1,721,053 research outputs found
Innovations in revision total knee arthroplasty
No full textOsteoarthritis (OA) is the most common joint disorder in the world and total knee arthroplasty (TKA) is thought to be the gold standard for the surgical treatment of end-stage OA. Despite good results, a significant proportion of patients need to have their knee prosthesis replaced, and an increase of the number of these so called revision TKAs (rTKAs) is seen and is expected to grow further. This thesis focuses on new techniques in rTKA and is divided into three parts: options during rTKA, alignment measurements and computer-assisted surgery (CAS). In the first part of this thesis survival rates were compared between primary and specially designed revision prostheses when implanted during rTKA. Trabecular Metal (TM) cones are designed to fill up major bone defects. Tibial components can be implanted in combination with a stem, but it is unclear whether this is necessary after reconstruction with a TM cone. This was investigated in this thesis. Prosthesis position is generally measured on conventional long-leg radiographs, but these measurements are not always accurate. With the EOS 2S/3D system the prosthesis position can be measured in 3D. In the second part of this thesis it is investigated whether EOS 3D measurements can be an alternative for measuring prosthesis position. CAS is developed to improve knee prosthesis position. It is not investigated yet if CAS also improves rotation of the prosthesis. It is also unknown whether CAS improves prosthesis position when used during rTKA. Both are being investigated in the third part of this thesis
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
The Measurement and Prediction of Physical Functioning after Trauma
No full textTrauma patients are at risk of developing remaining disability and complaints due to the injuries. These complaints importantly influence quality of life and patients’ ability to perform daily activities. It is important to be able to adequately assess (recovery of) physical functioning after trauma. Traditionally this was estimated physicians using X-ray imaging and the limitations in range of motion of affected joints. In his thesis, De Graaf evaluated whether physical functioning of trauma patients can be assessed using the Dutch Short Musculoskeletal Function Assessment (SMFA-NL) questionnaire. The research showed that the SMFA-NL questionnaire is best used using four subscales (functioning of the arms, legs, daily activities and mental and emotional problems), instead of the two subscales that have traditionally been used for scoring the questionnaire. The four subscales were considered appropriate to correctly assess (reliable, valid and responsive) physical functioning at one moment in time, as well as to be able to assess change in physical functioning over time. To make the scores of the SMFA-NL better understandable, normative data of the Dutch population were obtained. Furthermore, it was investigated which change in score reflects relevant change in physical functioning to patients that sustained an injury. Finally, De Graaf and colleagues developed a prognostic model that can be used to predict 6 weeks after trauma, whether patients’ physical functioning will be completely recovered after one year. According to De Graaf, the SMFA-NL is an appropriate instrument to assess and follow-up physical functioning of individual trauma patients in a clinical setting. The SMFA-NL may also be used in scientific research to evaluate different treatments in patients that sustained an injury
Computer-navigated minimally invasive total hip arthroplasty : Effectiveness, clinical outcome and gait performance
No full textOsteoartrose van de heup is de meest voorkomende indicatie voor een totale heupartroplastiek (THA). Gedurende de laatste jaren is de populariteit van Minimaal Invasieve (MIS) THA en het gebruik van computernavigatie toegenomen. Volgens voorstanders leidt MIS THA tot minder schade aan weke delen, minder bloedverlies, minder pijn, sneller herstel en een kleiner litteken. Het gebruik van computernavigatie tijdens MIS THA leidt wellicht tot een preciezere plaatsing van de prothese in vergelijking met conventionele THA.
Doelstelling van dit proefschrift is het vaststellen van het effect van computer genavigeerde MIS THA, in vergelijking met conventionele THA, op klinische uitkomstmaten en het fysiek functioneren van patiënten tot 6 maanden postoperatief. Een tweede doelstelling is de ontwikkeling van een gangbeeldanalyse methode op basis van body-fixed-sensors, waarmee inzicht verkregen kan worden in de loopfunctie van patiënten met heupartrose vóór en na THA.
Een gerandomiseerde gecontroleerde trial (N=82) is uitgevoerd naar de effectiviteit van computer genavigeerde MIS THA in vergelijking met conventionele THA. Naast klinische uitkomstmaten is het fysiek functioneren preoperatief, 6 weken en 3 en 6 maanden postoperatief gemeten door middel van vragenlijsten en de body-fixed-sensor gebaseerde gangbeeldanalyse methode.
De gemiddelde ligduur in het ziekenhuis was significant korter na computer genavigeerde MIS THA (5,2 in plaats van 6,9 dagen), ondanks hogere operatietijden en meer bloedverlies. Er was geen verschil in het aantal complicaties. Door het gebruik van computernavigatie werd de heupprothese nauwkeurig geplaatst. Er is geen bewijs gevonden voor een sneller herstel van het fysiek functioneren na computer genavigeerde MIS THA in vergelijking met conventionele THA.
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
- …
