Biomechanical factors and physical examination findings in osteoarthritis of the knee: associations with tissue abnormalities assessed by conventional radiography and high resolution 3.0 Tesla magnetic resonance imaging

INTRODUCTION: We aimed to explore the associations between knee osteoarthritis (OA)-related tissue abnormalities assessed by conventional radiography (CR) and by high-resolution 3.0 Tesla magnetic resonance imaging (MRI), as well as biomechanical factors and findings from physical examination in patients with knee OA. METHODS: This was an explorative cross-sectional study of 105 patients with knee OA. Index knees were imaged using CR and MRI. Multiple features from CR and MRI (cartilage, osteophytes, bone marrow lesions, effusion and synovitis) were related to biomechanical factors (quadriceps and hamstrings muscle strength, proprioceptive accuracy and varus-valgus laxity) and physical examination findings (bony tenderness, crepitus, bony enlargement and palpable warmth), using multivariable regression analyses. RESULTS: Quadriceps weakness was associated with cartilage integrity, effusion, synovitis (all detected by MRI) and CR-detected joint space narrowing. Knee joint laxity was associated with MRI-detected cartilage integrity, CR-detected joint space narrowing and osteophyte formation. Multiple tissue abnormalities including cartilage integrity, osteophytes and effusion, but only those detected by MRI, were found to be associated with physical examination findings such as crepitus. CONCLUSION: We observed clinically relevant findings, including a significant association between quadriceps weakness and both effusion and synovitis, detected by MRI. Inflammation was detected in over one-third of the participants, emphasizing the inflammatory component of OA and a possible important role for anti-inflammatory therapies in knee OA. In general, OA-related tissue abnormalities of the knee, even those detected by MRI, were found to be discordant with biomechanical and physical examination features

An ELPAT definition of the concept ‘Psychosocial’ in the context of Screening Living Organ Donors in Europe: A Concept Mapping approach

Introduction: Across Europe, transplant centers vary in the set of psychosocial screening criteria/guidelines used for the selection of eligible living donors. Our aim was to explore whether a common framework underlies this variation in screening criteria and, based on this framework, to develop a consensus on the essential elements of psychosocial screening of living liver and kidney donors. In order to do so, a research question was set out to define a conceptual framework of the concept ‘Psychosocial’ in the context of screening living organ donors in Europe. We formulated the following research question: Which psychosocial screening criteria are most commonly reported and considered as most important or effective in selecting eligible kidney and liver donors? Method: Concept mapping methodology was used to create a visual representation of the complex topic ‘Psychosocial’ in the context of screening living organ donors in Europe, in which underlying concepts, the relative importance of these concepts and the interplay between different concepts are organized. Initial psychosocial screening criteria (N=83) were derived from an extensive systematic literature review on guidelines, protocols and consensus statements on psychosocial screening practices, complemented by group brainstorm sessions. These criteria were then sorted and rated for their importance and effectiveness by 26 project participants. The data were analyzed using the Concept System Core© Software, which provided us with graphical depictions (concept maps) illustrating the view of project participants on these screening criteria. Pattern Matches and Go-Zones showed us the highlycommon, important and effective criteria. Results: The concept map procedure resulted in six clusters of psychosocial screening criteria: (1) Motivation and decision making (2) Personal resources (3) Psychopathology (4) Social resources (5) Ethical and Legal factors (6) Information and risk processing. Bivariate rating of these criteria revealed which important criteria are already frequently used for screening and which require more attention. Based on the cluster map and bivariate ratings we constructed a conceptual framework for non-medical risk factors that need to be considered when screening potential living organ donors. Conclusion: We provided a conceptual framework of psychosocial screening criteria which can serve as a practical recommendation for the psychosocial screening of potential living organ donors

The association between reduced knee joint proprioception and medial meniscal abnormalities using MRI in knee osteoarthritis: results from the Amsterdam osteoarthritis cohort.

BACKGROUND: Osteoarthritis (OA) of the knee is characterized by pain and activity limitations. In knee OA, proprioceptive accuracy is reduced and might be associated with pain and activity limitations. Although causes of reduced proprioceptive accuracy are divergent, medial meniscal abnormalities, which are highly prevalent in knee OA, have been suggested to play an important role. No study has focussed on the association between proprioceptive accuracy and meniscal abnormalities in knee OA. OBJECTIVE: To explore the association between reduced proprioceptive accuracy and medial meniscal abnormalities in a clinical sample of knee OA subjects. METHODS: Cross-sectional study in 105 subjects with knee OA. Knee proprioceptive accuracy was assessed by determining the joint motion detection threshold in the knee extension direction. The knee was imaged with a 3.0 T magnetic resonance (MR) scanner. Number of regions with medial meniscal abnormalities and the extent of abnormality in the anterior and posterior horn and body were scored according to the Boston-Leeds Osteoarthritis Knee Score (BLOKS) method. Multiple regression analyzes were used to examine whether reduced proprioceptive accuracy was associated with medial meniscal abnormalities in knee OA subjects. RESULTS: Mean proprioceptive accuracy was 2.9degree + 1.9degree. Magnetic resonance imaging (MRI)-detected medial meniscal abnormalities were found in the anterior horn (78%), body (80%) and posterior horn (90%). Reduced proprioceptive accuracy was associated with both the number of regions with meniscal abnormalities (P < 0.01) and the extent of abnormality (P = 0.02). These associations were not confounded by muscle strength, joint laxity, pain, age, gender, body mass index (BMI) and duration of knee complaints. CONCLUSION: This is the first study showing that reduced proprioceptive accuracy is associated with medial meniscal abnormalities in knee OA. The study highlights the importance of meniscal abnormalities in understanding reduced proprioceptive accuracy in persons with knee OA. Copyright 2013 Osteoarthritis Research Society International. All rights reserve

Dynamic model of basic oxygen steelmaking process based on multi-zone reaction kinetics : modelling of manganese removal

In the earlier work, a dynamic model for the BOF process based on the multi-zone reaction kinetics has been developed. In the preceding part, the mechanism of manganese transfer in three reactive zones of the converter has been analyzed. This study identifies that temperature at the slag-metal reaction interface plays a major role in the Mn reaction kinetics and thus a mathematical treatment to evaluate temperature at each reaction interface has been successfully employed in the rate calculation. The Mn removal rate obtained from different zones of the converter predicts that the first stage of the blow is dominated by the oxidation of Mn at the jet impact zone, albeit some additional Mn refining has been observed as a result of the oxidation of metal droplets in emulsion phase. The mathematical model predicts that the reversion of Mn from slag to metal primarily takes place at the metal droplet in the emulsion due to an excessive increase in slag-metal interface temperature during the middle stage of blowing. In the final stage of the blow, the competition between simultaneous reactions in jet impact and emulsion zone controls the direction of mass flow of manganese. Further, the model prediction shows that the Mn refining in the emulsion is a strong function of droplet diameter and the residence time. Smaller sized droplets approach equilibrium quickly and thus contribute to a significant Mn conversion between slag and metal compared to the larger sized ones. The overall model prediction for Mn in the hot metal has been found to be in good agreement with two sets of different size top blowing converter data reported in the literature

The behavior of manganese in oxygen steelmaking

The chemical behavior of manganese in oxygen steelmaking is complex because the element is readily oxidized in conditions found in steelmaking, and the stability of its oxide is a function of temperature and slag chemistry. This results in distinct oxidation and reversion stages during the steelmaking cycle. Recently, a multi-zone model (developed by the authors) of oxygen steelmaking has successfully predicted the plant behavior of manganese but also highlighted how the generation of droplets and their temperature play an important role in the kinetics of the process. This new understanding should result in improved control of this important alloying element

Analgesic use in patients with knee and/or hip osteoarthritis referred to an outpatient center: a cross-sectional study within the Amsterdam Osteoarthritis Cohort

Although analgesics are widely recommended in current guidelines, underuse and inadequate prescription of analgesics seem to result in suboptimal treatment effects in patients with knee and/or hip osteoarthritis (OA). This study aimed (i) to describe the use of analgesics; and (ii) to determine factors that are related to analgesic use in patients with knee and/or hip OA referred to an outpatient center. A cross-sectional study with data from 656 patients with knee and/or hip OA referred to an outpatient center (Amsterdam Osteoarthritis (AMS-OA) cohort) was conducted. Self-reported use of analgesic (yes/no) was administered and subdivided into acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs, including coxibs) and opioids. Logistic regression analyses were performed to analyze the association between analgesic use and disease-related, predisposing and enabling factors. Analgesic use was reported by 63% of the patients, with acetaminophen, NSAIDs and opioid use reported by 50, 30 and 12%, respectively. Factors related to analgesic use were higher pain severity, longer duration of symptoms, higher radiographic hip OA severity, overweight/obesity and psychological distress. These factors explained 21% of the variance of analgesic use. More than one-third of patients with established knee and/or hip OA referred to an outpatient center did not use any analgesics. Although multiple, mostly disease-related associated factors were found, analgesic use remained predominantly unexplained. Our study seems to indicate that prescription of analgesics should be guided more dominantly by clinical symptoms and needs, and preceded by a thorough shared decision-making process between patient and physician

Toward a Conceptualization of the Content of Psychosocial Screening in Living Organ Donors: An Ethical Legal Psychological Aspects of Transplantation Consensus

Background. Across Europe, transplant centers vary in the content of the psychosocial evaluation for eligible living organ donors. To identify whether a common framework underlies this variation in this evaluation, we studied which psychosocial screening items are most commonly used and considered as most important in current psychosocial screening programs of living organ donors. Methods. A multivariate analytic method, concept mapping, was used to generate a visual representation of the "psychosocial" screening items of living kidney and liver donors. A list of 75 potential screening items was derived from a systematic literature review and sorted and rated for their importance and commonness by multidisciplinary affiliated health care professionals from across Europe. Results were discussed and fine-tuned during a consensus meeting. Results. The analyses resulted in a 6-cluster solution. The following clusters on psychosocial screening items were identified, listed from most to least important: (1) personal resources, (2) motivation and decision making, (3) psychopathology, (4) social resources, (5) ethical and legal factors, and (6) information and risk processing. Conclusions. We provided a conceptual framework of the essential elements in psychosocial evaluation of living donors which can serve as a uniform basis for the selection of relevant psychosocial evaluation tools, which can be further tested in prospective studies

Association of lower muscle strength with self-reported knee instability in osteoarthritis of the knee: Results from the Amsterdam Osteoarthritis Cohort

Objective To determine whether muscle strength, proprioceptive accuracy, and laxity are associated with self-reported knee instability in a large cohort of knee osteoarthritis (OA) patients, and to investigate whether muscle strength may compensate for impairment in proprioceptive accuracy or laxity, in order to maintain knee stability. Methods. Data from 283 knee OA patients from the Amsterdam Osteoarthritis cohort were used. Univariable and multivariable logistic regression analyses were performed to assess the association between muscle strength, proprioceptive accuracy (motion sense), frontal plane varus-valgus laxity, and self-reported knee instability. Additionally, effect modification between muscle strength and proprioceptive accuracy and between muscle strength and laxity was determined. Results. Self-reported knee instability was present in 67% of the knee OA patients and mainly occurred during walking. Lower muscle strength was significantly associated with the presence of self-reported knee instability, even after adjusting for relevant confounding. Impaired proprioceptive accuracy and high laxity were not associated with self-reported knee instability. No effect modification between muscle strength and proprioceptive accuracy or laxity was found. Conclusion. Lower muscle strength is strongly associated with self-reported knee instability in knee OA patients, while impairments in proprioceptive accuracy and laxity are not. A compensatory role of muscle strength for impaired proprioceptive accuracy or high laxity, in order to stabilize the knee, could not be demonstrated