1,720,982 research outputs found
Retroacetabular stress-shielding in THA
No full textWe conducted a randomized clinical trial to compare periacetabular bone density changes after total hip arthroplasty using press-fit components with soft and hard liner materials. Bone density changes were assessed using quantitative computed tomography-assisted osteodensitometry. Twenty press-fit cups with alumina ceramic liners and 20 press-fit cups with highly cross-linked polyethylene liners were included; the nonoperated contralateral side was used as the control. Computed tomography scans were performed postoperatively and 1 year after the index operation. At the 1-year followup, we found no differences of periacetabular bone density changes between the alumina and polyethylene liner cohorts. However, we observed marked periacetabular cancellous bone density loss (up to −34%) in both cohorts. In contrast, we observed only moderate cortical bone density changes. The decrease of periacetabular cancellous bone density with retention of cortical bone density after THA suggests stress transfer to the cortical bone. One or more of the authors have received funding from the Wishbone Trust New Zealand (RPP) and Zimmer, Warsaw, IN (RPP). Each author certifies that his or her institution has approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent was obtained
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
CORR Insights®: Is potential malnutrition associated with septic failure and acute infection after revision total joint arthroplasty?
No full textThis CORR Insights®is a commentary on the article “Is Potential Malnutrition Associated With Septic Failure and Acute Infection After Revision Total Joint Arthroplasty? by Yi and colleagues available at: DOI: 10.1007/s11999-014-3685-8https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4390925
Accuracy of computer-assisted navigation for femoral head resurfacing decreases in hips with abnormal anatomy
No full textCurrent Concepts in the Aetiology, Pathogenesis and Management of Kienbock’s Disease
No full textSince the first description of “lunatomalacia” by the Viennese radiologist, Robert Kienböckthe aetiology, pathogenesis and management of Kienbock’s Disease has been debated. The
disease encompasses a spectrum of age and gender but is classically considered to affect
young-to-middle-aged male manual laborer’s.
Both mechanical and vascular factors play a role in disease aetiology, and it is likely that a
critical combination is important. Alteration in the normal homeostasis of arterial in-flow and
venous out-flow may lead to ischemia of the lunate. Loading conditions of the lunate are
affected by the morphology of both the lunate and the wrist, as well as occupational or
functional activities of the patient.
Clinical presentation is varied and depends on a number of factors, including the patient’s
functional levels and disease severity. History, examination and imaging is essential when
determining optimal treatment. Plain radiographs and 3D-CT scanning aid in determining the
osseous component of the disease. 4D-CT scanning allows dynamic assessment of the
kinematics of the Kienböck wrist. The vascular component of the disease can be assessed on
MRI scanning, with or without gadolinium contrast. The chondral aspect of the disease is best
assessed with arthroscopic examination.
Management of the disease requires consideration of a number of factors, both patient- and
surgeon-focused. An algorithm is presented in this thesis to guide the surgeon treating
Kienbock’s Disease. Primary considerations to the surgeon include the age (A) of the patient,
the state of the bone (B), and the state of the carpus (C). Treatment options include lunate
unloading procedures, lunate reconstruction, motion-preserving procedures, and salvage
procedures. We favour an arthroscopic approach for decision-making, as it allows
determination of the ‘functional surfaces’ of the wrist. Both arthroscopic and open techniques
can then be performed.
The long-term surgical outcomes of Kienbock’s Disease is presented in a cohort of patients
using an arthroscopic-based approach
Clinical faceoff: Ceramic-on-ceramic THA: Do the advantages outweigh the limitations?
No full texthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4160492
Pearls: How to Remove a Ceramic Liner From a Well-fixed Acetabular Component
No full texthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4686534
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