Patients With Moderate to Severe Liver Cirrhosis Have Significantly Higher Short-Term Complication Rates Following Total Knee Arthroplasty: A Retrospective Cohort Study.

BACKGROUND: Liver cirrhosis is associated with increased perioperative morbidity. Our study used the Model for End-Stage Liver Disease (MELD) score to assess the impact of cirrhosis severity on postoperative outcomes following total knee arthroplasty (TKA). METHODS: A retrospective review identified 59 patients with liver cirrhosis who underwent primary TKA at a large, urban, academic center from January 2013 to August 2022. Cirrhosis was categorized as mild (MELD < 10; n = 47) or moderate-severe (MELD ≥ 10; n = 12). Modified Clavien-Dindo classification was used to grade complications, where grade 2+ denoted significant intervention. Hospital length of stay, nonhome discharge, and mortality were collected. A 1:1 propensity matching was used to control for demographics and selected comorbidities. RESULTS: Moderate-severe cirrhosis was associated with significantly higher rates of intrahospital overall (58.33 versus 16.67%, P = .036) complications, 30-day overall complications (75 versus 33.33%, P = .042), and 90-day overall complications (75 versus 33.33%, P = .042) when compared to matched mild cirrhosis patients. Compared to matched noncirrhotic controls, mild cirrhosis patients had no significant increase in complication rate or other outcomes (P > .05). CONCLUSIONS: Patients with moderate-severe liver cirrhosis are at risk of short-term complications following primary TKA. Patients with mild cirrhosis have comparable outcomes to matched noncirrhotic patients. Surgeons can use MELD score prior to scheduling TKA to determine which patients require optimization or higher levels of perioperative care.

Blood Transfusion in the Age of Tranexamic Acid: Who Needs a Type and Screen Before Total Hip Arthroplasty?

BACKGROUND: Modern surgical protocols, particularly the use of tranexamic acid (TXA), have reduced, but not eliminated, blood transfusions surrounding total hip arthroplasty (THA). Identifying patients at risk for transfusion remains important for risk reduction and to determine type and screen testing. METHODS: We reviewed 6,405 patients who underwent primary, unilateral THA between January 2014 and January 2023 at a single academic institution, received TXA, and had preoperative hemoglobin (Hgb) values. We compared demographics, baseline hemoglobin levels, and surgical details between patients who were and were not transfused. Data were analyzed utilizing multivariate regression and receiver operating characteristic (ROC) curve analysis. RESULTS: The overall perioperative and intraoperative transfusion rates were 3.4 and 1.0%, respectively. Patients who were older, women, and American Society of Anesthesiologists (ASA) class >II demonstrated an increased risk of transfusion. Risk of transfusion demonstrated an inverse correlation with preoperative Hgb levels, a bimodal association with Body Mass Index (BMI), and a direct correlation with age, surgical time, and estimated blood loss on multivariate analysis. The Receiver Operating Characteristic (ROC) analysis demonstrated a preoperative Hgb cutoff of 12 g/dL for predicting any transfusion. Above the threshold of 12 g/dL, total and intraoperative transfusions were rare, with rates of 1.7 and 0.3%, respectively. Total and intraoperative transfusion rates with Hgb between 11 and 12 g/dL were 14.3 and 4.6%, respectively. Below 11 g/dL, total and intraoperative transfusion rates were 27.5 and 10.1%, respectively. CONCLUSION: In the age of TXA, blood transfusion is rare in THA when preoperative Hgb is > 12 g/dL, challenging the need for universal type and screening. Conversely, patients who have hemoglobin < 11.0 g/dL, remain at substantial risk for transfusion. Between hemoglobin 11 and 12 g/dL, patient age, sex, BMI, ASA classification, anticipated estimated blood loss (EBL), and surgical time may help predict transfusion risk and the need for a perioperative type and screen.

Trends in Revenue and Cost for Revision Total Knee Arthroplasty.

BACKGROUND: Over the past decade, reimbursement models and target payments have been modified in an effort to decrease costs of revision total knee arthroplasty (rTKA) while maintaining the quality of care. The goal of this study was to investigate trends in revenue and costs associated with rTKA. METHODS: We retrospectively reviewed all patients who underwent rTKA between 2011 and 2021 at our institution. Patients were stratified into groups based on insurance coverage: Medicare, government-managed or Medicaid (GMM), or commercial insurance. Patient demographics were collected, as well as revenue, costs, and contribution margin (CM) of the inpatient episode. Changes over time as a percentage of 2011 numbers were analyzed. Linear regressions were used to determine trend significance. In the 10-year study period, 1,698 patients were identified with complete financial data. RESULTS: Overall total cost has increased significantly (P < .01). While revenues and CM for Medicare and Commercial patients remained steady between 2011 and 2021, CM for GMM patients decreased significantly (P = .01) to a low of 53.2% of the 2011 values. Since 2018, overall CM and revenues decreased significantly (P = .05, P = .01, respectively). CONCLUSION: While from 2011 to 2018 general revenues and CM were relatively steady, since 2018 they have decreased significantly to their lowest values in over a decade for GMM and commercial patients. This trend is concerning and may potentially lead to decreased access to care. Re-evaluation of reimbursement models for rTKA may be necessary to ensure the financial viability of this procedure and prevent issues with access to care. LEVEL OF EVIDENCE: III.

Failed 2-Stage Revision Knee Arthroplasty for Periprosthetic Joint Infection-Patient Characteristics and Outcomes.

BACKGROUND: Chronic prosthetic joint infection (PJI) is most frequently treated with 2-stage revision in conjunction with antibiotic treatment. The aims of this study were 1) to investigate the characteristics of patients who have recurrent infection following 2-stage revision for PJI and 2) to identify risk factors associated with treatment failure. METHODS: A multicenter retrospective review of 90 total knee arthroplasty (TKA) patients who underwent 2-stage revision for treatment of PJI from March 1, 2003 to July 31, 2019, and had recurrent PJI was conducted. The minimum follow-up was 12 months (median follow up of 2.4 years). Microorganisms, subsequent revision, PJI control status, and final joint status were collected. The infection-free survival after initial 2-stage revision was plotted utilizing the Kaplan-Meier method. RESULTS: Mean survival time to reinfection was 21.3 months (range, 0.3 to 160.5). There were 14 recurrent infections that were acute PJIs treated with debridement, antibiotics, and implant retention (DAIR), while 76 were chronic and treated with repeat 2-stage revision. The most common pathogen identified for both index and recurrent PJI was coagulase-negative Staphylococci. Pathogen persistence was observed in 14 (22.2%) of recurrent PJIs. In total, 61 (67.8%) patients possessed a prosthetic reimplantation at their most recent follow-up, and 29 (35.6%) patients required intervention following repeat 2-stage. CONCLUSION: Overall, 31.1% of the patients obtained infection control after treatment of a failed 2-stage revision due to PJI. The high rate of pathogen persistence and the relatively low survival time to recurrence suggests a need to more closely monitor PJIs cases within 2 years.

Patient-Reported Outcomes Following Intra-articular Hyaluronic Acid for Knee Osteoarthritis.

BACKGROUND: Intra-articular hyaluronic acid (IAHA) has been commonly used in the management of knee osteoarthritis (OA). This study sought to assess patient-reported outcomes (PRO) following different formulations of hyaluronic acid injections for patients who have knee OA. METHODS: A retrospective analysis was performed on patients who have knee OA and received IAHA knee injections from October 2018 to May 2022 in sports medicine (SM) and adult reconstructive (AR) clinics. Patients completed PRO measures including the Patient-Reported Outcome Measurement Information System (PROMIS) Mobility, Pain Interference, and Pain Intensity at baseline, 6-week, 6-month, and 12-month follow-up. Univariate and multivariate analyses were used to evaluate changes in PRO measures between baseline and follow-up periods and to evaluate differences between the SM and AR divisions. A total of 995 patients received IAHA for knee OA and completed PRO assessments. RESULTS: There was no difference in the PROMIS measures based on molecular weight at 6 weeks, 6 months, and 12 months. Except for 6-month Mobility scores between the SM and AR patients (-0.52 ± 5.46 versus 2.03 ± 6.95; P = .02), all other PROMIS scores were similar. Mobility scores at 6 months were significantly different based on Kellgren and Lawrence grade (P = .005), but all other PROMIS scores were similar. CONCLUSION: Average change in PROMIS scores were significantly different only for 6-month Mobility scores based on divisions and Kellgren and Lawrence grade but did not achieve minimally clinical important difference at most timepoints. Further studies are needed to investigate whether improvement is observed in specific patient populations.

Gliosarcoma with PNET features mimicking a metastatic neuroendocrine carcinoma: A diagnostic dilemma.

OBJECTIVE: Gliosarcomas (GS) comprise ~ 2 - 8% of glioblastomas and are associated with a similar poor prognosis. GS have rarely been found with a primitive neuroectodermal component (PNET). We present a case of gliosarcoma with PNET features (GS-PNET) that mimicked a neuroendocrine carcinoma on initial biopsy. MATERIALS AND METHODS: A 68-year-old male presented with 2 weeks of increasing headaches and difficulties with reading, writing, and word-finding. He was found to have a left-sided parieto-occipital heterogeneously enhancing mass. RESULTS: Pathologic analysis after surgical resection initially diagnosed a poorly differentiated carcinoma with neuroendocrine features, and adjuvant therapy was guided by this diagnosis as well as systemic imaging, which was suggestive of gastrointestinal primary malignancy with central nervous system (CNS) metastasis. Subsequent progression and re-resection established a diagnosis of GS with PNET component. Genomic profiling showed shared PTEN, TERT promotor, and TP53 mutations in the original and recurrent tumors. CONCLUSION: There have only been 5 previously reported cases of GS-PNET, to our knowledge, with this case representing the first with comprehensive molecular profiling. The case also highlights the importance of further work-up of presumed metastatic carcinoma with indeterminate immunostaining and/or suspected non-epithelioid component.

The Implication of Substance P in the Development of Tendinopathy: A Case Control Study.

It was reported that substance P had beneficial effects in the healing of acute tendon injury. However, the relationship between substance P and degenerative tendinopathy development remains unclear. The purpose of this study was to determine the role of substance P in the pathogenesis of tendinopathy. Healthy and tendinopathy tendon were harvested from human and tenocytes were cultured individually. The expression levels of genes associated with tendinopathy were compared. Next, substance P was exogenously administered to the healthy tenocyte and the effect was evaluated. The results showed that tendinopathy tenocytes had higher levels of COL3A1, MMP1, COX2, SCX, ACTA2, and substance P gene expression compared to healthy tenocytes. Next, substance P treatment on the healthy tenocyte displayed similar changes to that of the tendinopathy tenocytes. These differences between the two groups were also determined by Western blot. Additionally, cells with substance P had the tendinopathy change morphologically although cellular proliferation was significantly higher compared to that of the control group. In conclusion, substance P enhanced cellular proliferation, but concomitantly increased immature collagen (type 3 collagen). Substance P plays a crucial role in tendinopathy development and could be a future therapeutic target for treatment.

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

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

Human versus artificial intelligence-generated arthroplasty literature: A single-blinded analysis of perceived communication, quality, and authorship source.

BACKGROUND: Large language models (LLM) have unknown implications for medical research. This study assessed whether LLM-generated abstracts are distinguishable from human-written abstracts and to compare their perceived quality. METHODS: The LLM ChatGPT was used to generate 20 arthroplasty abstracts (AI-generated) based on full-text manuscripts, which were compared to originally published abstracts (human-written). Six blinded orthopaedic surgeons rated abstracts on overall quality, communication, and confidence in the authorship source. Authorship-confidence scores were compared to a test value representing complete inability to discern authorship. RESULTS: Modestly increased confidence in human authorship was observed for human-written abstracts compared with AI-generated abstracts (p = 0.028), though AI-generated abstract authorship-confidence scores were statistically consistent with inability to discern authorship (p = 0.999). Overall abstract quality was higher for human-written abstracts (p = 0.019). CONCLUSIONS: AI-generated abstracts' absolute authorship-confidence ratings demonstrated difficulty in discerning authorship but did not achieve the perceived quality of human-written abstracts. Caution is warranted in implementing LLMs into scientific writing.

Electro-optical mechanically flexible coaxial microprobes for minimally invasive interfacing with intrinsic neural circuits.

Central to advancing our understanding of neural circuits is developing minimally invasive, multi-modal interfaces capable of simultaneously recording and modulating neural activity. Recent devices have focused on matching the mechanical compliance of tissue to reduce inflammatory responses. However, reductions in the size of multi-modal interfaces are needed to further improve biocompatibility and long-term recording capabilities. Here a multi-modal coaxial microprobe design with a minimally invasive footprint (8-14 µm diameter over millimeter lengths) that enables efficient electrical and optical interrogation of neural networks is presented. In the brain, the probes allowed robust electrical measurement and optogenetic stimulation. Scalable fabrication strategies can be used with various electrical and optical materials, making the probes highly customizable to experimental requirements, including length, diameter, and mechanical properties. Given their negligible inflammatory response, these probes promise to enable a new generation of readily tunable multi-modal devices for long-term, minimally invasive interfacing with neural circuits.

Iterative and Complex Asymmetric Divisions Control Cell Volume Differences in Ciona Notochord Tapering.

The notochord of the invertebrate chordate Ciona forms a tapered rod at tailbud stages consisting of only 40 cylindrical cells in a single-file column. This tapered shape involves differences in notochord cell volume along the anterior-posterior axis. Here, we quantify sibling cell volume asymmetry throughout the developing notochord and find that there are distinctive patterns of unequal cleavage in all 4 bilateral pairs of A-line primary notochord founder cells and also in the B-line-derived secondary notochord founder cells. A quantitative model confirms that the observed patterns of unequal cleavage are sufficient to explain all the anterior-posterior variation in notochord cell volume. Many examples are known of cells that divide asymmetrically to give daughter cells of different size and fate. Here, by contrast, a series of subtle but iterative and finely patterned asymmetric divisions controls the shape of an entire organ. Quantitative 3D analysis of cell shape and spindle positioning allows us to infer multiple cellular mechanisms driving these unequal cleavages, including polarized displacements of the mitotic spindle, contributions from the shape of the mother cell, and late changes occurring between anaphase and abscission that potentially involve differential cortical contractility. We infer differential use of these mechanisms between different notochord blastomeres and also between different rounds of cell division. These results demonstrate a new role for asymmetric division in directly shaping a developing organ and point toward complex underlying mechanisms.

Towards Microscale Flight: Fabrication, Stability Analysis, and Initial Flight Experiments for 300 µm × 300 µm × 1.5 µm Sized Untethered MEMS Microfliers.

This paper presents modeling, designs, and initial experimental results demonstrating successful untethered microscale flight of stress-engineered microscale structures propelled by thermal forces. These MEMS Microfliers are 300 µm×300 µm×1.5 µm in size and are fabricated out of polycrystalline silicon using a surface micromachining process. A concave chassis, created using a novel in-situ masked post-release stress-engineering process, promotes static in-flight stability. High-speed optical micrography was used to capture image sequences of their flight, and this imagery was subsequently used to analyze their mid-flight performance. Our analysis, combined with finite element modeling (FEM) confirms stable flight of the microfliers within the thermal gradient above the heaters. This novel microscale flying platform presented in this paper may pave the way for new types of aerial microrobots.