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Learning and retaining simulated arthroscopic meniscal repair skills.
BACKGROUND: Previous studies of task-specific skills have suggested that a loss of technical performance occurs if the skill is not practiced for a six-month period. The aims of this study were to objectively demonstrate the learning curve for a complex arthroscopic task (meniscal repair) by means of motion analysis and to determine the impact of task repetition on the retention of this skill. METHODS: Nineteen orthopaedic residents with experience in routine knee arthroscopy but not in arthroscopic meniscal repair were recruited into a randomized study. During the initial learning phase, all subjects performed twelve meniscal repairs on a knee simulator over a three-week period. A validated motion analysis tracking system was used to objectively record the performance and learning of each subject; the outcomes were the time taken, distance traveled, and number of hand movements. The subjects were then randomized into three groups. Group A performed one meniscal repair each month, Group B performed one meniscal repair at three months, and Group C performed no repairs during this interim phase. All three groups then returned at the six-month point for the final assessment phase, during which they carried out an additional twelve meniscal repairs over three weeks. RESULTS: All subjects demonstrated a clear learning curve during the initial learning phase, with significant objective improvement in all motion analysis parameters over the initial twelve episodes (p < 0.0001). Although some residents had reached a learning plateau by twelve episodes, others continued to make further improvements for up to another nine episodes. Importantly, Group C did not display any loss of skill between the initial learning phase and final evaluation phase despite a six-month break in task repetition (p > 0.05). CONCLUSIONS: In contrast to previous studies, residents did not lose any skill over a six-month interruption in task performance, and other residents took longer to produce a more consistent performance.
The critical role of water in spider silk and its consequence for protein mechanics.
Due to its remarkable mechanical and biological properties, there is considerable interest in understanding, and replicating, spider silk's stress-processing mechanisms and structure-function relationships. Here, we investigate the role of water in the nanoscale mechanics of the different regions in the spider silk fibre, and their relative contributions to stress processing. We propose that the inner core region, rich in spidroin II, retains water due to its inherent disorder, thereby providing a mechanism to dissipate energy as it breaks a sacrificial amide-water bond and gains order under strain, forming a stronger amide-amide bond. The spidroin I-rich outer core is more ordered under ambient conditions and is inherently stiffer and stronger, yet does not on its own provide high toughness. The markedly different interactions of the two proteins with water, and their distribution across the fibre, produce a stiffness differential and provide a balance between stiffness, strength and toughness under ambient conditions. Under wet conditions, this balance is destroyed as the stiff outer core material reverts to the behaviour of the inner core.
The case for partial knee replacement
The case for greater use of medial UKA in knee arthroplasty surgery rests on the benefits for patients of faster recovery, less morbidity, less mortality and better functional outcome when compared to TKA. This has been supported by improved longterm results and recognition of the large number of patients who meet the criteria for UKA. Medial UKA should, therefore, be seen as a definitive treatment for medial osteoarthritis and not as a pre-total knee replacement procedure. In a similar way, strong arguments for partial knee replacement in the lateral and patellofemoral joint are also emerging.
Development of a patient-reported outcome measure of activity and participation (the OKSAPQ) to supplement the Oxford knee score
The primary aim of this study was to develop a patient-reported Activity & Participation Questionnaire (the OKS-APQ) to supplement the Oxford knee score, in order to assess higher levels of activity and participation. The generation of items for the questionnaire involved interviews with 26 patients. Psychometric analysis (exploratory and confirmatory factor analysis and Rasch analysis) guided the reduction of items and the generation of a scale within a prospective study of 122 relatively young patients (mean age 61.5 years (42 to 71)) prior to knee replacement. A total of 99, completed pre-operative and six month postoperative assessments (new items, OKS, Short-Form 36 and American Knee Society Score). The eight-item OKS-APQ scale is unidimensional, reliable (Cronbach's alpha 0.85; intraclass correlation coefficient (ICC) 0.79; or 0.92 when one outlier was excluded), valid (r > 0.5 with related scales) and responsive (effect size 4.16). We recommend that it is used with the OKS with adults of all ages when further detail regarding the levels of activity and participation of a patient is required. © 2014 The British Editorial Society of Bone & Joint Surgery.
Behavioural physical activity interventions in participants with lower-limb osteoarthritis: a systematic review with meta-analysis.
OBJECTIVE: To assess effectiveness of osteoarthritis interventions to promote long-term physical activity behaviour change. DESIGN: A systematic review and meta-analysis. Protocol registration PROSPERO CRD4201300444 5 (http://www.crd.york.ac.uk/prospero/). STUDY SELECTION: Randomised controlled trials (RCTs) comparing physical activity interventions with placebo, no/or minimal intervention in community-dwelling adults with symptomatic knee or hip osteoarthritis. Primary outcomes were change in physical activity or cardiopulmonary fitness after a minimum follow-up of 6 months. DATA EXTRACTION: Outcomes were measures of physical activity (self-reported and objectively measured) and cardiovascular fitness. Standard mean differences between postintervention values were used to describe the effect sizes. RESULTS: 27,984 titles were screened and 180 papers reviewed in full. Eleven RCTs satisfied inclusion criteria, total study population of 2741 participants, mean age 62.2. The commonest reasons for study exclusion were follow-up less than 6 months and no physical activity measures. The majority of included interventions implement an arthritis self-management programme targeting coping skills and self-efficacy. Seven studies used self-report measures, the pooled effect of these studies was small with significant heterogeneity between studies (SMD 0.22 with 95% CI -0.11 to 0.56, z=1.30 (p=0.19) I(2) statistic of 85%). Subgroup analysis of 6-12 month outcome reduced heterogeneity and increased intervention effect compared to control (SMD 0.53, 95% CI 0.41 to 0.65, z=8.84 (p<0.00001) I(2) of 66%). CONCLUSIONS: Arthritis self-management programmes achieve a small but significant improvement in physical activity in the short term. Effectiveness of intervention declines with extended follow-up beyond 12 months with no significant benefit compared to control. The small number of studies (11 RCTs) limited ability to define effective delivery methods. Investigation of behavioural lifestyle interventions for lower limb osteoarthritis populations would benefit from consensus on methodology and outcome reporting. This includes use of validated physical activity reporting tools and planning for long-term follow-up.
Is osteoarthritis a metabolic disorder?
BACKGROUND: Obesity is associated with an increased risk of developing osteoarthritis (OA), even in non-weight bearing joints. High levels of adipose tissue-associated inflammation may explain this association. SOURCES OF DATA AND AREAS OF DEBATE: Published evidence looking at the associations between components of Metabolic Syndrome (MetS) and knee, hip or hand OA and the higher mortality described with knee OA. EMERGING POINTS: Development of MetS and OA shares a relationship with adipose tissue-associated inflammation. This review supports this inflammatory pathway being part of the shared mechanism behind obesity as a risk factor for OA and the recently described OA-associated increased mortality. TIMELY AREAS FOR DEVELOPMENT: In an era of an obesity epidemic, this review identifies a need for well-designed cohort studies assessing early metabolic changes in populations at high risk of OA and MetS, and to identify risk factors for increased mortality in patients with OA.
Adipokines as potential prognostic biomarkers in patients with acute knee injury.
This review considers adipokines as predictive biomarkers for early onset post-traumatic knee osteoarthritis (KOA). Serum concentrations of leptin and resistin can predict radiographic changes and are elevated in early KOA, with higher leptin concentrations independently associated with more severe knee changes. Plasma concentrations of resistin are chronically elevated after injury. Leptin, resistin, chemerin and vistfatin induce catabolic enzymes associated with cartilage degeneration. Available literature on adipokines in post-traumatic KOA pathogenesis suggests that they could contribute to risk prediction of early onset post-traumatic KOA. Further research is needed to further understand the association between adipokines, synovitis and long-term outcomes in this population.
The expression and functions of toll-like receptors in atherosclerosis.
Inflammation drives atherosclerosis. Both immune and resident vascular cell types are involved in the development of atherosclerotic lesions. The phenotype and function of these cells are key in determining the development of lesions. Toll-like receptors are the most characterised innate immune receptors and are responsible for the recognition of exogenous conserved motifs on pathogens, and, potentially, some endogenous molecules. Both endogenous and exogenous TLR agonists may be present in atherosclerotic plaques. Engagement of toll-like receptors on immune and resident vascular cells can affect atherogenesis as signalling downstream of these receptors can elicit proinflammatory cytokine release, lipid uptake, and foam cell formation and activate cells of the adaptive immune system. In this paper, we will describe the expression of TLRs on immune and resident vascular cells, highlight the TLR ligands that may act through TLRs on these cells, and discuss the consequences of TLR activation in atherosclerosis.
Toll-like receptors in atherosclerosis: a 'Pandora's box' of advances and controversies.
Seminal research over the past 20 years has revealed atherosclerosis to be a chronic inflammatory process that shares features with traditional inflammatory diseases including rheumatoid arthritis. More recently, emphasis has been placed on the role of innate immunity in the development and progression of atherosclerosis. In particular, pattern recognition receptors, including Toll-like receptors (TLRs), have been the focus of much attention as modulators of atherogenesis. This review provides an update on the developments in this area of research in the past 2 years, with a specific focus on the current controversies and how these may affect the design of therapeutics. Specifically, we will address the recent evidence that TLRs elicit both protective and detrimental effects in atherosclerosis and the emerging observation that the outcome of TLR signaling is dependent on the agonist and responding cell type.
Treating atherosclerosis: the potential of Toll-like receptors as therapeutic targets.
Atherosclerosis is an inflammatory disease with a strong involvement of innate immunity. Toll-like receptors (TLRs) are the best-characterized pattern recognition receptors of the innate immune system. Almost all cell types in lesions, inflammatory leukocytes and resident vascular cells alike express TLRs. TLRs are able to sense modified lipids, enhance foam cell formation, induce leukocyte recruitment, and increase cytokine and matrix metalloproteinase production within atherosclerotic lesions. As such, TLRs represent an important link between atheroma and inflammation, making them attractive targets for the treatment of cardiovascular disease. Novel TLR-specific biologics are being developed and tested in other inflammatory diseases. This article will describe the exciting potential of TLRs as therapeutic targets for the treatment of atherosclerosis and will also highlight the potential challenges in the clinical application of TLR-based therapeutics in cardiovascular disease.