESULTS: 0.3% (16/5195) of UKR in our institution had a DAIR within 3 months. 15 of 16 patients (93.8%) were culture positive, with the most common organism MSSA (n = 8, 50.0%). Patients were treated with an organism-specific intravenous antibiotic regime for a median of 6 weeks, followed by oral antibiotics for a median duration of 6 months. The Kaplan-Meier survivor estimate for revision for PJI was 57% (95%CI: 28-78%) at five years, and survivor estimate for all cause revision 52% (95%CI: 25-74%).The median Oxford Knee Score for patients with a viable implant at final follow-up was 45 points (range 39-46). CONCLUSION: Early, acute PJI after UKR is rare. DAIR had a moderate success rate, with infection-free survivorship of 57% at 5 years. Those successfully treated with DAIR had excellent functional outcome and implant survival.

Two-dimensional liquid chromatography measurement of meropenem concentration in synovial fluid of patients with periprosthetic joint infection.

Periprosthetic joint infection (PJI) is a catastrophic complication following joint replacement surgery. One potential treatment approach for PJI could be the combination of one-stage revision and intra-articular infusion of antibiotics. Meropenem is one of the commonly used intra-articular antibiotics in our institution. Determining the concentration of meropenem in the joint cavity could be crucial for optimizing its local application, effectively eradicating biofilm infection, and improving PJI treatment outcomes. In this study, we developed a simple, precise, and accurate method of two-dimensional liquid chromatography (2D-LC) for determining the concentration of meropenem in human synovial fluid. The method was then validated based on the guidelines of the Food and Drug Administration and the Chinese Pharmacopoeia. Meropenem showed good linearity in the range of 0.31-25.01 µg/mL (r ≥ .999). Selectivity, intra-day and inter-day precision and accuracy, extraction recovery, and stability validation results were all within the acceptance range. This method has been successfully applied to the determination of synovial fluid samples from PJI patients, providing a useful detection method for meropenem therapeutic drug monitoring (TDM) in PJI patients.

Left ventricular assist device-associated driveline infections as a specific form of complicated skin and soft tissue infection/acute bacterial skin and skin structure infection - issues and therapeutic options.

PURPOSE OF REVIEW: This review comments on the current guidelines for the treatment of wound infections under definition of acute bacterial skin and skin structure infections (ABSSSI). However, wound infections around a catheter, such as driveline infections of a left ventricular assist device (LVAD) are not specifically listed under this definition in any of the existing guidelines. RECENT FINDINGS: Definitions and classification of LVAD infections may vary across countries, and the existing guidelines and recommendations may not be equally interpreted among physicians, making it unclear if these infections can be considered as ABSSSI. Consequently, the use of certain antibiotics that are approved for ABSSSI may be considered as 'off-label' for LVAD infections, leading to rejection of reimbursement applications in some countries, affecting treatment strategies, and hence, patients' outcomes. However, we believe driveline exit site infections related to LVAD can be included within the ABSSSI definition. SUMMARY: We argue that driveline infections meet the criteria for ABSSSI which would enlarge the 'on-label' antibiotic armamentarium for treating these severe infections, thereby improving the patients' quality of life.

Host and microbial characteristics associated with recurrent prosthetic joint infections.

Approximately 20% of patients after resection arthroplasty and antibiotic spacer placement for prosthetic joint infection develop repeat infections, requiring an additional antibiotic spacer before definitive reimplantation. The host and bacterial characteristics associated with the development of recurrent infection is poorly understood. A case-control study was conducted for 106 patients with intention to treat by two-stage revision arthroplasty for prosthetic joint infection at a single institution between 2009 and 2020. Infection was defined according to the 2018 Musculoskeletal Infection Society criteria. Thirty-nine cases ("recurrent-periprosthetic joint infection [PJI]") received at least two antibiotic spacers before clinical resolution of their infection, and 67 controls ("single-PJI") received a single antibiotic cement spacer before infection-free prosthesis reimplantation. Patient demographics, McPherson host grade, and culture results including antibiotic susceptibilities were compared. Fifty-two (78%) single-PJI and 32 (82%) recurrent-PJI patients had positive intraoperative cultures at the time of their initial spacer procedure. The odds of polymicrobial infections were 11-fold higher among recurrent-PJI patients, and the odds of significant systemic compromise (McPherson host-grade C) were more than double. Recurrent-PJI patients were significantly more likely to harbor Staphylococcus aureus. We found no differences between cases and controls in pathogen resistance to the six most tested antibiotics. Among recurrent-PJI patients, erythromycin-resistant infections were more prevalent at the final than initial spacer, despite no erythromycin exposure. Our findings suggest that McPherson host grade, polymicrobial infection, and S. aureus infection are key indicators of secondary or persistent joint infection following resection arthroplasty and antibiotic spacer placement, while bacterial resistance does not predict infection-related arthroplasty failure.

The efficacy of antibiotic-eluting material in a two-stage model of periprosthetic joint infection.

Periprosthetic joint infections occur in about 2% of patients who undergo primary total joint arthroplasty, a procedure performed over 1 million times in the United States. The gold standard of treatment is a two-stage revision. This study aimed to establish a two-stage procedure in a preclinical small animal model (rat) to test and compare the efficacy of an antibiotic-eluting material in managing infection. Joint replacement was simulated by transchondylarly implanting a polyethylene (PE) plug into the distal femur and a titanium screw in the proximal tibia. Methicillin-sensitive Staphylococcus aureus (MSSA) 108 CFU/mL was injected into the tibial canal and the joint space before wound closure. The control groups were killed on postoperative day (POD) 18 (n = 12) and on POD 42 (n = 4) to assess both early and later-stage outcomes in the control group. The test group underwent revision surgery on POD 18 for treatment using gentamicin-eluting polyethylene (GPE, n = 4) and was observed until POD 42 to evaluate the efficacy of treatment. Our results showed that the bone loss for the treatment group receiving GPE was significantly less than that of the control (p < 0.05), which was supported by the histology images and an AI-tool assisted infection rate evaluation. Gait metrics duty factor imbalance and hindlimb temporal symmetry were significantly different between the treatment and control groups on Day 42. This animal model was feasible for evaluating treatments for peri-prosthetic joint infections (PJI) with a revision surgery and specifically that revision surgery and local antibiotic treatment largely hindered the peri-prosthetic bone loss. Statement of clinical significance: This revision model of peri-prosthetic infection has the potential of comparatively evaluating prophylaxis and treatment strategies and devices. Antibiotic-eluting UHMWPE is devised as at tool in treating PJI while providing weight bearing and joint space preservation.

Inferior Outcomes for Patients Transferred Between Surgical Stages for Knee Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infection (PJI) in total knee arthroplasty may result in 2-stage revision surgery. There are limited data describing outcomes when the first stage is completed at an outside hospital and the patient is referred to a tertiary center. We hypothesized that patients have greater success when both surgeries occur at a single center. METHODS: There were 25 knee PJI patients who presented with an antibiotic spacer and had a minimum 2-year follow-up who were retrospectively identified at a single tertiary referral center from 2014 to 2021. A cohort matched for age, sex, body mass index, Elixhauser comorbidity measure, spacer type, infectious organism, and year of surgery was established with patients who had both stages completed at the investigating institution. Modified Delphi success criteria of no subsequent surgery or reinfection with any species were compared. RESULTS: The transferred group demonstrated a treatment success of 40% compared to 84% in the continuous group (P < .01). The transferred group was more likely to have an additional procedure between stages (44 versus 8%, P < .01), with a higher number of surgeries after primary total knee arthroplasty (4.8 versus 3.0, P < .01), between stages (1.4 versus 0.2, P < .01), and after second stage (0.8 versus 0.2, P = .03). The transferred group had longer durations between stages (20.1 versus 7.0 weeks, P < .01). CONCLUSION: Patients who have PJIs transferred between stages demonstrated higher treatment failure. Surgeons should consider transfer early with a goal of continuous management by a single institution.

Suppressive Antibiotic Therapy After Debridement, Antibiotics, and Implant Retention is Well-Tolerated Without Inducing Resistance: A Multicenter Study.

BACKGROUND: Suppressive antibiotic therapy (SAT) after total joint arthroplasty (TJA) debridement, antibiotics, and implant retention (DAIR) maximizes reoperation-free survival. We evaluated SAT after DAIR of acutely infected primary TJA regarding: 1) adverse drug reaction (ADR)/intolerance; 2) reoperation for infection; and 3) antibiotic resistance. METHODS: Patients who underwent total knee arthroplasty (TKA) or total hip arthroplasty (THA) DAIR for acute periprosthetic joint infection at two academic medical centers from 2015 to 2020 were identified (n = 115). Data were collected on patient demographics, infecting organisms, antibiotics, ADR/intolerances, reoperations, and antibiotic resistances. Median SAT duration was 11 months. Stepwise multivariate logistic regressions were used to identify covariates significantly associated with outcomes of interest. RESULTS: There were 11.1 and 16.3% of TKA and THA DAIR patients, respectively, who had ADR/intolerance to SAT. Patients prescribed trimethoprim/sulfamethoxazole (P = .0014) or combination antibiotic therapy (P = .0169) after TKA DAIR had increased risk of ADR/intolerance. There was no difference in reoperation-free survival between TKA (83.3%) and THA (65.1%) DAIR (P = .5900) at mean 2.8-year follow-up. Risk of reoperation for infection was higher among TKA Staphylococcus aureus infections (P = .0004) and lower with increased SAT duration (P < .0450). The optimal duration of SAT was nearly 2 years. No cases of antibiotic resistance developed due to SAT. CONCLUSIONS: Consider SAT after TJA DAIR due to improved reoperation-free survival and favorable safety profile. Prolonged SAT did not induce antibiotic resistance. Use trimethoprim/sulfamethoxazole with caution because of the increased likelihood of ADR/intolerance. LEVEL OF EVIDENCE: Therapeutic Level III.

Therapeutic efficacy of vancomycin-loaded carbon fiber-reinforced polyetheretherketone hip stem for periprosthetic joint infection: A pilot study.

A carbon fiber-reinforced polyetheretherketone (CFR/PEEK) hip stem with a special antibiotic elution mechanism is under development to treat periprosthetic joint infection (PJI). The antibiotic elution characteristics of intramedullary implants were experimentally investigated, and the efficacy of revision surgery using a therapeutic stem in treating ovine PJI was examined. To evaluate elution characteristics, the intramedullary vancomycin-loaded CFR/PEEK cylindrical implants were inserted in the distal femur of nine sheep, and the vancomycin elution rate was measured at 2, 7, and 21 days. To evaluate therapeutic efficacy, the PJI model with staphylococcus aureus was attempted to create for five sheep. Moreover, the therapeutic vancomycin-loaded CFR/PEEK stem was implanted during one-stage revision surgery. Three weeks after revision surgery, the treatment efficacy was evaluated based on bacterial cultures and wound findings. In addition, the vancomycin elution rate from the stem was measured. On average, the cylindrical implants eluted approximately 70% vancomycin in 21 days. Of the five sheep attempting to create a PJI model, three were successfully infected with S. aureus as intended for verification of treatment efficacy. In all three joints, negative bacterial cultures and no purulence were observed 3 weeks after revision surgery. The vancomycin elution rates from the stems were >70%. Efficient elution of vancomycin was confirmed by the experimental implant inserted into the bone marrow and the stem in actual PJI treatment. Using a novel therapeutic stem with an antibiotic elution mechanism in one-stage revision surgery, successful treatment was demonstrated in all S. aureus-induced PJIs.

Demographics and Early Outcomes of Commercial Antibiotic Cement Usage for Infection Prophylaxis During Primary Total Knee Arthroplasty in Patients Older Than 65 Years: An American Joint Replacement Registry Study.

INTRODUCTION: The use of antibiotic-laden bone cement (ALBC) for infection prophylaxis in the setting of primary total knee arthroplasty (TKA) remains controversial. Using data from the American Joint Replacement Registry (AJRR), (1) we examined the demographics of ALBC usage in the United States and (2) identified the effect of prophylactic commercially available ALBC on early revision and readmission for prosthetic joint infection (PJI) after primary TKA. METHODS: This is a retrospective cohort study of the AJRR from 2017 to 2020. Patients older than 65 years undergoing primary cemented TKA with or without the use of commercially available antibiotic cement were eligible for inclusion (N = 251,506 patients). Data were linked to available Medicare claims to maximize revision outcomes. Demographics including age, sex, race/ethnicity, Charlson Comorbidity Index (CCI), preoperative inflammatory arthritis, region, and body mass index (BMI) class were recorded. Cox proportional hazards regression analysis was used to evaluate the association between the two outcome measures and ALBC usage. RESULTS: Patients undergoing cemented TKA with ALBC were more likely to be Non-Hispanic Black ( P < 0.001), have a CCI of 2 or 3 ( P < 0.001), reside in the South ( P < 0.001), and had a higher mean BMI ( P < 0.001). In the regression models, ALBC usage was associated with increased risk of 90-day revision for PJI (hazards ratio 2.175 [95% confidence interval] 1.698 to 2.787) ( P < 0.001) and was not associated with 90-day all-cause readmissions. Male sex, higher CCI, and BMI >35 were all independently associated with 90-day revision for PJI. DISCUSSION: The use of commercial ALBC in patients older than 65 years for primary TKA in the AJRR was not closely associated with underlying comorbidities suggesting that hospital-level and surgeon-level factors influence its use. In addition, ALBC use did not decrease the risk of 90-day revision for PJI and was not associated with 90-day readmission rates.