1,721,031 research outputs found
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
Surgical technique: articulated external fixator for treatment of complex knee dislocation
No full textBACKGROUND: Knee dislocation is a severe but relatively uncommon injury caused by violent trauma that can result in long-term complications, such as arthrofibrosis, stiffness, instability, and pain. Perhaps owing in part to its rarity, treatment of this injury is controversial. We therefore describe a treatment approach for these complex cases involving a novel dynamic knee external fixator. DESCRIPTION OF TECHNIQUE: We performed open PCL reconstruction when possible and/or repair of other associated lesions. At the end of the surgical procedure, the surgeon applied an external fixator that reproduced normal knee kinematics, allowing early motion exercises and reducing the risk of joint stiffness while protecting the bony and soft tissue structures involved in the repair during the first healing phase. PATIENTS AND METHODS: We retrospectively reviewed eight patients treated with this approach, four of whom had the PCL reconstructed and four of whom had only associated injuries reconstructed. We evaluated all patients with clinical scores (subjective International Knee Documentation Committee form, Lysholm score, and Tegner level), physical examination (objective International Knee Documentation Committee form), and KT-1000TM arthrometer for AP laxity. Minimum followup was 10 months (mean, 26 months; range, 10-45 months).
RESULTS: One patient had manipulation under anesthesia. The median Lysholm score was 76, Tegner level was 4, and subjective International Knee Documentation Committee was 73. All patients recovered to their preinjury work activity, except one unemployed patient. Stability was normal or nearly normal in five patients; the mean side-to-side difference in AP displacement with manual maximum force was 2.9 mm.
CONCLUSIONS: This approach with an external fixator allowed staged reconstruction and early motion and provided reasonable stability, ROM, and activity level at followup in patients with complex injuries. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence
Do Clinical Outcomes and Failure Rates Differ in Patients With Combined ACL and Grade 2 MCL Tears Versus Isolated ACL Tears?: A Prospective Study With 14-Year Follow-up
Get PDFBackground: A combined injury to the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) is a common injury pattern encountered during clinical practice. Recent systematic reviews have found no consensus on the optimal method of managing this combined ligament injury pattern, and no long-term studies with modern techniques are available in the literature. Purpose: To compare 2 groups of patients who underwent isolated ACL reconstruction in terms of failures and clinical scores at long-term follow-up. In the first group were patients with isolated ACL tears (ACL group), while the second was composed of patients with combined ACL and MCL grade 2 tears (ACL + MCL group). Study Design: Cohort study; Level of evidence, 3. Methods: A total of 57 patients (37 in the ACL group and 20 in the ACL + MCL group) underwent isolated ACL reconstruction with a double-bundle technique between January and December 2005. Patients were contacted for scores on the International Knee Documentation Committee subjective form, Western Ontario and McMaster Universities Osteoarthritis Index, and Tegner activity scale as well as data regarding ipsilateral or contralateral revision ACL surgery. A 2-way analysis of variance for repeated measures was used to statistically assess the differences between the groups. Results: Overall, 49 patients (86%) completed the survey and were therefore included in the study. The minimum follow-up was 14.6 years (range, 14.1-15.2 years). There was a significant reduction in both groups of all the outcome scores between the intermediate and final-follow-up. The number of failures was 3 of 31 (9.7%) in the ACL group and 1 of 18 (5.5%) in the ACL + MCL group; this difference was not significant. Moreover, there were no clinical differences between the groups in terms of graft failures, contralateral lesions, and clinical scores. Conclusion: At 14-year follow-up, no clinical difference or increased failure rate was observed between the study groups, suggesting that isolated ACL reconstruction could represent an appropriate treatment for a combined ACL and MCL grade 2 lesion
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
ACL, PCL, Collaterals and Meniscus
No full textSince the launch of this course format during the 10th EFORT Congress in Vienna in 2009, the EFORT Comprehensive Review Course (CRC) has been a huge success and sold out months ahead of time. Created during Pierre Hoffmeyer’s time as President of EFORT, the CRC aims to provide the knowledge and skills required by every specialist, and to broaden the participant’s orthopaedic horizon. This course provides up-to-date presentations in five major areas: Lower extremity Upper extremity Spine Pediatrics Basic science The CRC usually takes place parallel to the Annual Congress. Therefore, registration for this course comes in addition to the Congress’ registration
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
Novel nano-composite multilayered biomaterial for the treatment of patellofemoral cartilage lesions
No full textThe treatment of patellofemoral articular cartilage lesions remains challenging. Aside from their inherent limited capacity to heal and their articular location, the complexity of the patellofemoral joint proves to be refractory to treatment, even though recent research has reported different treatments that give satisfactory results.
The pathogenesis of patellar damage is complex and multifactorial, and a single procedure is often not enough to solve the problem. Therefore, the first step of any treatment option must be a complete and deep understanding of the causative factors that must be recognized and addressed to obtain synmptoms resolution and healing of cartilage lesions. In fact, all associated abnormalities should be treated before considering cartilage tissue damage. Small articular cartilage changes such as chondromalacia usually depend on unrecognized malalignment syndromes, and patellar realignment without regard for cartilage damage whose treatment may be sufficient to relieve symptoms. Articular cartilage abnormalities may consist of swelling and softening, and deep fissures can often be present and extend through the full thickness of the cartilage. In more severe cases the tissue may have a jelly-like consistency, and in some cases almost the entire articular surgace may have degenerated.
When the cartilage defect is severe, the treatment of the etiopathogenetic factors may not be sufficient and must be combined with the cartilage damage treatment in order to obtain a satisfactory clinical outcome.
Various therapeutic modalities have been used in clinical practice. Arthroscopic shaving has been proposted as a minimally invasive procedure, easy and not followes by prolonged morbidity. Shaving can be used when lesion is a circumscribed blistger and when there is articular fasciculation. In these disorders, the procedure most likely should be confined to the restoration of gross articular smoothness. Debridement consistign of excision and drilling may have some use in treating osteoarthritis, and improvement can be expected in approximately two thirds of the patients. Moreover, it may also be an alternative to shaving in the knees with basal chondromalacia. Cartilage repair, although unpredictable, does sometimes occur, and can be promoted by early motion. These methods can be used for superficial defect, but for a deeper lesion expanding to bone, deep excision through the subchondral bone is carried out with concurrent bevelling of the margin of the defect. However, this method cannot be considered an ideal solution, considering the contradictory results observed in the literature and the worsening at long-term follow-up. In cases of very extensive and deep alterations of the patellar surface, total patellectomy has also been performed. While the symptoms related to the lesion in the chondral surface were abolished, the shortcomings of this procedrue are obvious: habitual lateral gliding of the quadriceps tenedon and insufficiency of the extension mechanism due to a lack of patellar leverage. Other approaches include the insertion of periostium flaps into the debrided defects and the use of synovial tissue flaps for covering the entire articular surface of the patella.
More recently, other surgical solutions have been proposed aiming to preserve a more physiologic cartilaginous superficial layer. Mosaicplasty consist of the reconstruction of the chondral defect using small, cylindrical autologous osteochondral grafts taken from non-weight-bearing areas of the joint. This technique presents several advantages: a single procedure, low cost, press-fit fixation by compressed grafts, and host bone impaction. However, despite these positive aspects, the clinical experience showed lower results with respect to femoral and tibial grafts; this may be due to the higher concentration of shear stress in this location.
Regenerative techniques, such as autologous chondrocyte implantation (ACI), have emerged as a potential therapeutic option. Some studies suggest the durability of this treatment, especially at long-term follow-up, because of its ability to produce hyaline-like cartilage that is mechanically and functionally stable, and the alowance for integration with the adjacent articular surface. This approach, introduced in 1994 by Brittberg and Peterson, seems to offer good results, even with patellar lesions shown to have a less predictable outcome with lower satisfactory results compared to the treatment of femoral defects. The use of classic ACI has been associated with several limitations related to the complexity and the morbidity of the surgical procedure. This technique requires a large joint exposure and implies a higher risk of joint stiffness and arthrofibrosis; there is a frequent occurrence of periosteal hypertrophy, that occurs between 3 and 7 months after surgery in 10-25% of cases and often requires revision surgery. Some authors have shown a reoperation rate of up to 42%, due to joint stiffness, and have indicated that the use of the periosteal flap increases the risk of complications during the recovery period and produces more difficult rehabilitation. Other problems can be observed with standard ACI methods. These include the difficulty in handling a delicate liquid suspension of chondrocytes at implantation surgery, the need to make a hermetic periosteum seal using sutures, and the concerns related to the manteinance of the condrogenic phenotype in the liquid suspension. The development of the second-generation ACI, that used a tissue engineering technology to create a cartilage-like tissue in a three-dimensional culture system, allows one to address most of the concerns related to the cell culture and the surgical technique. Numerous biodegradable polymers such as hyaluronan, collagen, fibrin glue, alginate, agarose, and various synthetic polymers were developed and used as temporary scaffolds for the in vitro growth of living cells and their subsequent transplantation onto the defect site. Promising results have been obtained with this tissue engineering approach and nowadays matrix-assisted autologous chondrocyte transplantation is widely used in Europe. The results obtained are still controversial and there is no agreement about the effective superiority of this procedure to others. Moreover, despite the good potential reported, patellar lesions still present lower clinical outcome with respect to other location, and there is a worsening of the results over time even at medium term follow-up. This approach is also plagued by high cost and the need for a two-step surgery. To overcome all these problems, we developed and applied in clinical practice a new bi-composite, multilayer, biomimetic scaffold, which can mimic the osteocartilaginous anatomical structure in all of its components. This scaffold allows for the restoration of the articular surface in a one-step surgery without the need for cells and, thanks to the plasticity of the graft, even big osteochondral lesions can be treated through minor incisions
Single-bundle patellar tendon versus non-anatomical double-bundle hamstrings ACL reconstruction: a prospective randomized study at 8-year minimum follow-up
No full textLo scopo di questo studio era di confrontare a lungo periodo il risultato soggettivo, oggettivo e radiografico della ricostruzione di legamento crociato anteriore confrontando la tecnica a singolo fascio lateralizzato con tendine rotuleo autologo alla tecnica a doppio fascio non-anatomico mediante gli hamstring del ginocchio. Settantanove pazienti randomizzati con una insufficienza di LCA unilaterale sono stati valutati in modo prospettico, prima e dopo la ricostruzione del LCA mediante le suddette tecniche, con un follow-up minimo di 8 anni. I pazienti sono stati valutati soggettivamente ed oggettivamente mediante punteggio IKDC, livello di Tegner, test di spostamento massimo con artrometro KT-2000. La valutazione radiografica è stata eseguita secondo il sistema di classificazione IKDC, ed è stato registrato il tasso di re-intervento per le lesioni meniscali. Gli IKDC soggettivi ed oggettivi sono risultati simili in entrambi i gruppi, mentre il gruppo operato con il doppio-fascio ha mostrato un livello di Tegner significativamente maggiore, un recupero migliore del range di movimento passivo, una ripresa dello sport più veloce, un minor grado di pivot-shift e un più basso tasso di re-intervento rispetto al gruppo operato con tendine rotuleo. La valutazione radiografica ha mostrato cambiamenti degenerative oggettivi significativamente inferiore nella tecnica a doppio-fascio nella fase finale del follow-up. Anche se entrambe le tecniche danno risultati soddisfacenti, la tecnica a doppio-fascio del LCA mostra risultati funzionali migliori, con un più rapido ritorno all'attività sportiva, un più basso tasso di re-intervento ed inferiori cambiamenti degenerativi del ginocchio
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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