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The impact of cementing technique in polished taper fit hip stems: a modelling analysis of implant-cement interface
No full textAims
Cemented polished taper fit (PTF) stems are the femoral implant of choice for total hip arthroplasty (THA) in many locations worldwide. There is increasing evidence that periprosthetic fracture may be the single major contributor to reoperation with these stems. The aim of this study was to demonstrate how mismatches at the implant-cement interface may occur and the subsequent effect of these incongruities on the contacting area and the forces transmitted to the cement mantle.
Methods
A parametric equation-based model was developed to determine the contact mismatch relative to axial stem rotations. This model was also used to calculate the restoration of contact surface area with stem subsidence for both a dual-taper and triple-taper geometry. A finite element analysis (FEA) was used to compare the effects of reduced contact area due to the incongruent hip implant-cement interface.
Results
The contact model showed a large decrease in surface contact area with even only a small rotation going from 100% at 0° to 50.00% at 2.5° for the dual-taper geometry, and from 100% at 0° to 50.20% at 2.5° for the triple-taper geometry. There was a gradual but small ongoing decrease in contact surface with increasing rotation for both the dual-taper and triple-taper geometries. For both taper designs, there was an increase in contact surface area with an increase in subsidence resulting in contact for up to a 5° mismatch being restored with 2 mm subsidence. FEA showed that with increasing mismatches and consequent contact area reduction, there was an increase in von Mises stress in the implant-cement interface of up to 235%.
Conclusion
With increasing mismatch, there was an increase in maximum stresses, total strain, and subsidence in the cement mantle, highlighting the importance of achieving an optimal implant-cement interface at the time of implantation of cemented PTF femoral stems
Impact of COVID-19 pandemic on rates of congenital heart disease procedures among children:prospective cohort analyses of 26 270 procedures in 17 860 children using CVD-COVID-UK consortium record linkage data
Get PDFBACKGROUND: The COVID-19 pandemic necessitated major reallocation of healthcare services. Our aim was to assess the impact on paediatric congenital heart disease (CHD) procedures during different pandemic periods compared with the prepandemic period, to inform appropriate responses to future major health services disruptions. METHODS AND RESULTS: We analysed 26 270 procedures from 17 860 children between 1 January 2018 and 31 March 2022 in England, linking them to primary/secondary care data. The study period included prepandemic and pandemic phases, with the latter including three restriction periods and corresponding relaxation periods. We compared procedure characteristics and outcomes between each pandemic period and the prepandemic period. There was a reduction in all procedures across all pandemic periods, with the largest reductions during the first, most severe restriction period (23 March 2020 to 23 June 2020), and the relaxation period following second restrictions (3 December 2020 to 4 January 2021) coinciding with winter pressures. During the first restrictions, median procedures per week dropped by 51 compared with the prepandemic period (80 vs 131 per week, p=4.98×10-08). Elective procedures drove these reductions, falling from 96 to 44 per week (p=1.89×10-06), while urgent (28 vs 27 per week, p=0.649) and life-saving/emergency procedures (7 vs 6 per week, p=0.198) remained unchanged. Cardiac surgery rates increased, and catheter-based procedure rates reduced during the pandemic. Procedures for children under 1 year were prioritised, especially during the first four pandemic periods. No evidence was found for differences in postprocedure complications (age-adjusted OR 1.1 (95% CI 0.9, 1.4)) or postprocedure mortality (age and case mix adjusted OR 0.9 (95% CI 0.6, 1.3)). CONCLUSIONS: Prioritisation of urgent, emergency and life-saving procedures during the pandemic, particularly in infants, did not impact paediatric CHD postprocedure complications or mortality. This information is valuable for future major health services disruptions, though longer-term follow-up of the effects of delaying elective surgery is needed
A Soft Inflatable Cable-Driven Parallel Robot with A Variable Stiffness End-Effector for Advanced Interventional Endoscopy
Get PDFObjective: This paper presents a cable-driven parallel robot (CDPR) with a variable stiffness end-effector for Advanced Interventional Endoscopy. Methods: The CDPR consists of a soft inflatable scaffold that is made from plastic laminate sheets, capable of deploying into a hollow triangular prism. The end-effector comprises multiple units linked by two cables, which also actuate the rolling joint on the end-effector tip. Variable stiffness of the end-effector is achieved by adjusting the tensions in the two cables. Results: Through master-slave control tests, the mean manual tracking error of the robot is approximately 0.5 mm. Simulated endoscopic surgical tasks, including peg transfer, wire threading, and needle threading, demonstrate the robot's performance. Additionally, the two cables double up as force-transmission elements to estimate the contact force acting on the end-effector tip. A force estimation strategy is proposed, and preprogrammed palpation tests reveal a mean force estimation error of 0.026 N when the cable pretension is 1 N and the Bowden cable's bending angle is 90°. A study involving ten users indicates a 100% accuracy in ranking the stiffness of four blocks with visual feedback. Conclusion: We demonstrated a variable stiffness end-effector with rolling degree of freedom and force sensing function based on a CDPR platform. Significance: The method for achieving variable stiffness and force sensing is cost-effective and holds significant potential for application in gastrointestinal endoscopy
A cache-aware DAG scheduling method on multicores:Exploiting node affinity and deferred executions
Get PDFBrain functional imaging contributions in osteoarthritis-related pain: A viewpoint
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Neuroimaging investigations are critical to provide a more direct assessment of brain disturbances associated with osteoarthritis (OA)-related pain, and to better understand its pathophysiology to develop new treatment strategies. This viewpoint aims to summarize the importance of the brain in OA pain.
Method
A European working group on pain in osteoarthritis GO-PAIN (Going Inside Osteoarthritis-related Pain Phenotyping) has been created to work on a global assessment of the OA-related pain. Relevant scientific literature was evaluated, summarized and discussed to expose advances in functional brain alterations related-to OA pain.
Results
Findings of neuroimaging studies are highly heterogenous and based on small sample size, but some key brain alterations associated with OA pain can be identified across experiments. A systematic literature review conducted by Hall and colleagues (2023) found lower activity, connectivity, and grey matter volume in the right anterior insula in patients with OA than in healthy controls. Other works also pointed out that activity of specific brain regions could serve as a potential surrogate biomarker, but several limitations and confounding factors needs to be addressed.
Conclusions
Brain functional imaging provides opportunities to accurately address an OA-related pain endophenotype. To encompass limitations and fill the gaps from the previous studies, we propose a blueprint for the next 5 years and stimulate ideas for others working in the field
Discrimination of a single-item scale to measure intention to have a COVID-19 vaccine
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When developing public health measures in a pandemic, it is important to examine attitudes and beliefs relating to vaccination uptake. We report the discrimination of a single-item vaccination intention scale and derive cutpoints in terms of sensitivity (true positives) and specificity (true negatives) in relation to subsequent vaccination status.
Subject and Methods
In a sample of UK adults (n=1119) recruited through an online survey platform, vaccination intention was measured on a 0–10 numerical rating scale (0=very unlikely, 10=very likely) at the beginning of the UK COVID-19 vaccination rollout (January 2021), and self-reported vaccination status was gathered after vaccination had been offered to all adults (October 2021). Discrimination of the scale was measured by the area under the receiver operating characteristic (ROC) curve.
Results
The responders reporting being vaccinated or unvaccinated were 1034 (92.4%) and 85 (7.6%), respectively. The area under the ROC curve was.956 (95% CI.943,.967), indicating a high degree of discrimination. The combined value of sensitivity and specificity was greatest at a cutpoint of 8 on the scale (sensitivity =.821, specificity =.988). If, however, the individual values of sensitivity and specificity are required to be simultaneously optimized, this occurs at point 6 (sensitivity =.886, specificity =.871).
Conclusion
We recommend a 0–10 intention scale as a validated, practical measure of vaccination intention in public health practice, with a cutpoint of 8 on the scale as optimal, unless sensitivity and specificity are to be simultaneously optimized, when 6 is the optimal cutpoint
“Knowing how it works for me”: a qualitative interview study of the use of personalised approaches to manage common challenges during Dry January
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Participation in temporary abstinence challenges such as Dry January is associated with benefits including enduring reductions in alcohol consumption. However, undertaking temporary abstinence requires people to negotiate certain challenges. Building on previous research, we examined how and why particular strategies were used to address challenges and how use developed following January. Given differences in reported outcomes, we also explored differences and similarities in strategy use between ‘official’ UK Dry January registrants and those attempting an ‘unofficial’ alcohol-free January.
Methods
We conducted 16 online semi-structured interviews with individuals who participated ‘officially’ or ‘unofficially’ in Dry January 2022 and who, prior to this, were regular drinkers. Data was analysed using reflexive thematic analysis and themes constructed around the common challenges people faced and the strategies used to address them.
Results
Four themes were generated: breaking the routine, dealing with socialising whilst not drinking, avoiding loss of motivation, and dealing with the potential for ‘failure.’ People took personalised approaches to addressing these challenges, retaining the meaning of important rituals and practices whilst still changing their alcohol consumption. This personalisation was reflected in the variation in strategy use and adaptation of strategies over time. Despite overall variation in strategy use, many strategies were employed by both ‘official’ and ‘unofficial’ participants.
Conclusion
Dry January provides an opportunity for people to learn what strategies do and do not work for them. Capitalising on the flexibility of Dry January to offer additional opportunities for personalisation may help people get the most from their Dry January experience
A pragmatic approach to the investigation of stable chest pain: A UK, multi-centre, randomised trial to improve patient outcomes, quality of life and cost effectiveness (CE-MARC 3)
Get PDFExploited mutualism: the reciprocal effects of plant parasitic nematodes on the mechanisms underpinning plant–mutualist interactions
Get PDFWe are quickly gaining insights into the mechanisms and functions of plant–mutualist relationships with the common overarching aim of exploiting them to enhance food security and crop resilience. There is a growing mass of research describing various benefits of plant-mutualistic fungi, including increased nutrition, yields, and tolerance to biotic and abiotic factors. The bulk of this research has been focused on arbuscular mycorrhiza; however, there is now an expansion toward other plant mutualistic fungi. Contrary to the established ‘mycorrhizal induced resistance’ principle, increasing evidence shows that certain plant pests and pathogens may, in fact, exploit the benefits that mutualists provide their hosts, resulting in enhanced pathogenicity and reduced mutualist-derived benefits. In this Viewpoint, we propose that studying plant mutualistic fungi under controlled artificial conditions indeed provides in-depth knowledge but may mislead long-term applications as it does not accurately reflect multi-symbiont scenarios that occur in natura. We summarize the reciprocal impacts of plant pests, such as plant parasitic nematodes, on plant–fungal mutualisms and highlight how glasshouse experiments often yield contradictory results. We emphasize the need for collaborative efforts to increase the granularity of experimental systems, better reflecting natural environments to gain holistic insights into mutualist functions before applying them in sustainable crop protection strategies
The Rise and Fall of Twitter Data in Urban Analytics
Get PDFTwitter has established itself as a valuable social media platform for urban research over the last 10 years, by providing free and accessible data. However, recent shift towards the monetization of its data, raises questions on its future use. To investigate this, bibliometric analysis and topic modeling techniques are used to explore trends in urban research publications and wider consequences of reduced data access. The results illustrate a period of ‘hype’ towards Twitter data, followed by decline in recent years. Application areas and topics are also identified, highlighting the distinct ways in which social media data contributes to urban research
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