1,720,989 research outputs found
Additional Screw Added to the Femoral Neck System Could Enhance the Stability of Pauwel Type III Femoral Neck Fractures: a Finite Element Analysis
No full textBACKGROUD: This study explores effective fixation methods for Pauwel type III femoral neck fractures by evaluating the biomechanical benefits of adding a screw to the Femoral Neck System (FNS). METHODS: Computed tomography (CT) scans of an 82-year-old female patient with an intertrochanteric fracture were used to establish a finite element femur model with heterogeneous material properties. Finite element models of Pauwel type III fractures were created with and without an additional screw. The central and inferior trajectories of the FNS bolt were examined separately and combined with an additional screw for virtual fixation. Walking and stair-climbing loads were applied. RESULTS: With the addition of a screw, both peak maximum and minimum principal strains consistently stayed comparable or decreased in models with both central and inferior bolt trajectories, while the volume of elements with principal strain exceeding 1% decreased by more than half. The peak von Mises stress observed in the implants ranged from 215.7 to 359.3 MPa, remaining below the titanium alloy's yield strength of 800 MPa. For normal walking, the addition of a screw to the central bolt trajectory model decreased the fracture gap by 50.6% and reduced sliding distance by 8.6%. For the inferior bolt trajectory, the gap was reduced by 57.9% and sliding distance by 25.0%. Under stair-climbing conditions, these improvements were also evident; the central trajectory model saw a halved fracture gap and a 7.9% decrease in sliding distance, while the inferior trajectory model experienced a 55.7% gap reduction and a 27.2% decrease in sliding distance. The additional screw increased the area ratio of the fracture site experiencing interfragmentary compression 34%-39%, while the additional screw alleviated peak interfragmentary compression by 12%-18% under both normal walking and stair-climbing conditions. CONCLUSIONS: The addition of a screw reduced the fracture gap, sliding distance, and peak interfragmentary compression, while increasing the area ratio of interfragmentary compression under both walking and stair-climbing loads, regardless of the FNS bolt trajectory, suggesting a better mechanical environment for fracture healing
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Clinical and radiological results of early pin removal in pediatric radial neck fractures treated with stepwise percutaneous leverage technique
No full textOBJECTIVE: The aim of this study was to compare radiological and clinical results between early (≤3 weeks) and late (>3 weeks) removal of pins in patients treated with the stepwise percutaneous leverage technique for radial neck fractures. METHODS: 37 patients (aged 3-15) who underwent fixation with stepwise percutaneous leverage technique for Judet class III and class IV radial neck fractures between 2003 and 2019 were included in this retrospective study. Patients were divided into two groups according to the time of pin removal; 19 had early pin removal (≤3 weeks) and 18 had late pin removal (>3 weeks). The patients' radiological results were graded using the Metaizeau classification and their clinical results were evaluated by measuring their range of motion (ROM) and Mayo elbow performance scores (MEPS) at postoperative follow-ups. Statistical tests, including the Mann-Whitney U and Chi-square tests, were performed to compare the demographic factors and outcomes. RESULTS: The mean time of removal of pins for all patients was 21 (10-43) days. The mean time for early and late removal was 15.1 (10-21) and 27.6 (22-43) days, respectively. There was no statistically significant difference between groups radiologically according to the Metaizeau classification (P = .723). Furthermore, no statistically significant difference was found in the ROM (extension/flexion: P = .620, pronation/supination: P = .578) or MEPS (P = .695) between groups. CONCLUSION: This study has shown us that early removal of pins in patients with pediatric radial neck fractures treated with stepwise percutaneous leverage technique demonstrated good radiological and clinical results comparable to late pin removal. Level of Evidince: Level IV, Therapeutic Study
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Complications and outcomes of operative treatment for acute perilunate injuries: a systematic review
No full textWe systematically reviewed the incidence of complications and outcomes of different surgical methods for acute perilunate injury in the MEDLINE, Scopus, Embase and Cochrane Library databases. Forty-three articles with 880 patients were included. The most common complications were arthritis (30%), carpal instability (15%), avascular necrosis of the lunate (12%), complex regional pain syndrome (11%), and nonunion or avascular necrosis of the scaphoid (9%). In the meta-analysis, the mean scapholunate gap was 1.7 mm in the closed surgery group and 2.3 mm in the open surgery group, which was a statistically significant difference. The mean flexion–extension arc of the wrist and modified Mayo wrist score were better in the closed surgery group than in the open surgery group. However, these findings may relate to different cohorts in terms of injury severity. Therefore, the causal relationship between closed surgery and better outcomes may be uncertain as less severe subluxations are more likely to be treated closed
Factors affecting satisfaction in patients with a rotator cuff retear: CT arthrography-based study
No full textPurpose: The relationship between retear that may occur after rotator cuff repair and patient satisfaction is not well established. This study aimed to determine whether the types and size of the retear evaluated by computed tomography arthrography (CTA) influenced patient satisfaction. We also analyzed the patient factors that could affect patient satisfaction. Patients and methods: A total of 50 patients who were diagnosed with rotator cuff retear after undergoing arthroscopic rotator cuff repair were included in this study. All the patients were dichotomously classified into the satisfactory or dissatisfactory groups according to the patients’ self-classifications. CTA was used to assess the attachment status of the footprint, detect retear on the medial side of the footprint of the repaired cuff, and determine the retear size. Demographic factors, including sex, age, occupation, dominant upper extremity, duration of pain, presence of diabetes mellitus, trauma history, history of ipsilateral shoulder surgery, repair technique, worker’s compensation status, and functional shoulder score, were investigated. Results: Thirty-nine patients were classified into the satisfactory group and 11 patients were classified into the dissatisfactory group. There were no differences in age, sex, occupation, dominant hand, duration of pain, presence of diabetes mellitus, trauma history, history of ipsilateral shoulder surgery, repair technique, worker’s compensation, and duration of follow-up between the two groups. However, the postoperative American Shoulder and Elbow Surgeon (ASES) score (P < 0.01), visual analog scale (VAS) pain level (P < 0.01), anteroposterior (AP) length (P < 0.01), and area of the retear site (P < 0.01) were significantly different. Conclusion: The AP length and area of the retear site estimated using CTA were confirmed as the significant risk factors for dissatisfaction. However, the type of repaired rotator cuff judged by the attachment status of the footprint did not correlate with patient satisfaction. In addition, the postoperative VAS pain scale and ASES score was correlated with patient satisfaction
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