1,779 research outputs found
Hip Resurfacing Arthroplasty: Clinical and Material Considerations
No full textDespite the poor results of the first-generation metal-on-polyethylene hip resurfacing arthroplasties of the 1970s and 1980s, the concept was successfully reintroduced in the 1990s using second-generation metal-on-metal bearings.
The first paper describes the first 200 cases performed at the Ghent University Hospital from 1998 on. This is the first not designer-related report about the clinical success of the Birmingham Hip Resurfacing arthroplasty. Complications known to occur with the first-generation resurfacings were not seen and patients were able to regain high activity levels, including sports.
The second paper compares the clinical results of the resurfacing technique with those of conventional total hip replacement using a ceramic-on-ceramic bearing in young active patients. In general, the functional outcome was better and activity levels were higher in resurfacing patients.
The third paper emphasizes the clinical advantages of large-diameter metal bearings over constrained polyethylene devices in difficult primary total hip replacements or revision cases, when stability problems can be expected. Device-related complications and dislocations were significantly less frequent with large-diameter metal bearings.
Despite the excellent clinical results of modern hip resurfacing arthroplasty as a solution for polyethylene disease with resultant osteolysis and subsequent loosening of the prosthesis in young active patients, another potential health hazard arises when metal-on-metal bearings are used. Elevated blood levels of cobalt and chromium may have negative long-term health consequences, although a higher incidence of cancer has not been reported so far. Another potential hazard is the risk of local allergic reactions to cobalt-chromium devices.
The fourth paper compares three different second-generation metal-on-metal bearings, including two different resurfacing devices and one 28-mm metal bearing, with each other and with a 28-mm ceramic bearing control group. Despite substantial metallurgical differences, only a significant difference in blood levels of cobalt and chromium was found in favour of the Durom compared to the BHR resurfacing device. In all three metal bearing groups, however, outliers for cobalt and chromium levels were present, mainly due to improper implant positioning, although some outliers could not be clearly accounted for. No correlations were found between metal ion levels and activity level of the patients, supporting the tribology of metal-on-metal bearings.
The fifth paper looks for correlations between implant positioning and blood levels of cobalt and chromium in patients with unilateral hip resurfacings, in order to find out whether outliers for cobalt and chromium could be explained by abnormal positioning of the acetabular component. A significant correlation was found between cup inclination and ion levels. When the abduction of the acetabular cup exceeded 55°, significantly higher levels of cobalt and chromium were found, especially when smaller sizes were used, as eg. in women.
The sixth paper tries to validate blood levels of cobalt and chromium as a diagnostic tool for the functioning of metal-on-metal implants. A significant correlation was found between blood ion levels, cobalt and chromium levels in the synovial fluid of the artificial joint and the wear measurements of the retrieved implants. This suggests that blood levels of cobalt and chromium quite accurately reflect the functioning of a metal-on-metal bearing.
The seventh paper tries to determine whether modern cell saver devices, often used in hip revision surgery in order to avoid blood transfusions, were efficient in sufficiently removing cobalt and chromium from reinfused blood. Cobalt and chromium were equally removed by the devices, although the percentage reduction was only 76.3% and 78.6%, respectively. As metal ions are potentially hazardous to health, surgeons should be aware that the current cell saver devices do not adequately remove cobalt and chromium from reinfused blood.
Despite the excellent clinical results of hip resurfacing arthroplasty and the use of large metal-on-metal bearings, blood metal ion levels should be closely monitored if there is clinical or radiographic evidence of poor implant functioning. Implant positioning seems to be critical to optimal functioning of a metal-on-metal bearing
Tradução de uma disputa : Christophe versus Pétion em La tragédie du roi Christophe, de Aimé Césaire
Get PDFEsta contribuição propõe a tradução comentada da primeira cena da peça de teatro La Tragédie du roi Christophe (A tragédia do rei Christophe), de Aimé Césaire. O texto foi publicado pelo autor martinicano em 1963 e encenado a partir de 1964. A história aborda o embate histórico entre os dois líderes revolucionários haitianos, Alexandre Pétion (1770-1818) e Henry Christophe (1767-1820), após o estabelecimento da independência do Haiti, em 1804. O ex-escravizado Henry Christophe I, autoproclamado rei do Haiti em 1811, protagoniza, na peça, os impasses políticos decorrentes do processo de descolonização para a constituição de um novo estado haitiano livre e democrático. Optamos por traduzir a cena que anuncia e ilustra, na abertura do primeiro Ato, o caráter trágico que permeia o desenrolar dos eventos.This contribution proposes the commented translation of the first scene of the play La Tragédie du roi Christophe (The tragedy of King Christophe), by Aimé Césaire. The text was published by the Martinican author in 1963 and staged from 1964 onwards. The story addresses the historical clash between the two Haitian revolutionary leaders, Alexandre Pétion (1770-1818) and Henry Christophe (1767-1820), after the establishment of Haitian independence in 1804. The ex-enslaved Henry Christophe I, self-proclaimed King of Haiti in 1811, stars, in the play, political impasses resulting from the decolonization process, for the constitution of a new free and democratic Haitian state. We chose to translate the scene that announces and illustrates, in the opening of the first Act, the tragic character that permeates the unfolding of events
Evaluating the role of novel technologies in optimising surgery and training in hip arthroscopy
No full textOA of the hip is one of the most common forms of OA. The reported lifetime risk of developing OA of the hip amounts to 25%. Evidence is emerging that the majority of cases of primary OA are the result of a distinct morphological abnormality, termed FAI which is considered to be a precursor to primary OA of the hip. Hip arthroscopy (HA) has a long history but has grown exponentially over the last two decades. It is now the standard of care for the surgical management of FAI. However, although successful, a proportion of patients continue to remain symptomatic following HA. Furthermore, the rates for revision HA are on the rise.
One of main reasons for continual symptoms following surgical intervention is suboptimal correction of the morphological abnormality which could have a direct bearing on the surgical outcome. Failure to appreciate the 3D anatomy and dynamics of the morphological abnormality could result in suboptimal correction. Secondly, arthroscopic surgery of the hip has a steep learning curve and in the hands of an inexperienced operator the possibility of failing to access the whole morphological abnormality arthroscopically is high. Improved tools for optimisation of surgical management and for training of surgeons are therefore, urgently required. The aim of this PhD dissertation, therefore, was to investigate the role of novel technologies for optimising treatment of patients with FAI and for training of surgeons interested in hip arthroscopy. The dissertation took the form of two work packages (WP). WP1 focused on optimising planning and surgical accuracy via computer assistance and the WP2 focused on investigating the role of VR Simulation in Hip Arthroscopy training.
The first study involved defining a normal-equivalent femoral head neck junction of a subject's specific anatomy, using a SSM of the femur. We concluded that defining normal equivalent anatomy was effective in quantifying anatomical dysmorphism of the femoral head–neck junction which can potentially improve presurgical analysis of patients diagnosed with FAI. Next a cadaveric proof of concept study was performed to determine the accuracy of registration and the precision of the resection volume in navigated HA for cam-type FAI, using imageless and image-based registration. We found that the estimated accuracy of imageless registration in the arthroscopic setting was poor. It was concluded that, given the limited femoral surface that can be reached and digitised during HA, imageless registration was inaccurate and did not allow for reliable surgical navigation. However, image-based registration did acceptably allow for guided femoral osteochondroplasty. Based on this cadaveric proof of concept study, a randomised controlled clinical trial comparing conventional hip arthroscopy versus navigated hip arthroscopy was performed. The results showed that the mean maximal alpha angle improved significantly in the navigated group compared with the conventional group especially in the 12 o’ clock position. However, positioning time and radiation exposure were significantly longer in the navigated group.
The second set of experiments were focused on evaluating the role of the Simbionix Virtual Reality HA simulator in improving training in HA. The first study established the construct validity of the diagnostics module of the VR simulator. The results demonstrated that on the visualisation task, the expert group outperformed the novice group on time taken to perform the tasks, number of collisions with soft tissue and bone and the distance travelled by the arthroscope. The second study established the face validity of the hip diagnostics module of the same VR simulator. The diagnostic HA module was found to have an acceptable level of realism in all domains apart from the tactile feedback received from the soft tissue. The final study demonstrated learning curves for the diagnostic module of the same simulator with 25 medical students over a period of seven weeks. All performance metrics had improved, demonstrating sufficient visuo-haptic consistency within the virtual environment, enabling individuals to develop basic arthroscopic skills. Despite the temporal issues with logistics, our series of experiments were the first ones in the field of Hip Arthroscopy to validate the diagnostic module of the Simbionix VR HA simulator.
In conclusion, novel technologies and methods designed to improve surgical planning, intra-operative execution of a plan, improve precision and accuracy during surgery and help training in HA were developed in this PhD dissertation. Future work should focus further development of these technologies to ensure widespread use and on the short and long-term evaluation of their clinical benefit to patients
Morisset/PyNeb_devel: 1.1.9
No full textcommit ab6cdb8a4af2ff75b82fc1422004934945c82530
Author: morisset [email protected]
Date: Sat Jul 6 11:25:45 2019 -0700
1.1.9
V 1.1.9
commit f7e6a418d2affb8db163c8c6c2428173b5f4aacf
Author: morisset [email protected]
Date: Fri Jun 7 07:15:42 2019 -0700
Create _chianti_tools_9.py
commit 81213b885e2b359a62e3d6e73515e39dc7056561
Author: Christophe Morisset [email protected]
Date: Wed Jun 5 16:19:33 2019 -0700
Adding Chianti 9
commit 5a9a7dfc9a4d922a216ac11f39b76c2d63097d3b
Author: Christophe Morisset [email protected]
Date: Wed Jun 5 16:19:05 2019 -0700
1.1.9b4
commit 152f9192847cd7f3194e0a778caca66f966392c1
Author: morisset [email protected]
Date: Wed May 22 14:13:30 2019 -0700
T_min ans max were not used
commit 22aeec4db4efc7bcc377b54a92292e157335825d
Author: morisset [email protected]
Date: Sun May 19 10:18:52 2019 -0700
1.1.9b3
commit 4dc721eecdd2511fcde69f835fc6181f7be1b74d
Author: morisset [email protected]
Date: Sun May 19 10:18:34 2019 -0700
manage wl<Lyalpha master
commit 44192233b57ef46cc479e6bfc2a9020cbfc3d5f6
Author: morisset [email protected]
Date: Fri May 17 13:07:55 2019 -0700
1.1.9b2
commit 95e07d78fb38cc6267f38e11d3051738814a4dfd
Author: morisset [email protected]
Date: Fri May 17 13:07:47 2019 -0700
light wl array
commit 9a159290e931fbdbbff8b13968d7540f8b0cef18
Author: morisset [email protected]
Date: Fri May 17 13:07:27 2019 -0700
add continuum to init
commit da0e0b6ac19bc6808bc7366217ad4a0885e1ca0e
Author: morisset [email protected]
Date: Thu Mar 21 11:48:08 2019 -0300
1.1.9b1
before branch to Regresor developemen
Christophe Colomb, le caoutchouc et les tétines
No full textChristoph Kolumbus, Kautschuk und die Gummisauger.
Der Verfasser schildert kurz die Geschichte des Kautschuks und erwänt die apotheker welche daran beteiligt sind. Er legt anschliessend die Geschichte der Gummisauger und der Milchflaschen dar, deren eine der meistgängisten die « Robert'sche Milchflasche » gewesen ist.Christopher Columbus, rubber, and rubber nipples.
The author quickly traces the history of rubber, making note of the pharmacists who therein played a role. He exhibits the history of rubber nipples and that of infant bottles, of which one of the most widely used was the « Robert Bottle. »Labeÿ Robert. Christophe Colomb, le caoutchouc et les tétines. In: Revue d'histoire de la pharmacie, 82ᵉ année, n°300, 1994. pp. 55-63
Understanding the mechanical environment of the hip
No full textThe hip functions as a ball and socket joint, with cartilage layers that cover the joint surfaces on both sides protecting it from impacts and permitting smooth movements. When the cartilage is impaired by mechanical, infectious or inflammatory causes, the joint might eventually wear down - a disabling condition known as osteoarthritis. Recent literature indicates that up to 80\% of all osteoarthritis cases are potentially caused by subtle hip variations: the round shape of the ball (femur head) that is disturbed by a bump or/and the socket (acetabulum) that overcovers the femur head. These abnormal variants can give rise to conflicts and altered load distribution in the hip joint. When the load on the joint is no longer evenly distributed, peak stresses can arise in certain areas of the hip posing a risk of developing focal cartilage damage. Since the apparent prevalence of these morphological hip abnormalities is reported to be much higher than the number of actual patients, the question remains how to differentiate potential patients from incidental findings.The aim of this thesis was to describe and explore the impact of shape variation in the hip joint and by doing so improve the understanding of the mechanical environment of the hip joint.
First differences in hip anatomy between white and Chinese subjects were mapped using a cross sectional design. Pelvic computed tomography scans of 201 subjects (99 white Belgians and 102 Chinese; 105 men and 96 women; 18-40 years old) were assessed. Ten radiographic parameters predisposing to femoroacetabular impingement were evaluated. The white subjects had a less spherical femoral head than the Chinese subjects. The Chinese subjects had less lateral acetabular coverage than the white subjects. A shallower acetabular configuration was predominantly present in Chinese women.
Static and dynamic variation in hip joint reaction forces was evaluated using an experimental computational modeling design. We therefore calculated the hip joint reaction force and hip flexion angle in a virtual representative male Caucasian population by means of musculoskeletal modeling of three distinct sitting configurations: a simple chair, a car seat and a kneeling chair configuration. The observed median hip joint reaction force in relation to body weight and hip flexion angle, respectively, was 22.3 body weight and 63° for the simple chair, 22.5 body weight and 79° for the car seat and 8.7 body weight and 50° for the kneeling chair. The kneeling chair appears to hold the greatest potential as an ergonomic sitting configuration for the hip joint since it requires the lowest hip flexion angle and hip joint reaction force of these 3 distinct sitting configurations. Dynamic mapping of deep squat hip kinetics was performed in young, athletic adults using a personalized numerical model solution based on inverse dynamics. Thirty-five healthy subjects underwent deep squat motion capture acquisitions and MRI scans of the lower extremities. Musculoskeletal models were personalized using each subject’s lower limb anatomy. The average peak hip joint reaction force was found to be 274 body weight. Average peak hip and knee flexion angles were 107° and 112° respectively. Deep squatting kinetics in the younger population differ substantially from the previously reported in vivo data in older subjects.
In order to map variation in cartilage stress, a numerical discrete element analysis algorithm was developed. A validation study with hip joint contact stress data from 10 healthy subjects calculated by means of subject-specific finite element analysis was performed. Furthermore an efficient cartilage anatomy prediction tool was defined that does not require manual cartilage image segmentation. We showed that this novel population-averaged cartilage anatomy prediction method, integrated with the discrete element analysis algorithm could provide an efficient platform to predict cartilage contact stresses in large populations compared to subject specific finite element analysis.
The mechanical effect of arthroscopic cam resection in femoroacetabular impingement was explored with a case-control study design. For this purpose, patient-specific discrete element models from 10 cam type femoroacetabular patients (all male, aged 18-40 years old) were defined based on preoperative CT and postoperative MRI scans. Complete cam resection postoperatively on MRI was confirmed with alpha angles 55°. The preoperative and postoperative peak contact stress findings during impingement testing were compared against a matched virtual control group. Peak contact stress was significantly elevated in patients with cam type femoroacetabular impingement during impingement testing with increasing amount of internal rotation. This effect was however normalized following arthroscopic cam resection and loading patterns matched those of the control group.
Using multidimensional statistics and personalized load and stress predictions, we were able to demonstrate that the important population variation in shape and joint mechanics adds to differences in the onset and progression of cartilage lesions of the hip joint. Further, our work contributes to an improved identification and classification of patients who are truly at risk for developing cartilage damage. The final step of this thesis was to gradually transfer these findings into practice at the operating theater. We demonstrated that an accurate surgical treatment of cam lesions has the potential to effectively restore the normal mechanical environment of the hip
Modelling human anatomy for use in clinical and virtual population studies
No full textAbstract: abstract not availabl
Christophe Defeuilley, L’Entrepreneur et le Prince. La création du service public de l’eau
No full textBehind Christophe Defeuilley’s poetic title lies a comparative historical analysis of the establishment of public drinking water services in London, New York, and Paris, the three most populous cities at the dawn of the 20th century. The author combines the lens of economics and a long-term perspective (from the 16th to the beginning of the 20th century) focused largely on private and public actors, to trace how water distribution systems evolved and crystalized into the form they still have ..
Novel Dialogue 5.3 It’s on The Illabus: A Discussion with Jean-Christophe Cloutier and John Jennings (SW)
No full textJohn Jennings—Hugo Award winner, New York Times bestselling author, curator, scholar, and Artist—is keenly aware that in adapting novels for the graphic format, his decisions turn what has only been imagined into facts drawn on the page. In this conversation with critic, translator, and teacher of a creative course on the art of making comics, Jean-Christophe Cloutier, Jennings explores how he makes those decisions that range from the design of endpapers to selecting a character’s skin tone with the ultimate aim of championing Black culture and Black comics. Given that Jennings has just entered the Marvel Universe with the debut of Silver Surfer: Ghost Light, the timing is right to reflect on the pressures and pleasures of adapting beloved stories for a contemporary audience. Jennings is both teacher and student of comics’ powerful lessons, and lucky for listeners, his course comes with an illustrated syllabus, aka illabus. In the podcast’s first ever episode about graphic novels, Jennings and Cloutier talk comic book history, the power of collaboration, and the importance of long showers
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