Development and validation of the SAFE (Socially Ascribed intersectional identities For Equity) questionnaire.

Traditional questionnaires do not capture the complexity of how people are viewed by others and grouped into categories on the basis of what is inferred (or not) about them. This is critical in applying an intersectionality framework in research because people are negatively impacted because of "who they are" but also based on "how others see them." The purpose of this project was to develop and validate a questionnaire, grounded in intersectionality theory and a nuanced understanding of social position, that can be applied in large-scale, population-based surveys and studies. Drawing on 61 existing quantitative surveys collecting identity-based information and 197 qualitative studies on intersectionality describing the complex ways in which people's social positions are constructed and experienced, we created a draft questionnaire comprising five parts: 1) Sex and Gender, 2) Sexuality and Sexual Orientation, 3) Cultural Context, 4) Disability, Health, and Physical Characteristics, and 5) Socioeconomic Status. A draft of the questionnaire was then reviewed by experts via the Delphi process, which gauged the accessibility of the questionnaire (e.g., language used, length) and the relevance of its content using a 5-point scale and open-ended questions. These responses were ranked, analyzed, and synthesized to refine the questionnaire and, ultimately, to obtain ≥75 % consensus on each questionnaire item and response option. The SAFE questionnaire provides an opportunity to take a significant step forward in advancing our understanding of the complex, intersectional nature of social participation and marginalization.

Physical activity together for MS (PAT-MS): Secondary outcomes of a randomized controlled feasibility trial.

BACKGROUND: Care partners provide essential care to those with multiple sclerosis (MS). Dyadic interventions promoting health behaviours have wide-reaching benefits for individuals with MS and their care partners. However, behavioural interventions to promote physical activity in patient-caregiver dyads have yet to be explored in an MS-specific context. This study examined the secondary outcomes of the "Physical Activity Together for Multiple Sclerosis (PAT-MS)" intervention, including dyadic adjustment, caregiving tasks, caregiver quality of life, coping, and MS impact in MS dyads. METHODS: A randomized controlled feasibility trial of the 12-week behavioural PAT-MS intervention. The Dyadic Adjustment Scale, Caregiving Tasks in MS Scale, Caregiver Quality of Life in MS Scale, Coping with MS Caregiving Inventory, and MS Impact Scale measured secondary outcomes of interest. Mixed-model ANOVAs were used to test changes in variables between groups (PAT-MS vs wait-list control) over time. RESULTS: 20 participants, including 10 people with MS (51.4 ± 10.1 years old; median patient-determined disease steps (PDDS) score= 4, IQR= 1.25) and 10 care partners (48.5 ± 12.1 years old) were recruited and randomized. There was no statistically significant effect of the intervention on any of the secondary outcomes (p= 0.67-1.00). However, large effect sizes and condition-by-time interaction effects indicated improvement in dyadic adjustment (d= 1.03, ηp2= 0.45), the criticism-coercion coping subscale (d= -0.93, ηp2= 0.49), and caregiving tasks (d= 1.05, ηp2= 0.52), specifically within psycho-emotional (d= 1.47, ηp2= 0.38) and socio-practical (d= 1.10, ηp2 =0.37) sub-domains of caregiving tasks after the PAT-MS intervention compared to the wait-list condition. CONCLUSION: While this pilot feasibility study was not powered based on the secondary outcomes herein, our findings indicate improvement in dyadic adjustment and emotional and social caregiving tasks, with reduced reliance on criticism-coercion coping in the PAT-MS group compared to controls following the intervention. Findings indicate that PAT-MS may improve dyadic psychosocial well-being of people with moderate-to-severe MS and their care partners, and this should be examined next in a fully-powered study.

Awareness and knowledge of the Canadian 24-Hour Movement Guidelines for Adults among adults living in Canada.

Awareness and knowledge of national movement behaviour guidelines are needed to influence individual behaviour and public health policies. This study assessed the awareness and knowledge of the Canadian 24-Hour Movement Guidelines for Adults Aged 18-64 Years and Adults Aged 65 Years or Older (24HMG) recommendations among adults living in Canada across three timepoints. Online surveys were distributed to representative samples of adults living in Canada over a 6-month period. Findings suggest that short-term dissemination efforts were successful in increasing awareness of the 24HMG following guideline release. However, other strategies, such as education, may be needed to influence knowledge of guideline recommendations.

Relationships between sport and exercise participation and subjective well-being among adults with physical disabilities: Is participation quality more important than participation quantity?

Sport and exercise participation are associated with small, albeit positive changes in subjective well-being (SWB). Recent theorizing has emphasized the importance of distinguishing between performance aspects (i.e., frequency, intensity, time engaged) and the experiential aspects of sport and exercise participation among people with disabilities. This study assessed the relative contributions of time spent participating in sport and exercise (a performance measure) versus measures of participation experiences, in explaining variance in SWB. Participants were 535 adults with physical disabilities, recruited through a nation-wide survey, who participated in sport (n = 271; 62% male; 44 ± 14 years) or exercise (n = 264; 42% male; 57 ± 14 years). They completed measures of minutes/week of sport or exercise participation, experiential aspects of participation, and SWB (overall life satisfaction, satisfaction with physical, psychological and social life-domains, and positive/negative affect). Hierarchical multiple regression analyses showed minutes/week of sport did not explain significant variance in any SWB measure, but sport participation experiences explained significant variance (9.2%-20.9%) in all SWB measures (p < 0.05). Similarly, minutes/week of exercise explained significant variance only in physical life-domain satisfaction (ΔR2 = 2.6%, p = 0.026), but exercise participation experiences explained significant variance (4.8%-10.7%) in all SWB measures (p < 0.05). Experiences of belonging and mastery were particularly strong, consistent predictors across SWB outcomes. These results suggest participation experiences better explain relationships between sport and exercise participation and SWB than time spent performing sport and exercise. Findings have implications for designing future studies to test the effects of sport and exercise on SWB, and developing theories and interventions to explain and maximize the use of sport and exercise to improve SWB in adults with disabilities.

The Effects of Physical Activity Messages on Physical Activity Support Behaviors and Motivation Among Parents of Children with Disabilities.

Persuasive messages can motivate parent support for physical activity (PA). Many PA messages targeting parents are not necessarily inclusive of parents of children with disabilities (CWD). Guided by the theory of planned behavior and multi-process action control model, the relative effects of PA messages were examined among parents of CWD. Parents (N = 135) were randomized to view one of four PA messages. Parent support for PA and various psychosocial antecedents were assessed before and after message viewing, along with message preference. Baseline parent support for PA acted as a moderator on the effects of messages. Effects of messages did not differ between message conditions. Overall message effects were observed for attitudes, subjective norms and planning. Parent support for PA increased only among parents with low baseline parent support and the inclusive message was most preferred. This study can inform the development of PA messages targeting this population.

Exploring Zentangle as a virtual mindfulness-based art intervention for people with serious mental illness.

Introduction: Zentangle is an emerging art intervention that incorporates mindfulness into creative drawing. This pilot study explored Zentangle as a novel adjunct treatment for people with serious mental illness (SMI). Methods: Six participants with SMI completed an 8-week Zentangle program. Psychiatric outcomes were evaluated using the Brief Psychiatric Rating Scale (BPRS), Mindful Attention Awareness Scale (MAAS), Perceived Stress Scale (PSS), and Quality of Life Enjoyment and Satisfaction Scale (Q-LES-Q-SF). A focus group was conducted to better understand the experiences of the participants. Results: A significant reduction in psychiatric symptoms was observed as measured by the total score on the BPRS between baseline and 5-week post-intervention (40.7 ± 9.1 vs. 33.7 ± 8.9, mean ± SD, p = 0.02). Participants also showed a significant increase in mindful attention using the average score on the MAAS between 1- and 5-week post-intervention (3.5 ± 0.4 vs. 4.2 ± 0.7, mean ± SD, p = 0.04). Four themes were generated from the focus group: (1) approaching mindfulness through Zentangle; (2) power of uncomplicated art creation; (3) understanding the value of self-appreciation; and (4) fostering a positive environment. Discussion: Our preliminary data suggest that the use of Zentangle for participants with SMI may have a positive impact on overall psychiatric symptoms and mindfulness. Moreover, the Zentangle Method encourages positive emotions like gratitude and self-accomplishment to counteract negative feelings of self-criticism and failure in participants.

A Health App for Post-Pandemic Years (HAPPY) for people with physiological and psychosocial distress during the post-pandemic era: Protocol for a randomized controlled trial.

Objective: This article describes a protocol for a randomized controlled trial to evaluate the effects of a three-level Health App for Post-Pandemic Years (HAPPY) on alleviating post-pandemic physiological and psychosocial distress. Methods: Convenience and snowball sampling methods will be used to recruit 814 people aged 18+ with physiological and/or psychosocial distress. The experimental group will receive a 24-week intervention consisting of an 8-week regular supervision phase and a 16-week self-help phase. Based on their assessment results, they will be assigned to receive interventions on mindfulness, energy conservation techniques, or physical activity training. The waitlist control group will receive the same intervention in Week 25. The primary outcome will be changes in psychosocial distress, measured using the Kessler Psychological Distress Scale (K10). Secondary outcomes will include changes in levels of fatigue (Chinese version of the Brief Fatigue Inventory), sleep quality (Chinese version of the Pittsburgh Sleep Quality Index), pain intensity (Numeric Rating Scale), positive appraisal (Short version of the 18-item Cognitive Emotion Regulation Questionnaire), self-efficacy (Chinese version of the General Self-efficacy Scale), depression and anxiety (Chinese version of the 21-item Depression Anxiety Stress Scale), and event impact (Chinese version of the 22-item Impact of Event Scale-Revised). All measures will be administered at baseline (T0), Week 8 after the supervision phase (T1), and 24 weeks post-intervention (T2). A generalized estimating equations model will be used to examine the group, time, and interaction (Time × Group) effect of the interventions on the outcome assessments (intention-to-treat analysis) across the three time points, and to compute a within-group comparison of objective physiological parameters and adherence to the assigned interventions in the experimental group. Conclusions: The innovative, three-level mobile HAPPY app will promote beneficial behavioral strategies to alleviate post-pandemic physiological and psychosocial distress. Trial registration: ClinicalTrials.gov, NCT05459896. Registered on 15 July 2022.

Robotic arm-assisted unicondylar knee arthroplasty resulted in superior radiological accuracy: a propensity score-matched analysis.

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) is an effective surgical treatment for medial compartment arthritis of the knee, yet surgical outcomes are directly related to surgical execution. Robotic arm-assisted surgery aims to address these difficulties by allowing for detailed preoperative planning, real-time intraoperative assessment and haptic-controlled bone removal. This study aimed to compare the clinical and radiological outcomes between conventional manual mobile bearing and robot arm-assisted fixed bearing medial UKA in our local population. MATERIALS AND METHODS: This is a retrospective case-control study of 148 UKAs performed at an academic institution with a minimum of 1-year follow-up. 74 robotic arm-assisted UKAs were matched to 74 conventional UKAs via propensity score matching. Radiological outcomes included postoperative mechanical axis and individual component alignment. Clinical parameters included a range of motion, Knee Society knee score and functional assessment taken before, 6 and 12 months after the operation. RESULTS: Robot arm-assisted UKA produced a more neutral component coronal alignment in both femoral component (robotic -0.2 ± 2.8, manual 2.6 ± 2.3; P = 0.043) and tibial component (robotic -0.3 ± 4.0, manual 1.7 ± 5.3; P < 0.001). While the postoperative mechanical axis was comparable, robot arm-assisted UKA demonstrated a smaller posterior tibial slope (robotic 5.7 ± 2.7, manual 8.2 ± 3.3; P = 0.02). Clinical outcomes did not show any statistically significant differences. CONCLUSION: Compared with conventional UKA, robotic arm-assisted UKA demonstrated improved component alignment and comparable clinical outcomes. Improved radiological accuracy with robotic-arm assistance demonstrated promising early results.

Physical Activity Together for Multiple Sclerosis (PAT-MS): A randomized controlled feasibility trial of a dyadic behaviour change intervention.

Background: Many people with advanced multiple sclerosis (MS) and their care-partners do not engage in sufficient physical activity (PA) for health benefits. We developed "Physical Activity Together for MS (PAT-MS)", a 12-week dyadic behavioural intervention, to promote PA among these dyads. Herein, we evaluated the feasibility of PAT-MS before a definitive trial. Methods: A randomized controlled feasibility trial, with 1:1 allocation into the intervention or wait-list control condition. Predefined progression criteria included rates of recruitment, retention, safety, participant satisfaction and adherence. Changes in self-reported and accelerometer-measured PA were assessed at baseline and post-intervention using mixed-factor ANOVAs. Effects sizes were calculated as Cohen's d. Results: The recruitment rate (i.e., 20 participants in 10 months) was not acceptable. However, retention (80%) was acceptable. No serious adverse events were reported. There were high levels of participant satisfaction with the intervention (content (median = 6 out of 7), facilitator (median = 7 out of 7), and delivery (median = 5 out of 7)) and adherence (92% of the group sessions, 83% of the individual support calls, and 80% of the practice activities were completed). There were statistically significant time-by-condition interactions on self-reported PA, steps/day, and %wear time and minutes in sedentary behaviour, and moderate-to-vigorous PA from baseline to post-intervention in people with MS and their family care-partners. Conclusion: PAT-MS appears feasible, safe, and efficacious for PA promotion in MS dyads. We established effect size estimates to power a future definitive trial and identified necessary methodological changes to increase the efficiency of study procedures and improve the quality of the intervention. Trial registration: ClinicalTrials.gov NCT04267185; Registered February 12, 2020, https://clinicaltrials.gov/ct2/show/NCT04267185.

Prediction of Total Knee Arthroplasty Sizes with Demographics, including Hand and Foot Sizes.

Anticipating implant sizes before total knee arthroplasty (TKA) allows the surgical team to streamline operations and prepare for potential difficulties. This study aims to determine the correlation and derive a regression model for predicting TKA sizes using patient-specific demographics without using radiographs. We reviewed the demographics, including hand and foot sizes, of 1,339 primary TKAs. To allow for comparison across different TKA designs, we converted the femur and tibia sizes into their anteroposterior (AP) and mediolateral (ML) dimensions. Stepwise multivariate regressions were performed to analyze the data. Regarding the femur component, the patient's foot, gender, height, hand circumference, body mass index, and age was the significant demographic factors in the regression analysis (R-square 0.541, p < 0.05). For the tibia component, the significant factors in the regression analysis were the patient's foot size, gender, height, hand circumference, and age (R-square 0.608, p < 0.05). The patient's foot size had the highest correlation coefficient for both femur (0.670) and tibia (0.697) implant sizes (p < 0.05). We accurately predicted the femur component size exactly, within one and two sizes in 49.5, 94.2, and 99.9% of cases, respectively. Regarding the tibia, the prediction was exact, within one and two sizes in 53.0, 96.0, and 100% of cases, respectively. The regression model, utilizing patient-specific characteristics, such as foot size and hand circumference, accurately predicted TKA femur and tibia sizes within one component size. This provides a more efficient alternative for preoperative planning.

The MoXFo initiative - adherence: Exercise adherence, compliance and sustainability among people with multiple sclerosis: An overview and roadmap for research.

We know very little about exercise adherence, compliance and sustainability in multiple sclerosis (MS), yet adherence is seemingly important for yielding immediate and sustained health benefits. This paper is focused on exercise adherence, compliance and sustainability in the context of informing research and practice involving MS. This focus is critical for clarifying terminology for future research and providing a roadmap guiding clinical research and practice. Our objective was accomplished through a narrative summary of the literature by a panel of experts on exercise adherence from the Moving Exercise Research in Multiple Sclerosis Forward (MoXFo) initiative and a concluding summary of the state of the literature and future research directions. The panel of experts identified three overall themes (Background and Importance; Understanding and Promoting Exercise Adherence, Compliance and Sustainability and Challenges to Exercise Adherence, Compliance and Sustainability) that represented a categorization of nine subthemes. These overall themes and subthemes formed the basis of our recommendations regarding future research broadly involving exercise adherence in MS. Overall, there is limited evidence on rates and determinants of exercise adherence and compliance in MS, and little is known about techniques and interventions for immediate and long-term exercise behaviour change.

"It has to be more than exercise": exploring multiple perspectives to community-based exercise program design for persons with breast cancer.

PURPOSE: Connecting persons with cancer to exercise resources and/or supports requires a diverse team of professionals. As such, there is merit to engaging multiple individuals or "partners" along the cancer pathway to explore the relevant features of community-based exercise program (CBEP) design. The purpose of this study was to explore multi-partner perspectives to CBEP design for persons diagnosed with breast cancer (PWBC) to inform the implementation of a CBEP in a local setting. METHODS: PWBC, health care professionals and qualified exercise professionals participated in one of four 60-min focus group discussions. Rich dialogue about preferred program environments, program delivery teams, and core program practices was encouraged using a semi-structured discussion guide. Focus groups were audio recorded, transcribed verbatim, and analyzed using inductive thematic analysis. RESULTS: Five main themes were identified based on focus group discussions, each pointing to an important feature of CBEP design for PWBC. Themes included the desire for CBEPs to incorporate elements designed to improve cancer literacy, provide opportunities to participate with peers, foster self-efficacy, prioritize program accessibility, and meaningfully integrate CBEPs within a network of supportive cancer care. CONCLUSION: The collective effect of fostering such elements in CBEPs may serve to increase the uptake and maintenance of exercise among PWBC; ultimately enhancing their overall well-being and quality of life.

I AM FAMILY: Understanding the adapted sport experiences of family members of military personnel with physical and psychological illnesses and injuries through the lens of the Invictus Games.

Family are influential actors in adapted sport participation. However, little is known about their experiences with adapted sport. The current study sought to explore the experiences of families in adapted sport through the context of the Invictus Games, an international adapted sport competition for military personnel with physical and psychological illnesses and injuries that is unique in its inclusion of family programming. Family members (n = 21; partners, parents, siblings, and children) of Invictus Games Toronto 2017 competitors participated in semi-structured interviews. Data were analyzed using reflexive thematic analysis. Three themes were identified: recognition of family experiences during service and after onset of disability; creating a sense of belonging; and improving family knowledge and perceptions. This study provides insight regarding how adapted sport events can support the well-being of both individuals with illnesses and injuries and their families.

'On-the ground' strategy matrix for fostering quality participation experiences among persons with disabilities in community-based exercise programs.

OBJECTIVE: The purposes of this paper are to (1) document the generation and refinement of a quality participation strategy list to ensure resonance and applicability within community-based exercise programs (CBEPs) for persons with physical and intellectual disabilities, and (2) identify theoretical links between strategies and the quality participation constructs. METHODS: To address purpose one, a list of strategies to foster quality participation among members was extracted from qualitative interviews with providers from nine CBEPs serving persons with physical disabilities. Next, providers from CBEPs serving persons with physical (n = 9) and intellectual disabilities (n = 6) were asked to identify the strategies used, and examples of their implementation, within their programs. Additional strategies noted by providers and in recent published syntheses were added to the preliminary list. A re-categorization and revision process was conducted. To address purpose two, 22 researchers with expertise in physical and/or intellectual disability, physical activity, participation and/or health behaviour change theory completed a closed-sort task to theoretically link each strategy to the constructs of quality participation. RESULTS: The final list of 85 strategies is presented in a matrix. Each strategy has explicit examples and proposed theoretical links to the constructs of quality participation. CONCLUSIONS: The strategy matrix offers a theoretically-meaningful representation of how quality participation-enhancing strategies can be practically implemented "on-the-ground" in CBEPs for persons with disabilities.

The role of telemedicine in joint replacement surgery? An updated review.

The usage of telemedicine and telehealth services has grown tremendously and has become increasingly relevant and essential. Technological advancements in current telehealth services have supported its use as a viable alternative tool to conduct visits for consultations, follow-up, and rehabilitation in total joint arthroplasty. Such technology has been widely implemented, particularly during the coronavirus 2019 (COVID-19) pandemic, to deliver postoperative rehabilitation among patients receiving total joint arthroplasty (TJA), further demonstrating its feasibility with a lower cost yet comparable clinical outcomes when compared with traditional care. There remains ample potential to utilize telemedicine for prehabilitation to optimize the preoperative status and postoperative outcomes of patients with osteoarthritis. In this review, various implementations of telemedicine within total joint arthroplasty and future application of telemedicine to deliver tele-prehabilitation in TJA are discussed.

Application of machine learning in the prevention of periprosthetic joint infection following total knee arthroplasty: a systematic review.

BACKGROUND: Machine learning is a promising and powerful technology with increasing use in orthopedics. Periprosthetic joint infection following total knee arthroplasty results in increased morbidity and mortality. This systematic review investigated the use of machine learning in preventing periprosthetic joint infection. METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed was searched in November 2022. All studies that investigated the clinical applications of machine learning in the prevention of periprosthetic joint infection following total knee arthroplasty were included. Non-English studies, studies with no full text available, studies focusing on non-clinical applications of machine learning, reviews and meta-analyses were excluded. For each included study, its characteristics, machine learning applications, algorithms, statistical performances, strengths and limitations were summarized. Limitations of the current machine learning applications and the studies, including their 'black box' nature, overfitting, the requirement of a large dataset, the lack of external validation, and their retrospective nature were identified. RESULTS: Eleven studies were included in the final analysis. Machine learning applications in the prevention of periprosthetic joint infection were divided into four categories: prediction, diagnosis, antibiotic application and prognosis. CONCLUSION: Machine learning may be a favorable alternative to manual methods in the prevention of periprosthetic joint infection following total knee arthroplasty. It aids in preoperative health optimization, preoperative surgical planning, the early diagnosis of infection, the early application of suitable antibiotics, and the prediction of clinical outcomes. Future research is warranted to resolve the current limitations and bring machine learning into clinical settings.

Transitions in mental health and addiction care for youth and their families: a scoping review of needs, barriers, and facilitators.

INTRODUCTION: Transitional-aged youth (TAY) with mental health and/or addictions (MHA) concerns and their families experience significant challenges finding, accessing, and transitioning through needed MHA care. To develop appropriate supports that assist TAY and their families in navigating MHA care, their experiences of transitions in the MHA care system must be better understood. This scoping review identifies and explores the needs, barriers, and facilitators for TAY and their families when transitioning through MHA care. METHODS: This scoping review commenced with a search of five relevant databases. Three research team members were involved in title, abstract, and full-text scanning and data extraction. Sources focusing on TAY anywhere between the ages of 12-29 years and meeting the study objectives were included. Extractions compiled background and narrative information about the nature and extent of the data. Analysis and synthesis of findings involved numerical description of the general information extracted (e.g., numbers of sources by country) and thematic analysis of narrative information extracted (e.g., family involvement in TAY help-seeking). RESULTS: A total of 5894 sources were identified. Following title and abstract scanning, 1037 sources remained for full-text review. A total of 66 sources were extracted. Findings include background information about extracted sources, in addition to five themes that emerged pertaining to barriers and facilitators to access and transitions through care and the needs and roles of TAY and families in supporting help-seeking and care transitions: holistic supports, proactive preparation, empowering TAY and families, collaborative relationships, and systemic considerations. These five themes demonstrate approaches to care that can ensure TAY and families' needs are met, barriers are mitigated, and facilitators are enhanced. CONCLUSION: This review provides essential contextual information regarding TAY with MHA concerns and their families' needs when seeking care. Such findings lend to an enhanced understanding of how MHA programs can support this population's needs, involve family members as appropriate, reduce the barriers experienced, and work to build upon existing facilitators.

Metal-on-crosslinked polyethylene in total hip arthroplasty - an excellent combination at fifteen to twenty years of follow-up.

PURPOSE: Cross-linked polyethylene (PE) has been used with great clinical success in total hip arthroplasty (THA) since its debut in the late 1990's. However, reports regarding this bearing couple near the end of its second decade of service are still scant. The aim of this study was to first determine the long term clinical and radiological results and second Investigate what factors affect wear rates using a metal-on-crosslinked PE bearing articulation. METHODS: 55 THAs using a single brand of cross-linked liner, cementless cup and 28 mm hip ball were performed in 44 patients. Age, sex, Charlson Comorbidity Index (CCI) and need for revision surgery were recorded. Linear and volumetric wear was determined using the Martell method. RESULTS: Mean age at operation was 51.2 (29-73 ± 12.1) years. Mean duration of follow-up was 16.9 years (range 15.0-20.1 ± 1.1 years). Osteolysis was not present in the latest follow-up radiographs. Median linear and volumetric wear rate was 0.038 mm/year (95% CI 0.032-0.047) and 7.115mm3/year (95% CI 6.92-17.25) respectively. Acetabular component position was not found to be related to both linear and volumetric wear. No significant difference was found in the linear and volumetric wear rates of thinner and thicker liners (8 mm or below and > 8 mm) (p = 0.849 and p = 0.64 respectively). CONCLUSION: Metal-on-crosslinked PE is associated with low linear and volumetric wear rates which has virtually obviated osteolysis and has translated to excellent survivorship even at long term follow up. In-vivo oxidation does not appear to be of clinical concern at this point.

Does knowledge have a half-life? An observational study analyzing the use of older citations in medical and scientific publications.

OBJECTIVES: In the process of scientific progress, prior evidence is both relied on and supplanted by new discoveries. We use the term 'knowledge half-life' to refer to the phenomenon in which older knowledge is discounted in favour of newer research. By quantifying the knowledge half-life, we sought to determine whether research published in more recent years is preferentially cited over older research in medical and scientific articles. DESIGN: An observational study employing a directed, systematic search of current literature. DATA SOURCES: BMJ, PNAS, JAMA, NEJM, The Annals of Internal Medicine, The Lancet, Science and Nature were searched. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Eight high-impact medical and scientific journals were sampled examining original research articles from the first issue of every year over a 25-year span (1996-2020). The outcome of interest was the difference between the publication year of the article and references cited, termed 'citation lag'. DATA EXTRACTION AND SYNTHESIS: Analysis of variance was used to identify significant differences in citation lag. RESULTS: A total of 726 articles and 17 895 references were included with a mean citation lag of 7.5±8.4 years. Across all journals, >70% of references had been published within 10 years of the citing article. Approximately 15%-20% of referenced articles were 10-19 years old, and articles more than 20 years old were cited infrequently. Medical journals articles had references with significantly shorter citation lags compared with general science journals (p≤0.01). Articles published before 2009 had references with significantly shorter citation lags compared with those published in 2010-2020 (p<0.001). CONCLUSIONS: This study found evidence of a small increase in the citation of older research in medical and scientific literature over the past decade. This phenomenon deserves further characterisation and scrutiny to ensure that 'old knowledge' is not being lost.