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Introduction: A significant proportion of patients remain dissatisfied following total knee arthroplasty (TKA) surgery. Reasons for this are unclear. Contemporary implants seek to mirror innate anatomy. Such innovations are necessarily subject to scrutiny to validate their use. The Zimmer-Biomet Persona® Personalized Knee system is such an anatomic TKA. This work seeks to establish medium term survival data and patient reported outcomes for this implant., Methods: This was a cohort study of prospectively collected data on all patients undergoing Persona TKA at our institution. Patients were managed using a standardised protocol for intra- and post-operative care. Survivorship data were collected using our National Joint Registry and corroborated with local data. Range of motion, Oxford Knee Score (OKS) and patient satisfaction were recorded at six weeks and one year post-operatively. Hip-knee-ankle radiographs were used to record pre- and post-operative alignment., Results: Data were collected for 749 knees in 679 patients. Overall survivorship was 99.0% at a mean 5.35 years, with seven patients undergoing revision surgery during the study period. Significant improvements in the OKS (mean 20.7 points) and range of motion were observed (mean 104.6° at one year). 94.9% of patients were satisfied at one year. Mean correction was to a mechanical femoro-tibial angle of 0.8° varus., Conclusions: We demonstrate excellent medium term survival of the Persona TKA in this large cohort, coupled with improvements in patient reported outcomes, range of motion and patient satisfaction at one year which compare favourably to other implants., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Deteriorating meniscal function is thought to play a role in knee osteoarthritis. Meniscal proteoglycans maintain mechanical stiffness of the tissue through electrostatic effects. This study aimed to investigate whether the mechanical properties of macroscopically intact meniscus are preserved in osteoarthritis., Methods: Discs of lateral meniscal tissue two millimetres thick and of five millimetres diameter from osteoarthritic knees and from healthy donors were placed within a confined compression chamber, mounted in a materials testing machine and bathed in isotonic 0.14M PBS, hypotonic deionised water or hypertonic 3M PBS. Following equilibrium, a 10% ramp compressive strain was applied followed by a 7200 second hold. Resultant stress relaxation curves were fitted to a nonlinear poroviscoelastic model with strain dependent permeability using finite element modelling to determine mechanical parameters. All samples were assayed for proteoglycan content. Comparison of results was undertaken using multivariate ANOVA., Results: Thirty samples from osteoarthritic knees and 18 samples from healthy donors were tested. No significant differences in mechanical parameters or proteoglycan content was observed between groups. In both groups Young's modulus (E) was significantly greater, and zero-strain permeability significantly reduced, in samples tested in deionised water compared to samples tested in 0.14M or 3M PBS (all p < 0.05)., Conclusion: Mechanical parameters of intact lateral meniscus in osteoarthritic knees are similar to those found in healthy knees. Proteoglycan concentration and their electrostatic contribution to mechanical stiffness of the meniscus is maintained in menisci derived from osteoarthritic knees. Whilst macroscopic tears in the meniscal ultrastructure may contribute to osteoarthritis, intact meniscal tissue maintains its function., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Purpose: Venous thromboembolism (VTE) is a significant complication following lower limb arthroplasty (LLA). There is a paucity of evidence with regard to air travel following LLA. Orthopaedic surgeons are often asked by patients regarding air travel following LLA, and there is a need for evidence to guide these patients., Methods: This was a retrospective cohort study. We identified two cohorts, one travelling to and from the hospital by air and another, by land. All patients received routine preoperative and post-operative care, and thromboprophylaxis, as per our hospital guidelines. We collected baseline demographics, ASA score and incidence of VTE at 90 days using local patient records and a national joint registry. We also recorded data on flight time and overland distance of travel., Results: Two hundred and forty-three patients travelled by air; mean flight time was 74 min. In total, 5498 patients travelled a mean 25.3 miles over land to the hospital. No differences in baseline demographics or ASA score were observed. Four patients developed a VTE in the flight group, with 32 patients suffering a VTE in the control group. There was a significant difference in the VTE rate between the flight and control groups (p < 0.05); the relative risk of developing a VTE in the flight group was 2.85., Conclusions: In our cohort, perioperative short haul air travel is associated with an increased risk of VTE at 90 days following LLA. Orthopaedic surgeons must ensure that their patients are cognizant of the risks associated with perioperative air travel and take measures to minimise these risks., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Load transmission is an important function of the meniscus. In articular cartilage, proteoglycans help maintain hydration via negatively charged moieties. We aimed to investigate the influence of electrostatic effects on stiffness of meniscal tissue. Circular discs from bovine menisci of 8 mm diameter and 5 mm thickness were placed within a confined compression chamber. The apparatus was bathed in distilled water, 0.14 M PBS or 3 M PBS before being subjected to 5% ramp compressive strain and held for 300s. FEBio software was used to fit resultant relaxation curves to a non-linear poroviscoelastic model with strain dependent Holmes-Mow permeability. Analysis was conducted using one-way ANOVA with Tukey post-hoc analysis. 10 samples were tested in each solution. Significant differences (p < 0.05) were observed between the values for Young's modulus, zero strain dependent permeability and the viscoelastic coefficient for samples tested in 3 M PBS as compared to deionised water/0.14 M PBS. No significant differences were observed in the strain dependent/stiffening coefficients or the relaxation time. Approximately 79% of the stiffness of the meniscus appears attributable to ionic effects. Ionic effects play a significant role in the mechanical stiffness of the meniscus. It is important to include the influence of ionic effects when developing mathematical models of this tissue., (Copyright © 2018. Published by Elsevier Ltd.)

Background: A substantial component of care is provided to stroke survivors by informal caregivers. However, providing such care is often a new and challenging experience and has been linked to a number of adverse outcomes. A range of interventions targeted towards stroke survivors and their family or other informal caregivers have been tested in randomised controlled trials (RCTs). , Objectives: To evaluate the effect of interventions targeted towards informal caregivers of stroke survivors or targeted towards informal caregivers and the care recipient (the stroke survivor)., Search Strategy: We searched the Cochrane Stroke Group Trials Register (March 2011), CENTRAL (The Cochrane Library Issue 2010, Issue 4), MEDLINE (1950 to August 2010), EMBASE (1980 to December 2010), CINAHL (1982 to August 2010), AMED (1985 to August 2010), PsycINFO (1967 to August 2010) and 11 additional databases. In an effort to identify further published, unpublished and ongoing studies, we searched conference proceedings and trials registers, scanned reference lists of relevant articles and contacted authors and researchers. There were no language restrictions., Selection Criteria: We included RCTs if they evaluated the effect of non-pharmacological interventions (compared with no care or routine care) on informal caregivers of stroke survivors. We included trials of interventions delivered to stroke survivors and informal caregivers only if the stroke survivor and informal caregiver were randomised as a dyad. We excluded studies which included stroke survivors and caregivers if the stroke survivors were the primary target of the intervention., Data Collection and Analysis: Two review authors selected studies for inclusion, independently extracted data and assessed methodological quality. We sought original data from trialists. We categorised interventions into three groups: support and information, teaching procedural knowledge/vocational training type interventions, and psycho-educational type interventions. The primary outcome was caregivers' stress or strain. We resolved disagreements by consensus., Main Results: Eight studies, including a total of 1007 participants, met our inclusion criteria. We did not pool the results of all the studies because of substantial methodological, statistical and clinical heterogeneity. For caregivers' stress or strain we found no significant results within categories of intervention, with the exception of one single-centre study examining the effects of a 'vocational training' type intervention which found a mean difference between the intervention and comparator group at the end of scheduled follow-up of -8.67 (95% confidence interval -11.30 to -6.04, P < 0.001) in favour of the 'teaching procedural knowledge' type intervention group., Authors' Conclusions: It was not possible to carry out a meta-analysis of the evidence from RCTs because of methodological, clinical and statistical heterogeneity. One limitation across all studies was the lack of a description of important characteristics that define the informal caregiver population. However, 'vocational educational' type interventions delivered to caregivers prior to the stroke survivor's discharge from hospital appear to be the most promising intervention. However, this is based on the results from one, small, single-centre study.

This paper presents methods to build histo-anatomically detailed individualized cardiac models. The models are based on high-resolution three-dimensional anatomical and/or diffusion tensor magnetic resonance images, combined with serial histological sectioning data, and are used to investigate individualized cardiac function. The current state of the art is reviewed, and its limitations are discussed. We assess the challenges associated with the generation of histo-anatomically representative individualized in silico models of the heart. The entire processing pipeline including image acquisition, image processing, mesh generation, model set-up and execution of computer simulations, and the underlying methods are described. The multifaceted challenges associated with these goals are highlighted, suitable solutions are proposed, and an important application of developed high-resolution structure-function models in elucidating the effect of individual structural heterogeneity upon wavefront dynamics is demonstrated.