Is a Rapid Recovery Protocol for THA and TKA Associated With Decreased 90-day Complications, Opioid Use, and Readmissions in a Health Safety-net Hospital?

BACKGROUND: Patients treated at a health safety-net hospital have increased medical complexity and social determinants of health that are associated with an increasing risk of complications after TKA and THA. Fast-track rapid recovery protocols (RRPs) are associated with reduced complications and length of stay in the general population; however, whether that is the case among patients who are socioeconomically disadvantaged in health safety-net hospitals remains poorly defined. QUESTIONS/PURPOSES: When an RRP protocol is implemented in a health safety-net hospital after TKA and THA: (1) Was there an associated change in complications, specifically infection, symptomatic deep venous thromboembolism (DVT), symptomatic pulmonary embolism (PE), myocardial infarction (MI), and mortality? (2) Was there an associated difference in inpatient opioid consumption? (3) Was there an associated difference in length of stay and 90-day readmission rate? (4) Was there an associated difference in discharge disposition? METHODS: An observational study with a historical control group was conducted in an urban, academic, tertiary-care health safety-net hospital. Between May 2022 and April 2023, an RRP consistent with current guidelines was implemented for patients undergoing TKA or THA for arthritis. We considered all patients aged 18 to 90 years presenting for primary TKA and THA as eligible. Based on these criteria, 562 patients with TKAs or THAs were eligible. Of these 33% (183) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 67% (379) for evaluation. Patients in the historical control group (September 2014 to May 2022) met the same criteria, and 2897 were eligible. Of these, 31% (904) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 69% (1993) for evaluation. The mean age in the historical control group was 61 ± 10 years and 63 ± 10 years in the RRP group. Both groups were 36% (725 of 1993 and 137 of 379) men. In the historical control group, 39% (770 of 1993) of patients were Black and 33% (658 of 1993) were White, compared with 38% (142 of 379) and 32% (121 of 379) in the RRP group, respectively. English was the most-spoken primary language, by 69% (1370 of 1993) and 68% (256 of 379) of the historical and RRP groups, respectively. A total of 65% (245 of 379) of patients in the RRP group had a peripheral nerve block compared with 54% (1070 of 1993) in the historical control group, and 39% (147 of 379) of them received spinal anesthesia, compared with 31% (615 of 1993) in the historical control group. The main elements of the RRP were standardization of preoperative visits, nutritional management, neuraxial anesthesia, accelerated physical therapy, and pain management. The primary outcomes were the proportions of patients with 90-day complications and opioid consumption. The secondary outcomes were length of stay, 90-day readmission, and discharge disposition. A multivariate analysis adjusting for age, BMI, gender, race, American Society of Anaesthesiologists class, and anesthesia type was performed by a staff biostatistician using R statistical programming. RESULTS: After controlling for the confounding variables as noted, patients in the RRP group had fewer complications after TKA than those in the historical control group (odds ratio 2.0 [95% confidence interval 1.3 to 3.3]; p = 0.005), and there was a trend toward fewer complications in THA (OR 1.8 [95% CI 1.0 to 3.5]; p = 0.06), decreased opioid consumption during admission (517 versus 676 morphine milligram equivalents; p = 0.004), decreased 90-day readmission (TKA: OR 1.9 [95% CI 1.3 to 2.9]; p = 0.002; THA: OR 2.0 [95% CI 1.6 to 3.8]; p = 0.03), and increased proportions of discharge to home (TKA: OR 2.4 [95% CI 1.6 to 3.6]; p = 0.01; THA: OR 2.5 [95% CI 1.5 to 4.6]; p = 0.002). Patients in the RRP group had no difference in the mean length of stay (TKA: 3.2 ± 2.6 days versus 3.1 ± 2.0 days; p = 0.64; THA: 3.2 ± 2.6 days versus 2.8 ± 1.9 days; p = 0.33). CONCLUSION: Surgeons should consider developing an RRP in health safety-net hospitals. Such protocols emphasize preparing patients for surgery and supporting them through the acute recovery phase. There are possible benefits of neuraxial and nonopioid perioperative anesthesia, with emphasis on early mobility, which should be further characterized in comparative studies. Continued analysis of opioid use trends after discharge would be a future area of interest. Analysis of RRPs with expanded inclusion criteria should be undertaken to better understand the role of these protocols in patients who undergo revision TKA and THA. LEVEL OF EVIDENCE: Level III, therapeutic study.

The Pregnant Arthroplasty Surgeon: A Women in Arthroplasty Committee Editorial.

BACKGROUND: Women orthopaedic surgeons face unique challenges during their careers. There are extremely low numbers of women in the field, particularly in the specialty of adult reconstruction. Factors contributing to low numbers of women entering this subspecialty include increased perceived physical demand relative to other fields, occupational hazards during pregnancy such as exposure to radiation and polymethylmethacrylate bone cement, concerns for work-life balance, and limited number of women within the subspecialty. The following editorial provides a framework to understand and manage the potential occupational hazards to pregnant and lactating surgeons, parental leave, and postpartum return to work. We aim to dispel any unfounded myths and provide evidence-based education that may help overcome these barriers. In doing so, we hope to encourage more women to consider adult reconstruction as a potential career. METHODS: Our primary method consisted of completing an extensive literature review on the past and current articles about the aforementioned barriers which may contribute to the low number of women entering adult reconstruction. After this literature search was completed, we composed a comprehensive editorial that provided evidence-based education and recommendations for medical professionals. CONCLUSIONS: Issues pertaining to parenthood, pregnancy, and lactation pose barriers to success for women in orthopedic surgery. These concerns may dissuade talented women from pursuing a rewarding career in adult reconstruction. Education on these issues is needed to help our early-career colleagues plan and care for their families. Clearly stated and published policies should be made available in all training programs, fellowships, and clinical practices to allow understanding and unbiased implementation. By being more inclusive, adult reconstruction will have access to the best possible surgeons, which will benefit not only patients but the field as a whole.

New CMS Merit-Based Incentive Payment System Value Pathway After Total Knee and Hip Arthroplasty: Preparing for Mandatory Reporting.

This article discusses the implementation of a new Merit-Based Incentive Payment System Value Pathway (MVPs) applicable to elective total hip and total knee arthroplasty as created by Medicare and Medicaid Services (CMS) - the Improving Care for Lower Extremity Joint Repair MVP (MVP ID: G0058). We describe specific quality measures, surgeon-hospital collaborations, future developments with Quality Payment Program, and how lessons from early implementation will empower clinicians to participate in the refining of this MVP. The CMS has designed MVPs as a subset of measures relevant to a specialty or medical condition, in an effort to reduce the burden of reporting and improve assessment of care quality. Physicians and payors must be mindful of detrimental effects these measures in their current form may have on surgeons, institutions, and patients, including disincentivizing care for sicker or more vulnerable populations, and increased administrative costs. Early voluntary participation is crucial to gain valuable experience for the orthopedic community and in an effort to work alongside CMS to maximize care while minimizing cost for patients and burden for providers.

Patterns and Persistence of Perioperative Plasma and Cerebrospinal Fluid Neuroinflammatory Protein Biomarkers After Elective Orthopedic Surgery Using SOMAscan.

BACKGROUND: The neuroinflammatory response to surgery can be characterized by peripheral acute plasma protein changes in blood, but corresponding, persisting alterations in cerebrospinal fluid (CSF) proteins remain mostly unknown. Using the SOMAscan assay, we define acute and longer-term proteome changes associated with surgery in plasma and CSF. We hypothesized that biological pathways identified by these proteins would be in the categories of neuroinflammation and neuronal function and define neuroinflammatory proteome changes associated with surgery in older patients. METHODS: SOMAscan analyzed 1305 proteins in blood plasma (n = 14) and CSF (n = 15) samples from older patients enrolled in the Role of Inflammation after Surgery for Elders (RISE) study undergoing elective hip and knee replacement surgery with spinal anesthesia. Systems biology analysis identified biological pathways enriched among the surgery-associated differentially expressed proteins in plasma and CSF. RESULTS: Comparison of postoperative day 1 (POD1) to preoperative (PREOP) plasma protein levels identified 343 proteins with postsurgical changes ( P < .05; absolute value of the fold change [|FC|] > 1.2). Comparing postoperative 1-month (PO1MO) plasma and CSF with PREOP identified 67 proteins in plasma and 79 proteins in CSF with altered levels ( P < .05; |FC| > 1.2). In plasma, 21 proteins, primarily linked to immune response and inflammation, were similarly changed at POD1 and PO1MO. Comparison of plasma to CSF at PO1MO identified 8 shared proteins. Comparison of plasma at POD1 to CSF at PO1MO identified a larger number, 15 proteins in common, most of which are regulated by interleukin-6 (IL-6) or transforming growth factor beta-1 (TGFB1) and linked to the inflammatory response. Of the 79 CSF PO1MO-specific proteins, many are involved in neuronal function and neuroinflammation. CONCLUSIONS: SOMAscan can characterize both short- and long-term surgery-induced protein alterations in plasma and CSF. Acute plasma protein changes at POD1 parallel changes in PO1MO CSF and suggest 15 potential biomarkers for longer-term neuroinflammation that warrant further investigation.

Use of a Smart-Phone Mobile Application is Associated With Improved Compliance and Reduced Length of Stay in Patients Undergoing Primary Total Joint Arthroplasty of the Hip and Knee.

BACKGROUND: Patient compliance with perioperative protocols is paramount to improving outcomes and reducing adverse events in total joint arthroplasty (TJA) of the hip and knee. Given the widespread use of smartphones, mobile applications (MAs) may present an opportunity to improve outcomes in TJA. We aim to determine whether the use of a mobile application platform improves compliance with standardized pre-operative protocols and outcomes in TJA. METHODS: A non-randomized, prospective cohort study was conducted in adult patients undergoing primary elective TJA to determine whether the use of an MA with timed reminders starting 5 days pre-operatively, to perform a chlorhexidine gluconate (CHG) shower and oral hydration protocol improves compliance with these protocols. OUTCOME MEASURES: compliance, length of stay (LOS), surgical site infection (SSI), 90-day readmission. RESULTS: App-users had increased adherence to the hydration protocol (odds ratio [OR] = 3.17 [95% confidence interval {CI} = 1.42, 7.09: P = .003]). App-use was associated with shorter LOS (Median Interquartile ranges [IQR] 2.0 days [1.0, 2.0 days]) for App-users vs 2.0 days ([1.0, 3.0] for non-App users, P = .031), younger age, (63.3 vs 67.9 years, P = .0001), Caucasian race (OR = 3.32 [95% CI = 1.59, 6.94 P = .0009]) and male gender (48.2% vs 35.0%, P = .02). There was no difference in adherence to chlorhexidine gluconate (CHG), readmission, or surgical site infection (SSI) (2.2% App-users vs 2.9% non-App users; P = .74). CONCLUSION: Use of a mobile application was associated with increased compliance with a hydration protocol and reduced LOS. App-users were more likely to be younger, male and Caucasian. These disparities may reflect inequity of access to the requisite technology and warrant further study.

Machine Learning to Develop and Internally Validate a Predictive Model for Post-operative Delirium in a Prospective, Observational Clinical Cohort Study of Older Surgical Patients.

BACKGROUND: Our objective was to assess the performance of machine learning methods to predict post-operative delirium using a prospective clinical cohort. METHODS: We analyzed data from an observational cohort study of 560 older adults (≥ 70 years) without dementia undergoing major elective non-cardiac surgery. Post-operative delirium was determined by the Confusion Assessment Method supplemented by a medical chart review (N = 134, 24%). Five machine learning algorithms and a standard stepwise logistic regression model were developed in a training sample (80% of participants) and evaluated in the remaining hold-out testing sample. We evaluated three overlapping feature sets, restricted to variables that are readily available or minimally burdensome to collect in clinical settings, including interview and medical record data. A large feature set included 71 potential predictors. A smaller set of 18 features was selected by an expert panel using a consensus process, and this smaller feature set was considered with and without a measure of pre-operative mental status. RESULTS: The area under the receiver operating characteristic curve (AUC) was higher in the large feature set conditions (range of AUC, 0.62-0.71 across algorithms) versus the selected feature set conditions (AUC range, 0.53-0.57). The restricted feature set with mental status had intermediate AUC values (range, 0.53-0.68). In the full feature set condition, algorithms such as gradient boosting, cross-validated logistic regression, and neural network (AUC = 0.71, 95% CI 0.58-0.83) were comparable with a model developed using traditional stepwise logistic regression (AUC = 0.69, 95% CI 0.57-0.82). Calibration for all models and feature sets was poor. CONCLUSIONS: We developed machine learning prediction models for post-operative delirium that performed better than chance and are comparable with traditional stepwise logistic regression. Delirium proved to be a phenotype that was difficult to predict with appreciable accuracy.

No Difference Between Hemiarthroplasty and Total Hip Arthroplasty in the Treatment of Pathologic Femoral Neck Fractures.

BACKGROUND: Hemiarthroplasty (HA) and total hip arthroplasty (THA) have been widely discussed as treatment options for displaced osteoporotic femoral neck fractures. Pathologic femoral neck fractures from primary or metastatic tumors are comparatively rare and poorly investigated. The purpose of this study was to compare outcomes, complications, and perioperative survival for HA and THA in the treatment of pathologic femoral neck fractures of neoplastic etiology. METHODS: A multicenter retrospective cohort study identified patients with pathologic femoral neck fractures treated with HA or THA from 2005 to 2018. Demographics, American Society of Anesthesiologists classification, Charlson comorbidity index, Dorr classification, histopathologic diagnosis, and surgical data were compared. The primary outcome was reoperation. Secondary outcomes included 90-day mortality, estimated blood loss, length of stay, periprosthetic fracture, periprosthetic joint infection, and Eastern Cooperative Oncology Group performance status. RESULTS: There were 116 patients with HA and 48 patients with THA, with no differences between groups with regard to American Society of Anesthesiologists classification, Charlson comorbidity index, or Dorr classification. There were no differences between HA and THA in the primary outcome of reoperation (5.2% vs 4.2%, P = 1.00) or secondary outcomes of perioperative 90-day overall mortality (30.2% vs 25.0%, P = .51), estimated blood loss, transfusion rates, length of stay, discharge location, periprosthetic joint infection, periprosthetic fracture, or preoperative or postoperative Eastern Cooperative Oncology Group performance status. CONCLUSIONS: Both HA and THA are viable options for the treatment of patients with pathologic femoral neck fractures and demonstrated no differences in reoperations, complications, perioperative 90-day mortality, or functional outcome scores. LEVEL OF EVIDENCE: Level III.

Mobile Application Use and Patient Engagement in Total Hip and Knee Arthroplasty.

¼ Mobile applications (MAs) are widely available for use during the perioperative period and are associated with increased adherence to rehabilitation plans, increased satisfaction with care, and considerable cost savings when used appropriately.¼ MAs offer surgeons and health care stakeholders the ability to collect clinical data and quality metrics that are important to value-based reimbursement models and clinical research.¼ Patients are willing to use wearable technology to assist with data collection as part of MAs but prefer it to be comfortable, easy to apply, and discreet.¼ Smart implants have been developed as the next step in MA use and data collection, but concerns exist pertaining to patient privacy and cost.¼ The ongoing challenge of MA standardization, validation, equity, and cost has persisted as concerns regarding widespread use.

Product warranties by orthopaedic surgery companies. Quality control or a new fad?

Introduction: Product guarantees are known to the manufacturing industry, however warranties have been rare in Orthopaedic surgery. Over the last 10 years, select manufacturers of implants have instituted warranties of varying scope, length, and reimbursement. This phenomenon prompted us to investigate the landscape of warranties in Orthopaedics and compare that to other medical industries to better inform their impact on patient care. Methods: We conducted a systematic review of patient access material of over 120 Orthopaedic manufacturers including that of the Top 25 grossing companies of 2022 to identify the prevalence and scope of these warranties. Results: We identified eight companies that offer a warranty on implants. The expiration time for the implant warranties ranged from one year to lifetime. The scope of the warranties ranged from coverage of a one-time component replacement to outcome-based guarantees that cover any complications and revisions that may result from the surgery. Discussion: While the use of warranties remains uncommon in orthopaedics, their utility is expanding and evolving. Contemporary warranties appear to have a focus on enhancing product-marketability and improving quality-control.

Combined Single-Shot Infiltration Between the Popliteal Artery and Capsule of the Knee and Adductor Canal Block With Bupivacaine, Dexmedetomidine, and Dexamethasone for Total Knee Arthroplasty: A Propensity-Matched Analysis.

Background: To investigate if combined single-shot adductor canal blockade (ACB) and infiltration between the popliteal artery and capsule of the knee (IPACK) provide better postoperative pain management compared to ACB alone for patients undergoing unilateral total knee arthroplasty (TKA). Methods: This retrospective cohort study included adult patients who underwent primary, unilateral TKA. Patients were separated into 2 cohorts: single-shot ACB alone (performed with bupivacaine 0.25%) and combined single-shot ACB + IPACK (performed with bupivacaine 0.25%, dexmedetomidine 1 mg/kg, and dexamethasone 4 mg). Patients were propensity-matched 1:1. The primary study outcome was total opioid consumption converted to morphine milligram equivalents (MME) per eight-hour interval and postoperative day. Secondary outcomes included pain scores, length of stay, ambulation distance, return to emergency department, hospital readmission, and 30-day adverse events. Results: One hundred eighty patients were identified, of which propensity matching used 71% to yield 64 patients receiving ACB alone and 64 receiving combined ACB + IPACK. Combined ACB + IPACK had significantly lower total summative MME throughout the entire postoperative stay (P = .002) and cumulatively after the first 24 hours (P < .001). Combined ACB + IPACK also had lower mean pain scores for 0-8 hours (P = .005) and 8-16 hours (P = .009) postoperatively. There were no significant differences in secondary outcomes. Conclusions: Combined single-shot ACB + IPACK block was associated with lower total narcotic intake and mean pain scores during most of the immediate postoperative period following primary, unilateral TKA compared to ACB alone. Implementing longer-acting, single-shot ACB + IPACK for TKA can balance effective and more selective pain management with early rehabilitation.

Modular Knee Arthrodesis as Definitive Treatment for Periprosthetic Infection, Bone Loss, and Failure of the Extensor Mechanism After Total Knee Arthroplasty.

Background: Periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) can result in bone and soft-tissue loss, leg length discrepancies, and dysfunctional extensor mechanisms. While above-knee amputation (AKA) is an established salvage treatment, modular knee arthrodesis (MKA) is a viable option that provides rigid stability and maintains leg length even in patients with severe bone and soft-tissue loss. We sought to report the outcomes of patients with an MKA as the definitive treatment. Methods: We retrospectively reviewed 8 patients implanted with an MKA at 2 institutions between 2016 and 2022. The mean age was 69.63 years, and 50.0% of patients were women. All patients were indicated for conversion to an MKA as the definitive treatment in the setting of treated chronic PJI after TKA, severe bone loss, and failure of the extensor mechanism not amenable to repair. Medical records and radiographs were reviewed. Results: No patients required incision and drainage or exchange of their MKA for PJI at mean 2-year follow-up. One patient required 2 revisions for mechanical failure of his implant at 5.0 and 6.4 years postoperatively. Conclusions: MKA is a viable permanent alternative to AKA for patients with treated chronic PJI and dysfunctional extensor mechanism after TKA. The procedure restores leg lengths in the setting of severe bone and soft-tissue loss, therefore allowing patients to ambulate independently. Still, surgeons should be aware of the potential for mechanical failure requiring revision.

The Impact of the COVID-19 Pandemic on the Practice of Hip and Knee Arthroplasty.

¼ The COVID-19 global pandemic resulted in unprecedented disruptions in care including massive surgical cancelations, a shift to outpatient surgery, and novel medical risks posed by COVID-19 infection on patients undergoing joint replacement surgery.¼ Refined patient optimization pathways have facilitated safe, efficient outpatient total joint arthroplasty in patient populations that may not otherwise have been considered eligible.¼ Rapid innovations emerged to deliver care while minimizing the risk of disease transmission which included the widespread adoption of telemedicine and virtual patient engagement platforms.¼ The widespread adoption of virtual technology was similarly expanded to resident education and continuing medical activities, which has improved our ability to propagate knowledge and increase access to educational initiatives.¼ Novel challenges borne of the pandemic include profound personnel shortages and supply chain disruptions that continue to plague efficiencies and quality of care in arthroplasty and require creative, sustainable solutions.

Mobile Application's Effect on Patient Satisfaction and Compliance in Total Joint Arthroplasty: A Systematic Review and Meta-analysis.

Use of mobile applications to improve patient engagement is particularly promising in total joint arthroplasty (TJA) whereby successful outcomes are predicated by patient engagement. In accordance with published guidelines by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, studies were searched, screened, and appraised for quality on various search engines. Hedges' g or odds ratios of patient adherence were reported. Twelve studies met the inclusion criteria, and the average age of 9,521 patients included was 60 years. Six studies concluded that mobile applications improved patients' satisfaction, with Hedges' g revealing an effect size of 1.64 (95% confidence interval [CI] 0.90 to 2.37), P < 0.001, in favor of mobile applications increasing patient satisfaction. Six studies reported improvements in compliance demonstrating an odds ratio for improved adherence of 4.57 (95% CI, 1.66 to 12.62), P < 0.001. Two studies reported a reduction in unscheduled office or emergency department visits. With evolving reimbursement policies linked to outcomes paired with the exponentially increasing volume of TJA performed, innovative ways to efficiently deliver high-quality care are in demand. Our systematic review is limited by a dearth of research on the nascent technology, but the available data suggest that mobile applications may enhance patient satisfaction, improve compliance, and reduce unscheduled visits after TJA.

A Comparison of the Caprini Score With an Institutional Risk Assessment Tool for Prediction of Venous Thromboembolism After Total Joint Arthroplasty at an Urban Tertiary Care Health Safety Net Hospital.

Background: Patients undergoing total joint arthroplasty (TJA) are at increased risk for venous thromboembolism (VTE). Prediction tools such as the Caprini Risk Assessment Model (RAM) have been developed to identify patients at higher risk. However, studies have reported heterogeneous results when assessing its efficacy for TJA. Patients treated in an urban health safety net hospital have increased medical complexity, advanced degenerative joint disease, and severe disability prior to TJA increasing the risk of VTE. We hypothesize that use of a tool designed to account for these conditions-the Boston Medical Center (BMC) VTE score-will more accurately predict VTE in this patient population. Methods: A retrospective case-control study was performed including subjects 18 years of age and older who underwent primary or revision TJA in an urban academic health safety net hospital. Patients with hemiarthroplasties, simultaneous bilateral TJA, and TJA after acute trauma were excluded. A total of 80 subjects were included: 40 who developed VTE after TJA (VTE+) and 40 who did not develop VTE (controls). Subjects were matched by age, gender, and surgical procedure. Results: There was a statistically significant difference between the mean BMC VTE score for VTE+ and controls (4.40 and 3.13, respectively, P = .036). Conversely, there was no statistical difference between the mean Caprini scores for VTE+ and controls (9.50 and 9.35, respectively, P = .797). Conclusions: In a health safety-net patient population, an institutional RAM-the BMC VTE score-was found to be more predictive of VTE than the modified Caprini RAM following TJA. The BMC-VTE score should be externally validated to confirm its reliability in VTE prediction in similar patient populations.

Successful aging after elective surgery II: Study design and methods.

BACKGROUND: The Successful Aging after Elective Surgery (SAGES) II study was designed to increase knowledge of the pathophysiology and linkages between delirium and dementia. We examine novel biomarkers potentially associated with delirium, including inflammation, Alzheimer's disease (AD) pathology and neurodegeneration, neuroimaging markers, and neurophysiologic markers. The goal of this paper is to describe the study design and methods for the SAGES II study. METHODS: The SAGES II study is a 5-year prospective observational study of 400-420 community dwelling persons, aged 65 years and older, assessed prior to scheduled surgery and followed daily throughout hospitalization to observe for development of delirium and other clinical outcomes. Delirium is measured with the Confusion Assessment Method (CAM), long form, after cognitive testing. Cognitive function is measured with a detailed neuropsychologic test battery, summarized as a weighted composite, the General Cognitive Performance (GCP) score. Other key measures include magnetic resonance imaging (MRI), transcranial magnetic stimulation (TMS)/electroencephalography (EEG), and Amyloid positron emission tomography (PET) imaging. We describe the eligibility criteria, enrollment flow, timing of assessments, and variables collected at baseline and during repeated assessments at 1, 2, 6, 12, and 18 months. RESULTS: This study describes the hospital and surgery-related variables, delirium, long-term cognitive decline, clinical outcomes, and novel biomarkers. In inter-rater reliability assessments, the CAM ratings (weighted kappa = 0.91, 95% confidence interval, CI = 0.74-1.0) in 50 paired assessments and GCP ratings (weighted kappa = 0.99, 95% CI 0.94-1.0) in 25 paired assessments. We describe procedures for data quality assurance and Covid-19 adaptations. CONCLUSIONS: This complex study presents an innovative effort to advance our understanding of the inter-relationship between delirium and dementia via novel biomarkers, collected in the context of major surgery in older adults. Strengths include the integration of MRI, TMS/EEG, PET modalities, and high-quality longitudinal data.

The Paradox of Prosthetic Joint Infection and the Microbiome: Are Some Bacteria Actually Helpful?

Periprosthetic joint infection (PJI) is a potentially catastrophic complication of total joint arthroplasty of the lower extremity. PJI is associated with significant burden of illness and economic cost. There are a number of well-established modifiable risk factors for PJI. Myriad perioperative protocols are used with the intent of reducing the incidence of PJI. However, it remains unclear why infections occur despite correction of modifiable risk factors and/or adherence to prophylactic protocols. There is emerging evidence that the microbiome-the diverse population of commensal microorganisms that inhabit the human body-may play a role in the pathogenesis of musculoskeletal infections. The impact of the microbiome on PJI warrants further investigation and may change how we conceptualize, prevent, and treat PJI.