bluuebunny/crossref_metadata_2025 huggingface dataset:
Studying gas exceptions in blockchain-based cloud applications
Authors: Liu Chao , Gao Jianbo , Li Yue , Wang Huihui , Chen Zhong
Published: June 2020

Blockchain-based cloud application (BCP) is an emerging cloud application architecture. By moving trust-critical functions onto blockchain, BCP offers unprecedented function transparency and data integrity. Ethereum is by far the most popular blockchain platform chosen for BCP. In Ethereum, special programs named smart contracts are often used to implement key components for BCP. By design, users can send transactions to smart contracts, which will automatically lead to code execution and state modification. However, unlike regular programs, smart contracts are restricted in execution by gas limit, i.e., a form of runtime resource. If a transaction uses up all available gas, an out of gas exception () will trigger, reverting state until right before that transaction.In this work, we study the out of gas exceptions (or gas exceptions in short) on Ethereum empirically for the very first time. In particular, we collect exception transactions using an instrumented Ethereum client. By investigation, we found gas exceptions stand out in terms of both occurrences and losses. Moreover, we focused on individual contracts and transactions, aiming at discovering and identifying common causing factors triggering these exceptions. At last, we also investigate existing tools in preventing gas exceptions. Our results suggest further research and study in this direction.
Variations in soil properties and native woody plant species abundance under Prosopis juliflora invasion in Afar grazing lands, Ethiopia
Authors: Eshete Abeje , Treydte Anna C. , Hailemariam Mengsteab , Solomon Negasi , Dejene Tatek , Yilma Zewdu , Birhane Emiru
Published: June 2020

Introduction

Pastoralism and agro-pastoralism are the major modes of life in arid and semi-arid rangelands. However, rangeland quality and quantity are rapidly deteriorating due to a number of natural and human-induced factors, one of which is bush encroachment. Little is known on how bush encroachment affects the ecosystem functions and services expressed in terms of the native vegetation composition and structure, status of the soil seed bank, soil chemical and physical properties, and the abundance of mycorrhiza spores.

Methods

We assessed woody species in 64 plots distributed across four levels ofProsopis juliflorainvasion (high, medium, low, and none) at two sites, Amibara and Gewane, in the Afar Region, Ethiopia. We collected composite soil samples to investigate the soil seed bank, mycorrhizal associations, and spore abundance.

Results

Plant biodiversity was generally low, with eight and four woody species in Gewane and Amibara, respectively.Prosopis juliflorawas dominant in highly, moderately, and lowly invaded areas while Acacia senegal dominated the non-invaded areas. The average number ofP. julifloraindividuals ranged from 3/ha at non-invaded areas in Gewane to 4200/ha at highly invaded areas in Amibara while the total individual number of native woody species ranged from 0 to 88/ha at highly and lowly invaded areas, respectively. The population structure of trees/shrubs in all invasion areas showed an inverted J-shaped distribution, characterized by a high abundance of small individuals.Prosopis juliflorainvasion was associated with high soil OC, Na, Ca, P, bulk density, and moisture content. Herbaceous seed numbers and species richness were highest in the moderately and highly invaded areas. All sampled tree species were associated with mycorrhiza but the percentage of root length colonization by different arbuscular mycorrhizal fungus structures varied significantly (p< 0.05) across invasion categories and sites.

Conclusions

Our results revealed that althoughP. juliflorainvasion negatively impacted the availability of native woody livestock forage species, it had a positive effect on most soil physical and chemical properties. Such variable effects call out for sustainable management practices when invaded areas are restored.
The association of a reduced susceptibility to moxifloxacin in causative Clostridium (Clostridioides) difficile strain with the clinical outcome of patients
Authors: Krutova Marcela , Capek Vaclav , Nycova Elka , Vojackova Sabina , Balejova Magda , Geigerova Lenka , Tejkalova Renata , Havlinova Lenka , Vagnerova Iva , Cermak Pavel , Ryskova Lenka , Jezek Petr , Zamazalova Dana , Vesela Denisa , Kucharova Alice , Nemcova Dana , Curdova Martina , Nyc Otakar , Drevinek Pavel
Published: June 2020

Objectives

To investigate the relationship between Clostridium (Clostridioides) difficile strain characteristics and C. difficile infection (CDI) outcome.

Methods

Between October and December 2017, 16 hospitals collected epidemiological data according to the European Centre for Disease Prevention and Control (ECDC) surveillance protocol for CDI. C. difficile isolates were characterized by ribotyping, toxin genes detection and antibiotic susceptibility testing to metronidazole, vancomycin and moxifloxacin.

Results

The overall mean CDI incidence density was 4.5 [95% CI 3.6–5.3] cases per 10,000 patient-days. From the 433 CDI cases, 330 (76.2%) were healthcare-associated, 52 (12.0%) cases were community-associated or of unknown origin and 51 (11.8%) CDI cases recurrent; a complicated course of CDI was reported in 65 cases (15.0%). Eighty-eight (20.3%) of patients died and 59 of them within 30 days after the CDI diagnosis.

From the 379 C. difficile isolates, the most prevalent PCR ribotypes were 001 (n = 127, 33.5%) and 176 (n = 44, 11.6%). A total of 186 (49.1%) isolates showed a reduced susceptibility to moxifloxacin (> 4 mg/L) and 96.4% of them had Thr82Ile in the GyrA. Nineteen isolates revealed reduced susceptibility to metronidazole and two isolates to vancomycin (> 2 mg/L).

A fatal outcome was associated with a reduced susceptibility to moxifloxacin, the advanced age of the patients and a complicated course of CDI (p<0.05). No association between ribotype, binary toxin and a reduced susceptibility to moxifloxacin and complicated course or recurrent CDI was found.

Conclusions

A reduced susceptibility to moxifloxacin, in causative C. difficile strains was associated with fatal outcome of the patients, therefore it is an important marker in surveillance of CDI.
A portable standalone wireless electric cell-substrate impedance sensing (ECIS) system for assessing dynamic behavior of mammalian cells
Authors: Kasiviswanathan Uvanesh , Poddar Suruchi , Kumar Chandan , Jit Satyabrata , Mahto Sanjeev Kumar , Sharma Neeraj
Published: June 2020

In this study, we have developed a wireless, portable, standalone, and simple electric cell-substrate impedance sensing (ECIS) system to analyze in-depth functional aspects of cellular functions on the surface of a co-planar metal electrode coated on conventional glass substrate using a low-cost circuitry and correlated it with an equivalent electrical circuit (EEC) model. Low-cost circuitry was used for studying the dynamic behavior of the mouse myoblast cells (C2C12) in a culture chamber. Further, the developed ECIS system was connected with 8-bit Arduino UNO microcontroller board for establishing a compact sized measuring unit, which can be placed inside a CO2incubator to provide proper environmental condition for the biological cells during the entire measuring time. Integrating ZigBee RF module with the 8-bit Arduino UNO microcontroller board provides a wireless communication network. Theoretical calculation of the lumped-elemental electrical parameters associated with cell-electrolyte interface and metal-electrolyte interface was calculated. The calculation was performed by fitting the experimental impedance data to EEC model using least mean square method to determine the dynamic and vital functions of the mammalian cells such as proliferation (in real-time) with a change in intrinsic electrical parameters associated at any particular time point. Impedance measurements and the lumped-elemental electrical parameter were correlated with the respective microscopic images. The developed ECIS system was found to enable measuring of the extent of cellular proliferation over time. The compactness of the developed ECIS system integrated with the ZigBee RF module and the 8-bit Arduino UNO microcontroller board facilitates its utilization even when placed in the CO2incubator for a prolonged time.
Use of glucocorticoids in patients with acute respiratory distress syndrome: a meta-analysis and trial sequential analysis
Authors: Zayed Yazan , Barbarawi Mahmoud , Ismail Esraa , Samji Varun , Kerbage Josiane , Rizk Fatima , Salih Mohammad , Bala Areeg , Obeid Michele , Deliwala Smit , Demian Sherry , Al-Sanouri Ibrahim , Reddy Raju
Published: June 2020

Background

Acute respiratory distress syndrome (ARDS) is a common and disabling disease with high rates of mortality and morbidity. The role of steroids in treating ARDS remains controversial. We aim to examine the evidence behind using glucocorticoids in the management of ARDS from the available studies.

Methods

We performed a literature review of major electronic databases for randomized controlled trials (RCTs) comparing glucocorticoids versus placebo in treating patients with ARDS. Our primary outcome was hospital mortality. Other outcomes included ICU mortality, number of ventilator-free days at day 28, incidence of nosocomial infections, and hyperglycemia. We performed a meta-analysis using a random effects model to calculate risk ratios (RR) and mean difference (MD) with their corresponding 95% confidence intervals (CI). A subsequent trial sequential analysis was performed to examine the strength of evidence and to guard against statistical type I and type II errors for our results.

Results

Eight RCTs were included in the final analysis totaling of 1091 patients, with a mean age of 57 ± 16, and 56.2% were male. In our pooled analysis, use of glucocorticoids was associated with a significant reduction in hospital mortality (RR 0.79; 95% CI 0.64–0.98; P = 0.03) and ICU mortality (RR 0.64; 95% CI 0.42–0.97; P = 0.04). Furthermore, glucocorticoid use was associated with an increased number of ventilator-free days at day 28 (MD 4.06 days; 95% CI 2.66–5.45; P < 0.01). Regarding adverse events, glucocorticoids use was not associated with an increased risk for nosocomial infections (RR 0.82; 95% CI 0.68–1.00; P = 0.05); however, it was associated with an increased risk of hyperglycemia (RR 1.11; 95% CI 1.01–1.24; P = 0.04). In our trial sequential analysis, the required diversity-adjusted information size (sample size = 2692 patients) was not reached, and the evidence was insufficient from the available RCTs.

Conclusion

Among patients with ARDS, use of glucocorticoids is associated with a significant reduction in mortality and duration of mechanical ventilation, without increased risk of hospital-acquired infections. However, based on a trial sequential analysis, these findings may be secondary to a false-positive (type I) error. Further studies are needed for a firm conclusion with guarding against possible statistical errors.
Performance assessment of the 2 γpositronium imaging with the total-body PET scanners
Authors: Moskal P. , Kisielewska D. , Y. Shopa R. , Bura Z. , Chhokar J. , Curceanu C. , Czerwiński E. , Dadgar M. , Dulski K. , Gajewski J. , Gajos A. , Gorgol M. , Del Grande R. , C. Hiesmayr B. , Jasińska B. , Kacprzak K. , Kamińska A. , Kapłon Ł , Karimi H. , Korcyl G. , Kowalski P. , Krawczyk N. , Krzemień W. , Kozik T. , Kubicz E. , Małczak P. , Mohammed M. , Niedźwiecki Sz. , Pałka M. , Pawlik-Niedźwiecka M. , Pędziwiatr M. , Raczyński L. , Raj J. , Ruciński A. , Sharma S. , Shivani S. , Silarski M. , Skurzok M. , Stępień E. Ł. , Vandenberghe S. , Wiślicki W. , Zgardzińska B.
Published: June 2020

Purpose

In living organisms, the positron-electron annihilation (occurring during the PET imaging) proceeds in about 30% via creation of a metastable ortho-positronium atom. In the tissue, due to the pick-off and conversion processes, over 98% of ortho-positronia annihilate into two 511 keV photons. In this article, we assess the feasibility for reconstruction of the mean ortho-positronium lifetime image based on annihilations into two photons. The main objectives of this work include the (i) estimation of the sensitivity of the total-body PET scanners for the ortho-positronium mean lifetime imaging using 2γannihilations and (ii) estimation of the spatial and time resolution of the ortho-positronium image as a function of the coincidence resolving time (CRT) of the scanner.

Methods

Simulations are conducted assuming that radiopharmaceutical is labeled with44Scisotope emitting one positron and one prompt gamma. The image is reconstructed on the basis of triple coincidence events. The ortho-positronium lifetime spectrum is determined for each voxel of the image. Calculations were performed for cases of total-body detectors build of (i) LYSO scintillators as used in the EXPLORER PET and (ii) plastic scintillators as anticipated for the cost-effective total-body J-PET scanner. To assess the spatial and time resolution, the four cases were considered assuming that CRT is equal to 500 ps, 140 ps, 50 ps, and 10 ps.

Results

The estimated total-body PET sensitivity for the registration and selection of image forming triple coincidences (2γ+γprompt) is larger by a factor of 13.5 (for LYSO PET) and by factor of 5.2 (for plastic PET) with respect to the sensitivity for the standard 2γimaging by LYSO PET scanners with AFOV = 20 cm. The spatial resolution of the ortho-positronium image is comparable with the resolution achievable when using TOF-FBP algorithms already for CRT = 50 ps. For the 20-min scan, the resolution better than 20 ps is expected for the mean ortho-positronium lifetime image determination.

Conclusions

Ortho-positronium mean lifetime imaging based on the annihilations into two photons and prompt gamma is shown to be feasible with the advent of the high sensitivity total-body PET systems and time resolution of the order of tens of picoseconds.
Pneumonia among under-five children in Alexandria, Egypt: a case-control study
Authors: Fadl Noha , Ashour Ayat , Yousry Muhammad Yasmine
Published: June 2020

Background

Pneumonia among under-five children constitutes a major public health concern. Studies examining risk factors for pneumonia in Egypt are limited.

Aim

To identify risk factors of pneumonia among under-five children in Alexandria, Egypt.

Methods

An observational case-control study was conducted over a 5-month period (September 2017–January 2018) in three main pediatric hospitals in Alexandria. A predesigned questionnaire was used to interview 660 mothers of under-five children (330 pneumonia cases and 330 control). The questionnaire included potential risk factors for pneumonia which were categorized into child-related factors, socio-demographic factors, and environmental factors.

Results

The mean age of the children was 23.14 ± 18.61 months with a range of 1–59 months. Nearly two-thirds (58.5%) were boys. Nine factors were found to be independently associated with pneumonia: age ≤ 12 months (OR = 1.925; 95% CI, 1.356–2.733; P < 0.001), male gender (OR = 1.646; 95% CI, 1.162–2.332; P = 0.005), birth order ≥ 4 (OR = 2.154; 95% CI, 1.282–3.617; P = 0.004), low birth weight (OR = 2.562; 95% CI, 1.718–3.821; P < 0.001), prematurity (OR = 2.019; 95% CI, 1.154–3.531; P = 0.014), place of delivery either at home (OR = 5.669; 95% CI, 1.063–30.237; P = 0.042) or at a public hospital (OR = 1.616; 95% CI, 1.131–2.310; P = 0.008), presence of concomitant illness (OR = 1.902; 95% CI, 1.043–3.469; P = 0.036), poor home aeration (OR = 3.586; 95% CI, 1.971–6.522; P < 0.001), and exposure to outdoor air pollution (OR = 2.403; 95% CI, 1.417–4.076; P = 0.001).

Conclusion

Several risk factors were significantly related to pneumonia among under-five children. Identifying such factors is important for developing interventions to reduce pneumonia burden among under-five in Egypt.
Dynamic waitlisted design for evaluating a randomized trial of evidence-based quality improvement of comprehensive women’s health care implementation in low-performing VA facilities
Authors: Hamilton Alison B. , Olmos-Ochoa Tanya T. , Canelo Ismelda , Rose Danielle , Hoggatt Katherine J. , Than Claire , Yano Elizabeth M.
Published: June 2020

Background

Women’s Health Services (WHS) in the Veterans Health Administration (VA) has long partnered with VA researchers to evaluate how VA care is organized for women veterans. This partnership has yielded substantial evidence of (1) variations in women veterans’ access to comprehensive healthcare services that contribute to disparities in quality and patient experience and (2) the positive impacts of gender-specific care models for women veterans’ quality and satisfaction. In an effort to provide support specifically to sites that were low-performing in women’s health, WHS and the VA Quality Enhancement Research Initiative co-funded an effort to roll out and evaluate evidence-based quality improvement (EBQI), an implementation strategy with demonstrated effectiveness in a prior cluster randomized trial in women’s health clinics.

Methods

We will identify 21 low-performing VA facilities through a combination of practice data, VA quality metrics (by gender), and other indicators. In partnership with WHS, an EBQI contractor will deliver the EBQI “package”—local consensus development and priority setting using stakeholder panels, multilevel stakeholder engagement, practice facilitation, local EBQI team training, and formative feedback—to participating sites. We propose a dynamic wait-listed design to evaluate the WHS plans for seven EBQI launches per year over 3 years. The goal is to evaluate (1) barriers and facilitators to achieving delivery of comprehensive women’s health care in low-performing VA facilities; (2) effectiveness of EBQI in supporting low-performing VA facilities to achieve improved practice features (e.g., level of comprehensive services available, care coordination arrangements, Patient Aligned Care Team (PACT) features implemented, environment of care improvements), provider/staff attitudes (e.g., improved gender awareness, women’s health knowledge and practice), quality of care, and patient experience; and (3) contextual factors, local implementation processes, and organizational changes over time.

Discussion

Access to comprehensive women’s health care reduces fragmentation of care, improves patient satisfaction, and results in better patient outcomes. We hypothesize that EBQI implementation will result in changes in leadership awareness and buy-in, multilevel engagement in problem-solving, an enhanced culture of quality improvement, structural changes in care, improved provider/staff attitudes, and better quality and patient experience.

Trial registration

ClinicalTrials.gov, NCT03238417. Registered 3 August 2017. Retrospectively registered, https://clinicaltrials.gov/ct2/show/study/NCT03238417
Management of Breast Cancer During the COVID-19 Pandemic: A Stage- and Subtype-Specific Approach
Authors: Sheng Jennifer Y. , Santa-Maria Cesar A. , Mangini Neha , Norman Haval , Couzi Rima , Nunes Raquel , Wilkinson Mary , Visvanathan Kala , Connolly Roisin M. , Roussos Torres Evanthia T. , Fetting John H. , Armstrong Deborah K. , Tao Jessica J. , Jacobs Lisa , Wright Jean L. , Thorner Elissa D. , Hodgdon Christine , Horn Samantha , Wolff Antonio C. , Stearns Vered , Smith Karen L.
Published: June 2020

The COVID-19 pandemic has rapidly changed delivery of cancer care. Many nonurgent surgeries are delayed to preserve hospital resources, and patient visits to health care settings are limited to reduce exposure to SARS-CoV-2. Providers must carefully weigh risks and benefits of delivering immunosuppressive therapy during the pandemic. For breast cancer, a key difference is increased use of neoadjuvant systemic therapy due to deferral of many breast surgeries during the pandemic. In some cases, this necessitates increased use of genomic tumor profiling on core biopsy specimens to guide neoadjuvant therapy decisions. Breast cancer treatment during the pandemic requires multidisciplinary input and varies according to stage, tumor biology, comorbidities, age, patient preferences, and available hospital resources. We present here the Johns Hopkins Women’s Malignancies Program approach to breast cancer management during the COVID-19 pandemic. We include algorithms based on tumor biology and extent of disease that guide management decisions during the pandemic. These algorithms emphasize medical oncology treatment decisions and demonstrate how we have operationalized the general treatment recommendations during the pandemic proposed by national groups, such as the COVID-19 Pandemic Breast Cancer Consortium. Our recommendations can be adapted by other institutions and medical oncology practices in accordance with local conditions and resources. Guidelines such as these will be important as we continue to balance treatment of breast cancer against risk of SARS-CoV-2 exposure and infection until approval of a vaccine.
Panorama as Method
Authors: Braester Yomi
Published: June 2020

Diverse artifacts in contemporary Chinese visual culture—from urban screens to architectural models, art exhibits, and viral media—share a panoramic breadth. This article suggests, however, that we should regard panorama not as a preordained form but as a discursive construct that posits an imaginary vantage point. Panorama as method notes the use of scale, recording of the skyline, and mediation of the cityscape. The article asks what material conditions and ideological circumstances allow for the existence of the images at hand and what brings us to identify them as panoramic. The implications reach far beyond specific artifacts: panorama as method challenges accepted paradigms about the relationship between the modern subject and urban space, including the distinction between cartographic vision and street-level immersion. The article focuses on what may be called the panoramic imaginary in contemporary Chinese urbanism: a visual emphasis on expansive space by scaling the built environment up and down, thereby recalibrating social relations and relocating civic engagement to virtual spaces.
Risk Premia and the Real Effects of Money
Authors: Di Tella Sebastian
Published: June 2020

This paper proposes a flexible-price theory of the role of money in an economy with incomplete idiosyncratic risk sharing. When the risk premium goes up, money provides a safe store of value that prevents interest rates from falling, reducing investment. Investment is too high during booms when risk is low, and too low during slumps when risk is high. Monetary policy cannot correct this: money is superneutral and Ricardian equivalence holds. The optimal allocation requires the Friedman rule and a tax/subsidy on capital. The real effects of money survive even in the cashless limit. (JEL E32, E41, E43, E44, E52)
Relational Contracting, Negotiation, and External Enforcement
Authors: Watson Joel , Miller David A. , Olsen Trond E.
Published: June 2020

We study relational contracting and renegotiation in environments with external enforcement of long-term contractual arrangements. A long-term contract governs the stage games that the contracting parties will play in the future (depending on verifiable stage-game outcomes) until they renegotiate. In a contractual equilibrium, the parties choose their individual actions rationally, jointly optimize when selecting a contract, and exercise their relative bargaining power. Our main result is that in a wide variety of settings, the optimal contract is semi-stationary, with stationary terms for all future periods but special terms for the current period. In each period the parties renegotiate to this same contract. For example, in a simple principal-agent model with a choice of costly monitoring technology, the optimal contract specifies mild monitoring for the current period but intense monitoring for future periods. Because the parties renegotiate in each new period, intense monitoring arises only off the equilibrium path after a failed renegotiation. (JEL C73, C78, D23, D86)
Home Values and Firm Behavior
Authors: Bahaj Saleem , Foulis Angus , Pinter Gabor
Published: June 2020

The homes of firm owners are an important source of finance for ongoing businesses. We use UK microdata to show that a £1 increase in the value of the homes of a firm’s directors increases the firm’s investment by £0.03. This effect is concentrated among firms whose directors’ homes are valuable relative to the firm’s assets, that are financially constrained, and that have directors who are personally highly levered. An aggregation exercise shows that directors’ homes are as important as corporate property for collateral driven fluctuations in aggregate investment demand. (JEL D22, D25, E22, G31, G34, R31)
An articulated spacer made of new primary implants in two-stage exchange for infected total knee arthroplasty may provide durable results
Authors: Zamora Tomas , Garbuz Donald S. , Greidanus Nelson V. , Masri Bassam A.
Published: June 2020

Aims

Our objective is to describe our early and mid-term results with the use of a new simple primary knee prosthesis as an articulating spacer in planned two-stage management for infected knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a complete two-stage revision.

Methods

We included 47 patients (48 knees) with positive criteria for infection, with a minimum two-year follow-up, in which a two-stage approach with an articulating spacer with new implants was used. Patients with infection control, and a stable and functional knee were allowed to retain the initial first-stage components. Outcomes recorded included: infection control rate, reoperations, final range of motion (ROM), and quality of life assessment (QoL) including Western Ontario and McMaster Universities osteoarthritis index, Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score, 12-Item Short-Form Health Survey questionnaire, and University of California Los Angeles (UCLA) activity score and satisfaction score. These outcomes were evaluated and compared to additional cohorts of patients with retained first-stage interventions and those with a complete two-stage revision. Mean follow-up was 3.7 years (2.0 to 6.5).

Results

Eight knees failed directly related to lack of infection control (16%), and two patients (two knees) died within the first year for causes not directly related, giving an initial success rate of 79% (38/48). Secondary success rate after a subsequent procedure was 91% (44/48 knees). From the initially retained spacers, four knees (22%) required a second-stage revision for continuous symptoms and one (5%) for an acute infection. There were no significant differences regarding the failure rate due to infection, ROM, and QoL assessment between patients with a retained first-stage procedure and those who underwent a second-stage operation.

Conclusion

Our protocol of two-stage exchange for infected knee arthroplasties with an articulating spacer and using new primary knee implants achieves adequate infection control. Retained first-stage operations achieve comparable results in selected cases, with no difference in infection control, ROM, and QoL assessment in comparison to patients with completed two-stage revision surgery. Cite this article: Bone Joint J 2020;102-B(7):852–860.
The long-term impact of preoperative psychological distress on functional outcomes, quality of life, and patient satisfaction after total knee arthroplasty
Authors: Goh Graham S. , Liow Ming Han Lincoln , Tay You Wei Adriel , Chen Jerry Yongqiang , Xu Sheng , Pang Hee-Nee , Tay Darren Keng-Jin , Chia Shi-Lu , Lo Ngai-Nung , Yeo Seng-Jin
Published: June 2020

Aims

While patients with psychological distress have poorer short-term outcomes after total knee arthroplasty (TKA), their longer-term function is unknown. We aimed to 1) assess the influence of preoperative mental health status on long-term functional outcomes, quality of life, and patient satisfaction; and 2) analyze the change in mental health after TKA, in a cohort of patients with no history of mental health disorder, with a minimum of ten years’ follow-up.

Methods

Prospectively collected data of 122 patients undergoing primary unilateral TKA in 2006 were reviewed. Patients were assessed pre- and postoperatively at two and ten years using the Knee Society Knee Score (KSKS) and Function Score (KSFS); Oxford Knee Score (OKS); and the Mental (MCS) and Physical Component Summary (PCS) which were derived from the 36-Item Short-Form Health Survey questionnaire (SF-36). Patients were stratified into those with psychological distress (MCS < 50, n = 51) and those without (MCS ≥ 50, n = 71). Multiple regression was used to control for age, sex, BMI, Charlson Comorbidity Index (CCI), and baseline scores. The rate of expectation fulfilment and satisfaction was compared between patients with low and high MCS.

Results

There was no difference in the mean KSKS, KSFS, OKS, and SF-36 PCS at two years or ten years after TKA. Equal proportions of patients in each group attained the minimal clinically important difference for each score. Psychologically distressed patients had a comparable rate of satisfaction (91.8% (47/51) vs 97.1% (69/71); p = 0.193) and fulfilment of expectations (89.8% vs 97.1%; p = 0.094). The proportion of distressed patients declined from 41.8% preoperatively to 29.8% at final follow-up (p = 0.021), and their mean SF-36 MCS improved by 10.4 points (p < 0.001).

Conclusion

Patients with poor mental health undergoing TKA may experience long-term improvements in function and quality of life that are comparable to those experienced by their non-distressed counterparts. These patients also achieved a similar rate of satisfaction and expectation fulfilment. Undergoing TKA was associated with improvements in mental health in distressed patients, although this effect may be due to residual confounding. Cite this article: Bone Joint J 2020;102-B(7):845–851.
2020 Frank Stinchfield Award: Identifying who will fail following irrigation and debridement for prosthetic joint infection
Authors: Shohat Noam , Goswami Karan , Tan Timothy L. , Yayac Michael , Soriano Alex , Sousa Ricardo , Wouthuyzen-Bakker Marjan , Parvizi Javad ,   On behalf of the ESCMID Study Group of Implant Associated Infections (ESGIAI) and the Northern Infection Network of Joint Arthroplasty (NINJA)
Published: June 2020

Aims

Failure of irrigation and debridement (I&D) for prosthetic joint infection (PJI) is influenced by numerous host, surgical, and pathogen-related factors. We aimed to develop and validate a practical, easy-to-use tool based on machine learning that may accurately predict outcome following I&D surgery taking into account the influence of numerous factors.

Methods

This was an international, multicentre retrospective study of 1,174 revision total hip (THA) and knee arthroplasties (TKA) undergoing I&D for PJI between January 2005 and December 2017. PJI was defined using the Musculoskeletal Infection Society (MSIS) criteria. A total of 52 variables including demographics, comorbidities, and clinical and laboratory findings were evaluated using random forest machine learning analysis. The algorithm was then verified through cross-validation.

Results

Of the 1,174 patients that were included in the study, 405 patients (34.5%) failed treatment. Using random forest analysis, an algorithm that provides the probability for failure for each specific patient was created. By order of importance, the ten most important variables associated with failure of I&D were serum CRP levels, positive blood cultures, indication for index arthroplasty other than osteoarthritis, not exchanging the modular components, use of immunosuppressive medication, late acute (haematogenous) infections, methicillin-resistant Staphylococcus aureus infection, overlying skin infection, polymicrobial infection, and older age. The algorithm had good discriminatory capability (area under the curve = 0.74). Cross-validation showed similar probabilities comparing predicted and observed failures indicating high accuracy of the model.

Conclusion

This is the first study in the orthopaedic literature to use machine learning as a tool for predicting outcomes following I&D surgery. The developed algorithm provides the medical profession with a tool that can be employed in clinical decision-making and improve patient care. Future studies should aid in further validating this tool on additional cohorts. Cite this article: Bone Joint J 2020;102-B(7 Supple B):11–19.
The burden and utility of routine follow-up at one year after primary arthroplasty
Authors: Barrack Toby N. , Abu-Amer Wahid , Schwabe Maria T. , Adelani Muyibat A. , Clohisy John C. , Nunley Ryan M. , Lawrie Charles M.
Published: June 2020

Aims

Routine surveillance of primary hip and knee arthroplasties has traditionally been performed with office follow-up visits at one year postoperatively. The value of these visits is unclear. The present study aims to determine the utility and burden of routine clinical follow-up at one year after primary arthroplasty to patients and providers.

Methods

All patients (473) who underwent primary total hip (280), hip resurfacing (eight), total knee (179), and unicompartmental knee arthroplasty (six) over a nine-month period at a single institution were identified from an institutional registry. Patients were prompted to attend their routine one-year postoperative visit by a single telephone reminder. Patients and surgeons were given questionnaires at the one-year postoperative visit, defined as a clinical encounter occurring at nine to 15 months from the date of surgery, regarding value of the visit.

Results

Compliance with routine follow-up at one year was 35%. The response rate was over 80% for all questions in the patient and clinician surveys. Overall, 75% of the visits were for routine surveillance. Patients reported high satisfaction with their visits despite the general time for attendance, including travel, being over four hours. Surgeons found the visits more worthwhile when issues were identified or problems were addressed.

Conclusion

Patient compliance with follow-up at one year postoperatively after primary hip and knee is low. Routine visits of asymptomatic patients deliver little practical value and represent a large time and cost burden for patients and surgeons. Remote strategies should be considered for routine postoperative surveillance primary hip and knee arthroplasties beyond the acute postoperative period. Cite this article: Bone Joint J 2020;102-B(7 Supple B):85–89.
2020 Otto Aufranc Award: Malseating of modular dual mobility liners
Authors: Romero Joey , Wach Amanda , Silberberg Scott , Chiu Yu-Fen , Westrich Geoffrey , Wright Timothy M. , Padgett Douglas E.
Published: June 2020

Aims

This combined clinical and in vitro study aimed to determine the incidence of liner malseating in modular dual mobility (MDM) constructs in primary total hip arthroplasties (THAs) from a large volume arthroplasty centre, and determine whether malseating increases the potential for fretting and corrosion at the modular metal interface in malseated MDM constructs using a simulated corrosion chamber.

Methods

For the clinical arm of the study, observers independently reviewed postoperative radiographs of 551 primary THAs using MDM constructs from a single manufacturer over a three-year period, to identify the incidence of MDM liner-shell malseating. Multivariable logistic regression analysis was performed to identify risk factors including age, sex, body mass index (BMI), cup design, cup size, and the MDM case volume of the surgeon. For the in vitro arm, six pristine MDM implants with cobalt-chrome liners were tested in a simulated corrosion chamber. Three were well-seated and three were malseated with 6° of canting. The liner-shell couples underwent cyclic loading of increasing magnitudes. Fretting current was measured throughout testing and the onset of fretting load was determined by analyzing the increase in average current.

Results

The radiological review identified that 32 of 551 MDM liners (5.8%) were malseated. Malseating was noted in all of the three different cup designs. The incidence of malseating was significantly higher in low-volume MDM surgeons than high-volume MDM surgeons (p < 0.001). Pristine well-seated liners showed significantly lower fretting current values at all peak loads greater than 800 N (p < 0.044). Malseated liner-shell couples had lower fretting onset loads at 2,400 N.

Conclusion

MDM malseating remains an issue that can occur in at least one in 20 patients at a high-volume arthroplasty centre. The onset of fretting and increased fretting current throughout loading cycles suggests susceptibility to corrosion when this occurs. These results support the hypothesis that malseated liners may be at risk for fretting corrosion. Clinicians should be aware of this phenomenon. Cite this article: Bone Joint J 2020;102-B(7 Supple B):20–26.
Trends in the use of dual mobility bearings in hip arthroplasty
Authors: Heckmann Nathanael , Weitzman Dena S. , Jaffri Heena , Berry Daniel J. , Springer Bryan D. , Lieberman J. R.
Published: June 2020

Aims

Dual mobility (DM) bearings are an attractive treatment option to obtain hip stability during challenging primary and revision total hip arthroplasty (THA) cases. The purpose of this study was to analyze data submitted to the American Joint Replacement Registry (AJRR) to characterize utilization trends of DM bearings in the USA.

Methods

All primary and revision THA procedures reported to AJRR from 2012 to 2018 were analyzed. Patients of all ages were included and subdivided into DM and traditional bearing surface cohorts. Patient demographics, geographical region, hospital size, and teaching affiliation were assessed. Associations were determined by chi-squared analysis and logistic regression was performed to assess outcome variables.

Results

A total of 406,900 primary and 34,745 revision THAs were identified, of which 35,455 (8.7%) and 8,031 (23.1%) received DM implants respectively. For primary THA, DM usage increased from 6.7% in 2012 to 12.0% in 2018. Among revision THA, DM use increased from 19.5% in 2012 to 30.6% in 2018. Patients < 50 years of age had the highest rates of DM implantation in every year examined. For each year of increase in age, there was a 0.4% decrease in the rate of DM utilization (odds ratio (OR) 0.996 (95% confidence interval (CI) 0.995 to 0.997); p < 0.001). Females were more likely to receive a DM implant compared to males (OR 1.077 (95% CI 1.054 to 1.100); p < 0.001). Major teaching institutions and smaller hospitals were associated with higher rates of utilization. DM articulations were used more commonly for dysplasia compared with osteoarthritis (OR 2.448 (95% CI 2.032 to 2.949); p < 0.001) during primary THA and for instability (OR 3.130 (95% CI 2.751 to 3.562) vs poly-wear; p < 0.001) in the revision setting.

Conclusion

DM articulations showed a marked increase in utilization during the period examined. Younger patient age, female sex, and hospital characteristics such as teaching status, smaller size, and geographical location were associated with increased utilization. DM articulations were used more frequently for primary THA in patients with dysplasia and for revision THA in patients being treated for instability. Cite this article: Bone Joint J 2020;102-B(7 Supple B):27–32.
Patient-related risk factors associated with less favourable outcomes following hip arthroscopy
Authors: Kuroda Yuichi , Saito Masayoshi , Çınar Ece Nur , Norrish Alan , Khanduja Vikas
Published: June 2020

Aims

This paper aims to review the evidence for patient-related factors associated with less favourable outcomes following hip arthroscopy.

Methods

Literature reporting on preoperative patient-related risk factors and outcomes following hip arthroscopy were systematically identified from a computer-assisted literature search of Pubmed (Medline), Embase, and Cochrane Library using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and a scoping review.

Results

Assessment of these texts yielded 101 final articles involving 90,315 hips for qualitative analysis. The most frequently reported risk factor related to a less favourable outcome after hip arthroscopy was older age and preoperative osteoarthritis of the hip. This was followed by female sex and patients who have low preoperative clinical scores, severe hip dysplasia, altered hip morphology (excess acetabular retroversion or excess femoral anteversion or retroversion), or a large cam deformity. Patients receiving workers’ compensation or with rheumatoid arthritis were also more likely to have a less favourable outcome after hip arthroscopy. There is evidence that obesity, smoking, drinking alcohol, and a history of mental illness may be associated with marginally less favourable outcomes after hip arthroscopy. Athletes (except for ice hockey players) enjoy a more rapid recovery after hip arthroscopy than non-athletes. Finally, patients who have a favourable response to local anaesthetic are more likely to have a favourable outcome after hip arthroscopy.

Conclusion

Certain patient-related risk factors are associated with less favourable outcomes following hip arthroscopy. Understanding these risk factors will allow the appropriate surgical indications for hip arthroscopy to be further refined and help patients to comprehend their individual risk profile. Cite this article: Bone Joint J 2020;102-B(7):822–831.
Risk factors for secondary displacement in conservatively treated proximal humeral fractures
Authors: Frank Florian A. , Niehaus Richard , Borbas Paul , Eid Karim
Published: June 2020

Aims

Conservative treatment of moderately displaced proximal humeral head fractures yields good clinical results, but secondary fragment displacement may occur. Identification of those fractures at risk of displacement may influence initial decision-making.

Methods

A total of 163 shoulders in 162 patients with conservatively treated isolated proximal humeral fractures were included. The fractures occurred between January 2015 and May 2018. The mean age of the patients was 69 years (26 to 100) and the mean follow-up was 144 days (42 to 779). The fractures were classified according to Neer. Scores for osteoporosis (Tingart, Deltoid Tuberosity Index (DTI)) and osteoarthritis (OA) of the glenohumeral joint were assessed. Translation of the head on follow-up radiographs of more than 10 mm was defined as displacement. Eccentric head index (EHI) describes the offset of the humeral head centre in relation to the diaphyseal axis. The ratio was estimated on anteroposterior (AP) and Neer views. Medial hinge was considered intact if the medial cortex proximal and distal to the fracture was in line on AP view.

Results

Secondary fracture displacement occurred in 41 patients (25.2%). Clinical risk factors were alcohol abuse (odds ratio (OR) 6.8; 95% confidence interval (CI) 1.3 to 36; p = 0.025) and previously diagnosed osteoporosis (OR 4.6; 95% CI 0.6 to 34; p = 0.136). Age (OR 1.1; 95% CI 1.0 to 1.1; p = 0.003) and sex (OR 0.9; 95% CI 0.3 to 2.8; p = 0.867) were not independent factors. Radiological risk factors were OA grade 3 (OR 16.4; 95% CI 0.25 to 37.6; p = 0.107) and osteoporosis with the DTI (OR 10; 95% CI 0.8 to 250; p = 0.031) being more predictive than the Tingart score (OR 2.3; 95% CI 0.8 to 4.7; p = 0.041). A high EHI (AP/Neer > 0.4, OR 18.9; 95% CI 2.1 to 30.9/3.0; 95% CI 1.1 to 8.0; p = 0.002/p = 0.033) and a disrupted medial hinge (OR 3.7; 95% CI 1.1 to 12.6; p = 0.039) increased the risk of secondary displacement significantly. Neer classification had no influence.

Conclusion

During conservative treatment, a quarter of patients showed secondary fracture displacement of at least 10 mm. Patients with alcohol abuse, severe OA, and osteoporosis are at risk. Newly defined EHI and disrupted medial hinge are relevant predictors for secondary displacement. Cite this article: Bone Joint J 2020;102-B(7):881–889.
Conocimientos matemáticos al acceder a la universidad. Un estudio diacrónico (1999-2017) con estudiantes de ingeniería
Authors: Nieto-Isidro Susana , Martínez-Abad Fernando , Rodríguez-Conde María José
Published: June 2020

INTRODUCCIÓN. Aunque existen diversos estudios sobre los conocimientos matemáticos de los estudiantes que acceden a la universidad en España, son escasos los que abarcan largos periodos de tiempo y tienen en cuenta la legislación de acceso en cada periodo. MÉTODO. Se analizan las respuestas en una prueba objetiva de cálculo básico de 627 estudiantes de nuevo ingreso en 8 titulaciones de ingeniería durante 18 años, de 1999 hasta 2017, siguiendo dos normativas de acceso a la universidad vigentes en las etapas 1999-2009 y 2010-2017. El instrumento aplicado incluyó cuestiones teóricas y prácticas, de las cuales se han seleccionado siete ítems relacionados con logaritmos, exponenciales, derivación e integración. Se realiza un estudio diacrónico agrupando los datos en ocho bienios, cinco con la primera normativa y tres con la segunda, mediante cálculo de proporciones y análisis inferencial, incluyendo el tamaño del efecto. RESULTADOS. Los estudiantes presentan comportamientos estadísticamente diferentes en cada etapa legislativa, y la legislación vigente en 2011-2017 permite la generación de grupos con distintos conocimientos en función de sus elecciones y/o resultados en la Prueba de Acceso a la Universidad. El tipo de contenido matemático de cada ítem seleccionado también es relevante, mostrando mejores resultados en logaritmos y exponenciales, y peores en integración. DISCUSIÓN. Se muestra la gran variabilidad del nivel de conocimientos matemáticos de los alumnos que acceden a estudios de ingeniería y la influencia de la legislación de acceso en estos conocimientos; estos resultados pueden servir de referencia para el diseño de futuras pruebas de acceso a la universidad.
Percepciones del docente en formación hacia la respuesta educativa en centros de educación especial. Diseño y propiedades psicométricas de una escala
Authors: Pegalajar M.ª del Carmen
Published: June 2020

INTRODUCCIÓN. El actual sistema educativo español, definido en la Ley Orgánica para la Mejora de la Calidad Educativa (2013) considera el centro específico de educación especial como una modalidad de escolarización para el alumnado con discapacidad grave y permanente, cuya respuesta educativa debe ir más allá del ámbito asistencial. Además, se debe promover su aprendizaje, autonomía personal e integración social, lo cual requiere de una adecuada formación inicial del docente. Para ello, el docente constituye un elemento de primer orden para la atención al alumnado con discapacidad, siendo de interés disponer de un instrumento de evaluación hacia las percepciones docentes de educación infantil y primaria en formación hacia la respuesta educativa al alumnado con discapacidad grave y permanente. MÉTODO. El objetivo de este trabajo es mostrar los resultados del análisis psicométrico de una escala ad hoc que permite examinar las percepciones del docente en formación hacia la respuesta educativa al alumnado con discapacidad escolarizado en centros específicos de educación especial. RESULTADOS. Los resultados obtenidos muestran una adecuada validez de contenido, obtenida a partir del juicio de expertos. Además, la totalidad de los ítems de la escala se han agrupado a partir de 5 factores, confirmándose la adecuada validez de constructo (obtenida a partir del análisis factorial exploratorio y confirmatorio), así como un alto nivel de fiabilidad. DISCUSIÓN. Dicha escala se considera un instrumento de evaluación sólido para el análisis de las percepciones del docente en formación hacia la respuesta educativa al alumnado con discapacidad grave y permanente. Un instrumento que puede ser utilizado por el profesorado universitario responsable de la formación inicial del docente con fines de investigación. De hecho, resulta preciso conocer las percepciones de los futuros profesionales de la educación hacia la atención a la diversidad, para así ajustar la respuesta formativa ofertada desde las instituciones universitarias a sus necesidades e intereses.