Transcatheter pulmonary valve replacement (TPVR), also known as percutaneous pulmonary valve implantation, refers to a minimally invasive technique that replaces the pulmonary valve by delivering an ...artificial pulmonary prosthesis through a catheter into the diseased pulmonary valve under the guidance of X‐ray and/or echocardiogram while the heart is still beating not arrested. In recent years, TPVR has achieved remarkable progress in device development, evidence‐based medicine proof and clinical experience. To update the knowledge of TPVR in a timely fashion, and according to the latest research and further facilitate the standardized and healthy development of TPVR in Asia, we have updated this consensus statement. After systematical review of the relevant literature with an in‐depth analysis of eight main issues, we finally established eight core viewpoints, including indication recommendation, device selection, perioperative evaluation, procedure precautions, and prevention and treatment of complications.
Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to ...investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments.
Validated finite element (FE) models, for internal and external malrotations from 0° to 10° with regard to the neutral position, were developed to evaluate the effect of malrotation on the femoral component in TKA. Femoral malrotation in TKA on the knee joint was simulated in walking stance-phase gait and squat loading conditions.
Contact stress on the medial side of the PE insert increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. There was an opposite trend in the lateral side of the PE insert case. Contact stress on the patellar button increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. In particular, contact stress on the patellar button increased by 98% with internal malrotation of 10° in the squat loading condition. The force on the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) increased with internal and external femoral malrotations, respectively.
These findings provide support for orthopaedic surgeons to determine a more accurate femoral component alignment in order to reduce post-operative PE problems.Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, C. Baek, S. H. Jung, K. K. Park. Measuring the effect of femoral malrotation on knee joint biomechanics for total knee arthroplasty using computational simulation. Bone Joint Res 2016;5:552-559. DOI: 10.1302/2046-3758.511.BJR-2016-0107.R1.
Experiential learning through service provides opportunities to nurture and practice empathy. Of growing concern, studies showed significantly decreased empathy scores as students progress through ...medical school. Additionally, peer-to-peer learning provides an effective way for students to learn. Constructing Care Collaboration (CCC) is a student initiated, structured-service-learning-program that promotes the development of empathy and peer-to-peer teaching. CCC is conducted in cycles of 6 sessions. This is a mixed methods study that explores the effectiveness of CCC as a service learning platform in developing student participants' empathy, social and cultural competencies, communication skills and peer-to-peer teaching skills, ultimately aiming to promote a culture of serving the underprivileged.
The study comprised of a self-administered quantitative questionnaire and qualitative interviews. Both evaluated if CCC participation developed volunteers' social-awareness, cultural competency, communication, confidence and motivation to teach their peers.
Quantitative data were collated from 38 completed student volunteers' questionnaires. Volunteers generally agreed CCC improved social-awareness and cultural competency. It increased confidence of participants in approaching migrant-workers, communicating with people from different social backgrounds, and promoted a culture of peer-to-peer teaching. Thematic analysis of 17 interviews was conducted. Themes identified include: increased empathy towards migrant-workers, improved communication skills, and identifying benefits and challenges in peer-to-peer teaching.
From the quantitative and qualitative information gathered, CCC has been shown to be effective in nurturing participants' self-reported empathy, cultural competence, communication skills and improved attitude towards peer-to-peer teaching. Given its effectiveness, CCC can be adopted as a model for structured service-learning.
Summary
The progression of fractured vertebral collapse is not rare after a conservative treatment of vertebral compression fracture (VCF). Teriparatide has been shown to directly stimulate bone ...formation and improve bone density, but there is a lack of evidence regarding its use in fracture management. Conservative treatment with short-term teriparatide is effective for decreasing the progression of fractured vertebral body collapse.
Introduction
Few studies have reported on the prevention of collapsed vertebral body progression after osteoporotic VCF. Teriparatide rapidly enhances bone formation and increases bone strength. This study evaluated preventive effects of short-term teriparatide on the progression of vertebral body collapse after osteoporotic VCF.
Methods
Radiographs of 68 women with single-level osteoporotic VCF at thoracolumbar junction (T11–L2) were reviewed. Among them, 32 patients were treated conservatively with teriparatide (minimum 3 months) (group I), and 36 were treated with antiresorptive (group II). We measured kyphosis and wedge angle of the fractured vertebral body, and ratios of anterior, middle, and posterior heights of the collapsed body to posterior height of a normal upper vertebra were determined. The degree of collapse progression was compared between two groups.
Results
The progression of fractured vertebral body collapse was shown in both groups, but the degree of progression was significantly lower in group I than in group II. At the last follow-up, mean increments of kyphosis and wedge angle were significantly lower in group I (4.0° ± 4.2° and 3.6° ± 3.6°) than in group II (6.8° ± 4.1° and 5.8° ± 3.5°) (
p
= 0.032 and
p
= 0.037). Decrement percentages of anterior and middle border height were significantly lower in group I (9.6 ± 10.3 and 7.4 ± 7.5 %) than in group II (18.1 ± 9.7 and 13.8 ± 12.2 %) (
p
= 0.001 and
p
= 0.025), but not in posterior height (
p
= 0.086).
Conclusions
In female patients with single-level osteoporotic VCF at the thoracolumbar junction, short-term teriparatide treatment did not prevent but did decrease the progression of fractured vertebral body collapse.
Machine learning (ML) is a technique that learns to detect patterns and trends in data. However, the quality of reporting ML in research is often suboptimal, leading to inaccurate conclusions and ...hindering progress in the field, especially if disseminated in literature reviews that provide researchers with an overview of a field, current knowledge gaps, and future directions. While various tools are available to assess the quality and risk-of-bias of studies, there is currently no generalized tool for assessing the reporting quality of ML in the literature. To address this, this study presents a new screening tool called STAR-ML (Screening Tool for Assessing Reporting of Machine Learning), accompanied by a guide to using it. A pilot scoping review looking at ML in chronic pain was used to investigate the tool. The time it took to screen papers and how the selection of the threshold affected the papers included were explored. The tool provides researchers with a reliable and systematic way to evaluate the quality of reporting of ML studies and to make informed decisions about the inclusion of studies in scoping or systematic reviews. In addition, this study provides recommendations for authors on how to choose the threshold for inclusion and use the tool proficiently. Lastly, the STAR-ML tool can serve as a checklist for researchers seeking to develop or implement ML techniques effectively.
Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that ...a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA.
We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical simulation.
Tibial posterior translation and internal rotation in patient-specific bicruciate-retaining prostheses preserved near-normal kinematics better than other standard off-the-shelf prostheses under gait loading conditions. Differences from normal kinematics were minimised for femoral rollback and internal-external rotation in patient-specific bicruciate-retaining, followed by standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under deep knee bend loading conditions. Moreover, the standard off-the-shelf posterior cruciate-retaining TKA in this study showed the most abnormal performance in kinematics under gait and deep knee bend loading conditions, whereas patient-specific bicruciate-retaining TKA led to near-normal kinematics.
This study showed that restoration of the normal geometry of the knee joint in patient-specific bicruciate-retaining TKA and preservation of the anterior cruciate ligament can lead to improvement in kinematics compared with the standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining TKA.
: Y-G. Koh, J. Son, S-K. Kwon, H-J. Kim, O-R. Kwon, K-T. Kang. Preservation of kinematics with posterior cruciate-, bicruciate- and patient-specific bicruciate-retaining prostheses in total knee arthroplasty by using computational simulation with normal knee model.
2017;6:557-565. DOI: 10.1302/2046-3758.69.BJR-2016-0250.R1.
•A novel hybrid system comprising flexible connector and “gill cells” is proposed.•Gill cells are VLFS compartments with holes or slits to allow free passage of water.•The fluid-structure interaction ...is solved by hybrid boundary-finite element method.•The distribution of gill cells is optimized by constrained genetic algorithm.•The optimized hybrid system significantly reduces the hydroelastic response of VLFS.
This paper presents the use of flexible connector and “gill cells” to mitigate the hydroelastic response of pontoon-type, very large floating structure (VLFS) under wave action. Gill cells are compartments in VLFS with holes or slits at their bottom surfaces to allow free passage of water and they are modeled by eliminating the buoyancy forces at their locations. In the hydroelastic analysis, the water is assumed to be an ideal fluid and its motion is irrotational so that a velocity potential exists. The VLFS is modeled as an isotropic plate according to the Mindlin plate theory. In order to decouple the fluid–structure interaction problem, the modal expansion method is adopted for the hydroelastic analysis which is carried out in the frequency domain. The boundary element method is used to solve the Laplace equation for the velocity potential, whereas the finite element method is employed for solving the equations of motion of the floating plate. Genetic algorithm is adopted as an optimization tool to optimize the layouts of gill cells. It is found that by appropriately positioning the flexible connector and a suitably distributing the gill cells in the VLFS, the hydroelastic response and stress resultants of the VLFS can be significantly reduced.
Malalignment of the tibial component could influence the long-term survival of a total knee arthroplasty (TKA). The object of this study was to investigate the biomechanical effect of varus and ...valgus malalignment on the tibial component under stance-phase gait cycle loading conditions.
Validated finite element models for varus and valgus malalignment by 3° and 5° were developed to evaluate the effect of malalignment on the tibial component in TKA. Maximum contact stress and contact area on a polyethylene insert, maximum contact stress on patellar button and the collateral ligament force were investigated.
There was greater total contact stress in the varus alignment than in the valgus, with more marked difference on the medial side. An increase in ligament force was clearly demonstrated, especially in the valgus alignment and force exerted on the medial collateral ligament also increased.
These results highlight the importance of accurate surgical reconstruction of the coronal tibial alignment of the knee joint. Varus and valgus alignments will influence wear and ligament stability, respectively in TKA.
: D-S. Suh, K-T. Kang, J. Son, O-R. Kwon, C. Baek, Y-G. Koh. Computational study on the effect of malalignment of the tibial component on the biomechanics of total knee arthroplasty: A Finite Element Analysis.
2017;6:623-630. DOI: 10.1302/2046-3758.611.BJR-2016-0088.R2.
Genetic algorithms (GA) have proved to be a robust, efficient search technique for many problems. As the number of variables involved increases, classical GA will often have difficulty and/or require ...long computational time in obtaining acceptable results. In this paper, a modified GA strategy is proposed to improve the accuracy and computational time for parameter identification of multiple degree-of-freedom (DOF) structural systems. The strategy includes multiple populations or ‘species’, a search space reduction procedure and new operators designed to provide a robust and reliable identification. Average absolute error in the estimated stiffness values of 1.4% is achieved for a 20-DOF unknown mass system with 5% noise, and even more importantly the maximum error is reduced to only 3.8%.
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