1,720,963 research outputs found
Fracture of ceramic bearing surfaces following total hip replacement: A systematic review
No full textCeramic bearing surfaces are increasingly used for total hip replacement, notwithstanding that concern is still related to ceramic
brittleness and its possible mechanical failure. The aim of this systematic review is to answer three questions: (1) Are there risk
factors for ceramic component fracture following total hip replacement? (2) Is it possible to perform an early diagnosis of ceramic
component failure before catastrophic fracture occurs? (3) Is it possible to draw guidelines for revision surgery after ceramic
components failure? A PubMed and Google Scholar search was performed and reference citations from publications identified
in the literature search were reviewed. The use of 28 mm short-neck femoral head carries an increased risk of fracture. Acetabular
component malposition might increase the risk of ceramic liner fractures. Synovial fluid microanalysis and CT scan are promising
in early diagnosis of ceramic head and liner failure. Early revision is suggested in case of component failure; no consensus exists
about the better coupling for revision surgery. Ceramic brittleness remains a major concern. Due to the increased number of ceramic
on ceramic implants, more revision surgeries and reports on ceramic components failure are expected in the future. An algorithm
of diagnosis and treatment for ceramic hip failure is proposed
Anterior minimally invasive subcapital osteotomy without hip dislocation for slipped capital femoral epiphysis
No full textPurpose: A minimally invasive anterior approach appears to be an attractive alternative to achieve capital realignment without violating femoral head vascular supply and avoiding hip dislocation in slipped capital femoral epiphysis. The aim of this study was to detail the technical steps of subcapital realignment through a minimally invasive anterior approach and to report the preliminary results of this procedure in a prospective cohort of patients with stable slips. Methods: Nine patients underwent subcapital cuneiform wedge resection through a minimally invasive anterior approach without hip dislocation for moderate or severe stable slips between April 2012 and April 2013. Prophylactic stabilization of the contralateral hip was performed in all cases. A minimum 18 months follow-up was available. Clinical course was assessed using the Harris hip score and the hip range of motion. The degree of slippage as proposed by Southwick, the lateral α angle and the epiphyseal-metaphyseal distance allowed radiographic assessment. Results: No patients were lost during follow-up, which was on average 28 months. No intraoperative complications occurred; one postoperative transient apraxia of the femoral cutaneous nerve, which completely recovered in six months, was recorded. Southwick angle, lateral α angle and epiphyseal-metaphyseal distance all improved substantially postoperatively. No cases of avascular necrosis were detected. Conclusion: Subcapital cuneiform wedge resection through a minimally invasive anterior approach without hip dislocation can be an easier alternative to restore proximal femoral anatomy in moderate to severe stable slips. Prospective case control studies are required to confirm these preliminary results
Outcomes of total hip replacement in limbs affected by poliomyelitis
No full textIntroduction: The outcomes of total hip replacement in patients suffering from residual poliomyelitis are poorly covered in the literature. In this retrospective study we posed the question of whether total hip replacement performed for degenerative hip diseases in limbs with residual poliomyelitis could determine satisfactory mid-term clinical and radiographic results, with a reasonable complication rate. Methods: A retrospective study was carried out to assess the results of 14 total hip replacements performed on 14 patients with residual poliomyelitis on the involved limb from June 1999 to September 2011. Average age at the time of surgery was 51 years (range 26-66 years). Mean duration of follow-up was 92 months (range 52-156 months). Surgery was performed through a direct lateral approach on all hips. All but one were cementless implants. Results: 2 implants failed, 1 due to traumatic acetabular fracture 6 days after surgery, and 1 due to aseptic cup loosening 13 years after surgery. Surgery was uneventful in all patients except 1 (7%), who experienced a transient sensory sciatic nerve palsy. At the latest follow up Harris Hip Score was 83.3 (range 72-91) with a marked improvement when compared to preoperative score (average 52, range 32-78). No dislocations had occurred. Conclusions: Total hip replacement can be considered a feasible option for hip osteoarthritis in patients with limbs affected by residual poliomyelitis. Longer follow-up studies are needed to assess the effectiveness of unconstrained total hip replacement in polio patients
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
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
Effect of different postoperative flexion regimes on the outcomes of total knee arthroplasty: randomized controlled trial
No full textPurpose: A consistent limb position strategy could be an attractive and easier alternative to reduce blood loss and increase range of motion following total knee arthroplasty. The aim of this study was to understand the proper amount of flexion required to improve functional outcomes with limited patients’ discomfort. Methods: Eighty-five patients undergoing total knee arthroplasty were randomly assigned to receive mild (30° of knee flexion) or high-flexion protocol (70° of knee flexion), 48 h after surgery. The same daily rehabilitation scheme was followed. Total blood loss, hidden blood loss, haemoglobin and haematocrit levels, fixed flexion deformity, range of motion and limb circumference at the superior patellar pole were evaluated preoperatively and 7 days after surgery. Results: Demographics, blood parameters and preoperative range of motion did not show any significant difference between the two groups. No complications were recorded in both groups. High-flexion group had greater rate of dropout due to excessive patients’ discomfort. A significantly lower Hb at day 1 was found in the high-flexion group. No differences were recorded regarding the remaining parameters. Conclusion: No significant differences were found between the high-flexion and mild-flexion protocols; however, mild-flexion protocol was better tolerated by patients. We therefore recommend a 30° flexion protocol to be routinely used 48 h postoperatively after total knee arthroplasty. This is an easy strategy to improve functional outcomes, which is a fundamental issue considering the steady increase in knee prostheses utilization. Level of evidence: Randomized controlled trial, Level II
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