Development and Evaluation of a Preoperative Risk Calculator for Periprosthetic Joint Infection Following Total Joint Arthroplasty

Obesity and Primary Total Knee Arthroplasty: The Absolute Versus Relative Risk of Periprosthetic Joint Infection at 15 Years

BACKGROUND

When indicating patients for primary total knee arthroplasty (TKA), surgeons and patients must understand the absolute and relative risks of periprosthetic joint infection (PJI) to make an informed decision. We sought to evaluate the long-term risk of PJI following primary TKA stratified by body mass index (BMI) and PJI-related risk factors.

METHODS

We identified 25,160 primary TKAs performed from 2000 to 2021 at a single institution. Patients were stratified as having 0, 1, or ≥ 2 PJI risk factors (diabetes, chronic kidney disease, nonprimary osteoarthritis, immunosuppression, or active smoking) and into BMI categories. The 15-year cumulative risk of PJI was evaluated by BMI and PJI risk factors.

RESULTS

For the entire cohort, the 15-year absolute risk of PJI was 3%. For patients who did not have PJI risk factors, the absolute risk of PJI at 15 years was 3% in normal weight, 4% in class III obesity, and 4% in class IV obesity. Patients who had class III obesity had a 3-time higher relative risk of PJI when than normal-weight patients (P = 0.01). Among patients who had ≥ 2 PJI risk factors, the absolute risk of PJI at 15 years was 5% in normal weight and 6% in patients who have class III obesity.

CONCLUSIONS

Healthy patients who had class III obesity had a 3-time increased risk of PJI relative to healthy, normal-weight patients; however, the absolute risk of PJI at 15 years after primary TKA was 4% in this group. Surgeons and patients must consider both a 3-time increased relative risk of PJI and a 4% absolute risk of PJI at 15 years after primary TKA when considering surgery in otherwise healthy patients who have BMI ≥ 40.

LEVEL OF EVIDENCE

IV.

The Application of artificial intelligence in periprosthetic joint infection

Periprosthetic joint infection (PJI) represents one of the most devastating complications following total joint arthroplasty, often necessitating additional surgeries and antimicrobial therapy, and potentially leading to disability. This significantly increases the burden on both patients and the healthcare system. Given the considerable suffering caused by PJI, its prevention and treatment have long been focal points of concern. However, challenges remain in accurately assessing individual risk, preventing the infection, improving diagnostic methods, and enhancing treatment outcomes. The development and application of artificial intelligence (AI) technologies have introduced new, more efficient possibilities for the management of many diseases. In this article, we review the applications of AI in the prevention, diagnosis, and treatment of PJI, and explore how AI methodologies might achieve individualized risk prediction, improve diagnostic algorithms through biomarkers and pathology, and enhance the efficacy of antimicrobial and surgical treatments. We hope that through multimodal AI applications, intelligent management of PJI can be realized in the future.

Predicting periprosthetic joint infection in primary total knee arthroplasty: a machine learning model integrating preoperative and perioperative risk factors

BACKGROUND

Periprosthetic joint infection leads to significant morbidity and mortality after total knee arthroplasty. Preoperative and perioperative risk prediction and assessment tools are lacking in Asia. This study developed the first machine learning model for individualized prediction of periprosthetic joint infection following primary total knee arthroplasty in this demographic.

METHODS

A retrospective analysis was conducted on 3,483 primary total knee arthroplasty (81 with periprosthetic joint infection) from 1998 to 2021 in a Chinese tertiary and quaternary referral academic center. We gathered 60 features, encompassing patient demographics, operation-related variables, laboratory findings, and comorbidities. Six of them were selected after univariate and multivariate analysis. Five machine learning models were trained with stratified 10-fold cross-validation and assessed by discrimination and calibration analysis to determine the optimal predictive model.

RESULTS

The balanced random forest model demonstrated the best predictive capability with average metrics of 0.963 for the area under the receiver operating characteristic curve, 0.920 for balanced accuracy, 0.938 for sensitivity, and 0.902 for specificity. The significant risk factors identified were long operative time (OR, 9.07; p = 0.018), male gender (OR, 3.11; p < 0.001), ASA > 2 (OR, 1.68; p = 0.028), history of anemia (OR, 2.17; p = 0.023), and history of septic arthritis (OR, 4.35; p = 0.030). Spinal anesthesia emerged as a protective factor (OR, 0.55; p = 0.022).

CONCLUSION

Our study presented the first machine learning model in Asia to predict periprosthetic joint infection following primary total knee arthroplasty. We enhanced the model's usability by providing global and local interpretations. This tool provides preoperative and perioperative risk assessment for periprosthetic joint infection and opens the potential for better individualized optimization before total knee arthroplasty.

Declining Trends in Septic Revision Following Total Knee Arthroplasty From 2010 to 2019: A National Cohort Analysis

BACKGROUND

Periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA) are associated with high patient morbidity, mortality, and health care costs. Methods to reduce the burden of PJI have been shown to be efficacious on a small scale. On a national scale, it is unknown whether these methods have reduced PJI rates.

METHODS

A retrospective trend analysis was conducted using a national database. The incidence of 2-year septic revision was observed for the entire cohort in patients who had high-risk comorbidities from 2010 to 2019. A multivariable logistic regression was performed to compare the odds ratios of 2-year septic revision rates from 2011 to 2019 to the reference year of 2010. Linear regression was used to compare the change in the overall and high-risk subanalysis groups.

RESULTS

Among the 860,185 patients, 5,589 underwent septic revision within 2 years. The 2-year septic revision rate decreased from 0.75% in 2010 to 0.69% in 2019 (compounded annual growth rate = -0.94%, P = 0.049). Multivariable logistic regressions demonstrated that the odds of septic revision in 2019 were significantly lower than those in 2010 (odds ratio: 0.83, 95% CI [confidence interval]: [0.70 to 0.96], P = 0.017). In high-risk patients, the septic revision rate decreased from 1.04 to 0.80% (compounded annual growth rate = -2.80%, P = 0.004), specifically in those who had a history of psychoses, Medicaid insurance, anemia, heart failure, obesity, liver disease, tobacco use, and drug abuse (P < 0.05 for all).

CONCLUSIONS

This study demonstrated a national reduction in the 2-year septic revision rate in all TKA patients, including patients considered at high risk for PJI. This suggests that current preventative methods may be efficacious on a national scale in TKA. Further research is needed to identify more modalities to reduce the national incidence of this morbid and costly complication.

Identifying Critical Evidence Gaps in Wound Closure and Incision Management After Total Knee Arthroplasty: Delphi Panel Insights

BACKGROUND

Effective surgical wound management in total knee arthroplasty (TKA) is crucial for optimal healing and patient outcomes. Despite surgical advances, managing wounds to prevent complications remains challenging. This study aimed to identify and address evidence gaps in TKA wound management, including preoperative optimization, intraoperative options, and postoperative complication avoidance. Addressing these issues is vital for patient recovery and surgical success.

METHODS

This study used the Delphi method with 20 experienced orthopedic surgeons from Europe and North America. Conducted from April to September 2023, the process involved three stages: an initial electronic survey, a virtual meeting, and a concluding electronic survey. The panel reviewed and reached a consensus on 26 statements about TKA wound management based on a comprehensive literature review. Additionally, the panel aimed to identify critical evidence gaps in wound management practices.

RESULTS

The panel achieved consensus on various wound management practices but highlighted significant evidence gaps. Consensus was reached on wound closure methods, including mesh-adhesive dressings, skin glue, staples, barbed sutures, and negative pressure wound therapy. However, further evidence is needed to address the cost-effectiveness of these methods and develop best practices for patient outcomes. Identifying these gaps highlights the need for more research to improve TKA wound care.

CONCLUSIONS

Identifying major evidence gaps underscores the need for targeted research in TKA wound management. Addressing these gaps is crucial for developing effective, efficient, and patient-friendly wound care strategies. Future research should focus on comparative effectiveness studies and developing guidelines for emerging technologies. Bridging these gaps could improve patient outcomes, reduce complications, and enhance TKA surgery success.

Outpatient Total Joint Arthroplasty in the "Unhealthy": Staying Safe Using Institutional Protocols

BACKGROUND

Recent expansion in the indications for outpatient total joint arthroplasty has led to debates over patient selection. The purpose of this study was to compare early clinical outcomes and complications of same-day discharge (SDD) hip and knee arthroplasties from a high-volume institution based on the American Society of Anesthesiologists (ASA) physical status classification.

METHODS

Prospectively collected data were reviewed for all SDD primary joint arthroplasties between January 2013 and August 2023. There were 8 surgeons who performed 7,258 cases at hospital outpatient (n = 4,288) or ambulatory surgery centers (n = 2,970). This included 3,239 total hip arthroplasties, 1,503 total knee arthroplasties, and 2,516 unicompartmental knee arthroplasties. The ASA 1 group comprised 506 subjects, compared to 5,005 for ASA 2 and 1,736 for ASA 3. The primary outcomes included emergency department (ED) visits, readmissions, complications, and revisions within 24 hours and 90 days of surgery. The ASA 3 group was older (ASA 1 = 55 versus ASA 2 = 63 versus ASA 3 = 66 years; P < .01) and had a higher body mass index (ASA 1 = 25.4 versus ASA 2 = 28.5 versus ASA 3 = 32.7; P < .01).

RESULTS

There were no differences between ASA groups in joint-related ED visits, readmissions, and complications within 24 h and 90 days of surgery (P > .05). Subjects in the ASA 3 group experienced greater 90-day revisions compared to the other groups (ASA 1 = 1 of 506, 0.2% versus ASA 2 = 15 of 5,005, 0.3% versus ASA 3 = 15 of 1,736, 0.9%; P = .01). Regarding systemic events, ASA 1 subjects experienced significantly greater 24-hour complications (8 of 506, 1.6%) and ED visits (5 of 506, 1.0%), and the ASA 3 subjects had a higher incidence of 90-day readmissions (19 of 1,736, 1.1%) compared to the other groups (P < .05). Within 24 hours of discharge, urinary retention and syncope were the most frequent complications that required additional health care utilization.

CONCLUSIONS

Medically optimized patients categorized as ASA 3 can safely undergo SDD hip and knee arthroplasty without increased risk of 24-hour or 90-day complications. Patient preference for outpatient care, reliable social support, and independent functional status are imperative for a successful outpatient program.

Clinical prediction models for patients undergoing total hip arthroplasty: an external validation based on a systematic review and the Dutch Arthroplasty Register

BACKGROUND AND PURPOSE

 External validation is a crucial step after prediction model development. Despite increasing interest in prediction models, external validation is frequently overlooked. We aimed to evaluate whether joint registries can be utilized for external validation of prediction models, and whether published prediction models are valid for the Dutch population with a total hip arthroplasty.

METHODS

 We identified prediction models developed in patients undergoing arthroplasty through a systematic literature search. Model variables were evaluated for availability in the Dutch Arthroplasty Registry (LROI). We assessed the model performance in terms of calibration and discrimination (area under the curve [AUC]). Furthermore, the models were updated and evaluated through intercept recalibration and logistic recalibration.

RESULTS

 After assessing 54 papers, 19 were excluded for not describing a prediction model (n = 16) or focusing on non-TJA populations (n = 3), leaving 35 papers describing 44 prediction models. 90% (40/44) of the prediction models used outcomes or predictors missing in the LROI, such as diabetes, opioid use, and depression. 4 models could be externally validated on LROI data. The models' discrimination ranged between poor and acceptable and was similar to that in the development cohort. The calibration of the models was insufficient. The model performance improved slightly after updating.

CONCLUSION

 External validation of the 4 models resulted in suboptimal predictive performance in the Dutch population, highlighting the importance of external validation studies.

Predicting periprosthetic joint infection: external validation of preoperative prediction models

Introduction: Prediction models for periprosthetic joint infections (PJIs) are gaining interest due to their potential to improve clinical decision-making. However, their external validity across various settings remains uncertain. This study aimed to externally validate promising preoperative PJI prediction models in a recent multinational European cohort. Methods: Three preoperative PJI prediction models - by Tan et al. (2018), Del Toro et al. (2019), and Bülow et al. (2022) - that have previously demonstrated high levels of accuracy were selected for validation. A retrospective observational analysis of patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) at centers in the Netherlands, Portugal, and Spain between January 2020 and December 2021 was conducted. Patient characteristics were compared between our cohort and those used to develop the models. Performance was assessed through discrimination and calibration. Results: The study included 2684 patients, 60 of whom developed a PJI (2.2 %). Our cohort differed from the models' original cohorts with respect to demographic variables, procedural variables, and comorbidity prevalence. The overall accuracies of the models, measured with the c  statistic, were 0.72, 0.69, and 0.72 for the Tan, Del Toro, and Bülow models, respectively. Calibration was reasonable, but the PJI risk estimates were most accurate for predicted infection risks below 3 %-4 %. The Tan model overestimated PJI risk above 4 %, whereas the Del Toro model underestimated PJI risk above 3 %. Conclusions: The Tan, Del Toro, and Bülow PJI prediction models were externally validated in this multinational cohort, demonstrating potential for clinical application in identifying high-risk patients and enhancing preoperative counseling and prevention strategies.

Prediction of Early Adverse Events After THA: A Comparison of Different Machine-Learning Strategies Based on 262,356 Observations From the Nordic Arthroplasty Register Association (NARA) Dataset

OBJECTIVE

Preoperative risk prediction models can support shared decision-making before total hip arthroplasties (THAs). Here, we compare different machine-learning (ML) approaches to predict the six-month risk of adverse events following primary THA to obtain accurate yet simple-to-use risk prediction models.

METHODS

We extracted data on primary THAs (N = 262,356) between 2010 and 2018 from the Nordic Arthroplasty Register Association dataset. We benchmarked a variety of ML algorithms in terms of the area under the receiver operating characteristic curve (AUROC) for predicting the risk of revision caused by periprosthetic joint infection (PJI), dislocation or periprosthetic fracture (PPF), and death. All models were internally validated against a randomly selected test cohort (one-third of the data) that was not used for training the models.

RESULTS

The incidences of revisions because of PJI, dislocation, and PPF were 0.8%, 0.4%, and 0.3%, respectively, and the incidence of death was 1.2%. Overall, Lasso regression with stable iterative variable selection (SIVS) produced models using only four to five input variables but with AUROC comparable to more complex models using all 32 variables available. The SIVS-based Lasso models based on age, sex, preoperative diagnosis, bearing couple, fixation, and surgical approach predicted the risk of revisions caused by PJI, dislocations, and PPF, as well as death, with AUROCs of 0.61, 0.67, 0.76, and 0.86, respectively.

CONCLUSION

Our study demonstrates that satisfactory predictive potential for adverse events following THA can be reached with parsimonious modeling strategies. The SIVS-based Lasso models may serve as simple-to-use tools for clinical risk assessment in the future.

Obesity and Primary Total Hip Arthroplasty: The Absolute versus Relative Risk of Periprosthetic Joint Infection at 15 Years

BACKGROUND

To make an informed decision about total hip arthroplasty (THA), surgeons and patients need to understand the absolute and relative risks of periprosthetic joint infection (PJI). We sought to evaluate the long-term risk of PJI following primary THA stratified by body mass index (BMI) and PJI-related risk factors.

METHODS

We identified 21,550 primary THAs performed from 2000 to 2021 at a single institution. Patients were stratified as having 0, 1, or ≥ 2 PJI risk factors (diabetes, chronic kidney disease, nonprimary osteoarthritis, immunosuppression, or active smoking) and into BMI categories. The 15-year cumulative risk of PJI was evaluated by BMI and PJI risk factors.

RESULTS

For the entire cohort, the 15-year absolute risk of PJI was 2%. For patients who did not have PJI risk factors, the absolute risk of PJI at 15 years was 1% in normal weight, 2% in class III obesity, and 4% in class IV obesity. Patients who had class III and IV obesity had a 3-times and 9-times higher relative risk of PJI, respectively (P = .03, P < .001). Among patients who had ≥ 2 PJI risk factors, the absolute risk of PJI at 15 years was 2% in normal weight, 4% in class III obesity, and 18% in class IV obesity.

CONCLUSIONS

Healthy patients who had class III and IV obesity had a 3-times and 9-times increased risk of PJI at 15 years relative to normal weight patients. However, the absolute risk of PJI at 15 years was 2 and 4%, respectively. Given emerging data questioning whether BMI modification decreases PJI risk, surgeons and patients must consider both a 3-times to 9-times increased relative risk of PJI and a 2 to 4% absolute risk of PJI at 15 years for healthy patients who had a BMI ≥ 40.

LEVEL OF EVIDENCE

IV.

Immobile to Ambulation: Complex Multijoint Pathologies in a Patient with Advanced HIV Disease: A Case Report

CASE

A 30-year-old man with a history of advanced HIV disease (AHD) presented with bilateral equinocavus, leg, and foot muscle paresis, Brooker grade 4 heterotopic ossification of hips and knee stiffness, and was unable to sit upright, stand independently, or walk. Electromyography showed demyelinating sensorimotor and axonal polyneuropathy of lower extremities. Multiple surgeries of bilateral hips, ankles, and feet enabled joint mobility, plantigrade feet, and independent ambulation.

CONCLUSION

Patients with AHD may develop multijoint pathologies, secondary to HIV, antiretroviral therapy, or prolonged immobility, resulting in loss of ambulation and independence. Restoring ambulation may necessitate multiple surgeries, with potential for success.

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.

Risk equations for prosthetic joint infections (PJIs) in UK: a retrospective study using the Clinical Practice Research Datalink (CPRD) AURUM and GOLD databases

BACKGROUND

Prosthetic joint infections (PJIs) are a serious negative outcome of arthroplasty with incidence of about 1%. Risk of PJI could depend on local treatment policies and guidelines; no UK-specific risk scoring is currently available.

OBJECTIVE

To determine a risk quantification model for the development of PJI using electronic health records.

DESIGN

Records in Clinical Practice Research Datalink (CPRD) GOLD and AURUM of patients undergoing hip or knee arthroplasty between January 2007 and December 2014, with linkage to Hospital Episode Statistics and Office of National Statistics, were obtained. Cohorts' characteristics and risk equations through parametric models were developed and compared between the two databases. Pooled cohort risk equations were determined for the UK population and simplified through stepwise selection.

RESULTS

After applying the inclusion/exclusion criteria, 174 905 joints (1021 developed PJI) were identified in CPRD AURUM and 48 419 joints (228 developed PJI) in CPRD GOLD. Patients undergoing hip or knee arthroplasty in both databases exhibited different sociodemographic characteristics and medical/drug history. However, the quantification of the impact of such covariates (coefficients of parametric models fitted to the survival curves) on the risk of PJI between the two cohorts was not statistically significant. The log-normal model fitted to the pooled cohorts after stepwise selection had a C-statistic >0.7.

CONCLUSIONS

The risk prediction tool developed here could help prevent PJI through identifying modifiable risk factors pre-surgery and identifying the patients most likely to benefit from close monitoring/preventive actions. As derived from the UK population, such tool will help the National Health Service reduce the impact of PJI on its resources and patient lives.

International Delphi Study on Wound Closure and Dressing Management in Joint Arthroplasty: Part 1: Total Knee Arthroplasty

BACKGROUND

The purpose of this modified Delphi study was to obtain consensus on wound closure and dressing management in total knee arthroplasty (TKA).

METHODS

The Delphi panel included 20 orthopaedic surgeons from Europe and North America. There were 26 statements identified using a targeted literature review. Consensus was developed for the statements with up to three rounds of anonymous voting per topic. Panelists ranked their agreement with each statement on a five-point Likert scale. An a priori threshold of ≥ 75% was required for consensus.

RESULTS

All 26 statements achieved consensus after three rounds of anonymous voting. Wound closure-related interventions that were recommended for use in TKA included: 1) closing in semi-flexion versus extension (superior range of motion); 2) using aspirin for venous thromboembolism prophylaxis over other agents (reduces wound complications); 3) barbed sutures over non-barbed sutures (lower wound complications, better cosmetic appearances, shorter closing times, and overall cost savings); 4) mesh-adhesives over other skin closure methods (lower wound complications, higher patient satisfaction scores, lower rates of readmission); 5) silver-impregnated dressings over standard dressings (lower wound complications, decreased infections, fewer dressing changes); 6) in high-risk patients, negative pressure wound therapy over other dressings (lower wound complications, decreased reoperations, fewer dressing changes); and 7) using triclosan-coated over non-antimicrobial-coated sutures (lower risks of surgical site infection).

CONCLUSIONS

Using a modified Delphi approach, the panel achieved consensus on 26 statements pertaining to wound closure and dressing management in TKA. This study forms the basis for identifying critical evidence supported by clinical practice for wound management to help reduce variability, advance standardization, and ultimately improve outcomes during TKA. The results presented here can serve as the foundation for knowledge, education, and improved clinical outcomes for surgeons performing TKAs.

What to Know about Antimicrobial Coatings in Arthroplasty: A Narrative Review

Periprosthetic joint infections (PJIs) are one of the most worrying complications orthopedic surgeons could face; thus, methods to prevent them are evolving. Apart from systemic antibiotics, targeted strategies such as local antimicrobial coatings applied to prosthetics have been introduced. This narrative review aims to provide an overview of the main antimicrobial coatings available in arthroplasty orthopedic surgery practice. The search was performed on the PubMed, Web of Science, SCOPUS, and EMBASE databases, focusing on antimicrobial-coated devices used in clinical practice in the arthroplasty world. While silver technology has been widely adopted in the prosthetic oncological field with favorable outcomes, recently, silver associated with hydroxyapatite for cementless fixation, antibiotic-loaded hydrogel coatings, and iodine coatings have all been employed with promising protective results against PJIs. However, challenges persist, with each material having strengths and weaknesses under investigation. Therefore, this narrative review emphasizes that further clinical studies are needed to understand whether antimicrobial coatings can truly revolutionize the field of PJIs.

Clinical characteristics and long-term outcomes of septic arthritis of the native hip joint: a 20-year retrospective review

BACKGROUND

The primary purpose of this retrospective case series was to describe the prevalence and outcomes of single-stage hip arthroplasty in patients who were previously treated for septic arthritis of the native hip at our institution over a 20-year period. This study also examined rates of persistent or recurrent infection, reoperation, and mortality for septic arthritis of the native hip.

METHODS

Adult patients treated for septic arthritis of the native hip at our institution from 1995 to 2015 were retrospectively identified. Exclusion criteria included age <18 years, missing or incomplete medical records, treatment at an outside institution, and prior surgery of the hip.

RESULTS

97 patients were included in this study. 3 patients (3.1%) who were previously treated for septic arthritis of the native hip underwent single-stage hip arthroplasty an average of 40 ± 25 months from the date of infection. 3 of the 18 (16.7%) patients who were treated with resection arthroplasty underwent second-stage joint reconstruction. There were no cases of periprosthetic joint infection (PJI). 1 patient who underwent single-stage arthroplasty experienced implant-induced metallosis, necessitating removal of the implant. There were no other cases of revision arthroplasty.

CONCLUSIONS

The prevalence of single-stage hip arthroplasty in patients with a history of septic arthritis of the native hip joint was 3.1%, which is higher than the prevalence of hip arthroplasty in the United States general population, suggesting that a history of septic arthritis may increase the risk of requiring hip arthroplasty. In the small number of patients who went on to receive a hip replacement, there were no reported cases of PJI. This study suggests that hip arthroplasty is a viable option for patients with symptomatic osteoarthritis and a history of septic arthritis of their hip.

International Delphi Study on Wound Closure and Incision Management in Joint Arthroplasty Part 2: Total Hip Arthroplasty

BACKGROUND

This modified Delphi study aimed to develop a consensus on optimal wound closure and incision management strategies for total hip arthroplasty (THA). Given the critical nature of wound care and incision management in influencing patient outcomes, this study sought to synthesize evidence-based best practices for wound care in THA procedures.

METHODS

An international panel of 20 orthopedic surgeons from Europe, Canada, and the United States evaluated a targeted literature review of 18 statements (14 specific to THA and 4 related to both THA and total knee arthroplasty). There were 3 rounds of anonymous voting per topic using a modified 5-point Likert scale with a predetermined consensus threshold of ≥ 75% agreement necessary for a statement to be accepted.

RESULTS

After 3 rounds of voting, consensus was achieved for all 18 statements. Notable recommendations for THA wound management included (1) the use of barbed sutures over non-barbed sutures (shorter closing times and overall cost savings); (2) the use of subcuticular sutures over skin staples (lower risk of superficial infections and higher patient preferences, but longer closing times); (3) the use of mesh-adhesives over silver-impregnated dressings (lower rate of wound complications); (4) for at-risk patients, the use of negative pressure wound therapy over other dressings (lower wound complications and reoperations, as well as fewer dressing changes); and (5) the use of triclosan-coated sutures (lower risk of surgical site infection) over standard sutures.

CONCLUSIONS

Through a structured modified Delphi approach, a panel of 20 orthopedic surgeons reached consensus on all 18 statements pertaining to wound closure and incision management in THA. This study provides a foundational framework for establishing evidence-based best practices, aiming to reduce variability in patient outcomes and to enhance the overall quality of care in THA procedures.

The Use of Artificial Intelligence for the Prediction of Periprosthetic Joint Infection Following Aseptic Revision Total Knee Arthroplasty

Periprosthetic joint infection (PJI) following revision total knee arthroplasty (TKA) for aseptic failure is associated with poor outcomes, patient morbidity, and high health care expenditures. The aim of this study was to develop novel machine learning algorithms for the prediction of PJI following revision TKA for patients with aseptic indications for revision surgery. A single-institution database consisting of 1,432 consecutive revision TKA patients with aseptic etiologies was retrospectively identified. The patient cohort included 208 patients (14.5%) who underwent re-revision surgery for PJI. Three machine learning algorithms (artificial neural networks, support vector machines, k-nearest neighbors) were developed to predict this outcome and these models were assessed by discrimination, calibration, and decision curve analysis. This is a retrospective study. Among the three machine learning models, the neural network model achieved the best performance across discrimination (area under the receiver operating characteristic curve = 0.78), calibration, and decision curve analysis. The strongest predictors for PJI following revision TKA for aseptic reasons were prior open procedure prior to revision surgery, drug abuse, obesity, and diabetes. This study utilized machine learning as a tool for the prediction of PJI following revision TKA for aseptic failure with excellent performance. The validated machine learning models can aid surgeons in patient-specific risk stratifying to assist in preoperative counseling and clinical decision making for patients undergoing aseptic revision TKA.

Preoperative infection risk assessment in hip arthroplasty a matched-pair study of the reliability of 3 validated risk scales

Peri-prosthetic infection (PJI) represents one of the most devastating complications of total hip arthroplasty (THA). The aim of this study is to assess the reliability of different PJI risk assessment scales between two matched pairs of THA groups. This study included 37 patients with PJI following THA performed between 2012 and 2020 (Group A). Each patient in this group was matched, based on sex, age, and follow-up duration, with a control patient who underwent the same surgical procedure without any septic complications (Group B) during the same period. Each patient's assessment included the American Society of Anesthesiologists (ASA) score and a retrospective evaluation using three different preoperative, specific PJI risk assessment scales: the International Consensus Meeting (ICM) Preoperative Risk Calculator for PJI, the Mayo PJI Risk Score, and the KLIC-score. The two groups were statistically compared using descriptive analyses, both for binomial data and numerical variables. Statistically significant higher values were observed in the preoperative ASA score and surgical time in Group A. Statistically different higher scores were determined only with the ICM risk calculator score in Group A. No significant differences were found using the KLIC score and Mayo score between the two groups. We emphasize the reliability of the ASA score as a nonspecific preoperative assessment scale for PJI. The ICM risk calculator was confirmed as a reliable, specific preoperative assessment scale for PJI, suggesting its routine adoption in THA clinical practice.

The Use of Oral Antibiotics After Total Joint Arthroplasty: A Critical Analysis Review

» There is conflicting and insufficient evidence that extended oral antibiotic (EOA) therapy prevents infection in high-risk patients undergoing primary total joint arthroplasty (TJA), limiting recommendation for or against the practice.» In the case of aseptic revision TJA, the evidence is also conflicting and limited by underlying confounders, preventing recommendation for use of EOA.» There is fair evidence that use of EOA after debridement antibiotic therapy and implant retention of the prosthesis prolongs infection-free survival, but randomized controlled trials are needed. On the other hand, there is strong evidence that patients undergoing 2-stage revision should receive a period of suppressive oral antibiotics after the second stage.» The optimal duration of EOA in primary TJA, aseptic revision, and debridement antibiotic therapy and implant retention of the prosthesis is unknown. However, there is strong evidence that 3 months of EOA suppression may be appropriate after reimplantation as part of 2-stage exchange arthroplasty.» Complications secondary to EOA are reported to be between 0% and 13.7%, yet are inconsistently reported and poorly defined. The risks associated with antibiotic use, including development of antimicrobial resistance, must be weighed against a possible decrease in infection rate.

Debridement, Antibiotic Pearls, and Retention of the Implant (DAPRI) in the Treatment of Early Periprosthetic Joint Infections: A Consecutive Series

INTRODUCTION

Periprosthetic joint infections (PJI) represent a devastating consequence following total joint arthroplasty (TJA). In this study, the authors describe a modified surgical technique developed to enhance the classical irrigation and debridement procedure (DAIR) to improve the possibilities of retaining an acutely infected TJA.

MATERIALS AND METHODS

This technique, debridement antibiotic pearls and retention of the implant (DAPRI), aims to remove the intra-articular biofilm allowing a higher and prolonged local antibiotic concentration by using calcium sulphate antibiotic-added beads in a setting of acute (<4 weeks from symptoms onset) PJI with pathogen identification. The combination of three different surgical techniques (tumor-like synovectomy, argon beam/acetic acid application and chlorhexidine gluconate brushing) aims to remove the bacterial biofilm from the implant without explanting the original hardware.

RESULTS

In total, 62 patients met the acute infection criteria (<4 weeks of symptoms); there were 57 males and five females. The patients' average age at the time of treatment was 71 years (62-77) and the average BMI was 37 kg/m². The micro-organism, always identified through synovial fluid analysis (culture, multiplex PCR or Next Generation Sequencing), was an aerobic Gram + in 76% (S. Coag-Neg 41%; S. aureus 16%), Gram-in 10% (E. coli 4%) and anaerobic Gram + in 4%. The DAPRI treatment was performed at an average of 3 days from symptoms onset (1-7 days). All patients underwent a 12-week course of post-operative antibiotic therapy (6 weeks I.V. and 6 weeks oral). All patients were available at the 2-year minimum FU (24-84 months). A total of 48 (77.5%) patients were infection-free at the final FU, while 14 patients underwent 2-stage revision for PJI recurrence. In total, four patients (6.4%) had a prolonged drainage from the wound after placement of the calcium sulphate beads.

CONCLUSIONS

This study suggests that the DAPRI technique could represent a valid alternative to the classic DAIR procedure. The current authors do not recommend this procedure outside of the main inclusive criteria (acute scenario micro-organism identification).

Application of the Mayo Periprosthetic Joint Infection Risk Score for Total Ankle Arthroplasty

BACKGROUND

Assessing patient's risk of infection is fundamental for prevention of periprosthetic joint infection (PJI) after total ankle arthroplasty (TAA). The Mayo Prosthetic Joint Infection Risk Score (Mayo Score) is based on data from total hip and knee arthroplasty and has not been validated for application for TAA.

METHODS

A total of 405 consecutive TAA cases were followed for 6 months for PJI. Individual patients' Mayo Scores were calculated and analyzed with logistic regression and receiver operating characteristic (ROC) for predictability for PJI. A critical cut-off Mayo Score for patients at high risk of PJI was determined by best Youden index. Among the Mayo Score-defined high-risk patients, the contribution of different risk factors were compared between the PJI and non-PJI patients.

RESULTS

There were 10 cases of PJI (2.5%) among the 405 cases within 6 months after TAA. Of the 405 patients, the Mayo Scores ranged between -4 and 13 (median 2; interquartile range 0-5). The average Mayo Score was 2.5 ± 3.4 in the non-PJI patients and 7.7 ± 3.1 in the PJI patients (P < .001). Logistic regression showed that the probability of PJI increased with higher Mayo Scores (odds ratio 1.48, 95% CI 1.23-1.78). All but 1 PJI patients had a Mayo Score >5. The sensitivity and specificity were 90.0% and 84.3%, respectively, when a Mayo Score >5 was used as a criterion for high risk of PJI.

CONCLUSION

This study demonstrated that the Mayo Score could similarly predict PJI risk after TAA as in total hip and knee arthroplasty. Data analysis suggests that a Mayo Score >5 could be a criterion for identifying high-risk patients for PJI, although further validation with a large number of PJI cases is necessary.

LEVEL OF EVIDENCE

II, developing diagnositic criteria with consecutive cases.

External Validation of Prediction Models for Surgical Complications in People Considering Total Hip or Knee Arthroplasty Was Successful for Delirium but Not for Surgical Site Infection, Postoperative Bleeding, and Nerve Damage: A Retrospective Cohort Study

Although several models for the prediction of surgical complications after primary total hip or total knee replacement (THA and TKA, respectively) are available, only a few models have been externally validated. The aim of this study was to externally validate four previously developed models for the prediction of surgical complications in people considering primary THA or TKA. We included 2614 patients who underwent primary THA or TKA in secondary care between 2017 and 2020. Individual predicted probabilities of the risk for surgical complication per outcome (i.e., surgical site infection, postoperative bleeding, delirium, and nerve damage) were calculated for each model. The discriminative performance of patients with and without the outcome was assessed with the area under the receiver operating characteristic curve (AUC), and predictive performance was assessed with calibration plots. The predicted risk for all models varied between <0.01 and 33.5%. Good discriminative performance was found for the model for delirium with an AUC of 84% (95% CI of 0.82-0.87). For all other outcomes, poor discriminative performance was found; 55% (95% CI of 0.52-0.58) for the model for surgical site infection, 61% (95% CI of 0.59-0.64) for the model for postoperative bleeding, and 57% (95% CI of 0.53-0.61) for the model for nerve damage. Calibration of the model for delirium was moderate, resulting in an underestimation of the actual probability between 2 and 6%, and exceeding 8%. Calibration of all other models was poor. Our external validation of four internally validated prediction models for surgical complications after THA and TKA demonstrated a lack of predictive accuracy when applied in another Dutch hospital population, with the exception of the model for delirium. This model included age, the presence of a heart disease, and the presence of a disease of the central nervous system as predictor variables. We recommend that clinicians use this simple and straightforward delirium model during preoperative counselling, shared decision-making, and early delirium precautionary interventions.

Rates and Outcomes of Periprosthetic Joint Infection in Persons Who Inject Drugs

BACKGROUND

The risk of periprosthetic joint infection (PJI) is higher in persons who inject drugs (PWID) after total joint arthroplasty (TJA), though reported rates vary widely. This study was designed to assess outcomes of TJA in PWID and to describe factors associated with improved PJI outcomes among PWID.

METHODS

A retrospective matched cohort study was performed using a 1:4 match among those with and those without a history of injection drug use (IDU) undergoing TJA. Demographic, surgical, and outcome variables were compared in multivariate logistic regressions to determine PJI predictors. Kaplan-Meier analyses were constructed to characterize the difference in survival of patients who did not have PJI or undergo joint explantation between PWID and the matching cohort.

RESULTS

PWID had a 9-fold increased risk of PJI compared to the matched cohort (odds ratio 9.605, 95% CI 2.781-33.175, P < .001). Ten of 17 PWID whose last use was within 6 months (active use) of primary TJA had a PJI, while 7 of 41 PWID who did not have active use developed a PJI. Of PWID with PJI, treatment failure was seen in 15 of 17, while in patients who did not have an IDU history, 5 of 8 with PJI had treatment failure.

CONCLUSION

IDU is a significant risk factor for PJI following TJA. Future work investigating the effect of a multidisciplinary support team to assist in cessation of IDU and to provide social support may improve outcomes and reduce morbidity in this vulnerable population.

"Recommendations for periprosthetic joint infections (PJI) prevention: the European Knee Associates (EKA)-International Committee American Association of Hip and Knee Surgeons (AAHKS)-Arthroplasty Society in Asia (ASIA) survey of members"

PURPOSE

Periprosthetic joint infections (PJIs) represent a devastating consequence of total joint arthroplasty. The European Knee Associates (EKA), the American Association of Hip and Knee Surgeons (AAHKS) International Committee, and the Arthroplasty Society in Asia (ASIA) board members were interested in quantifying differences in arthroplasty surgeons' use of various PJI prevention measures to provide clinical recommendations to reduce PJI incidence.

METHODS

A prospective Microsoft Forms online survey was distributed among EKA, AAHKS International Committee, and ASIA members and their affiliated arthroplasty surgeons. The survey consisted of 20 single and multiple response questions focused on PJI prevention strategies at three perioperative periods: preoperatively, intraoperatively, and postoperatively.

RESULTS

Three hundred and ninety-four arthroplasty surgeons from 6 different continents completed the survey. Preoperative: (A) PJI Risk Stratification: 40.6% routinely set thresholds (e.g., BMI, HgbA1C) to be met to qualify for surgery, 36.5% only review past medical history; 9.1% use machine learning to personalize PJI risk; (B) BMI limit: 36% no limit; 15.4% BMI < 35; 30.9% BMI < 40; 17.2% BMI < 45; (C) Nutritional status: 55.3% do not screen; among those who screen their patients (44.7%), albumin is the single most used marker (86.3%); (D) Hyperglycemia/Diabetes: 83.3% check this comorbidity; 88.1% use HgbA1C as single best screening test; (E) MRSA nasal colonization: 63.7% do not test; 28.9% test all patients; 7.4% test selectively. Intraoperative: (A) Antibiotic prophylaxis in high-risk patients: 43.4% use single antibiotic for 24 h; 21.3% use double antibiotic for 24 h; 14.2% use single/double antibiotic for 7 days postoperatively; (B) Skin-cleansing: 68.7% at home (45.6% chlorhexidine sponge; 11.9% clippers); (C) Intraoperative skin disinfection: 46.9% single chlorhexidine; 25% double chlorhexidine-povidone-iodine;15.4% single povidone-iodine; (D) Tranexamic acid (TXA) to reduce bleeding/SSI: 96% yes (51% double IV dose, 35.2% single IV dose, 23.6% intra-articular injection); (E) Surgical suction drain: 52% do not use drains; 19.7% use a drain < 24 h; (F) Intra-articular lavage: 64.9% use only saline; 28.1% use dilute povidone-iodine; (G) Antibiotic local delivery to prevent PJI: 82.4% use antibiotic-added cement. Postoperative: (A) Routine monitoring of PJI serologic markers: 42% only in symptomatic patients; 34.2% do not; 20.8% in all patients; (B) Serologic markers to rule in/out PJI: 95.9% CRP; 71% SEDRATE; 60.6% WBC; (C) Synovial fluid test to rule in/out PJI: 79.6% culture/sensitivity; 69.5% WBC count; 31.4% CRP.

CONCLUSIONS

This survey demonstrated that notable differences still exist in the application of PJI preventive measures across different geographic areas: Optimizing the patient preoperatively and applying multimodal intraoperative strategies represent newer, clinically relevant steps in the effort to reduce the burden of PJI. More uniform guidelines still need to be produced from international scientific societies in order facilitate a more comprehensive approach to this devastating complication.

LEVEL OF EVIDENCE

IV.

Comparison study of patient demographics and risk factors for infections following primary total hip arthroplasty for femoral neck fractures

INTRODUCTION

While studies have shown favorable outcomes in the treatment of femoral neck fractures with the utilization of total hip arthroplasty (THA), adverse events, such as infections, can still occur. Therefore, the aims of this study were to 1) compare baseline demographics and 2) identify risk factors associated with developing either surgical site infections (SSIs) or peri-prosthetic joint infections (PJIs).

MATERIALS AND METHODS

A retrospective analysis of patients who underwent primary THA for femoral neck fractures were queried from the Medicare database. The inclusion criteria consisted of patients developing SSIs within 90 days or PJIs within 3 years following the index procedure. The query yielded 2502 patients who developed infections in the form of either SSIs (n = 987) or PJIs (n = 1515) out of 57,191 patients treated for femoral neck fractures with primary THA. Primary endpoints were to compare baseline demographic profiles and determine risk factors associated with developing infections. Multivariate binomial logistic regression analyses were performed to determine the odds (OR) of developing infections. A p value less than 0.001 was considered to be statistically significant.

RESULTS

Patients who developed either infections were found to be significantly different when compared to patients who did not develop infections. SSI (10 vs. 8, p < 0.0001) and PJI (9 vs. 5, p < 0.0001) patients both had significantly higher mean Elixhauser Comorbidity Index (ECI) scores compared to their counterparts. The regression model found the greatest risks for developing SSIs included hypertension (OR 1.63, p = 0.001), pathologic weight loss (OR 1.58, p < 0.0001), and iron deficiency anemia (IDA) (OR 1.48, p < 0.0001), whereas IDA (OR 2.14, p < 0.0001), pathologic weight loss (OR 1.75, p < 0.0001), and rheumatoid arthritis (OR 1.57, p < 0.0001) increased the odds for PJIs.

CONCLUSION

This study can be utilized by orthopedic surgeons and other healthcare professionals to adequately educate these patients of the complications which may occur following their surgery.

Less Than 1-Year Quiescent Period After Septic Arthritis of the Hip is Associated With High Risk of Periprosthetic Joint Infection Following Total Hip Arthroplasty

BACKGROUND

Approximately 20,000 patients are diagnosed with septic arthritis annually, with 15% specifically affecting the hip joint. These cases exacerbate arthritic changes, often warranting a total hip arthroplasty (THA). Given their prior history of infection, these patients are predisposed to subsequent periprosthetic joint infections (PJIs). Multiple studies suggest delaying THA after a native septic hip, but no study utilizing a large cohort examined the specific timing to mitigate post-THA PJI risk within a short (<1 year) quiescent period after septic arthritis. We sought to compare patients who were diagnosed with septic hip arthritis at time intervals (0-6, or 6-12 months) prior to an ipsilateral primary THA to a cohort of THA patients who never had a septic hip history. Specifically, we assessed: from 90 days to 2 years (1) revisions due to PJI and (2) associated risk factors for PJI at 2-years.

METHODS

A national, all-payer database was queried to identify all patients who underwent a primary THA between 2010 and 2021 and patients who had prior ipsilateral septic hip arthritis were characterized using International Classification of Disease and Current Practice Terminology codes (n = 1,052). A randomized sample of patients who never had a history of septic arthritis prior to undergoing THA was used as a nonseptic group comparison (n = 5,000). The incidences of PJI at 90 days through two years were then identified and compared using bivariate chi-square analyses. Risk factors for post-THA PJIs were then analyzed using multivariate regression models.

RESULTS

The septic arthritis cohorts were more likely to require revisions due to PJIs, as compared to the non-septic group at 90 days, 1 year, and 2 years (all P < .0001). Patients who were diagnosed with septic arthritis between 0 and 6 months prior to THA were at greater PJI risk at both one-year (odds ratio (OR) of 43.1 versus 29.6, P < .0001) and two years (OR of 38.3 versus 22.1, P < .0001) compared to patients who had diagnoses between 6 and 12 months. Diabetes mellitus, obesity, and tobacco use were associated risk factors for PJIs at 2 years in the septic hip cohort in comparison to the cohort without a septic hip history.

CONCLUSION

Less than a 1-year quiescent period after septic arthritis is associated with a 38 times increased risk and a 22 times risk for post-THA PJI, at 0 and 6 months and 6 and 12 months, respectively. Though patients who undergo THA greater than 6 months after their septic arthritis treatment have a decreased risk compared to those between 0 and 6 months the risks are still high. Orthopaedic surgeons should be aware of the increased risks of PJIs when considering performing a THA in patients with a history of septic arthritis.

Patients at a high risk of PJI: Can we reduce the incidence of infection using dual antibiotic-loaded bone cement?

Prosthetic joint infection (PJI) is one of the most devastating complications of orthopedic surgery. However, not all patients are equally at the risk of severe infection. The incidences of PJI vary with the host and surgery-related risk factors. It is now generally accepted that some important medical comorbidities may predispose the patients to a high risk of PJI. Time-consuming and invasive surgical procedures, such as revision arthroplasties, are also associated with a high incidence of PJI, presumably due to the increased risk of surgical site contamination. Effective infection-preventing strategies should begin with identifying and optimizing the patients at a high risk of infection prior to surgery. Optimizing the operating room environment and antibiotic prophylaxis are also essential strategies that help minimize the overall incidence of infection in orthopedic surgery. The ideal antibiotic prophylaxis is still under debate, and discussions have emerged about whether variations or adjustments to the standard protocol are justified in patients at a high risk of infection. This also includes evaluating the possible benefits and risks of using high-dose dual antibiotic-loaded bone cement instead of low-dose single antibiotic-loaded bone cement in arthroplasty. This review summarizes the evidence showing that the combination of two local antibiotics in bone cement exerts a strong and longer-lasting antimicrobial effect against PJI-associated pathogens. This conclusion is consistent with the preliminary clinical studies showing a low incidence of PJI in high-risk patients undergoing cemented hemiarthroplasty, cemented revision, and primary arthroplasty if dual ALBC is used. These results may encourage clinicians to consolidate this hypothesis in a wider clinical range.

The role of antibiotic calcium sulfate beads in acute periprosthetic knee infection: a retrospective cohort study

Background

The study aimed to compare debridement, antibiotics, and implant retention (DAIR) vs. debridement antibiotic bead and retention of the implant (DABRI) in terms of infection-free success rate and treatment cost for acute periprosthetic joint infections after total knee arthroplasty (TKA).

Method

Between 2017 and 2020, 32 patients with acute periprosthetic joint infection who were treated by total knee arthroplasty were retrospectively reviewed. The patients were divided into a DAIR group (n=15) and a DABRI group (n=17). During the DABRI, additional calcium ulphate antibiotic beads were used. Patient age, the Musculoskeletal Infection Society score, microorganisms involved, and success rate were assessed.

Results

The mean age of DAIR group (n=15) was 69 years, with 7 being male, and 8 female. The mean follow-up period lasted 30 months. The success rate was 80% (12/15). The mean age of DABRI group (n=17) was 64 years, with 10 patients being male and 7 female. The mean follow-up period was 16 months. The success rate was 88% (15/17). There were no significant differences in patient age (P>0.05), the Musculoskeletal Infection Society score (P>0.05), and success rate (P>0.05). A significant difference was found in the follow-up period between the two groups (P<0.05).

Conclusion

Both DAIR and DABRI could be used to treat acute periprosthetic joint infections and the outcomes and treatment costs of the two procedures were comparable. Additional use of calcium sulfate beads was safe, but might not improve the treatment result. Randomized controlled studies are warranted for the routine use.

Outcomes of revision arthroplasty for hip joint infection in matched groups of HIV-positive and HIV-negative patients

BACKGROUND

Several studies reported on periprosthetic infection after primary THA in HIV-positive patients, but very few showed the results of its revision.

OBJECTIVE

The aim was to compare primary and secondary clinical outcomes after revision arthroplasty for hip joint infection in matched groups of HIV-infected and HIV-negative patients.

METHODS

Using the hospital database, thirteen HIV-positive patients (13 infected hips) and thirteen HIV-negative patients of the matched control group (13 infected hips) were identified and their records were studied retrospectively. They underwent revision surgery aimed at infection arrest and total hip replacement due to infection developed after primary THA or infected spacers. Harris Hip Score, reinfection rate, limb shortening, and definite outcomes were evaluated with Wilcoxon, Mann-Whitney, and Chi-squared tests.

RESULTS AND DISCUSSION

Spacers with antibiotics were implanted in patients of both groups at the first step of revision, except one HIV-infected patient who had resection arthroplasty. The mean follow-up was 29.4±2.7 and 33.±2.9 months for the HIV-group and control group, respectively. Three patients of the HIV-group completed two-stage revision arthroplasty versus ten patients from the control group. Re-infection rate was higher in the HIV-group. At final follow-ups, the mean HHS was significantly different (53±3.2 points in the HIV-group versus 79.14±3.1 points in the control group) along with limb length discrepancy (3.71±0.43 versus 1.4±0.32).

CONCLUSION

Both primary and secondary clinical outcomes of revision arthroplasty for hip joint infection in HIV-positive patients were significantly worse than in the matched group of HIV-negative patients. Revisions in HIV-positive group resulted in a higher reinfection rate, a small number of definite two-stage revisions, and lower functional scores.

Machine learning models accurately predict recurrent infection following revision total knee arthroplasty for periprosthetic joint infection

PURPOSE

This study aimed to develop and validate machine-learning models for the prediction of recurrent infection in patients following revision total knee arthroplasty for periprosthetic joint infection.

METHODS

A total of 618 consecutive patients underwent revision total knee arthroplasty for periprosthetic joint infection. The patient cohort included 165 patients with confirmed recurrent periprosthetic joint infection (PJI). Potential risk factors including patient demographics and surgical characteristics served as input to three machine-learning models which were developed to predict recurrent periprosthetic joint. The machine-learning models were assessed by discrimination, calibration and decision curve analysis.

RESULTS

The factors most significantly associated with recurrent PJI in patients following revision total knee arthroplasty for PJI included irrigation and debridement with/without modular component exchange (p < 0.001), > 4 prior open surgeries (p < 0.001), metastatic disease (p < 0.001), drug abuse (p < 0.001), HIV/AIDS (p < 0.01), presence of Enterococcus species (p < 0.01) and obesity (p < 0.01). The machine-learning models all achieved excellent performance across discrimination (AUC range 0.81-0.84).

CONCLUSION

This study developed three machine-learning models for the prediction of recurrent infections in patients following revision total knee arthroplasty for periprosthetic joint infection. The strongest predictors were previous irrigation and debridement with or without modular component exchange and prior open surgeries. The study findings show excellent model performance, highlighting the potential of these computational tools in quantifying increased risks of recurrent PJI to optimize patient outcomes.

LEVEL OF EVIDENCE

IV.

For Patients With Acute PJI Treated With Debridement, Antibiotics, and Implant Retention, What Factors Are Associated With Systemic Sepsis and Recurrent or Persistent Infection in Septic Patients?

BACKGROUND

Periprosthetic joint infection (PJI) can lead to a severe systemic inflammatory response and may result in systemic sepsis. However, little is known about how often systemic sepsis may occur in patients with PJI, and whether sepsis is associated with a greater likelihood of persistent or recurrent PJI.

QUESTIONS/PURPOSES

(1) Among patients who present with acute or acute hematogenous PJI and who were treated with debridement, antibiotics, and implant retention (DAIR), what proportion have sepsis and what factors are associated with a presentation with sepsis? (2) For patients presenting with sepsis, what factors are associated with persistent or recurrent PJI?

METHODS

In all, 320 patients who underwent DAIR for the treatment of acute postoperative or acute hematogenous PJI between January 2000 and December 2019 were included in this study. Exclusion criteria were patients with other known sources of infection, such as pneumonia or urinary tract infections, which could contribute to systemic sepsis (6% [18 of 320]), patients with chronic PJI, and those with less than 6 months of follow-up (21% [66 of 320]). Our final cohort consisted of 236 patients presenting with an acute postoperative or acute hematogenous PJI who underwent an irrigation and debridement procedure. Sepsis was defined by the criteria for systemic inflammatory response syndrome (SIRS) or bacteria-positive blood culture results. Inclusion of patients with positive blood culture by organisms that caused their joint infection was important as all patients presented with fulminant acute infection of a prosthetic joint. Data, including vital signs, surgical variables, and treatment outcomes, were collected retrospectively through a chart review of an electronic medical record system. The statistical analysis comparing patients with sepsis versus patients without sepsis consisted of logistic regression to identify factors associated with sepsis. After confirming its ability to identify patients with a higher association with the development of sepsis through area under the curve models, a nomogram was generated to standardize our results from the regression, which was supported by the area under the curve model, to help readers better identify patients who are more likely to develop sepsis.

RESULTS

A total of 44% (103 of 236) of patients had infections that met the criteria for sepsis. After controlling for confounding variables, including congestive heart failure, anemia, serum C-reactive protein (CRP), and the male sex, it was revealed that serum CRP (odds ratio 1.07 [95% confidence interval 1.04 to 1.11]; p < 0.001) and male sex (OR 1.96 [95% CI 1.03 to 3.81]; p = 0.04) were associated with the development of systemic sepsis. For patients presenting with sepsis, persistent or recurrent PJI were associated with an increased CRP level (OR 1.06 [95% CI 1.02 to 1.11]; p = 0.01) and number of prior surgical procedures on the joint (OR 2.30 [95% CI 1.21 to 4.89]; p = 0.02).

CONCLUSION

Overall, our findings support that patients with systematic sepsis may benefit from two-stage revision rather than DAIR to decrease the bioburden more effectively, especially in those with methicillin-resistant Staphylococcus aureus and polymicrobial infections. High serum CRP levels and a history of prior surgical procedures on the involved joint should trigger prompt, aggressive surgical treatment if the patient's overall clinical status can tolerate such an intervention.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Outcome and Predictors of Septic Failure Following Total Joint Arthroplasty for Prior Septic Arthritis of Hip and Knee Joint

BACKGROUND

Arthroplasty patients with prior septic arthritis are at a high risk of developing periprosthetic joint infection (PJI). The aims of this study are to investigate the outcome and predictors of septic failure following total joint arthroplasty (TJA) for prior septic arthritis. In addition, the optimal timing of TJA is also discussed.

METHODS

A retrospective review of 105 TJA patients with prior septic arthritis between January 2000 and December 2019 was performed. Patient-specific and surgery-related factors, organism profiles, and other relevant variables were recorded.

RESULTS

At a mean follow-up of 10.3 years, the PJI rate was 16.2%. The adjusted Cox proportional hazards model showed that male gender (HR, 9.95; P < .01), end-stage renal disease (HR, 37.34; P < .01), debridement surgery ≥3 times (HR,4.75; P = .04) and polymicrobial infection in primary septic arthritis (HR, 10.02; P = .02) were independent risk factors for PJI. Neither the types of initial debridement, nor one-stage vs two-stage arthroplasty was related to the risk of PJI. While delaying the timing of TJA did not correlate with a reduction of PJI rate, there was a higher risk of PJI re-infection by the same microorganisms isolated in prior septic arthritis if TJA was performed within 6 months after septic arthritis.

CONCLUSIONS

Our study demonstrated that male gender, end-stage renal disease (ESRD), multiple debridement surgeries and polymicrobial septic arthritis predisposed septic failure of TJA following prior septic arthritis. Surgeons should counsel patients with the potential complications, and be cognizant about the risk factors pertaining to septic failure when considering TJA.

Intra-Articular Corticosteroid or Hyaluronic Acid Injections Are Not Associated with Periprosthetic Joint Infection Risk following Total Knee Arthroplasty

This study evaluated whether the preoperative use and timing of the use of hyaluronic acid (HA) and/or corticosteroid (CS) injections were associated with an increased risk of periprosthetic joint infections (PJIs) following primary total knee arthroplasty (TKA). We tested the hypothesis that preoperative injection of HA or CS within 3 months prior to primary TKA was associated with an increased risk of PJI by specifically evaluating the association between PJI risk and (1) injection type; (2) timing; (3) patient demographic factors; and (4) surgery-related factors, such as surgeon injection volume, knee arthroscopy (pre- and postoperative), and hospital length of stay. The 5% Medicare part B claims database was queried for patients who received CS and/or HA injections. Cox proportional hazards regressions evaluated the risk of PJIs after TKA, adjusting for patient and clinical factors, as well as propensity scores. The unadjusted incidence of PJI at 2-year post-TKA was 0.75% for the CS group, 0.89% for the HA group, 0.96% for both CS and HA group, and 0.75% for those who did not use HA or CS in the 12 months before TKA. For patients who used HA and/or CS within 3 months prior to TKA, the unadjusted incidence of PJI at 2-year post-TKA was 0.75% for the CS group, 1.07% for the HA group, and 1.00% for both CS and HA group, compared with 0.77% for those who did not use HA or CS. The number of injections performed per year was inconsistently associated with PJI risk. Overall, we found that intra-articular injections given within the 4-month period prior to TKA were not associated with elevated PJI risk (evaluated at 1, 3, 12, and 24 months after the index TKA) within the elderly Medicare patient population.

Has modern human immunodeficiency virus therapy decreased complications following total knee arthroplasty?

BACKGROUND

Anti-retroviral therapy (ART) remains the cornerstone of decreasing morbidity and mortality in human immunodeficiency virus (HIV) patients. However, a large study comparing HIV patients taking ART prior to total knee arthroplasty (TKA) is lacking. We sought to examine: (1) readmissions; (2) post-operative complications; and (3) revisions in ART-treated or untreated HIV patients compared with a non-HIV population.

METHODS

We queried a national, all-payer database to identify TKA patients from 2010-2020 (n = 1,393,357). The presence or absence of ART was identified and matched with non-HIV patients based on age, sex, diabetes, obesity, and tobacco status resulting in 889 patients in each cohort. Readmissions, post-operative complications, and revisions were assessed.

RESULTS

Readmissions were higher among all HIV patients and even higher in those not taking ART, as compared to the matching cohort (4.8 versus 1.6%, p < 0.01). Prosthetic joint infections (PJIs) at 1-year were higher among HIV patients who were either taking ART (4.0%; OR, 1.41 [0.82-2.45]) or not taking ART (5.1%; OR, 2.44 [1.42-4.21]) as compared to non-HIV patients (2.1%, all p < 0.03). Revision rates at 1-year trended higher in HIV patients who were taking ART (2.6%; Odds Ratio (OR), 1.94 [0.96-3.93]) and who did not take ART (3.1%; OR, 2.38 [1.20-4.70]), compared to non-HIV patients (1.3%, all p < 0.09).

CONCLUSIONS

ART-treated HIV patients are associated with lower readmissions, post-operative complications, and revisions when compared to HIV patients not taking ART. The findings of this study underscore the utility of ART and patient optimization to reduce risk in HIV patients.

Cumulative Intraarticular Injections Are Not a Risk Factor for Periprosthetic Joint Infection Following total Knee Arthroplasty

BACKGROUND

While injections within 90 days prior to total knee arthroplasty (TKA) are associated with an increased risk of periprosthetic joint infection (PJI), there is a paucity of literature regarding the impact of cumulative injections on PJI risk. This study was conducted to assess the association between cumulative corticosteroid and hyaluronic acid (HA) injections and PJI risk following TKA.

METHODS

This retrospective study using an injection database included patients undergoing TKA with a minimum 1-year follow-up from 2015 to 2020. Patients with injections within 90 days prior to surgery were excluded. The sum of corticosteroid and HA injections within five years prior to TKA was recorded. The primary outcome was PJI within 90 days following TKA. Area under the curve (AUC) values were calculated for a cumulative number of injections.

RESULTS

648 knees with no injections and 672 knees with injections prior to TKA were included, among whom 243 received corticosteroids, 151 received HA, and 278 received both. No significant differences in early PJI rates existed between patients who received injections (0.60%) or not (0.93%) (P = .541). No significant differences existed in early PJI rates between patients injected with corticosteroids (0.82%), HA (0.66%), or both (0.36%) (P = .832). No cutoff number of injections was predictive for PJI.

DISCUSSION

A cumulative amount of steroid or HA injections, if given more than 90 days prior to TKA, does not appear to increase the risk of PJI within 90 days postoperatively. Multiple intraarticular corticosteroid injections and HA injections may be safely administered before TKA, without increased risk for early PJI.

Is sonication superior to dithiothreitol in diagnosis of periprosthetic joint infections? A meta-analysis

PURPOSE

Even though effective techniques in diagnosis of periprosthetic joint infections (PJIs) have been developed, the optimal modality has yet to be determined. The present meta-analysis aimed to compare the diagnostic accuracy of dithiothreitol (DTT) and sonication against the Musculoskeletal Infection Society criteria in patients undergoing revision joint surgery.

METHODS

We searched the PubMed, Scopus, and Central Cochrane register of controlled trials as well as gray literature until the 9th of November, 2021. We included articles considering the comparative diagnostic accuracy of sonication and DTT in adult patients having revision hip and knee arthroplasty for septic or aseptic reasons. We calculated pooled sensitivity, specificity, and diagnostic accuracy of the above diagnostic techniques against the Musculoskeletal Infection Society (MSIS) criteria and created receiver operating characteristics (ROC) curves to enable comparisons between each other. The quality of included papers was evaluated utilizing QUADAS-2 and QUADAS-C tools.

RESULTS

Data from five comparative studies totaling 726 implants were pooled together. The diagnostic accuracy of DTT and sonication were 86.7% (95% CI 82.7 to 90.1) and 83.9% (95% CI 79.7 to 87.5), respectively. Pooled sensitivity and specificity showed no statistically significant differences between DTT and sonication (0.7 [95% CI 0.62 to 0.77] vs 0.72 [95% CI 0.65 to 0.78], p = 0.14; and 0.99 [95% CI 0.97 to 1] vs 0.97 [95% CI 0.93 to 0.99], p = 5.5, respectively).

CONCLUSIONS

This meta-analysis did not identify any clinically meaningful difference between the diagnostic potential of sonication and the chemical-based biofilm dislodgment methods. This finding remained robust after adjusting for the administration of antibiotics prophylaxis, implementation of the polymerase chain reaction of sonicated fluid, and study quality.

An Evaluation of the Effect of the Use of N95 Respirators by Surgical Teams on Early Surgical Site Infections in Orthopedic Cases

Background

Surgical site infections (SSIs) are seen in the postoperative period in orthopedic and traumatology clinics. Just as in all surgical clinics, SSIs lead to patient dissatisfaction with the results, prolong the length of stay in the hospital, and increase treatment costs. SSIs are known to occur as a result of wound contamination through inoculation of microorganisms found mainly in the air or in the surgical area. Because of the coronavirus disease 2019 pandemic, N95 masks have been widely used in the operating rooms of our hospital by nurses, residents, and surgeons since March 2020. This study aims to evaluate the effect of N95 respirator use by the surgical team on SSIs determined in patients operated on in our clinic compared to surgical mask use.

Methodology

In this retrospective study, the use of N95 respirators by the surgical team was compared with the use of surgical masks to evaluate the effect on SSIs in patients operated on in our clinic. Two groups were formed of patients operated on by the surgical team wearing surgical masks between February 2019 and February 2020 and those operated on with the surgical team using N95 respirators between March 2020 and March 2021. Each patient was diagnosed with postoperative SSIs by two different surgeons in the same clinic and by an infection clinic specialist based on clinical and laboratory findings.

Results

A total of 1,486 patients were examined; 729 patients in February 2019-February 2020 period (Group 1) and 757 in March 2020-March 2021 period (Group 2). In total, 124 and 104 patients were excluded from the first and second groups, respectively, for various reasons, including revision surgery, open fractures, diabetes, smoking, peripheral vascular disease, or other comorbidities that could affect infection rates. SSIs were determined in 35 patients in Group 1 and 13 patients in Group 2. The SSI rates in the second period in both types of procedures (arthroplasty and trauma surgeries) were determined to be significantly lower.

Conclusions

Because of the use of intraoperative N95 respiratory masks by surgical teams in orthopedics and traumatology procedures, the number of SSIs decreased significantly compared to the use of surgical masks.

Prediction of Early Periprosthetic Joint Infection After Total Hip Arthroplasty

Purpose

To develop a parsimonious risk prediction model for periprosthetic joint infection (PJI) within 90 days after total hip arthroplasty (THA).

Patients and Methods

We used logistic LASSO regression with bootstrap ranking to develop a risk prediction model for PJI within 90 days based on a Swedish cohort of 88,830 patients with elective THA 2008–2015. The model was externally validated on a Danish cohort with 18,854 patients.

Results

Incidence of PJI was 2.45% in Sweden and 2.17% in Denmark. A model with the underlying diagnosis for THA, body mass index (BMI), American Society for Anesthesiologists (ASA) class, sex, age, and the presence of five defined comorbidities had an area under the curve (AUC) of 0.68 (95% CI: 0.66 to 0.69) in Sweden and 0.66 (95% CI: 0.64 to 0.69) in Denmark. This was superior to traditional models based on ASA class, Charlson, Elixhauser, or the Rx Risk V comorbidity indices. Internal calibration was good for predicted probabilities up to 10%.

Conclusion

A new PJI prediction model based on easily accessible data available before THA was developed and externally validated. The model had superior discriminatory ability compared to ASA class alone or more complex comorbidity indices and had good calibration. We provide a web-based calculator (https://erikbulow.shinyapps.io/thamortpred/) to facilitate shared decision making by patients and surgeons.

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Outcome and technical consideration of conversion total hip arthroplasty after failed fixation of intracapsular and extracapsular hip fractures: Are they really that different?

INTRODUCTION

Conversion Total Hip Arthroplasty (cTHA) is a rescue strategy for proximal femur osteosynthesis failures. However, it is unclear whether cTHAs performed for extra-capsular fracture fixation failures (ECF) or for intra-capsular fracture fixation failures (ICF) share the same complexity and efficacy. The purpose of our study was to compare cTHAs performed on pre-existing ICFs and pre-existing ECFs, focusing on surgical complications and functional outcomes in both groups.

METHODS

An observational retrospective study was conducted on cTHA patients, treated between 2014 and 2018, divided into 2 groups: ICF-group and ECF-group. The main outcomes were: type of implant used, duration of surgery, need for transfusions, incidence of complications, functional outcomes.

RESULTS

28 patients were included (15 in the ECF group and 13 in the ICF group); the average follow-up was of 31 ± 17.3 months. No significant differences were identified in terms of the type of implant used and duration of surgery. The number of transfused patients was 4 in the ICF group and 12 in the ECF group (p = 0.02); the average transfused units were 0.4 ± 0.7 in the ICF group and 1.3 ± 0.9 in the ECF group (p = 0.01). The incidence of complications - an infection and a dislocation, both of which occurred in the ICF group - and functional outcomes did not present significant differences.

CONCLUSION

The conversion surgery on ECFs patients is technically more difficult for the surgeon and prone to greater blood loss. The outcomes are satisfactory and overlap between the two groups.

Obesity, Comorbidities, and Prior Operations Additively Increase Failure in 2-Stage Revision Total Knee Arthroplasty for Prosthetic Joint Infection

BACKGROUND

Prosthetic joint infection (PJI) of the knee carries significant morbidity, mortality, and economic cost. We hypothesize that obese and poor medical hosts will have a significant and additive increase in failure rate undergoing 2-stage revision total knee arthroplasty for PJI.

METHODS

All 2-stage revision total knee arthroplasty procedures for PJI performed at one institution were identified between 2005 and 2020. In total, 144 patients were included and defined as success or failure based on published criteria regarding infection eradication, further intervention, or mortality. The American Society of Anesthesiologists score and the Charlson Comorbidity Index were utilized to assess host grade. Patient, surgical, and microbiologic variables were investigated with univariable and multivariable analysis to explore association with risk of failure.

RESULTS

In the cohort, 32.4% of patients failed with mean follow-up of 5.1 years. In multivariable analysis, the number of major operations requiring arthrotomy and implantation of new material between the primary and first stage, host grade, and elevated body mass index were the major contributors to failure. Combining these factors, with body mass index >30 and 2 or more major operations, the failure rate increased to 76.5% and 71.4% respectively for American Society of Anesthesiologists score 3 (P ≤ .001) and Charlson Comorbidity Index ≥2 (P ≤ .001).

CONCLUSION

In this cohort, multiple major operations between the primary and first stage, host grade, and obesity were the major contributors to failure. When combining these factors, patients had an additive increase in failure rate. Treatments such as amputation or less invasive options and suppression should be discussed and considered in these patients.

Revision Risk in a Cohort of US Patients Younger Than 55 Undergoing Primary Elective Total Hip Arthroplasty

BACKGROUND

As indications for elective total hip arthroplasty (THA) expand to younger patients, we sought to (1) compare revision risk following primary elective THA in patients <55 years at the time of their THA to patients aged ≥65 years and (2) identify specific risk factors for revision in patients <55 years.

METHODS

A Kaiser Permanente's total joint replacement registry was used to conduct a cohort study including primary elective THA patients aged ≥18 (2001-2018). In total, 11,671 patients <55 years and 53,106 patients ≥65 years were included. Multiple Cox regression was used to evaluate cause-specific revision risk, including septic revision, aseptic loosening, instability, and periprosthetic fracture. Stepwise Cox regression was used to identify patient and surgical factors associated with cause-specific revision in patients <55 years.

RESULTS

Patients <55 years had a higher risk of septic revision (hazard ratio [HR] = 1.30, 95% confidence interval [CI] = 1.02-1.66), aseptic loosening (HR = 2.60, 95% CI = 1.99-3.40), and instability (HR = 1.35, 95% CI = 1.09-1.68), but a lower risk of revision for periprosthetic fracture (HR = 0.36, 95% CI = 0.22-0.59) compared to patients aged ≥65 years. In the <55 age group, risk factors for septic revision included higher body mass index, drug abuse, and liver disease. Hypertension, anterior approach, and ceramic-on-ceramic were associated with aseptic loosening. White race, American Society of Anesthesiologists classification ≥3, smoker, paralysis, posterior approach, ceramic-on-ceramic, and smaller head diameter were associated with instability.

CONCLUSION

Identified risk factors varied depending on the cause for revision. Although septic revisions were related to patient characteristics, more modifiable factors, such as implant or surgical approach, were associated with revision due to aseptic loosening and instability.

LEVEL OF EVIDENCE

III.

The Use of Artificial Neural Networks for the Prediction of Surgical Site Infection Following TKA

This is a retrospective study. Surgical site infection (SSI) is associated with adverse postoperative outcomes following total knee arthroplasty (TKA). However, accurately predicting SSI remains a clinical challenge due to the multitude of patient and surgical factors associated with SSI. This study aimed to develop and validate machine learning models for the prediction of SSI following primary TKA. This is a retrospective study for patients who underwent primary TKA. Chart review was performed to identify patients with superficial or deep SSIs, defined in concordance with the criteria of the Musculoskeletal Infection Society. All patients had a minimum follow-up of 2 years (range: 2.1-4.7 years). Five machine learning algorithms were developed to predict this outcome, and model assessment was performed by discrimination, calibration, and decision curve analysis. A total of 10,021 consecutive primary TKA patients was included in this study. At an average follow-up of 2.8 ± 1.1 years, SSIs were reported in 404 (4.0%) TKA patients, including 223 superficial SSIs and 181 deep SSIs. The neural network model achieved the best performance across discrimination (area under the receiver operating characteristic curve = 0.84), calibration, and decision curve analysis. The strongest predictors of the occurrence of SSI following primary TKA, in order, were Charlson comorbidity index, obesity (BMI >30 kg/m²), and smoking. The neural network model presented in this study represents an accurate method to predict patient-specific superficial and deep SSIs following primary TKA, which may be employed to assist in clinical decision-making to optimize outcomes in at-risk patients.

Reasons for failure of total temporomandibular joint replacement: a systematic review and meta-analysis

The aim of this study was to evaluate the revision rate after total alloplastic temporomandibular joint replacement (TMJR) and determine whether there is a higher risk of revision surgery with stock or custom-fitted prostheses (the two most current TMJR prosthesis types). A systematic review was performed, with a search of PubMed, Google Scholar, and the Cochrane Library in November 2020. Overall, 27 articles were included in this study, describing Biomet and TMJ Concepts prostheses and including postoperative data on complications requiring a return to the operating room. A total of 2247 prostheses were analysed: 1350 stock Biomet prostheses and 897 custom-fitted TMJ Concepts and custom-fitted Biomet prostheses. The global revision rate was 1.19 per 100 prosthesis-years. The most common reason for revision was heterotopic bone formation. Stock prostheses appeared to have a lower risk of revision compared to custom prostheses: rate ratio 0.52 (95% confidence interval 0.33-0.81, P-value 0.003). Regarding causes of revision, the only significant difference between the types of devices was a higher rate of heterotopic bone formation for custom-made prostheses (P = 0.001). The results of this study revealed a low revision rate post TMJR revision, with stock devices even less prone to such risk. Nevertheless, these results can be explained by the fact that custom-made prostheses are more likely to be used for cases in which the anatomy is significantly abnormal or there is a history of multiple joint surgeries, which carry a greater risk of complications and heterotopic bone formation.

Assessment of risk factors for early-onset deep surgical site infection following primary total hip arthroplasty for osteoarthritis

The aim of this study was to determine the incidence, annual trend, and perioperative outcomes and identify risk factors of early-onset (≤90 d) deep surgical site infection (SSI) following primary total hip arthroplasty (THA) for osteoarthritis. We performed a retrospective study using prospectively collected patient-level data from January 2013 to March 2020. The diagnosis of deep SSI was based on the published Centre for Disease Control/National Healthcare Safety Network (CDC/NHSN) definition. The Mann–Kendall trend test was used to detect monotonic trends. Secondary outcomes were 90 d mortality and 90 d readmission. A total of 22 685 patients underwent primary THA for osteoarthritis. A total of 46 patients had a confirmed deep SSI within 90 d of surgery representing a cumulative incidence of 0.2 %. The annual infection rate decreased over the 7-year study period (p=0.026). Risk analysis was performed on 15 466 patients. Risk factors associated with early-onset deep SSI included a BMI > 30 kg m-2 (odds ratio (OR) 3.42 [95 % CI 1.75–7.20]; p<0.001), chronic renal disease (OR, 3.52 [95 % CI 1.17–8.59]; p=0.011), and cardiac illness (OR, 2.47 [1.30–4.69]; p=0.005), as classified by the Canadian Institute for Health Information. Early-onset deep SSI was not associated with 90 d mortality (p=0.167) but was associated with an increased chance of 90 d readmission (p<0.001). This study establishes a reliable baseline infection rate for early-onset deep SSI after THA for osteoarthritis through the use of a robust methodological process. Several risk factors for early-onset deep SSI are potentially modifiable, and therefore targeted preoperative interventions of patients with these risk factors is encouraged.

History of previous surgery is associated with higher risk of revision after primary total knee arthroplasty: a cohort study from the Geneva Arthroplasty Registry

Background and purpose - Prior to primary total knee arthroplasty (pTKA), 6-34% of patients have undergone surgical procedure(s) of their knee. We investigated whether history of previous surgeries influences the risk of revision of pTKA, the risk according to the type of previous surgery, and how previous surgery influences specific causes of revision and the time of revision.Patients and methods - This is a prospective cohort study from the Geneva Arthroplasty Registry. All pTKA between 2000 and 2016 were included and followed until December 31, 2019. Outcomes were risk of revision, evaluated using Kaplan-Meier survival and Cox and competing risks regression, the specific causes, and time of revision.Results - Of 3,945 pTKA included (mean age 71 years, 68% women), 21% had a history of previous surgery, with 8.3% revisions vs. 4.3%, at 3-20 years' follow-up (mean 8.6). 5- and 10-year cumulative failure by previous surgery (yes vs. no) were 6.6% (95% CI 5.1-8.5) vs. 3.3% (CI 2.7-4.0), and 8.4% (CI 6.6-10.6) vs. 4.5% (CI 3.8-5.4). Baseline differences explained only part of the higher risk (adjusted HR 1.5, CI 1.1-2.1). The risk of failure was higher for all causes of revision considered. Patients in the previous surgery group had a higher risk of an early revision.Interpretation - A history of previous surgery adversely affected the outcome with a 1.5 times higher cumulative risk of all-cause revision over the course of up to 20 years after index surgery. The increased risk was seen for all causes of revision and was highest in the first years.

The mildly decreased preoperative bilirubin level is a risk factor for periprosthetic joint infection after total hip and knee arthroplasty

BACKGROUND

Many serologic markers are routinely tested prior to joint arthroplasty, but only few are commonly used to guide surgeons in determining patients most at risk of periprosthetic joint infection (PJI). The objective of this study was to investigate the association between preoperative bilirubin level and PJI after primary hip and knee arthroplasty.

METHODS

A retrospective analysis was performed on patients undergoing revision hip and knee arthroplasty at our hospital from January 2016 to December 2019. Laboratory biomarkers were collected before the primary arthroplasty, as well as general patient information. The association between the above serologic markers and postoperative PJI was analyzed.

RESULTS

A total of 72 patients (30 hips/42 knees) were analyzed, including 39 patients with PJI and 33 patients without PJI. Except for total bilirubin (TB) and direct bilirubin (DB), there was no significant difference between the remaining laboratory biomarkers. The preoperative TB and DB in the PJI group were 10.84 ± 0.61 μmol/L and 3.07 ± 0.19 μmol/L, respectively, which were lower than those in the non-PJI group (14.68 ± 0.75 μmol/L and 4.70 ± 0.39 μmol/L, P < 0.001). The area under the curve (AUC) of preoperative TB to predict PJI was 0.755 (P < 0.001, cutoff = 11.55 μmol/L, sensitivity = 66.67%, specificity = 75.76%). Meanwhile, the AUC of preoperative DB was 0.760 (P < 0.001, cutoff = 4.00 μmol/L, sensitivity = 84.62%, specificity = 54.45%).

CONCLUSIONS

The serum levels of TB and DB before the primary arthroplasty were lower in PJI patients than in non-PJI patients, and the preoperative values lower than 11.55 μmol/L and 4.00 μmol/L could be considered as a risk factor for postoperative PJI.

Antibiotics- and Heavy Metals-Based Titanium Alloy Surface Modifications for Local Prosthetic Joint Infections

Prosthetic joint infection (PJI) is the second most common cause of arthroplasty failure. Though infrequent, it is one of the most devastating complications since it is associated with great personal cost for the patient and a high economic burden for health systems. Due to the high number of patients that will eventually receive a prosthesis, PJI incidence is increasing exponentially. As these infections are provoked by microorganisms, mainly bacteria, and as such can develop a biofilm, which is in turn resistant to both antibiotics and the immune system, prevention is the ideal approach. However, conventional preventative strategies seem to have reached their limit. Novel prevention strategies fall within two broad categories: (1) antibiotic- and (2) heavy metal-based surface modifications of titanium alloy prostheses. This review examines research on the most relevant titanium alloy surface modifications that use antibiotics to locally prevent primary PJI.

Therapeutic assessment of N-formyl-methionyl-leucyl-phenylalanine (fMLP) in reducing periprosthetic joint infection

Despite many preventive measures, including prophylactic antibiotics, periprosthetic joint infection (PJI) remains a devastating complication following arthroplasty, leading to pain, suffering, morbidity and substantial economic burden. Humans have a powerful innate immune system that can effectively control infections, if alerted quickly. Unfortunately, pathogens use many mechanisms to dampen innate immune responses. The study hypothesis was that immunomodulators that can jumpstart and direct innate immune responses (particularly neutrophils) at the surgical site of implant placement would boost immune responses and reduce PJI, even in the absence of antibiotics. To test this hypothesis, N-formyl-methionyl-leucyl-phenylalanine (fMLP) (a potent chemoattractant for phagocytic leukocytes including neutrophils) was used in a mouse model of PJI with Staphylococcus aureus (S. aureus). Mice receiving intramedullary femoral implants were divided into three groups: i) implant alone; ii) implant + S. aureus; iii) implant + fMLP + S. aureus. fMLP treatment reduced S. aureus infection levels by ~ 2-Log orders at day 3. Moreover, fMLP therapy reduced infection-induced peri-implant periosteal reaction, focal cortical loss and areas of inflammatory infiltrate in mice distal femora at day 10. Finally, fMLP treatment reduced pain behaviour and increased weight-bearing at the implant leg in infected mice at day 10. Data indicated that fMLP therapy is a promising novel approach for reducing PJI, if administered locally at surgical sites. Future work will be toward further enhancement and optimisation of an fMLP-based therapeutic approach through combination with antibiotics and/or implant coating with fMLP.

External Validation Demonstrates Limited Clinical Utility of a Preoperative Prognostic Calculator for Periprosthetic Joint Infection

BACKGROUND

Preoperative calculation of treatment failure risk in patients undergoing surgery for periprosthetic joint infection (PJI) is imperative to allow for medical optimization and targeted prevention. A preoperative prognostic model for PJI treatment failure was previously developed, and this study sought to externally validate the model.

METHODS

A retrospective review was performed of 380 PJIs treated at two institutions. The model was used to calculate the risk of treatment failure, and receiver operating characteristic curves were generated to calculate the area under the curve (AUC) for each institution.

RESULTS

When applying this model to institution 1, an AUC of 0.795 (95% confidence interval [CI]: 0.693-0.897) was found, whereas institution 2 had an AUC of 0.592 (95% CI: 0.502-0.683). Comparing all institutions in which the model had been applied to, we found institution 2 represented a significantly sicker population and different infection profile.

CONCLUSION

In this cohort study, we externally validated the prior published model for institution 1. However, institution 2 had a decreased AUC using the prior model and represented a sicker and less homogenous cohort compared with institution 1. When matching for chronicity of the infection, the AUC of the model was not affected. This study highlights the impact of comorbidities and their distributions on PJI prognosis and brings to question the clinical utility of the algorithm which requires further external validation.