Training improves interobserver reliability for the diagnosis of scaphoid fracture displacement

Background The diagnosis of displacement in scaphoid fractures is notorious for poor interobserver reliability.

Questions/purposes We tested whether training can improve interobserver reliability and sensitivity, specificity, and accuracy for the diagnosis of scaphoid fracture displacement on radiographs and CT scans.

Methods Sixty-four orthopaedic surgeons rated a set of radiographs and CT scans of 10 displaced and 10 nondisplaced scaphoid fractures for the presence of displacement, using a web-based rating application. Before rating, observers were randomized to a training group (34 observers) and a nontraining group (30 observers). The training group received an online training module before the rating session, and the nontraining group did not. Interobserver reliability for training and nontraining was assessed by Siegel’s multirater kappa and the Z-test was used to test for significance.

Results There was a small, but significant difference in the interobserver reliability for displacement ratings in favor of the training group compared with the nontraining group. Ratings of radiographs and CT scans combined resulted in moderate agreement for both groups. The average sensitivity, specificity, and accuracy of diagnosing displacement of scaphoid fractures were, respectively, 83%, 85%, and 84% for the nontraining group and 87%, 86%, and 87% for the training group. Assuming a 5% prevalence of fracture displacement, the positive predictive value was 0.23 in the nontraining group and 0.25 in the training group. The negative predictive value was 0.99 in both groups.

Conclusions Our results suggest training can improve interobserver reliability and sensitivity, specificity and accuracy for the diagnosis of scaphoid fracture displacement, but the improvements are slight. These findings are encouraging for future research regarding interobserver variation and how to reduce it further.

Interobserver reliability of computed tomography to diagnose scaphoid waist fracture union

Purpose : To determine the interobserver agreement and diagnostic performance characteristics of computed tomography (CT) for determining union of scaphoid waist fractures.

Methods : A total of 59 orthopedic and trauma surgeons rated for union a set of 30 sagittal CT scans of 30 scaphoid waist fractures. Of these fractures, 20 were treated nonoperatively, were imaged between 6 and 10 weeks after injury, and were known to have eventually achieved union. Ten were operatively confirmed to be ununited. We rated each scan as united or ununited using a Web-based rating application. We assessed interobserver reliability using Siegel's multirater Kappa. We calculated diagnostic performance characteristics using Bayesian formulas.

Results : The interobserver agreement among 59 raters was substantial. The average sensitivity, specificity, and accuracy of diagnosing union of scaphoid waist fractures on sagittal CT scans were 78%, 96%, and 84%, respectively. Assuming a 90% prevalence of fracture union of the scaphoid, the positive predictive value of a diagnosis of union on sagittal CT scan was 0.99 and the negative predictive value was 0.41.

Conclusions : Our results suggest that CT scans are accurate and reliable for diagnosis of union but inadequate for ruling out nonunion of scaphoid waist fractures between 6 and 10 weeks after injury.

Interobserver reliability of coronoid fracture classification : two-dimensional versus three-dimensional computed tomography

Purpose : This study tests the hypothesis that 3-dimensional computed tomography (CT) reconstructions improve interobserver agreement on classification and treatment of coronoid fractures compared with 2-dimensional CT.

Methods : A total of 29 orthopedic surgeons evaluated 10 coronoid fractures on 2 occasions (first with radiographs and 2-dimensional CT and then with radiographs and 3-dimensional CT), separated by a minimum of 2 weeks. Surgeons classified fractures according to the classifications of Regan and Morrey and of O'Driscoll et al., identified specific characteristics, recommended the most appropriate treatment approach, and made treatment recommendations. The kappa multirater measure (κ) was calculated to estimate agreement between observers.

Results : Regardless of the imaging modality used, there was fair to moderate agreement for most of the observations. Three-dimensional CT improved interobserver agreement in Regan and Morrey's classsication (κ3-dimensional = 0.51 vs κ2-dimensional = 0.40; p < .001) and O'Driscoll et al.'s classifications (κ3-dimensional = 0.48 vs κ2-dimensional = 0.42; p = .009). There were trends toward better reliability for 3-dimensional reconstruction in recognition of coronoid tip fractures (κ3-dimensional = 0.19, κ2-dimensional = 0.03; p = .268), comminution (κ3-dimensional = 0.41 vs κ2-dimensional = 0.29; p = .133), and impacted fragments (κ3-dimensional = 0.39 vs κ2-dimensional = 0.27; p = .094), and in surgeons' opinions on the need for something other than screws or plate for surgical fixation (κ3-dimensional = 0.31 vs κ2-dimensional = 0.15; p = .138). Interobserver agreement on treatment approach was better with 2-dimensional CT (κ3-dimensional = 0.27, κ2-dimensional = 0.32; p = .015).

Conclusions : Three-dimensional CT reconstructions improve interobserver agreement with respect to fracture classification compared with 2-dimensional CT.

Migratory birds reinforce local circulation of avian influenza viruses

Migratory and resident hosts have been hypothesized to fulfil distinct roles in infectious disease dynamics. However, the contribution of resident and migratory hosts to wildlife infectious disease epidemiology, including that of low pathogenic avian influenza virus (LPAIV) in wild birds, has largely remained unstudied. During an autumn H3 LPAIV epizootic in free-living mallards (Anas platyrhynchos) - a partially migratory species - we identified resident and migratory host populations using stable hydrogen isotope analysis of flight feathers. We investigated the role of migratory and resident hosts separately in the introduction and maintenance of H3 LPAIV during the epizootic. To test this we analysed (i) H3 virus kinship, (ii) temporal patterns in H3 virus prevalence and shedding and (iii) H3-specific antibody prevalence in relation to host migratory strategy. We demonstrate that the H3 LPAIV strain causing the epizootic most likely originated from a single introduction, followed by local clonal expansion. The H3 LPAIV strain was genetically unrelated to H3 LPAIV detected both before and after the epizootic at the study site. During the LPAIV epizootic, migratory mallards were more often infected with H3 LPAIV than residents. Low titres of H3-specific antibodies were detected in only a few residents and migrants. Our results suggest that in this LPAIV epizootic, a single H3 virus was present in resident mallards prior to arrival of migratory mallards followed by a period of virus amplification, importantly associated with the influx of migratory mallards. Thus migrants are suggested to act as local amplifiers rather than the often suggested role as vectors importing novel strains from afar. Our study exemplifies that a multifaceted interdisciplinary approach offers promising opportunities to elucidate the role of migratory and resident hosts in infectious disease dynamics in wildlife.

Transfer of maternal antibodies against avian influenza virus in mallards (Anas platyrhynchos)

Maternal antibodies protect chicks from infection with pathogens early in life and may impact pathogen dynamics due to the alteration of the proportion of susceptible individuals in a population. We investigated the transfer of maternal antibodies against avian influenza virus (AIV) in a key AIV host species, the mallard (Anas platyrhynchos). Combining observations in both the field and in mallards kept in captivity, we connected maternal AIV antibody concentrations in eggs to (i) female body condition, (ii) female AIV antibody concentration, (iii) egg laying order, (iv) egg size and (v) embryo sex. We applied maternity analysis to the eggs collected in the field to account for intraspecific nest parasitism, which is reportedly high in Anseriformes, detecting parasitic eggs in one out of eight clutches. AIV antibody prevalence in free-living and captive females was respectively 48% and 56%, with 43% and 24% of the eggs receiving these antibodies maternally. In both field and captive study, maternal AIV antibody concentrations in egg yolk correlated positively with circulating AIV antibody concentrations in females. In the captive study, yolk AIV antibody concentrations correlated positively with egg laying order. Female body mass and egg size from the field and captive study, and embryos sex from the field study were not associated with maternal AIV antibody concentrations in eggs. Our study indicates that maternal AIV antibody transfer may potentially play an important role in shaping AIV infection dynamics in mallards.

Minor differences in body condition and immune status between avian influenza virus-infected and noninfected mallards: a sign of coevolution?

Wildlife pathogens can alter host fitness. Low pathogenic avian influenza virus (LPAIV) infection is thought to have negligible impacts on wild birds; however, effects of infection in free-living birds are largely unstudied. We investigated the extent to which LPAIV infection and shedding were associated with body condition and immune status in free-living mallards (Anas platyrhynchos), a partially migratory key LPAIV host species. We sampled mallards throughout the species' annual autumn LPAIV infection peak, and we classified individuals according to age, sex, and migratory strategy (based on stable hydrogen isotope analysis) when analyzing data on body mass and five indices of immune status. Body mass was similar for LPAIV-infected and noninfected birds. The degree of virus shedding from the cloaca and oropharynx was not associated with body mass. LPAIV infection and shedding were not associated with natural antibody (NAbs) and complement titers (first lines of defense against infections), concentrations of the acute phase protein haptoglobin (Hp), ratios of heterophils to lymphocytes (H:L ratio), and avian influenza virus (AIV)-specific antibody concentrations. NAbs titers were higher in LPAIV-infected males and local (i.e., short distance) migrants than in infected females and distant (i.e., long distance) migrants. Hp concentrations were higher in LPAIV-infected juveniles and females compared to infected adults and males. NAbs, complement, and Hp levels were lower in LPAIV-infected mallards in early autumn. Our study demonstrates weak associations between infection with and shedding of LPAIV and the body condition and immune status of free-living mallards. These results may support the role of mallards as asymptomatic carriers of LPAIV and raise questions about possible coevolution between virus and host.

Spatial variation in tuber depletion by swans explained by differences in net intake rates

We tested whether the spatial variation in resource depletion by Tundra Swans (Cygnus columbianus) foraging on belowground tubers of sago pondweed (Potamogeton pectinatus) was caused by differences in net energy intake rates. The variation in giving-up densities within the confines of one lake was nearly eightfold, the giving-up density being positively related to water depth and, to a lesser extent, the silt content of the sediment. The swans' preference (measured as cumulative foraging pressure) was negatively related to these variables. We adjusted a model developed for diving birds to predict changes in the time allocation of foraging swans with changes in power requirements and harvest rate. First, we compared the behavior of free-living swans foraging in shallow and deep water, where they feed by head-dipping and up-ending, respectively. Up-ending swans had 1.3-2.1 times longer feeding times than head-dipping swans. This was contrary to our expectation, since the model predicted a decrease in feeding time with an increase in feeding power. However, up-ending swans also had 1.9 times longer trampling times than headdipping swans. The model predicted a strong positive correlation between trampling time and feeding time, and the longer trampling times may thus have masked any effect of an increase in feeding power. Heart rate measurements showed that trampling was the most energetically costly part of foraging. However, because the feeding time and trampling time changed concurrently, the rate of energy expenditure was only slightly higher in deep water (1.03-1.06 times). This is a conservative estimate since it does not take into account that the feeding costs of up-ending are possibly higher than that of head-dipping. Second, we compared captive swans foraging on sandy and clayey sediments. We found that the harvest rate on clayey sediment was only 0.6 times that on sandy sediment and that the power requirements for foraging were 1.2-1.4 times greater. Our results are in qualitative agreement with the hypothesis that the large spatial variation in giving-up densities was caused by differences in net rates of energy intake. This potentially has important implications for the prey dynamics, because plant regrowth has been shown to be related to the same habitat factors (water depth and sediment type).

Weak negative associations between avian influenza virus infection and movement behaviour in a key host species, the mallard Anas platyrhynchos

Animal movements may contribute to the spread of pathogens. In the case of avian influenza virus, [migratory] birds have been suggested to play a role in the spread of some highly pathogenic strains (e.g. H5N1, H5N8), as well as their low pathogenic precursors which circulate naturally in wild birds. For a better understanding of the emergence and spread of both highly pathogenic (HPAIV) and low pathogenic avian influenza virus (LPAIV), the potential effects of LPAIVs on bird movement need to be evaluated. In a key host species, the mallard Anas platyrhynchos, we tested whether LPAIV infection status affected daily local (< 100 m) and regional (> 100 m) movements by comparing movement behaviour 1) within individuals (captured and sampled at two time points) and 2) between individuals (captured and sampled at one time point). We fitted free-living adult males with GPS loggers throughout the autumn LPAIV infection peak, and sampled them for LPAIV infection at logger deployment and at logger removal on recapture. Within individuals, we found no association between LPAIV infection and daily local and regional movements. Among individuals, daily regional movements of LPAIV infected mallards in the last days of tracking were lower than those of non-infected birds. Moreover, these regional movements of LPAIV infected birds were additionally reduced by poor weather conditions (i.e. increased wind and/or precipitation and lower temperatures). Local movements of LPAIV infected birds in the first days of tracking were higher when temperature decreased. Our study thus demonstrates that bird-assisted dispersal rate of LPAIV may be lower on a regional scale than expected on the basis of the movement behaviour of non-infected birds. Our study underlines the importance of understanding the impact of pathogen infection on host movement in order to assess its potential role in the emergence and spread of infectious diseases.

Identifying knowledge gaps in seagrass research and management: An Australian perspective.

Seagrass species form important marine and estuarine habitats providing valuable ecosystem services and functions. Coastal zones that are increasingly impacted by anthropogenic development have experienced substantial declines in seagrass abundance around the world. Australia, which has some of the world's largest seagrass meadows and is home to over half of the known species, is not immune to these losses. In 1999 a review of seagrass ecosystems knowledge was conducted in Australia and strategic research priorities were developed to provide research direction for future studies and management. Subsequent rapid evolution of seagrass research and scientific methods has led to more than 70% of peer reviewed seagrass literature being produced since that time. A workshop was held as part of the Australian Marine Sciences Association conference in July 2015 in Geelong, Victoria, to update and redefine strategic priorities in seagrass research. Participants identified 40 research questions from 10 research fields (taxonomy and systematics, physiology, population biology, sediment biogeochemistry and microbiology, ecosystem function, faunal habitats, threats, rehabilitation and restoration, mapping and monitoring, management tools) as priorities for future research on Australian seagrasses. Progress in research will rely on advances in areas such as remote sensing, genomic tools, microsensors, computer modeling, and statistical analyses. A more interdisciplinary approach will be needed to facilitate greater understanding of the complex interactions among seagrasses and their environment.

The execution of Van Nguyen: an Australian perspective

The execution of 25-year-old Melbourne man, Van Nguyen, by Singaporean authorities on 2 December 2005 for attempting to smuggle 400 grams of heroin out of Singapore was cruel. It was also futile. Yet, there are three important lessons that can be learned from his killing. The first lesson is that if Australia is to exert genuine moral pressure on nations to abolish the death penalty it must do so in a principled manner, rather than making expedient pleas when Australians happen to be on the wrong end of the cruel practice. Secondly, sentencing practice in Australia, while not condoning capital punishment, is unjustifiably punitive and we should ameliorate the harshness of some of our sentencing laws. Finally, the death of Nguyen, while tragic, was no more tragic than the millions of other preventable deaths that occur daily throughout the world. The compassion displayed toward Nguyen should be used as a catalyst for enlarging our sympathy gland in relation to all preventable deaths. I now discuss these in further detail.

Defuturing an architecture of destruction: a reconciliation of Van Berkel and Bos to the new design philosophy of Tony Fry

For some time now Tony Fry has promoted the idea of 'The Sustainment', an idea that asserts a paradigm shift in attitudes to consumption. 'The Sustainment' recognises that increasingly human futures are products of self-determination and not chance. Fry’s hypothesis can be understood through his concept of Defuturing, a philosophy that questions the role of design and the responsibility of designers to facilitating the ability to sustain (Fry 1999).
Central to Fry’s philosophy is an awareness that it is in the best interests of designers and their clients, as inhabitants of cultures increasingly driven by technology, to be aware of the relationships between the products and theories of design and the processes and implications of technological change. This is an awareness that is central to the concepts, work, and methodologies of the ‘UN Studio’ of Van Berkel and Bos described and elaborated upon in Move – Imagination, Techniques, and Effects (Van Berkel & Bos 1999). Here, Ben Van Berkel defines the parameters and methodologies employed by UN Studio in an environment of technological and socio-economic change. The Dutch practice could be said to exemplify something of a zeitgeist in current architectural design that sees architects, as Van Berkel and Bos view them, as “fashion designers of the future, dressing events to come and holding up a mirror to the world (Van Berkel & Bos 1999, back cover).” It is a zeitgeist that Fry might see as aligned to the resilient hype of ‘new creativity’, ‘globalisation’ the ‘romance with technology’, and the vacuous-ness of the world of fashion. (Fry The Voice of Sustainment: on Design Intelligence 2005).
A source of breaking down such design propaganda is identified by Fry in the notion of ‘scenarios,’ which “provide a mechanism for politico-practice assemblage in which dialogues and narratives of change can be rehearsed in ways that enable participants to re-educate themselves via critical confrontations” (Fry The Voice of Sustainment: on Design Intelligence 2005). From such a perspective this paper aims to practically illustrate and ground the Defuturing of Fry by establishing a dialogue between his writings and the theories that have generated the architectural designs of Van Berkel and Bos and there UN Studio. This will be a ‘scenario’ that examines therefore an appropriation and transformation of the applied intellectual practice of Van Berkel and Bos. Through this confrontation we shall explore the question of why sustainability appears to be so low in the agenda of many pre-eminent contemporary architects, and how we might refocus therefore practice and theory on the ability to sustain.