Biomechanical factors associated with the development of tibiofemoral knee osteoarthritis: protocol for a systematic review and meta-analysis

INTRODUCTION: Altered biomechanics, increased joint loading and tissue damage, might be related in a vicious cycle within the development of knee osteoarthritis (KOA). We have defined biomechanical factors as joint-related factors that interact with the forces, moments and kinematics in and around a synovial joint. Although a number of studies and systematic reviews have been performed to assess the association of various factors with the development of KOA, a comprehensive overview focusing on biomechanical factors that are associated with the development of KOA is not available. The aim of this review is (1) to identify biomechanical factors that are associated with (the development of) KOA and (2) to identify the impact of other relevant risk factors on this association. METHODS AND ANALYSIS: Cohort, cross-sectional and case–control studies investigating the association of a biomechanical factor with (the development of) KOA will be included. MEDLINE, EMBASE, CINAHL and SPORTDiscus will be searched from their inception until August 2015. 2 reviewers will independently screen articles obtained by the search for eligibility, extract data and score risk of bias. Quality of evidence will be evaluated. Meta-analysis using random effects model will be applied in each of the biomechanical factors, if possible. ETHICS AND DISSEMINATION: This systematic review and meta-analysis does not require ethical approval. The results of this systematic review and meta-analysis will be disseminated through publications in peer-reviewed journals and presentations at (inter)national conferences. TRIAL REGISTRATION NUMBER: CRD42015025092

Effects of tai chi on postural control during dual-task stair negotiation in knee osteoarthritis : a randomised controlled trial protocol

Stair ascent and descent require complex integration between sensory and motor systems; individuals with knee osteoarthritis (KOA) have an elevated risk for falls and fall injuries, which may be in part due to poor dynamic postural control during locomotion. Tai chi exercise has been shown to reduce fall risks in the ageing population and is recommended as one of the non-pharmocological therapies for people with KOA. However, neuromuscular mechanisms underlying the benefits of tai chi for persons with KOA are not clearly understood. Postural control deficits in performing a primary motor task may be more pronounced when required to simultaneously attend to a cognitive task. This single-blind, parallel design randomised controlled trial (RCT) aims to evaluate the effects of a 12-week tai chi programme versus balance and postural control training on neuromechanical characteristics during dual-task stair negotiation. Sixty-six participants with KOA will be randomised into either tai chi or balance and postural control training, each at 60 min per session, twice weekly for 12 weeks. Assessed at baseline and 12 weeks (ie, postintervention), the primary outcomes are attention cost and dynamic postural stability during dual-task stair negotiation. Secondary outcomes include balance and proprioception, foot clearances, self-reported symptoms and function. A telephone follow-up to assess symptoms and function will be conducted at 20 weeks. The findings will help determine whether tai chi is beneficial on dynamic stability and in reducing fall risks in older adults with KOA patients in community. Ethics approval was obtained from the Ethics Committee of the Affiliated Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine (#2018KY-006-1). Study findings will be disseminated through presentations at scientific conferences or publications in peer-reviewed journals. ChiCTR1800018028. [Abstract copyright: © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

Defoliation of the Invasive Tree Falcataria moluccana on Hawaii Island by the Native Koa Looper Moth (Geometridae: Scotorythra paludicola), and Evaluation of Five Fabaceous Trees as Larval Hostplants

The koa looper (Geometridae: Scotorythra paludicola) is an endemic Hawaiian moth whose caterpillars feed on Acacia koa, and experience occasional outbreaks, producing vast defoliations of forests. During an extensive and ongoing outbreak of this species on the island of Hawaii, patchy defoliation of Falcataria moluccana (“albizia”) was observed in the vicinity of Akaka Falls State Park, relatively distant from the main defoliation of koa, raising questions about the host range of the koa looper. To identify suitable host plants in the laboratory, we of- fered the koa looper foliage from five fabaceous tree species (A. koa, A. confusa, F. moluccana, Prosopis pallida, and Leucaena leucocephala), and recorded feeding and performance on these diets. Among the five tree species, only A. koa and F. moluccana were accepted as food; caterpillars on the other three species all died by the fifth day of the trial. Survival of the koa looper to pupation and adulthood on F. moluccana did not differ significantly from that on A. koa phyllodes, indicating that this tree is a suitable host, though it does not appear to be widely utilized in the field. Both oviposition preference and larval requirements are likely important determinants of the realized diet breadth for the koa looper. Additionally, develop- ment times at 19°C on A. koa and F. moluccana were nearly twice as long as at 23°C, highlighting the importance of temperature for development of this insect

The Design and Operation of The Keck Observatory Archive

The Infrared Processing and Analysis Center (IPAC) and the W. M. Keck Observatory (WMKO) operate an archive for the Keck Observatory. At the end of 2013, KOA completed the ingestion of data from all eight active observatory instruments. KOA will continue to ingest all newly obtained observations, at an anticipated volume of 4 TB per year. The data are transmitted electronically from WMKO to IPAC for storage and curation. Access to data is governed by a data use policy, and approximately two-thirds of the data in the archive are public.Comment: 12 pages, 4 figs, 4 tables. Presented at Software and Cyberinfrastructure for Astronomy III, SPIE Astronomical Telescopes + Instrumentation 2014. June 2014, Montreal, Canad

Baseline meniscal extrusion associated with incident knee osteoarthritis after 30 months in overweight and obese women

Objective: To investigate the association between baseline meniscal extrusion and the incidence of knee osteoarthritis (KOA) after 30 months in a high-risk population of overweight and obese women, free of clinical and radiological KOA at baseline. Methods: 407 middle-aged overweight women (body mass index - BMI ≥ 27 kg/m2) were evaluated at baseline and after 30 months of follow-up. Meniscal extrusion was defined as grade ≥2 on MRI according to MRI Osteoarthritis Knee Score (MOAKS). The primary outcome measure was KOA after 30 months follow-up, defined using the following criteria: either incidence of radiographic KOA (Kellgren & Lawrence grade 2 or higher), or clinical osteoarthritis (OA) according to the American College of Radiology (ACR) criteria, or medial or lateral joint space narrowing (JSN) of ≥1.0 mm. Using generalized estimating equations (GEE), we determined the association between knees with and without meniscal extrusion and both outcomes, corrected for the baseline differences. Results: 640 knees were available at baseline of which 24% (153) had meniscal extrusion. There was a significantly higher incidence of KOA according to the primary outcome measure in women with meniscal extrusion compared to those without extrusion (28.8%, odds ratio - OR 2.39, 95% CI 1.53, 3.73). A significantly higher incidence was found for the development of radiographic KOA (12.4%, OR 2.61, 95% CI 1.11, 6.13) and medial JSN (11.8%, OR 3.19, 95% CI 1.59, 6.41). Meniscal extrusion was not significantly associated with clinical KOA and lateral JSN. Conclusion: Meniscal extrusion was associated with a significantly higher incidence of KOA, providing an interesting target for early detection of individuals at risk for developing KOA

Classification of patients with knee osteoarthritis in clinical phenotypes: data from the osteoarthritis initiative

<div><p>Objectives</p><p>The existence of phenotypes has been hypothesized to explain the large heterogeneity characterizing the knee osteoarthritis. In a previous systematic review of the literature, six main phenotypes were identified: Minimal Joint Disease (MJD), Malaligned Biomechanical (MB), Chronic Pain (CP), Inflammatory (I), Metabolic Syndrome (MS) and Bone and Cartilage Metabolism (BCM). The purpose of this study was to classify a sample of individuals with knee osteoarthritis (KOA) into pre-defined groups characterized by specific variables that can be linked to different disease mechanisms, and compare these phenotypes for demographic and health outcomes.</p><p>Methods</p><p>599 patients were selected from the OAI database FNIH at 24 months’ time to conduct the study. For each phenotype, cut offs of key variables were identified matching the results from previous studies in the field and the data available for the sample. The selection process consisted of 3 steps. At the end of each step, the subjects classified were excluded from the further classification stages. Patients meeting the criteria for more than one phenotype were classified separately into a ‘complex KOA’ group.</p><p>Results</p><p>Phenotype allocation (including complex KOA) was successful for 84% of cases with an overlap of 20%. Disease duration was shorter in the MJD while the CP phenotype included a larger number of Women (81%). A significant effect of phenotypes on WOMAC pain (F = 16.736 p <0.001) and WOMAC physical function (F = 14.676, p < 0.001) was identified after controlling for disease duration.</p><p>Conclusion</p><p>This study signifies the feasibility of a classification of KOA subjects in distinct phenotypes based on subgroup-specific characteristics.</p></div

Identification of clinical phenotypes in knee osteoarthritis: a systematic review of the literature

Background: Knee Osteoarthritis (KOA) is a heterogeneous pathology characterized by a complex and multifactorial nature. It has been hypothesised that these differences are due to the existence of underlying phenotypes representing different mechanisms of the disease.Methods: The aim of this study is to identify the current evidence for the existence of groups of variables which point towards the existence of distinct clinical phenotypes in the KOA population. A systematic literature search in PubMed was conducted. Only original articles were selected if they aimed to identify phenotypes of patients aged 18 years or older with KOA. The methodological quality of the studies was independently assessed by two reviewers and qualitative synthesis of the evidence was performed. Strong evidence for existence of specific phenotypes was considered present if the phenotype was supported by at least two high-quality studies.Results: A total of 24 studies were included. Through qualitative synthesis of evidence, six main sets of variables proposing the existence of six phenotypes were identified: 1) chronic pain in which central mechanisms (e.g. central sensitisation) are prominent; 2) inflammatory (high levels of inflammatory biomarkers); 3) metabolic syndrome (high prevalence of obesity, diabetes and other metabolic disturbances); 4) Bone and cartilage metabolism (alteration in local tissue metabolism); 5) mechanical overload characterised primarily by varus malalignment and medial compartment disease; and 6) minimal joint disease characterised as minor clinical symptoms with slow progression over time.Conclusions: This study identified six distinct groups of variables which should be explored in attempts to better define clinical phenotypes in the KOA population