bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Pain Phenotypes in Knee Osteoarthritis Using Latent Profile Analysis
Authors: Kittelson Andrew J , Schmiege Sarah J , Maluf Katrina , George Steven Z , Stevens-Lapsley Jennifer E 
Published: December 2020

Abstract

Objective
To identify clinical phenotypes of knee osteoarthritis (OA) using measures from the following domains: 1) multimorbidity; 2) psychological distress; 3) pain sensitivity; and 4) knee impairment or pathology.

Design
Data were collected from 152 people with knee OA and from 31 pain-free individuals. In participants with knee OA, latent profile analysis (LPA) was applied to the following measures: normalized knee extensor strength, Functional Comorbidity Index (FCI), Pain Catastrophizing Scale (PCS), and local (knee) pressure pain threshold. Comparisons were performed between empirically derived phenotypes from the LPA and healthy older adults on these measures. Comparisons were also made between pheonotypes on pain intensity, functional measures, use of health care, and history of knee injury.

Results
LPA resulted in a four-group solution. Compared with all other groups, group 1 (9% of the study population) had higher FCI scores. Group 2 (63%) had elevated pain sensitivity and quadriceps weakness relative to group 4 and healthy older adults. Group 3 (11%) had higher PCS scores than all other groups. Group 4 (17%) had greater leg strength, except relative to healthy older adults, and reduced pain sensitivity relative to all groups. Groups 1 and 3 demonstrated higher pain and worse function than other groups, and group 4 had higher rates of knee injury.

Conclusion
Four phenotypes of knee OA were identified using psychological factors, comorbidity status, pain sensitivity, and leg strength. Follow-up analyses supported the replicability of this phenotype structure, but future research is needed to determine its usefulness in knee OA care.
Trapped modes in a multi-layer fluid
Authors: Cal F S , Dias G A S , Pereira B M M , Videman J H 
Published: December 2020

Summary
In this article, we study the existence of solutions for the problem of interaction of linear water waves with an array of three-dimensional fixed structures in a density-stratified multi-layer fluid, where in each layer the density is assumed to be constant. Considering time-harmonic small-amplitude motion, we present recursive formulae for the coefficients of the eigenfunctions of the spectral problem associated with the water-wave problem in the absence of obstacles and for the corresponding dispersion relation. We derive a variational and operator formulation for the problem with obstacles and introduce a sufficient condition for the existence of propagating waves trapped in the vicinity of the array of obstacles. We present several (arrays of) structures supporting trapped waves and discuss the possibility of approximating the continuously stratified fluid by a multi-layer model.
Base of thumb osteoarthritis in UK interface services—a cohort and survey-based study to assess current practice
Authors: Dean Benjamin J F , Kluzek Stefan , Carr Andrew J , Hopewell Sally , Richards Duncan , Riley Nicholas , Cuff Andrew ,   Oxford Base of Thumb Collaborative
Published: December 2020

Abstract

Objective
Base of thumb OA (BTOA) is a common age-related disease that has a significant negative impact on quality of life, while little is known about the structure and pathways of interface services. Our aim was to assess disease burden, referral pathways, service structure and management pathways in UK interface services.

Methods
A structured questionnaire was carried out with a participating clinician at each centre to detail the local guidelines and management of BTOA. Five patients referred with BTOA were prospectively identified in each of 32 UK interface centres.

Results
Most centres (72%) had a local guideline and a standardized treatment regime consisting of education (100%), joint protection (100%), range of motion exercises (84%), strengthening exercises (88%), splintage (100%) and use of assistive devices (78%). No centre routinely offered a steroid injection at the first appointment and no centre had a specific threshold for offering an injection. Injection delivery was variable. Most patients had not been referred previously (82%). Most patients used analgesia (72%), but a minority of patients had been treated with a splint (46%), therapy (43%) and steroid injection (27%) prior to their latest attendance.

Conclusion
Most BTOA patients newly referred to interface services have been treated with analgesics and have not received comprehensive multimodal intervention. The management of BTOA at interface services is standardized in terms of education, splintage and therapy. However, there is a lack of standardization in terms of both the threshold for, timing of and mode of delivery of injection therapy.
Recent studies on railway-track substructure at TTCI
Authors: Li Dingqing , Wilk Stephen 
Published: December 2020

Abstract
Railway-track substructure is the foundation of the railway-track infrastructure and consists of four major components: ballast, sub-ballast, subgrade and drainage. Safety and performance of the track infrastructure, to a large degree, depends on the performance of the track substructure. Adequate support from the track substructure is the most critical element needed for good track performance. When properly constructed and maintained, the ballasted track is the most cost-effective track structure for railway operations, especially for heavy-haul freight operations. Good track-substructure support is characterized by good drainage and strong resistance of the ballast, sub-ballast and subgrade layers to excessive deformation and failures under repeated dynamic wheel loads. As the track substructure plays such important roles, research concerning track substructure has been broad and extensive around the world, with many universities and research institutes conducting various studies and investigations. This paper provides an overview of the recent research conducted at Transportation Technology Center, Inc. (TTCI), a subsidiary of the Association of American Railroads (AAR), in the following areas: ballast mud pumping and its effects on track performance, remediation of subgrade mud pumping, remediation of ballast pockets, ground-penetrating radar (GPR) for inspecting track substructure, and development of software tools with focus on track-substructure functions and management.
Preoperative and Postoperative, Three-dimensional Gait Analysis in Surgically Treated Patients With High-grade Spondylolisthesis
Authors: Trivedi Jayesh , Srinivas Shreya , Trivedi Rishi , Davidson Neil , Munigangaiah Sudarshan , Bruce Colin , Bass Alf , Wright David 
Published: December 2020

Background:
High-grade spondylolisthesis (HGS) (Myerding grade III-V) in adolescents can lead to a marked alteration of gait pattern and maybe the presenting symptom in these patients. This characteristic gait pattern in patients with HGS has been referred to as the “pelvic waddle.” Modern 3-dimensional (3D) gait analysis serves an important tool to objectively analyze the different components of this characteristic gait preoperatively and postoperatively and is an objective measure of postoperative improvement.
This study demonstrates the use of 3D gait analysis preoperatively and postoperatively in a cohort of 4 consecutive patients with HGS treated surgically at a single tertiary referral center and utilize this to objectively evaluate outcome of surgical treatment in these patients. This has not been reported previously in a cohort of patients.

Methods:
This is a prospective analysis of patients with HGS who underwent surgical intervention for spondylolisthesis at a single institution. Patient demographics, clinical, and radiologic assessment were recorded, and all patients underwent 3D gait analysis before and after surgical intervention. Kinetic, kinematic, and spatial parameters were recorded preoperatively and postoperatively for all patients. This allowed the outcome of change in gait deviation index, before and after surgical treatment, to be evaluated.

Results:
We were able to review complete records of 4 adolescent patients who underwent surgical treatment for HGS. Mean age at surgery was 13.5 years with a minimum follow-up of 2.5 years postoperatively (average 40 mo). Preoperative gait analysis revealed marked posterior pelvic tilt in 2 patients, reduced hip and knee extension in all 4 patients and external foot progression in 3 of the 4 patients. Along with an observed improvement in gait, there was an objective improvement in gait parameters postoperatively in all 4 patients. Gait deviation index score improved significantly from 78.9 to 101.3 (mean).

Conclusions:
Preoperative gait abnormalities exist in HGS and can be objectively analyzed with gait analysis. Surgical intervention may successfully resolve these gait abnormalities and gait analysis is a useful tool to assess the outcome of surgery and quantify an otherwise intangible benefit of surgical intervention.

Level of Evidence:
Level IV—case series.
Predictors of Readmission and Prolonged Length of Stay After Cervical Disc Arthroplasty
Authors: Zeidan Michelle , Goz Vadim , Lakomkin Nikita , Spina Nicholas , Brodke Darrel S. , Spiker William R. 
Published: December 2020

Study Design.
Retrospective cohort study.

Objective.
The aim of the study was to assess which factors increase risk of readmission within 30 days of surgery or prolonged length of stay (LOS) (≥2 days) after cervical disc arthroplasty (CDA).

Summary of Background Data.
Several studies have shown noninferiority at mid- and long-term outcomes after cervical disc arthroplasty (CDA) compared to anterior cervical discectomy and fusion ACDF, but few have evaluated short-term outcomes regarding risk of readmission or prolonged LOS after surgery.

Methods.
Demographics, comorbidities, operative details, postoperative complications, and perioperative outcomes were collected for patients undergoing single level CDA in the National Surgical Quality Improvement Program (NSQIP) database. Patients with prolonged LOS, defined as >2 days, and readmission within 30 days following CDA were identified. Univariable and multivariable logistic regression models were used to identify risk factors for prolonged LOS and readmission.

Results.
A total of 3221 patients underwent single level CDA. Average age was 45.6 years (range 19–82) and 53% of patients were male. A total of 472 (14.7%) experienced a prolonged LOS and 36 (1.1%) patients were readmitted within 30 days following surgery. Predictors of readmission were postoperative superficial wound infection (odds ratio [OR] = 73.83, P < 0.001), American Society of Anesthesiologists (ASA) classification (OR = 1.98, P = 0.048), and body mass index (BMI) (OR = 1.06, P = 0.02). Female sex (OR = 1.76, P < 0.001), diabetes (OR = 1.50, P = 0.024), postoperative wound dehiscence (OR = 13.11, P = 0.042), ASA class (OR = 1.43, P < 0.01), and operative time (OR = 1.01, P < 0.001) were significantly associated with prolonged LOS.

Conclusion.
From a nationwide database analysis of 3221 patients, wound complications are predictors of both prolonged LOS and readmission. Patient comorbidities, including diabetes, higher ASA classification, female sex, and higher BMI also increased risk of prolonged LOS or readmission.

Level of Evidence: 3
PLF Versus PLIF and the Fate of L5-S1
Authors: Guppy Kern H. , Royse Kathryn E. , Norheim Elizabeth P. , Harris Jessica E. , Brara Harsimran S. 
Published: December 2020

Study Design.
A retrospective cohort study with chart review.

Objective.
The aim of this study was to compare the reoperation rates for symptomatic nonunions (operative nonunion rates) between posterolateral fusions with pedicle screws (PLFs) and posterior interbody fusion with pedicle screws (PLIFs).

Summary of Background Data.
Although radiographic nonunions in PLFs and PLIFs are well documented in the literature, there is no consensus on which technique has lower nonunions. Since some radiographic nonunions may be asymptomatic, a more clinically useful measure is operative nonunions, of which there is minimal research.

Methods.
A retrospective cohort study, using data from the Kaiser Permanente Spine Registry, identified adult patients (≥18 years’ old) who had elective single and multilevel PLFs and PLIFs. Descriptive statistics and 2-year incidence rates for operative nonunions were calculated by fusion-level (1–3), fusion type (PLF vs. PLIF), and levels fused (L3 to S1). Time-dependent multivariable Cox-Proportional Hazards regression was used to evaluate nonunion reoperation rates with adjustment for covariates.

Results.
The cohort consisted of 3065 patients with PLFs (71.6%) and PLIFs (28.4%). Average age was 65.0 ± 11.7, average follow-up time was 4.8 ± 3.1 years, and average time to operative nonunion was 1.6 (±1.3) years. Single and multilevel incidence rates for nonunions after PLF versus PLIF were similar except for three-level fusions (2.9% [95% confidence interval, CI = 1.0–6.7] vs. 7.1% [95% CI = 0.2–33.9]). In adjusted models, there was no difference in risk of operative nonunions in PLIF compared to PLF (hazard ratio [HR]: 0.8, 95% CI = 0.4–1.6); however, patients with L5-S1 constructs with PLFs had 2.8 times the risk of operative nonunion compared to PLIFs (PLF: HR = 2.8, 95% CI = 1.3–6.2; PLIF: HR = 1.5, 95% CI = 0.4–5.1).

Conclusion.
In a large cohort of patients with >4 years of follow-up, we found no difference in operative nonunions between PLF and PLIF except for constructs that included L5-S1 in which the risk of nonunion was limited to PLF patients.

Level of Evidence: 3
A Prospective Cohort Study of Dysphagia After Subaxial Cervical Spine Surgery
Authors: Sakai Kenichiro , Yoshii Toshitaka , Arai Yoshiyasu , Hirai Takashi , Torigoe Ichiro , Inose Hiroyuki , Tomori Masaki , Sakaki Kyohei , Yuasa Masato , Yamada Tsuyoshi , Matsukura Yu , Oyaizu Takuya , Morishita Shingo , Okawa Atsushi 
Published: December 2020

Study Design.
Prospective observational cohort study.

Objective.
To prospectively examine dysphagia after subaxial cervical spine surgery.

Summary of Background Data.
Although dysphagia after anterior cervical spine surgery is common and well-studied, it has rarely been examined in posterior subaxial cervical spine surgery.

Methods.
This study analyzed 191 consecutive patients (132 male, 59 female; mean age, 64.9 yrs) who underwent subaxial cervical spine surgery for degenerative disease and completed 1 year of follow-up. Anterior decompression with fusion (ADF) was performed in 87 patients, posterior decompression with fusion (PDF) in 21, and laminoplasty (LAMP) in 83. Dysphagia was evaluated by a self-administered questionnaire using the Bazaz dysphagia scale before, 6 months, and 1 year after surgery. Diagnosis, levels and number of operative segments, C2–7 lordotic angle (CL), O–C2 angle (OC2A), C2–7 range of motion (ROM), Japanese Orthopedic Association for cervical myelopathy (C-JOA) score, and neck pain visual analog scale (VAS) were examined.

Results.
Thirty-two patients (16.8%) reported dysphagia before surgery. New dysphagia after surgery, defined as more than or equal to 1 grade worsening of the Bazaz score after surgery compared with the preoperative status, was observed in 38 patients (19.9%) at 6 months and 32 patients (16.8%) at 1 year. The incidence of new dysphagia at 1 year was 25.3% in the ADF group, 23.8% in the PDF group, and 6.0% in the LAMP group. Fusion surgery (ACDF or PDF) and increased CL after surgery were found as risk factors at 1 year in multivariate analysis; receiver operating characteristic analysis determined a postsurgical change in CL cutoff of 5°.

Conclusion.
Fusion surgery and increased CL after surgery were risk factors for development of dysphagia after subaxial cervical spine surgery. Cervical alignment change due to anterior and posterior fusion surgery can cause postoperative dysphagia.

Level of Evidence: 3
Biomechanical Evaluation of a Dynamic Stabilization System for the Prevention of Proximal Junctional Failure in Adult Deformity Surgery
Authors: Ha Alex S. , Hong Daniel Y. , Coury Josephine R. , Luzzi Andrew J. , Yerukhimov Alex L. , Kim Jisoo , Huang Peng , Sengupta Dilip K. 
Published: December 2020

Study Design.
Biomechanical spine model. Comparison of stress in the implant and the adjacent cranial segment was done with conventional rigid versus dynamic stabilization system (DS) fixation.

Objective.
The aim of this study was to study stress at the proximal end of spinal fixation with a novel DS.

Summary of Background Data.
High stress at the implant bone junction may cause proximal junctional failure (PJF) in adult deformity surgery.

Methods.
Five life-size spine models were instrumented with pedicle screws and a 5.5-mm Titanium rod from T8-S1. The same models were subsequently instrumented with a similar rod and DS between T8-9 pedicle screws. The spine model was loaded with 25 Nm static load cranial to the proximal fixation in six directions. Strains were measured from the proximal screws. Disc pressure was measured from the proximal instrumented segment (T8-9) and cranial adjacent segment (T7-8).

Results.
Rigid fixation produced highest strain at T8, followed by T10 then T9. In contrast, DS fixation produced highest strain at T10, followed by T9 then T8. Strain at T8 was significantly less with DS fixation than rigid fixation (P = 0.019). The T10 screw strain was not significantly higher with DS stabilization compared to rigid fixation (P = 0.091). Rigid fixation allowed no load-sharing or pressure rise at T8-9 but an abrupt rise at T7-8. DS system permitted load-sharing and pressure rise in T8-9; the difference compared to rigid fixation was significant in flexion loading (P = 0.04) and similar trend but not significant in extension (P = 0.09). DS system produced a rise in the adjacent segment disc pressure (T7-8), which was smaller than rigid fixation but not significant.

Conclusion.
Long spinal fixation using rigid rods produces maximum stress at the proximal end screw and increases adjacent disc pressure, possibly leading to PJF. Dynamic stabilization at the cranial end segment may prevent PJF by reducing these factors.

Level of Evidence: N/A
Leukemia Cutis With Histopathologic and Immunophenotypic Features Resembling S100-Negative CD1a-Positive Cutaneous Histiocytosis
Authors: Kamili Nourine A. , Morrison Casey E. , Bagg Adam , Westheim Alan , Hafeez Farhaan 
Published: December 2020

Abstract:
S100-negative CD1a-positive cutaneous histiocytosis is an exceedingly rare histiocytosis that is defined histopathologically by a dense dermal infiltrate of ovoid mononuclear cells with grooved nuclei and ample cytoplasm with variable nuclear atypia and mitoses that are immunohistochemically positive for CD1a and negative for S100 and CD207 (langerin). The histogenesis of S100-negative CD1a-positive histiocytosis is unclear, and its precursor cell has yet to be characterized. Although all cases thus far have been described as benign and occasionally self-resolving, the clinical course and outcome of this disease are not fully understood. This case expands the spectrum of disease associated with S100-negative CD1a-positive histiocytosis given its malignant course.
The Pregnancy Heart Team Approach for the Adult with Hypertrophic Cardiomyopathy and Severe Left Ventricular Outflow Tract Obstruction
Authors: Huang Sihong , Samuel Bennett P. , Cordoba Marcos , Romero Vivian C. , Chalifoux Laurie , Fermin David R. , Cook Stephen C. 
Published: December 2020

Abstract
Hypertrophic cardiomyopathy (HCM), the most common single-gene cardiovascular disease, is associated with increased risk for arrhythmias, heart failure, and sudden cardiac death. The hemodynamic changes known to occur during pregnancy can exacerbate heart failure and arrhythmias in women with HCM. We present a 30-year-old woman with HCM to illustrate the benefits of multidisciplinary team management of severe left ventricular outflow tract obstruction (peak gradient >100 mmHg) for optimal maternal and fetal outcomes.
Country of birth and mortality risk in hypertension with and without diabetes: the Swedish primary care cardiovascular database
Authors: Andersson Tobias , Pikkemaat Miriam , Schiöler Linus , Hjerpe Per , Carlsson Axel C. , Wändell Per , Manhem Karin , Kahan Thomas , Bengtsson Boström Kristina 
Published: December 2020

Objectives:
Hypertension and diabetes are common and are both associated with high cardiovascular morbidity and mortality. We aimed to investigate associations between mortality risk and country of birth among hypertensive individuals in primary care with and without concomitant diabetes, which has not been studied previously. In addition, we aimed to study the corresponding risks of myocardial infarction and ischemic stroke.

Methods:
This observational cohort study of 62 557 individuals with hypertension diagnosed 2001–2008 in the Swedish Primary Care Cardiovascular Database assessed mortality by the Swedish Cause of Death Register, and myocardial infarction and ischemic stroke by the National Patient Register. Cox regression models were used to estimate study outcome hazard ratios by country of birth and time updated diabetes status, with adjustments for multiple confounders.

Results:
During follow-up time without diabetes using Swedish-born as reference, adjusted mortality hazard ratios per country of birth category were Finland: 1.26 (95% confidence interval 1.15–1.38), high-income European countries: 0.84 (0.74–0.95), low-income European countries: 0.84 (0.71–1.00) and non-European countries: 0.65 (0.56–0.76). The corresponding adjusted mortality hazard ratios during follow-up time with diabetes were high-income European countries: 0.78 (0.63–0.98), low-income European countries: 0.74 (0.57–0.96) and non-European countries: 0.56 (0.44–0.71). During follow-up without diabetes, the corresponding adjusted hazard ratio of myocardial infarction was increased for Finland: 1.16 (1.01–1.34), whereas the results for ischemic stroke were inconclusive.

Conclusion:
In Sweden, hypertensive immigrants (with the exception for Finnish-born) with and without diabetes have a mortality advantage, as compared to Swedish-born.
Caring work environments and clinician emotional exhaustion
Authors: Rathert Cheryl , Ishqaidef Ghadir , Porter Tracy H. 
Published: December 2020

Background
Burnout has been a chronic problem in the workplace, especially in health care. Although the literature has examined many antecedents to burnout, specific workplace practices to reduce burnout remain elusive. Nascent research has begun to examine how health care work places can become more caring for workers. Although psychological safety has been proposed as an important predictor of burnout, relations have not yet been comprehensively examined.

Purpose
Underpinned by conservation of resources theory, we argue that a caring work environment, in which compassion and interpersonal support are key priorities, provides resources for workers, which should increase psychological safety and in turn help reduce emotional exhaustion.

Method
To explore our proposed model, we conducted a paper-and-pencil survey of clinical health care providers working in medical units of a large acute care hospital. Response rate was 44% (n = 631).

Results
Analysis found support for a moderated-mediation model in which psychological safety partially mediated relations between caring climate and emotional exhaustion, and this effect was stronger for those who were less empowered in their jobs.

Conclusion
Our findings suggest that a caring work environment holds psychological resources that may help buffer against resource losses through increased psychological safety.

Practical Implications
Although health care work environments will continue to experience constraints on key resources, worker emotional exhaustion may be mitigated through a focus on systematically increasing caring and compassion in the work environment, as opposed to relying on individual workers to support one another in an uncaring workplace.