Arthroscopic versus open ankle arthrodesis: a multicenter comparative case series

BACKGROUND Ankle arthrodesis results in measurable improvements in terms of pain and function in patients with end-stage ankle arthritis. Arthroscopic ankle arthrodesis has gained increasing popularity, with reports of shorter hospital stays, shorter time to solid fusion, and equivalent union rates when compared with open arthrodesis. However, there remains a lack of high-quality prospective data. METHODS We evaluated the results of open and arthroscopic ankle arthrodesis in a comparative case series of patients who were managed at two institutions and followed for two years. The primary outcome was the Ankle Osteoarthritis Scale score, and secondary outcomes included the Short Form-36 physical and mental component scores, the length of hospital stay, and radiographic alignment. There were thirty patients in each group. RESULTS Both groups showed significant improvement in the Ankle Osteoarthritis Scale score and the Short Form-36 physical component score at one and two years. There was significantly greater improvement in the Ankle Osteoarthritis Scale score at one year and two years and shorter hospital stay in the arthroscopic arthrodesis group. Complications, surgical time, and radiographic alignment were similar between the two groups. CONCLUSIONS Open and arthroscopic ankle arthrodesis were associated with significant improvement in terms of pain and function as measured with the Ankle Osteoarthritis Scale score. Arthroscopic arthrodesis resulted in a shorter hospital stay and showed better outcomes at one and two years.

Catch Rates, Composition and Fish Size from Reefs Managed with Periodically-Harvested Closures

Periodically-harvested closures are commonly employed within co-management frameworks to help manage small-scale, multi-species fisheries in the Indo-Pacific. Despite their widespread use, the benefits of periodic harvesting strategies for multi-species fisheries have, to date, been largely untested. We examine catch and effort data from four periodically-harvested reef areas and 55 continuously-fished reefs in Solomon Islands. We test the hypothesis that fishing in periodically-harvested closures would yield: (a) higher catch rates, (b) proportionally more short lived, fast growing, sedentary taxa, and (c) larger finfish and invertebrates, compared to catches from reefs continuously open to fishing. Our study showed that catch rates were significantly higher from periodically-harvested closures for gleaning of invertebrates, but not for line and spear fishing. The family level composition of catches did not vary significantly between open reefs and periodically-harvested closures. Fish captured from periodically-harvested closures were slightly larger, but Trochus niloticus were significantly smaller than those from continuously open reefs. In one case of intense and prolonged harvesting, gleaning catch rates significantly declined, suggesting invertebrate stocks were substantially depleted in the early stages of the open period. Our study suggests periodically-harvested closures can have some short term benefits via increasing harvesting efficiency. However, we did not find evidence that the strategy had substantially benefited multi-species fin-fisheries.

Daptomycin versus vancomycin for osteoarticular infections due to methicillin-resistant Staphylococcus aureus (MRSA): a nested case-control study

Vancomycin is the standard antibiotic for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. While daptomycin is approved for MRSA bacteremia, its effectiveness in osteoarticular infections (OAIs) has not been established. A 1:2 nested case-control study of adult patients with MRSA OAIs admitted to an academic center from 2005 to 2010 was carried out. Clinical outcomes and drug toxicity in patients treated with daptomycin versus vancomycin were compared. Twenty patients with MRSA OAIs treated with daptomycin were matched to 40 patients treated with vancomycin. The median age of the patients was 52 years (range, 25-90), and 40 (67 %) were male. Most patients had osteomyelitis (82 %), predominantly from a contiguous source (87 %). Forty percent were diabetics. Diabetic patients were more likely to receive vancomycin than daptomycin [20 (50 %) vs. 4 (20 %); p = 0.03]. Vancomycin was more often combined with antibiotics other than daptomycin [22 (55 %) vs. 5 (25 %); p = 0.03]. The median total antibiotic treatment duration was 48 (daptomycin) vs. 46 days (vancomycin) (p = 0.5). Ninety percent of daptomycin-treated patients had previously received vancomycin for a median of 14.5 days (range, 2-36). Clinical success rates were similar between daptomycin and vancomycin at 3 months [15 (75 %) vs. 27 (68 %); p = 0.8] and 6 months [14 (70 %) vs. 23 (58 %); p = 0.5], even after propensity score-based adjustment for antibiotic assignment. The frequency of adverse events was similar between treatment groups [1 (5 %) vs. 7 (18 %); p = 0.2]. Daptomycin and vancomycin achieved similar rates of clinical success and drug tolerability. Daptomycin is a reasonable alternative for treating MRSA OAIs, particularly in patients where therapy with vancomycin has not been well tolerated.

Paleo erosion rates and climate shifts recorded by Quaternary cut-and-fill sequences in the Pisco valley, central Peru

Fluvial cut-and-fill sequences have frequently been reported from various sites on Earth. Nevertheless, the information about the past erosional regime and hydrological conditions have not yet been adequately deciphered from these archives. The Quaternary terrace sequences in the Pisco valley, located at ca. 13°S, offer a manifestation of an orbitally-driven cyclicity in terrace construction where phases of sediment accumulation have been related to the Minchin (48–36 ka) and Tauca (26–15 ka) lake level highstands on the Altiplano. Here, we present a 10Be-based sediment budget for the cut-and-fill terrace sequences in this valley to quantify the orbitally forced changes in precipitation and erosion. We find that the Minchin period was characterized by an erosional pulse along the Pacific coast where denudation rates reached values as high as 600±80 mm/ka600±80 mm/ka for a relatively short time span lasting a few thousands of years. This contrasts to the younger pluvial periods and the modern situation when 10Be-based sediment budgets register nearly zero erosion at the Pacific coast. We relate these contrasts to different erosional conditions between the modern and the Minchin time. First, the sediment budget infers a precipitation pattern that matches with the modern climate ca. 1000 km farther north, where highly erratic and extreme El Niño-related precipitation results in fast erosion and flooding along the coast. Second, the formation of a thick terrace sequence requires sufficient material on catchment hillslopes to be stripped off by erosion. This was most likely the case immediately before the start of the Minchin period, because this erosional epoch was preceded by a >50 ka-long time span with poorly erosive climate conditions, allowing for sufficient regolith to build up on the hillslopes. Finally, this study suggests a strong control of orbitally and ice sheet forced latitudinal shifts of the ITCZ on the erosional gradients and sediment production on the western escarpment of the Peruvian Andes at 13° during the Minchin period.

Seizures in patients with Alzheimer's disease or vascular dementia: a population-based nested case-control analysis

PURPOSE Patients with Alzheimer's disease (AD) have an increased risk of developing seizures or epilepsy. Little is known about the role of risk factors and about the risk of developing seizures/epilepsy in patients with vascular dementia (VD). The aim of this study was to assess incidence rates (IRs) of seizures/epilepsy in patients with AD, VD, or without dementia, and to identify potential risk factors of seizures or epilepsy. METHODS We conducted a follow-up study with a nested case-control analysis using the United Kingdom-based General Practice Research Database (GPRD). We identified patients aged ≥65 years with an incident diagnosis of AD or VD between 1998 and 2008 and a matched comparison group of dementia-free patients. Conditional logistic regression was used to estimate the odds ratio (OR) with a 95% confidence interval (CI) of developing seizures/epilepsy in patients with AD or VD, stratified by age at onset and duration of dementia as well as by use of antidementia drugs. KEY FINDINGS Among 7,086 cases with AD, 4,438 with VD, and 11,524 matched dementia-free patients, we identified 180 cases with an incident diagnosis of seizures/epilepsy. The IRs of epilepsy/seizures for patients with AD or VD were 5.6/1,000 person-years (py) (95% CI 4.6-6.9) and 7.5/1,000 py (95% CI 5.7-9.7), respectively, and 0.8/1,000 py (95% CI 0.6-1.1) in the dementia-free group. In the nested case-control analysis, patients with longer standing (≥3 years) AD had a slightly higher risk of developing seizures or epilepsy than those with a shorter disease duration, whereas in patients with VD the contrary was observed. SIGNIFICANCE Seizures or epilepsy were substantially more common in patients with AD and VD than in dementia-free patients. The role of disease duration as a risk factor for seizures/epilepsy seems to differ between AD and VD.

Dendrogeomorphology in badlands: Methods, case studies and prospects

Soil and vegetation are interacting factors controlling erosion. Soil degradation processes may affect the normal tree and shrub development and inversely, vegetation can modulate the velocity and intensity of soil development or denudation. A dendrogeomorphological approach can be used to study these interactions, allowing to obtain a date and estimate mean or specific erosion rates. This is especially useful in an unrecorded badlands and gullied environments, where the scarce vegetation may be the only proxy available to quantify the different geomorphic processes which have occurred. This paper provides a fundamental review of the dendrogeomorphological methodology applied to erosion measurement in badlands. Focusing on the response of the vegetation to the geomorphic processes, this paper: (a) describes the methodology developed to estimate erosion rates with exposed roots; (b) shows new advances through case studies; and finally, (c) discusses future lines of research to reduce methodological uncertainties and for making dendrogeomorphology more widely applicable.

A relation between screening masses and real-time rates

Thermal screening masses related to the conserved vector current are determined for the case that the current carries a non-zero Matsubara frequency, both in a weak-coupling approach and through lattice QCD. We point out that such screening masses are sensitive to the same infrared physics as light-cone real-time rates. In particular, on the perturbative side, the inhomogeneous Schrödinger equation determining screening correlators is shown to have the same general form as the equation implementing LPM resummation for the soft-dilepton and photon production rates from a hot QCD plasma. The static potential appearing in the equation is identical to that whose soft part has been determined up to NLO and on the lattice in the context of jet quenching. Numerical results based on this potential suggest that screening masses overshoot the free results (multiples of 2πT) more strongly than at zero Matsubara frequency. Four-dimensional lattice simulations in two-flavour QCD at temperatures of 250 and 340 MeV confirm the non-static screening masses at the 10% level. Overall our results lend support to studies of jet quenching based on the same potential at T ≳ 250 MeV.

Reversal of gender differences in Educational Attainment – historical analysis of the West German Case

Background information: During the late 1970s and the early 1980s, West Germany witnessed a reversal of gender differences in educational attainment, as females began to outperform males. Purpose: The main objective was to analyse which processes were behind the reversal of gender differences in educational attainment after 1945. The theoretical reflections and empirical evidence presented for the US context by DiPrete and Buchmann (Gender-specific trends in the value of education and the emerging gender gap in college completion, Demography 43: 1–24, 2006) and Buchmann, DiPrete, and McDaniel (Gender inequalities in education, Annual Review of Sociology 34: 319–37, 2008) are considered and applied to the West German context. It is suggested that the reversal of gender differences is a consequence of the change in female educational decisions, which are mainly related to labour market opportunities and not, as sometimes assumed, a consequence of a ‘boy’s crisis’. Sample: Several databases, such as the German General Social Survey, the German Socio-economic Panel and the German Life History Study, are employed for the longitudinal analysis of the educational and occupational careers of birth cohorts born in the twentieth century. Design and methods: Changing patterns of eligibility for university studies are analysed for successive birth cohorts and gender. Binary logistic regressions are employed for the statistical modelling of the individuals’ achievement, educational decision and likelihood for social mobility – reporting average marginal effects (AME). Results: The empirical results suggest that women’s better school achievement being constant across cohorts does not contribute to the explanation of the reversal of gender differences in higher education attainment, but the increase of benefits for higher education explains the changing educational decisions of women regarding their transition to higher education. Conclusions: The outperformance of females compared with males in higher education might have been initialised by several social changes, including the expansion of public employment, the growing demand for highly qualified female workers in welfare and service areas, the increasing returns of women’s increased education and training, and the improved opportunities for combining family and work outside the home. The historical data show that, in terms of (married) women’s increased labour market opportunities and female life-cycle labour force participation, the raising rates of women’s enrolment in higher education were – among other reasons – partly explained by their rising access to service class positions across birth cohorts, and the rise of their educational returns in terms of wages and long-term employment.

Incidence of and risk factors for severe hypoglycaemia in treated type 2 diabetes mellitus patients in the UK - a nested case-control analysis

AIMS To assess incidence rates (IRs) of and identify risk factors for incident severe hypoglycaemia in patients with type 2 diabetes newly treated with antidiabetic drugs. METHODS Using the UK-based General Practice Research Database, we performed a retrospective cohort study between 1994 and 2011 and a nested case-control analysis. Ten controls from the population at risk were matched to each case with a recorded severe hypoglycaemia during follow-up on general practice, years of history in the database and calendar time. Using multivariate conditional logistic regression analyses, we adjusted for potential confounders. RESULTS Of 130,761 patients with newly treated type 2 diabetes (mean age 61.7 ± 13.0 years), 690 (0.5%) had an incident episode of severe hypoglycaemia recorded [estimated IR 11.97 (95% confidence interval, CI, 11.11-12.90) per 10,000 person-years (PYs)]. The IR was markedly higher in insulin users [49.64 (95% CI, 44.08-55.89) per 10,000 PYs] than in patients not using insulin [8.03 (95% CI, 7.30-8.84) per 10,000 PYs]. Based on results of the nested case-control analysis increasing age [≥ 75 vs. 20-59 years; adjusted odds ratio (OR), 2.27; 95% CI, 1.65-3.12], cognitive impairment/dementia (adjusted OR, 2.00; 95% CI, 1.37-2.91), renal failure (adjusted OR, 1.34; 95% CI, 1.04-1.71), current use of sulphonylureas (adjusted OR, 4.45; 95% CI, 3.53-5.60) and current insulin use (adjusted OR, 11.83; 95% CI, 9.00-15.54) were all associated with an increased risk of severe hypoglycaemia. CONCLUSIONS Severe hypoglycaemia was recorded in 12 cases per 10,000 PYs. Risk factors for severe hypoglycaemia included increasing age, renal failure, cognitive impairment/dementia, and current use of insulin or sulphonylureas.

Application of a computational model for complex fluvial ecosystems: The population dynamics of zebra mussel Dreissena polymorpha as a case study

The potential and adaptive flexibility of population dynamic P-systems (PDP) to study population dynamics suggests that they may be suitable for modelling complex fluvial ecosystems, characterized by a composition of dynamic habitats with many variables that interact simultaneously. Using as a model a reservoir occupied by the zebra mussel Dreissena polymorpha, we designed a computational model based on P systems to study the population dynamics of larvae, in order to evaluate management actions to control or eradicate this invasive species. The population dynamics of this species was simulated under different scenarios ranging from the absence of water flow change to a weekly variation with different flow rates, to the actual hydrodynamic situation of an intermediate flow rate. Our results show that PDP models can be very useful tools to model complex, partially desynchronized, processes that work in parallel. This allows the study of complex hydroecological processes such as the one presented, where reproductive cycles, temperature and water dynamics are involved in the desynchronization of the population dynamics both, within areas and among them. The results obtained may be useful in the management of other reservoirs with similar hydrodynamic situations in which the presence of this invasive species has been documented.

Consecutive series of 226 journey bicruciate substituting total knee replacements: early complication and revision rates

BACKGROUND The Journey bicruciate substituting (BCS) total knee replacement (TKR) is intended to improve knee kinematics by more closely approximating the surfaces of a normal knee. The purpose of this analysis was to address the safety of Journey BCS knees by studying early complication and revision rates in a consecutive case series. METHODS Between December 2006 and May 2011, a single surgeon implanted 226 Journey BCS total knee prostheses in 191 patients (124 women, 67 men) who were eligible for study. Mean age at surgery was 68 years (41-85 years).Outcome measures were early complications and minor and major revision rates. All complications were considered, irrespective of whether conservative treatment or revision was required. RESULTS The average implantation time was 3.5 years (range 1.3-5.8 years). Thirty-three complications (14.6% of 226 knees) required minor or major revision surgery in 25 patients. The remaining eight patients were treated conservatively. Sixteen minor revisions were performed in 12 patients. Thirteen major revisions were required in 13 patients, which results in a rate of 1.65 major revisions per 100 component years. The linear trend of the early complication rate by treatment year was not significant (p = .22).Multivariate logistic regression showed no significant predictors for the occurrence of a complication or for revision surgery. A tendency towards higher complication rates was observed in female patients, although it was not significant (p = .066). CONCLUSIONS The complication and revision rates of the Journey BCS knee implant are high in comparison with those reported for other established total knee systems. Caution is advised when using this implant, particularly for less experienced knee surgeons.

Avalanche related damage potential - changes of persons and mobile values since the mid-twentieth century, case study Galtür

When determining risk related to natural hazard processes, many studies neglect the investigations of the damage potential or are limited to the assessment of immobile values like buildings. However, persons as well as mobile values form an essential part of the damage potential. Knowledge of the maximum number of exposed persons in an endangered area is of great importance for elaborating evacuation plans and immediate measures in case of catastrophes. In addition, motor vehicles can also be highly damaged, as was shown by the analysis of avalanche events. With the removal of mobile values in time as a preventive measure this kind of damage can be minimised. This study presents a method for recording the maximum number of exposed persons and monetarily assessing motor vehicles in the municipality of Galt¨ur (Tyrol, Austria). Moreover, general developments of the damage potential due to significant socio-economic changes since the mid-twentieth century are pointed out in the study area. The present situation of the maximum number of persons and mobile values in the official avalanche hazard zones of the municipality is described in detail. Information on the number of persons is derived of census data, tourism and employment statistics. During the winter months, a significant increase overlaid by strong short-term fluctuation in the number of persons can be noted. These changes result from a higher demand of tourism related manpower as well as from varying occupancy rates. The number of motor vehicles in endangered areas is closely associated to the number of exposed persons. The potential number of motor vehicles is investigated by means of mapping, statistics on the stock of motor vehicles and the density distribution. Diurnal and seasonal fluctuations of the investigated damage potential are pointed out. The recording of the number of persons and mobile values in endangered areas is vital for any disaster management.

Collagen application reduces complication rates of mid-substance ACL tears treated with dynamic intraligamentary stabilization.

PURPOSE Dynamic intraligamentary stabilization was recently proposed as an option for the treatment of acute ACL ruptures. The aim of this study was to investigate the feasibility of the procedure in mid-substance ACL ruptures and examine whether the additional application of a bilayer collagen I/III membrane would provide for a superior outcome. METHODS The study group consisted of patients presenting with a mid-substance ACL rupture undergoing dynamic intraligamentary stabilization using the Ligamys™ device along with application of a collagen I/III membrane to the surface of the ACL (group A, n = 23). The control group comprised a matched series of patients presenting with a mid-substance ACL rupture also treated by dynamic intraligamentary stabilization Ligamys™ repair, however, without additional collagen application (group B, n = 33). Patients were evaluated preoperatively and at 24-month follow-up for stability as well as Tegner and Lysholm scores. Knee laxity was measured as a difference in anterior translation (ΔAP) and pivot shift. Any events occurring during the follow-up period of 24 months were documented. Logistic regression of complications was performed, and adjustment undertaken where necessary. RESULTS A high total complication rate of 78.8 % was noted in group B, compared to group A (8.7 %) (p = 0.002). The addition of a collagen membrane was the only independent prognostic factor associated with reduced complications (OR 8.0, CI 2.0-32.2, p = 0.003, for collagen-free treatment). In group B, 6 patients suffered a re-rupture with subsequent instability requiring secondary hamstring reconstruction surgery, and 11 developed extension loss requiring arthroscopic debridement, whilst in group A, 2 patients required arthroscopic debridement for loss of exension, with no further encountered complication. Median Lysholm score was significantly higher in group A compared to group B (median 100 range 93-100 vs median 95 range 60-100, p = 0.03) at final follow-up. CONCLUSIONS A high complication rate following ACL Ligamys™ repair of mid-substance ruptures was noted. Application of a collagen membrane to the surface of the ACL resulted in a reduced incidence of extension deficit and re-ruptures. The results indicate that solitary ACL Ligamys™ repair does not present an appropriate treatment modality for mid-substance ACL ruptures. Collage application proved to provide healing benefits with superior clinical outcome after ACL repair. LEVEL OF EVIDENCE Case control study, Level III.

Provenance analysis using Raman spectroscopy of carbonaceous material: A case study in the Southern Alps of New Zealand

Detrital provenance analyses in orogenic settings, in which sediments are collected at the outlet of a catchment, have become an important tool to estimate how erosion varies in space and time. Here we present how Raman Spectroscopy on Carbonaceous Material (RSCM) can be used for provenance analysis. RSCM provides an estimate of the peak temperature (RSCM-T) experienced during metamorphism. We show that we can infer modern erosion patterns in a catchment by combining new measurements on detrital sands with previously acquired bedrock data. We focus on the Whataroa catchment in the Southern Alps of New Zealand and exploit the metamorphic gradient that runs parallel to the main drainage direction. To account for potential sampling biases, we also quantify abrasion properties using flume experiments and measure the total organic carbon content in the bedrock that produced the collected sands. Finally, we integrate these parameters into a mass-conservative model. Our results first demonstrate that RSCM-T can be used for detrital studies. Second, we find that spatial variations in tracer concentration and erosion have a first-order control on the RSCM-T distributions, even though our flume experiments reveal that weak lithologies produce substantially more fine particles than do more durable lithologies. This result implies that sand specimens are good proxies for mapping spatial variations in erosion when the bedrock concentration of the target mineral is quantified. The modeling suggests that highest present-day erosion rates (in Whataroa catchment) are not situated at the range front but around 10 km into the mountain belt.

Detecting single-target changes in multiple object tracking: The case of peripheral vision

In the current study it is investigated whether peripheral vision can be used to monitor multi-ple moving objects and to detect single-target changes. For this purpose, in Experiment 1, a modified MOT setup with a large projection and a constant-position centroid phase had to be checked first. Classical findings regarding the use of a virtual centroid to track multiple ob-jects and the dependency of tracking accuracy on target speed could be successfully replicat-ed. Thereafter, the main experimental variations regarding the manipulation of to-be-detected target changes could be introduced in Experiment 2. In addition to a button press used for the detection task, gaze behavior was assessed using an integrated eye-tracking system. The anal-ysis of saccadic reaction times in relation to the motor response shows that peripheral vision is naturally used to detect motion and form changes in MOT because the saccade to the target occurred after target-change offset. Furthermore, for changes of comparable task difficulties, motion changes are detected better by peripheral vision than form changes. Findings indicate that capabilities of the visual system (e.g., visual acuity) affect change detection rates and that covert-attention processes may be affected by vision-related aspects like spatial uncertainty. Moreover, it is argued that a centroid-MOT strategy might reduce the amount of saccade-related costs and that eye-tracking seems to be generally valuable to test predictions derived from theories on MOT. Finally, implications for testing covert attention in applied settings are proposed.