The bony morphology of both tibia and femur has been found to influence the risk of anterior cruciate ligament (ACL) injuries. Quantifying the femoral condylar’s sagittal morphology, the lateral ...femoral condyle ratio (LFCR) has been associated with injuries to the anterolateral knee joint capsule, including the anterolateral ligament in ACL-injured knees. Rotational instability may be in part attributable to femoral anisometry with an increase of the LFCR contributing to increased laxity and risk for ACL ruptures as well as concomitant injuries. While there is currently no surgical treatment available to change the bony morphology of the femur, possibilities such as the addition of a lateral extra-articular tenodesis, adjustment of graft selection, or modification of surgical techniques may mitigate the risk of ACL rerupture in patients with a high LFCR.
An increasing number of surgeons adopt the concept of vancomycin soaking of the graft in anterior cruciate ligament reconstruction and report drastically reduced numbers of postoperative septic knee ...arthritis. This reduction of incidence is supported by in vitro data, showing no influence of vancomycin on tendon material properties. Although the applied antibiotic concentration has reported to be potent in eradicating graft contamination, no evidence of chondrotoxicity has been shown. Based on the increasing evidence, the call for randomized controlled trials stands in ethical contrast with the medical responsibility not to withhold patients an infection prophylaxis that has already been proven to be safe and effective.
Background:
Lateral extra-articular tenodesis (LET) is being increasingly added to primary and revision anterior cruciate ligament (ACL) reconstruction to address residual anterolateral rotatory ...instability. However, currently there is a lack of knowledge on how close the femoral tunnels are when combining these procedures.
Purpose/Hypotheses:
To assess the risk of tunnel convergence in combined ACL and LET procedures using 2 different surgical techniques (Lemaire and MacIntosh). It was hypothesized that the risk of tunnel convergence would be greater when using the more distally located Lemaire position. The authors further hypothesized that tunnel proximity would be influenced by knee size.
Study Design:
Controlled laboratory study.
Methods:
Ten fresh-frozen cadaveric knees were used for this study. In each specimen, an anatomic ACL femoral tunnel and 2 LET tunnels were drilled using the Lemaire and MacIntosh positions, respectively. After knee dissection, minimal distances between each ACL and LET tunnel were directly measured on the lateral femoral cortex. Furthermore, computed tomography scans were obtained to measure intertunnel convergence and lateral femoral condyle (LFC) width. On the basis of the average LFC width, knees were divided into large and small knees to determine a relationship between knee size and tunnel convergence.
Results:
Convergence of ACL and LET tunnels occurred in 7 of 10 cases (70%) using the Lemaire attachment position. All tunnel collisions occurred directly on the lateral femoral cortex, while intertunnel (intramedullary) conflicts were not observed. Collisions emerged in both small (n = 4) and large (n = 3) knees. Critical tunnel convergence did not occur using the MacIntosh position. The mean minimal distance between the LET and ACL tunnel using the Lemaire and MacIntosh positions was 3.1 ± 4.6 mm and 9.8 ± 5.4 mm, respectively.
Conclusion:
Tunnel convergence was more frequently observed in combined ACL and LET reconstruction using the Lemaire technique, independent of the knee size. LET femoral tunnel positioning according to the MacIntosh reconstruction was not associated with tunnel collision.
Clinical Relevance:
These findings help to raise the awareness for the risk of tunnel convergence in combined ACL and LET procedures. Surgeons may contemplate adjustments on the ACL femoral tunnel drilling technique or fixation device when applying an additional Lemaire procedure. However, in the absence of clinical outcome studies comparing different LET techniques, it remains unclear which technique is superior in a clinical setting.
The replicability of some scientific findings has recently been called into question. To contribute data about replicability in economics, we replicated 18 studies published in the American Economic ...Review and the Quarterly Journal of Economics between 2011 and 2014. All of these replications followed predefined analysis plans that were made publicly available beforehand, and they all have a statistical power of at least 90% to detect the original effect size at the 5% significance level. We found a significant effect in the same direction as in the original study for 11 replications (61%); on average, the replicated effect size is 66% of the original. The replicability rate varies between 67% and 78% for four additional replicability indicators, including a prediction market measure of peer beliefs.
The capability to ferment sugars into ethanol is a key metabolic trait of yeasts. Crabtree-positive yeasts use fermentation even in the presence of oxygen, where they could, in principle, rely on the ...respiration pathway. This is surprising because fermentation has a much lower ATP yield than respiration (2 ATP vs. approximately 18 ATP per glucose). While genetic events in the evolution of the Crabtree effect have been identified, the selective advantages provided by this trait remain controversial. In this review we analyse explanations for the emergence of the Crabtree effect from an evolutionary and game-theoretical perspective. We argue that an increased rate of ATP production is likely the most important factor behind the emergence of the Crabtree effect.
The importance of microbial communities (MCs) cannot be overstated. MCs underpin the biogeochemical cycles of the earth's soil, oceans and the atmosphere, and perform ecosystem functions that impact ...plants, animals and humans. Yet our ability to predict and manage the function of these highly complex, dynamically changing communities is limited. Building predictive models that link MC composition to function is a key emerging challenge in microbial ecology. Here, we argue that addressing this challenge requires close coordination of experimental data collection and method development with mathematical model building. We discuss specific examples where model-experiment integration has already resulted in important insights into MC function and structure. We also highlight key research questions that still demand better integration of experiments and models. We argue that such integration is needed to achieve significant progress in our understanding of MC dynamics and function, and we make specific practical suggestions as to how this could be achieved.
Centralized processing is expected to bring about substantial benefits for wireless networks both on the technical side and on the economic side. While this concept is considered an important part of ...future radio access network architectures, it is more and more recognized that the current approach to fronthauling by employing the Common Public Radio Interface protocol will be inefficient for large-scale network deployments in many respects, and particularly for the new radio network generation 5G. In this paper, an overview is given of currently available optical fronthaul technologies, and of recently started activities toward more efficient and scalable solutions, and finally an outlook is given into which 5G specific service characteristics may further impact future backhaul, midhaul, and fronthaul networks.
Concerns about a lack of reproducibility of statistically significant results have recently been raised in many fields, and it has been argued that this lack comes at substantial economic costs. We ...here report the results from prediction markets set up to quantify the reproducibility of 44 studies published in prominent psychology journals and replicated in the Reproducibility Project: Psychology. The prediction markets predict the outcomes of the replications well and outperform a survey of market participants’ individual forecasts. This shows that prediction markets are a promising tool for assessing the reproducibility of published scientific results. The prediction markets also allow us to estimate probabilities for the hypotheses being true at different testing stages, which provides valuable information regarding the temporal dynamics of scientific discovery. We find that the hypotheses being tested in psychology typically have low prior probabilities of being true (median, 9%) and that a “statistically significant” finding needs to be confirmed in a well-powered replication to have a high probability of being true. We argue that prediction markets could be used to obtain speedy information about reproducibility at low cost and could potentially even be used to determine which studies to replicate to optimally allocate limited resources into replications.
Pericyte-mediated capillary constriction decreases cerebral blood flow in stroke after an occluded artery is unblocked. The determinants of pericyte tone are poorly understood. We show that a small ...rise in cytoplasmic Ca2+ concentration (Ca2+i) in pericytes activated chloride efflux through the Ca2+-gated anion channel TMEM16A, thus depolarizing the cell and opening voltage-gated calcium channels. This mechanism strongly amplified the pericyte Ca2+i rise and capillary constriction evoked by contractile agonists and ischemia. In a rodent stroke model, TMEM16A inhibition slowed the ischemia-evoked pericyte Ca2+i rise, capillary constriction, and pericyte death; reduced neutrophil stalling; and improved cerebrovascular reperfusion. Genetic analysis implicated altered TMEM16A expression in poor patient recovery from ischemic stroke. Thus, pericyte TMEM16A is a crucial regulator of cerebral capillary function and a potential therapeutic target for stroke and possibly other disorders of impaired microvascular flow, such as Alzheimer's disease and vascular dementia.
The reproducibility of published research has become an important topic in science policy. A number of large-scale replication projects have been conducted to gauge the overall reproducibility in ...specific academic fields. Here, we present an analysis of data from four studies which sought to forecast the outcomes of replication projects in the social and behavioural sciences, using human experts who participated in prediction markets and answered surveys. Because the number of findings replicated and predicted in each individual study was small, pooling the data offers an opportunity to evaluate hypotheses regarding the performance of prediction markets and surveys at a higher power. In total, peer beliefs were elicited for the replication outcomes of 103 published findings. We find there is information within the scientific community about the replicability of scientific findings, and that both surveys and prediction markets can be used to elicit and aggregate this information. Our results show prediction markets can determine the outcomes of direct replications with 73% accuracy (n = 103). Both the prediction market prices, and the average survey responses are correlated with outcomes (0.581 and 0.564 respectively, both p < .001). We also found a significant relationship between p-values of the original findings and replication outcomes. The dataset is made available through the R package "pooledmaRket" and can be used to further study community beliefs towards replications outcomes as elicited in the surveys and prediction markets.
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