Centro Científico Tecnológico - Patagonia Norte

BACKGROUND: The WOMAC score is a validated outcome measure for use in patients undergoing TKA. Defining meaningful changes in the WOMAC score is important for sample-size calculations in clinical research and for interpreting published studies. However, inconsistencies among published studies regarding key definitions for changes in the WOMAC score after TKA potentially could result in incorrectly powered studies and the misinterpretation of clinical research results. QUESTIONS/PURPOSES: (1) To identify the minimum clinically important difference (MCID) for the total WOMAC score and its components 1 year after TKA using an anchor-based methodology. (2) To define the minimum important change (MIC) and the minimum detectable change with 95% confidence (MDC95) for the total WOMAC score and its components 1 year after TKA. METHODS: Between 2003 and 2013, 3641 patients underwent primary TKA at one center. Of those, 460 patients (13%) were excluded from this retrospective study for prespecified reasons (mainly secondary OA and bilateral surgery), and 592 patients (16%) were either lost to followup or could not be included because of incomplete questionnaires. WOMAC scores were recorded preoperatively and at 1 year postoperatively. Patient demographics and preoperative Short Form-12 and WOMAC scores were no different for the 16% of patients who were lost to followup or failed to complete 1-year questionnaires and the study cohort (n = 2589). At 1 year, patients were asked "How much did the knee replacement surgery improve the quality of your life?" Their responses were recorded as: a great improvement, moderate improvement, little improvement, no improvement at all, or the quality of my life is worse. The MCID was defined as the difference in the mean change in the WOMAC score between patients with no improvement compared with those with little improvement according to the anchor question. The MIC was defined as the change in the WOMAC score relative to the baseline score for patients who reported a little improvement in their quality of life. The MDC is the smallest change for an individual who is likely to be beyond the measurement error of the scoring tool and represents true change rather than variability in the scoring measure; we report it with 95% confidence bounds defining real change rather than variability in the scoring measure (MDC95). We calculated this with distribution-based methods for the whole cohort. Patients recording a little improvement (n = 211) and no improvement (n = 115) were used as anchor responses to calculate the MCID (using regression analysis to adjust for potential confounding variables such as age, gender, BMI and preoperative Short Form-12 or WOMAC scores) and the MIC (using receiver operative characteristics curves). RESULTS: After adjusting for confounding variables such as age, gender, BMI as well as preoperative Short Form-12 and WOMAC scores, the MCID was 11 for pain, 9 for function, 8 for stiffness and 10 for the total WOMAC score. The MIC was 21 for pain, 16 for function, 13 for stiffness and 17 for the total WOMAC score. The MDC95 was 23 for pain, 11 for function, 27 for stiffness and 12 for the total WOMAC score. CONCLUSIONS: The MCID and MIC for the WOMAC score represent the smallest meaningful effect sizes when comparing the outcome of two groups (difference in mean change between the groups) or when assessing a cohort (a change in score for the group) after TKA, respectively, helping the reader to distinguish between a clinically important effect size and a mere statistical difference. We determined that the error in measurement (based on the MDC95) for the function component and total WOMAC scores were less than the MIC, which suggests changes beyond the MIC are clinically real and not due to uncertainty in the score. These parameters are essential to interpret TKA outcomes research and to ensure clinical research studies are amply powered to detect meaningful differences. Future studies using the WOMAC score to assess TKA outcomes should report not only the statistical significance (a p value) but also the clinical importance using the reported MCID and MIC values. LEVEL OF EVIDENCE: Level III, diagnostic study.

Spatial heterogeneity of vegetation types and the abiotic environment can influence the occurrence and spread of wildfires, but in some landscapes the importance of these effects varies under conditions of severe fire weather. In the northern Patagonian landscape of forests and shrublands we examined the effects of vegetation type (tall forest vs. tall shrubland) and abiotic factors (elevation, topography, and precipitation) on fire occurrence at a broad scale and on fire spread at a fine scale. We used satellite images (1985–1999) and aerial photography (1950–1999) to map fires in relation to pre-burn vegetation type and abiotic factors. Fire extent is greatest at intermediate elevations and locations of intermediate precipitation. Fire extent is limited by lack of fuel quantity at the lower end of the precipitation gradient and by infrequent or insufficient fuel desiccation at the upper end. Tall shrublands are proportionally more affected by fire than are adjacent mesic forests of Nothofagus dombeyi and N. pumilio. Patches of subalpine forests often tend to serve as natural fire breaks, except under the most severe fire weather. Tall shrublands are dominated by species that resprout vigorously so that fuels quickly recover. In contrast, forests are dominated by species dependent on seed reproduction that sometimes fails after severe fires so that shrublands tend to replace burned forests. The greater propensity of shrublands to burn is a positive feedback that is favorable to fire and that accelerates the replacement of forest by shrublands. Infrequently occurring severe weather is important in the burning of otherwise relatively fire-resistant subalpine forests. Past burning, associated both with drought and early forest clearing, expanded shrublands at the expense of forests so that in the modern landscape an increase in anthropogenic ignitions and the positive feedback of fire and shrublands are synergistically accelerating conversion from forest to shrubland.

BACKGROUND: Future projections for both TKA and THA in the United States and other countries forecast a further increase of already high numbers of joint replacements. The consensus is that in industrialized countries, this increase is driven by demographic changes with more elderly people being less willing to accept activity limitations. Unlike the United States, Germany and many other countries face a population decline driven by low fertility rates, longer life expectancy, and immigration rates that cannot compensate for population aging. Many developing countries are likely to follow that example in the short or medium term amid global aging. Due to growing healthcare expenditures in a declining and aging population with a smaller available work force, reliable predictions of procedure volume by age groups are requisite for health and fiscal policy makers to maintain high standards in arthroplasty for the future population.Questions/purposes (1) By how much is the usage of primary TKA and THA in Germany expected to increase from 2016 through 2040? (2) How is arthroplasty usage in Germany expected to vary as a function of patient age during this time span? METHODS: The annual number of primary TKAs and THAs were calculated based on population projections and estimates of future healthcare expenditures as a percent of the gross domestic product (GDP) in Germany. For this purpose, a Poisson regression analysis using age, gender, state, healthcare expenditure, and calendar year as covariates was performed. The dependent variable was the historical number of primary TKAs and THAs performed as compiled by the German federal office of statistics for the years 2005 through 2016. RESULTS: Through 2040, the incidence rate for both TKA and THA will continue to increase annually. For TKA, the incidence rate is expected to increase from 245 TKAs per 100,000 inhabitants to 379 (297-484) (55%, 95% CI 21 to 98). The incidence rate of THAs is anticipated to increase from 338 to 437 (357-535) per 100,000 inhabitants (29% [95% CI 6 to 58]) between 2016 and 2040. The total number of TKAs is expected to increase by 45% (95% CI 14 to 8), from 168,772 procedures in 2016 to 244,714 (95% CI 191,920 to 312,551) in 2040. During the same period, the number of primary THAs is expected to increase by 23% (95% CI 0 to 50), from 229,726 to 282,034 (95% CI 230,473 to 345,228). Through 2040, the greatest increase in TKAs is predicted to occur in patients aged 40 to 69 years (40- to 49-year-old patients: 269% (95% CI 179 to 390); 50- to 59-year-old patients: 94% (95% CI 48 to 141); 60- to 69-year-old patients: 43% (95% CI 13 to 82). The largest increase in THAs is expected in the elderly (80- to 89-year-old patients (71% [95% CI 40 to 110]). CONCLUSIONS: Although the total number of TKAs and THAs is projected to increase in Germany between now and 2040, the increase will be smaller than that previously forecast for the United States, due in large part to the German population decreasing over that time, while the American population increases. Much of the projected increase in Germany will be from the use of TKA in younger patients and from the use of THA in elderly patients. Knowledge of these trends may help planning by surgeons, hospitals, stakeholders, and policy makers in countries similar to Germany, where high incidence rates of arthroplasty, aging populations, and overall decreasing populations are present. LEVEL OF EVIDENCE: Level III, economic and decision analysis.

Tree mortality is a key driver of forest dynamics and its occurrence is projected to increase in the future due to climate change. Despite recent advances in our understanding of the physiological mechanisms leading to death, we still lack robust indicators of mortality risk that could be applied at the individual tree scale. Here, we build on a previous contribution exploring the differences in growth level between trees that died and survived a given mortality event to assess whether changes in temporal autocorrelation, variance, and synchrony in time-series of annual radial growth data can be used as early warning signals of mortality risk. Taking advantage of a unique global ring-width database of 3065 dead trees and 4389 living trees growing together at 198 sites (belonging to 36 gymnosperm and angiosperm species), we analyzed temporal changes in autocorrelation, variance, and synchrony before tree death (diachronic analysis), and also compared these metrics between trees that died and trees that survived a given mortality event (synchronic analysis). Changes in autocorrelation were a poor indicator of mortality risk. However, we found a gradual increase in inter-annual growth variability and a decrease in growth synchrony in the last ∼20 years before mortality of gymnosperms, irrespective of the cause of mortality. These changes could be associated with drought-induced alterations in carbon economy and allocation patterns. In angiosperms, we did not find any consistent changes in any metric. Such lack of any signal might be explained by the relatively high capacity of angiosperms to recover after a stress-induced growth decline. Our analysis provides a robust method for estimating early-warning signals of tree mortality based on annual growth data. In addition to the frequently reported decrease in growth rates, an increase in inter-annual growth variability and a decrease in growth synchrony may be powerful predictors of gymnosperm mortality risk, but not necessarily so for angiosperms.

Abstract This study examined the foraging locations of lactating female and pre‐breeding adult male South American sea lions Otaria flavescens in the Patagonian continental shelf, south‐west Atlantic ocean. Research on females included the diving pattern, and was conducted during the 1994–98 breeding seasons in five northern and central Patagonian rookeries. Twenty females were satellite‐tracked using the Argos system and yielded 1558 locations at sea. Satellite transmitters were also deployed on two adult males tracked for a total of 94 days ( n = 364 locations) before the onset of the 1999 breeding season. Foraging trips for both sexes were confined to the temperate waters of the Patagonian continental shelf although males travelled greater distances than females, and arrived close ( c. 80 km) to the edge of the shelf. Females from the same rookery dispersed widely and locations at sea often overlapped. Individual differences were apparent between coastal and pelagic animals. Trips lasted a mean of 3.4 days ( sd = 1.3, n = 115 trips). Mean travel distance per trip was 206 km ( sd = 117 km, maximum 864 km, n = 115 trips). Females reached further distances by travelling faster rather than by extending the duration of trips. Consistent with the shallow continental shelf, 65% of 75 087 dives recorded for nine animals were in the range of 2–30 m. Males alternated periods on the coast with trips to sea lasting a mean of 5.7 days ( sd = 3.0, n = 8 trips). Mean travel distance exceeded 591 km (1 sd = 301 km, n = 8 trips). Results are consistent with sex differences reported from diet studies. Locations overlap with the summer operation of shelf fisheries targeting species that are also part of the sea lion diet.

We review the status of the freshwater fish fauna of Patagonia, an assemblage with 26 native species, comprising fishes of Gondwanan origin, marine dispersants, and oceanic elements of local origin. Several processes, old and new, have shaped the landscape of Patagonia and its fauna: a Gondwanan heritage, the Andes uplifting, Pleistocene ice, volcanic activity, introduction of exotic fishes, mostly Salmonids, and climate change. While there is a significant tradition of taxonomic work on native fish species, research on life history, trophic relationships, and community structure has started to emerge only in the last 15 years. Most studies were conducted in oligotrophic lakes of the Andes; while fauna of streams remains poorly observed. While documentation of impacts by salmonids is scarce, there is some compelling evidence indicating that freshwater communities have been significantly shaped by exotic fish. Impacts by exotic species appear to be dependent on temperature on the east side of the Andes, and land use and watershed perturbation on the west side. In general, freshwater habitat conditions and how they affect fishes are poorly studied. In lakes, habitat complexity and its specialized use by native fishes may have ameliorated the impact by introduced salmonids. Although impacts on rivers abound, led by dam construction, the relationship between stream habitat integrity and native species health is still poorly understood. The future of freshwater resources will largely depend on how able we are to inform managers, the general public and colleagues about their value and the costs of not taking action. But current research capacity is insufficient to deal with most demands because of limitations in people, resources and baseline information. To support our claims, we need to promote regional assessments of freshwater resources and of major threats to their integrity, the building blocks of a regional agenda for their sustainable use.

BACKGROUND: In a typical osteoarthritic knee with varus deformity, distal femoral resection based off the worn medial femoral condyle may result in an elevated joint line. In a setting of fixed flexion contracture, the surgeon may choose to resect additional distal femur to obtain extension, thus purposefully raising the joint line. However, the biomechanical effect of raising the joint line is not well recognized. QUESTIONS/PURPOSES: (1) What is the effect of the level of the medial joint line (restored versus raised) on coronal plane stability of a TKA? (2) Does coronal alignment technique (mechanical axis versus kinematic technique) affect coronal plane stability of the knee? (3) Can the effect of medial joint-line elevation on coronal plane laxity be predicted by an analytical model? METHODS: A TKA prosthesis was implanted in 10 fresh frozen nonarthritic cadaveric knees with restoration of the medial joint line at its original level (TKA0). Coronal plane stability was measured at 0°, 30°, 60°, 90°, and 120° flexion using a navigation system while applying an instrumented 9.8-Nm varus and valgus force moment. The joint line then was raised in two steps by recutting the distal and posterior femur by an extra 2 mm (TKA2) and 4 mm (TKA4), downsizing the femoral component and, respectively, adding a 2- and a 4-mm thicker insert. This was done with meticulous protection of the ligaments to avoid damage. Second, a simplified two-dimensional analytical model of the superficial medial collateral ligament (MCL) length based on a single flexion-extension axis was developed. The effect of raising the joint line on the length of the superficial MCL was simulated. RESULTS: Despite that at 0° (2.2° ± 1.5° versus 2.3° ± 1.1° versus 2.5° ± 1.1°; p = 0.85) and 90° (7.5° ± 1.9° versus 9.0° ± 3.1° versus 9.0° ± 3.5°; p = 0.66), there was no difference in coronal plane laxity between the TKA0, TKA2, and TKA4 positions, increased laxity at 30° (4.8° ± 1.9° versus 7.9° ± 2.3° versus 10.2° ± 2.0°; p < 0.001) and 60° (5.7° ± 2.7° versus 8.8° ± 2.9° versus 11.3° ± 2.9°; p < 0.001) was observed when the medial joint line was raised 2 and 4 mm. At 30°, this corresponds to an average increase of 64% (3.1°; p < 0.01) in mid-flexion laxity with a 2-mm raised joint line and a 111% (5.4°; p < 0.01) increase with a 4-mm raised joint line compared with the 9-mm baseline resection. No differences in coronal alignment were found between the knees implanted with kinematic alignment versus mechanical alignment at any flexion angle. The analytical model was consistent with the cadaveric findings and showed lengthening of the superficial MCL in mid-flexion. CONCLUSIONS: Despite a well-balanced knee in full extension and at 90° flexion, increased mid-flexion laxity in the coronal plane was evident in the specimens where the joint line was raised. CLINICAL RELEVANCE: When recutting the distal and posterior femur and downsizing the femoral component, surgeons should be aware that this action might increase the laxity in mid-flexion, even if the knee is stable at 0° and 90°.

In mammalian embryonic gonads, SOX9 is required for the determination of Sertoli cells that orchestrate testis morphogenesis. To identify genetic networks directly regulated by SOX9, we combined analysis of SOX9-bound chromatin regions from murine and bovine foetal testes with sequencing of RNA samples from mouse testes lacking Sox9. We found that SOX9 controls a conserved genetic programme that involves most of the sex-determining genes. In foetal testes, SOX9 modulates both transcription and directly or indirectly sex-specific differential splicing of its target genes through binding to genomic regions with sequence motifs that are conserved among mammals and that we called 'Sertoli Cell Signature' (SCS). The SCS is characterized by a precise organization of binding motifs for the Sertoli cell reprogramming factors SOX9, GATA4 and DMRT1. As SOX9 biological role in mammalian gonads is to determine Sertoli cells, we correlated this genomic signature with the presence of SOX9 on chromatin in foetal testes, therefore equating this signature to a genomic bar code of the fate of foetal Sertoli cells. Starting from the hypothesis that nuclear factors that bind to genomic regions with SCS could functionally interact with SOX9, we identified TRIM28 as a new SOX9 partner in foetal testes.

BACKGROUND: We developed an augmented reality (AR)-based portable navigation system in which the surgeon can view the pelvic plane and placement angle of an acetabular cup on the display of a smartphone during THA. QUESTIONS/PURPOSES: (1) Is acetabular component placement more accurate using the AR-based portable navigation system compared with the conventional freehand technique? (2) Is intraoperative measurement of placement angle more accurate when using the AR-based portable navigation system compared with a goniometer? METHODS: Forty-six patients were randomly assigned to undergo acetabular cup placement during THA using the AR-based portable navigation system (AR navigation group) or placement of a mechanical alignment guide (conventional group). All surgeries were performed with the patient in the lateral decubitus position. We compared the absolute value of the difference between the targeted placement angle and postoperative measured placement angle between the groups using two types of imaging (radiography and CT). RESULTS: In terms of radiographic inclination, the mean differences between the targeted placement angle and postoperative measured angle were smaller in the AR navigation group than in the conventional group for both radiographs and CT images (2.3° ± 1.4° versus 3.9° ± 2.4°, respectively; p = 0.009 and 1.9° ± 1.3° versus 3.4° ± 2.6°, respectively; p = 0.02). There were no differences in radiographic anteversion between the two groups. No complications were associated with the use of the AR-based portable navigation system. CONCLUSIONS: This system yielded no differences in acetabular anteversion accuracy, and no clinically important differences in acetabular inclination. Therefore, at this time we cannot recommend this device as its costs and risks cannot be justified based on the absence of a clinically meaningful difference in cup placement accuracy. Although we detected no complications, this was a small series, and this approach adds both surgical time and pins in the ilium. LEVEL OF EVIDENCE: Level I, therapeutic study.

History Patellar dislocation has a prevalence of approximately 5.8 per 100,000 patients. The prevalence rises substantially to 29 per 100,000 in the 10- to 17-year-old population [14]. Multiple studies have reported that trochlear dysplasia may be present in patients with patellar instability (Fig. 1) [13, 14, 18]. Trochlear dysplasia is defined as a flattened femoral groove that provides inadequate bony stability for lateral patella translation. This lack of inherent osseous stability leads to repetitive overload of the medial patellofemoral ligament, further contributing to patellar instability [6].Fig. 1: Clinical photographs of a patient with patellar dislocation on exam.Malghem and Maldague [18] were radiologists who initially identified trochlear dysplasia by measuring the depth of the trochlear sulcus on lateral radiographs. In his seminal work on trochlear dysplasia, Henri Dejour et al. [12] identified the crossing sign on lateral radiographs as a radiographic marker of trochlear dysplasia. The crossing sign is the radiographic representation of the deepest point of the trochlear sulcus crossing the anterior border of the femoral condyles. The authors classified trochlear dysplasia into Types I to III based on the level at which the crossing sign was observed on lateral radiographs, with a more distal crossing sign representing a shorter length of the trochlear grove and therefore a more severe dysplasia. Later, Henri Dejour et al. [13] used radiographs and CT scans to modify his initial classification by removing the trochlear length from the classification and adding the presence of a supratrochlear spur. In 1998 David DeJour et al. [11] further modified the classification into a four-type system (Types A to D) that combined the true lateral knee radiograph with an axial CT scan. Although initially described on a CT scan, in current practice, it is classified based on either CT or MRI scan. [1, 10, 11]. The current four-type Dejour classification is based on the presence of supratrochlear spurs, double contours, and the crossing sign on lateral radiographs (Fig. 2A-B) combined with different trochlear morphologies as seen on axial images (Fig. 3A-C).Fig. 2 A-B: (A) Lateral knee radiograph with radiographic signs of trochlear dysplasia without labels. (B) Lateral knee radiograph with radiographic signs of trochlear dysplasia with labels: the blue line is the “Crossing sign,” representing the deepest point of the trochlear sulcus crossing the anterior border of the femoral condyles, the red line is a “Supratrochlear spur”, the prominence of the trochlea on the anterior aspect of the femoral cortex, and the green line is the “Double contour” line, the hypoplastic medial facet posterior to the lateral facet.Fig. 3 A-C: These images demonstrate trochlear dysplasia consistent with Dejour B trochlear dysplasia. (A) In this lateral knee radiograph, the asterisk (*) identifies the “Supratrochlear spur” and the arrow points to she “Crossing sign.” (B) This axial MRI shows a flattened trochlear groove. (C) This is an arthroscopic view of a flattened trochlea.Other objective measurements have also been used to describe trochlear dysplasia including the tibial trochlear-trochlear groove distance, trochlear depth index, trochlear sulcus volume, trochlear length, medial condylar trochlear offset, lateral trochlear inclination, lateral condyle index, and patellotrochlear index [3-5, 9, 21, 23, 26]. There are other approaches for assessing patellar instability, but with respect to classifications of trochlear dysplasia, the Dejour classification may be the most widely used system. However, from the best evidence currently available, we believe this classification lacks utility in clinical practice and in the research setting due to unsatisfactory grading of the degree of dysplasia, lack of reproducibility and reliability, and its inability to guide treatment [17, 22, 24, 25]. Purpose Classification systems are most valuable when they are reproducible and helpful in guiding clinical management. Patellar instability can be caused by multiple different anatomic factors, including trochlear dysplasia, patella alta, patellar tilt, rotational deformities, and increased tibial trochlear-trochlear groove distances [6, 13]. Dejour et al. [13] found that among patients with a history of patellofemoral dislocation, 85% had radiographically observed trochlear dysplasia. The crossing sign was identified in 96% of patients with trochlear dysplasia compared with 3% of controls. The four-type Dejour classification system was originally devised to help identify and categorize trochlear dysplasia and potentially determine treatment options; however, we believe it does not accurately or consistently grade the severity of trochlear dysplasia [13]. Moreover, by itself, the Dejour classification may not be helpful in preoperative planning and counseling. There is some inconsistency in the literature regarding which Dejour types should be considered severe dysplasia. Some authors have simplified the four-type Dejour classification into two grades (low and high grade) for evaluation of trochlear dysplasia. Some authors believe that medial patellofemoral ligament reconstruction alone may improve clinical and functional outcomes in moderate dysplasia while reserving a combined medial patellofemoral ligament with trochleoplasty for severe dysplasia [27]. Others have reported that as an isolated procedure, trochleoplasty should be all that is necessary in the presence of any grade of trochlear dysplasia [7]. Still others have reported that trochleoplasty, as a stand-alone procedure, is effective in knees with substantial features of high-grade trochlear dysplasia [8]. Fucentese et al. [15], using a modified classification combining patients with Dejour B and D as high-grade and A and C as low-grade trochlear dysplasia, evaluated the clinical outcomes at a mean follow-up of 4 years for 44 knees in 38 patients who underwent trochleoplasty for patellar instability. The authors found that patients with Dejour Types B and D dysplasia, in which a supratrochlear spur is present, had better outcomes with lower subjective knee pain and pain during sporting activities than patients with Dejour Type A or C dysplasia, in which a supratrochlear spur is not present. Description The Dejour classification of trochlear dysplasia is assessed using lateral knee radiographs as well as axial CT or MRI imaging to evaluate abnormal trochlear morphology. The classification is based on the presence of the crossing sign, a supratrochlear spur, and double contour sign on lateral radiographs [11, 13]. A crossing sign, believed to be pathognomonic for trochlear dysplasia, is described as the radiographic representation of the deepest point on the trochlear sulcus that crosses the anterior border of the femoral condyles. This reflects a deficient proximal trochlea with a reduced relative height of the lateral trochlear wall [12]. A supratrochlear spur is a prominence of the trochlea above the anterior femoral cortex and is measured by the distance between a line tangential to the anterior femoral cortex and a line parallel to it through the trochlear groove. A spur larger than > 3 mm is believed to exemplify high-grade dysplasia. This indicates an elevation of the trochlear floor with loss of relative lateral trochlear height and increased susceptibility to patellar instability [2]. A double contour is present when the medial facet is hypoplastic and can be visualized posterior to the lateral facet. The classification further differentiates dysplasia based on axial CT or MRI imaging. On axial images, the trochlea may be seen as shallow but concave and flattened, having lateral facet convexity and medial facet hypoplasia, and a “cliff” (clearly asymmetric facets with a vertical inclination between the facets) in Dejour Types A to D, respectively (Fig. 4). A sulcus angle can also be measured from the highest point on the condyles to the lowest point of the intercondylar groove, with an average measurement of 137° ± 8° in healthy individuals [13]. Although not a part of the Dejour classification, a sulcus angle measuring more than 145° in a Merchant view knee radiograph with the knee in 45° knee flexion and the beam at 30° inclination caudal down the patellar femoral joint is characteristic of trochlear dysplasia (Fig. 5) [13, 19].Fig. 4 A-D: Illustrations of the Dejour classification on axial and lateral projection depicted as: (A) Dejour A, (B) Dejour B, (C) Dejour C, and (D) Dejour D.Fig. 5 A-B: A sulcus angle is drawn on a Merchant view of the knee from the highest points of the medial and lateral condyle to the lowest point of the intercondylar notch. (A) This figure shows normal trochlear sulcus measurement (138° ± 6°). (B) In this image, a sulcus angle > 145° is indicative of trochlear dysplasia.The Dejour classification system is divided into Types A, B, C, and D dysplasia using specific radiographic parameters (Table 1). In type A dysplasia (Fig. 4A), there is a crossing sign on the lateral radiographs and the trochlear groove is symmetric but shallower than normal, with a sulcus angle greater than 145° on axial images. In type B (Fig. 4B), there is a crossing sign as well as a supratrochlear spur on lateral radiographs, with a flat trochlea on axial images. In Type C (Fig. 4C), there is a crossing sign and double contour on lateral radiographs, with lateral facet convexity and medial facet hypoplasia on axial images. In Type D (Fig. 4D), there is a crossing sign, supratrochlear spur, and double contour on lateral radiographs, and a “cliff” on axial images because of asymmetry of the lateral and medial femoral trochlear facets.Table 1.: Imaging findings characteristic of different trochlear dysplasia types based on the Dejour classificationValidation Three studies have evaluated the reliability of the Dejour classification. Current evidence suggests that the four-type Dejour classification has substantial intra- and interobserver variability, and therefore offers little value in day-to-day clinical assessment of grading and classifying trochlear dysplasia and for communication in research. The classification by itself does not reliably grade trochlear dysplasia unless it is simplified to a two-grade classification, that is, low-grade versus high-grade, and therefore does not provide any guidelines for treatment. Moreover, there is no agreement as to which Dejour types should be classified as low- and high-grade dysplasia. Remy et al. [22] reported on the validity of the original Dejour classification, with seven observers evaluating 68 lateral knee radiographs. They found poor intraobserver and interobserver reliability, with kappa correlation coefficients of 0.3 and 0.17, respectively. That study did find that the crossing sign was a good indicator of trochlear dysplasia, with only 3.1% of dysplastic trochleas being rated as normal. Various authors have found that the reliability of the Dejour classification may be potentially improved if the trochlear morphology is grouped into low-grade (Dejour Type A) or high-grade dysplasia (Dejour Types B, C, and D). In a study of 50 knees, Lippacher et al. [17] reported on the intra- and interobserver reliability of the Dejour classification, with four surgeons first evaluating lateral radiographs and then independently evaluating axial MRIs at two time points 4 weeks apart. For the lateral radiographs, the four classification types had intraobserver reliabilities ranging from 30% to 78% and on axial MRI ranging between 32% and 74%. The interobserver reliability on lateral radiographs ranged from 24% to 58% and on axial MRI ranged from 28% to 60%. When using a two-grade simplified grouping with Type A as low-grade and Types B, C, and D as high-grade dysplasia, the authors demonstrated improved the intra- and interobserver reliability. With this grouping, the intra- and interobserver reliability on lateral radiographs ranged from 56% to 88% and 60% to 76% respectively. On axial MRI, the intra- and interobserver reliability ranged from 70% to 90% and 62% to 96%, respectively. However, it must be noted that this grouping was not described for the grading of trochlear dysplasia in the original Dejour classification and potentially gives up some utility by pooling dissimilar entities. Nevertheless, the reliability of this simplified classification is still moderate to low in this study. More recently, Tscholl et al. [25] evaluated the agreement between lateral radiographs and axial MRI in analyzing Dejour’s classification of trochlear dysplasia in 228 knees with recurrent patellar dislocations. The authors demonstrated that the overall agreement of the four-type Dejour classification scheme was just 45% when trochlear dysplasia was measured at the mid-patellar height approximately 3.8 ± 0.6 cm above the joint line, but increased to 82% when patients were grouped into low-grade (Dejour Types A and C) and high-grade dysplasia (Dejour Types B and D) [25]. In a study of 38 skeletally immature patients undergoing surgery for patellar instability, Stepanovich et al. [24], compared the Dejour classification and the medial condylar trochlear offset, trochlear depth index, and lateral trochlear inclination to assess their reliability and correlation with patellar instability. The authors found that the four Dejour types as seen on MRI had low interobserver (kappa = 0.687) and intraobserver reliability (kappa = 0.596). Other measurements used in this study [24], including the medial condylar trochlear offset (kappa = 0.86 and 0.95), trochlear depth index (kappa = 0.93 and 0.98), and lateral trochlear inclination (kappa = 0.94 and 0.93), showed higher inter and intraobserver reliability, respectively. Although the Dejour classification is widely known, these alternative measurements of trochlear morphometry may be more reliable and reproducible than the Dejour types in describing trochlear dysplasia. Data from the studies currently available suggest that the Dejour classification is unreliable and should not be used routinely in clinical practice, as better alternatives are available. Nevertheless, further validation studies are needed to better evaluate the best alternative measurements to use to grade trochlear dysplasia. The Dejour classification is a well-known classification system of trochlear dysplasia evaluating the risk of patellar instability. However, many other methods have been described for evaluating trochlear dysplasia and patellar instability [4, 6, 9, 20, 21]. MRI can be used to evaluate several different anatomic structures, including the medial patellofemoral ligament, and measurements can be made for evaluating trochlear morphology. Carrillon et al. [9] describe the lateral trochlear inclination, measured by drawing a line parallel to the posterior femoral condyle and another line parallel to the articular surface of the lateral trochlear facet; the angle thus formed was found to be 93% sensitive and 87% specific for identifying patellar instability using a cutoff of 11°. However, currently there are no studies evaluating the intra- and interobserver reliability for these trochlear morphometric measurements. The trochlear depth index is measured using a modification of the technique previously described by Pfirrmann et al. [21]. A line is initially drawn parallel to the posterior condyle that intersects at the lowest point of the trochlea. Using this line, the maximum perpendicular height of the medial and lateral trochlear facets is measured. The trochlear depth index is finally calculated as the average of the medial and lateral trochlear facet heights. One radiographic study found that a trochlear depth cut off of less than 3 mm was 100% sensitive and 96% specific in adults and 81% sensitive and 89% specific in a pediatric population for the diagnosis of trochlear dysplasia [21]. Biedert et al. [3, 4] described two additional measurements of trochlear morphology, the lateral condyle index and patellotrochlear index, which are measured on a lateral cut of a sagittal MRI with the knee in 0° flexion. Alternative methods for evaluating trochlear morphology for dysplasia have thus been described, but have not undergone substantial validation studies. Limitations The Dejour classification has several limitations. The most important limitation of this classification is that the reliability and reproducibility is too low for routine use in research and clinical practice. The classification system is based on true lateral radiographs with knees in 30° of flexion with superimposition of the femoral condyles and an axial CT or MRI. As a result, the findings are sensitive to the quality of lateral radiographs. Even 5° of rotation of the distal femur can cause a false-positive or false-negative result in identifying the crossing sign, which is an indication of trochlear dysplasia [16]. The classification also does not provide any measurements of trochlear length or depth of the trochlear groove, diminishing its utility in describing all types of trochleas. It also does not provide any cumulative grading of trochlea dysplasia, and thus does not offer firm guidelines regarding surgical management. As in adults, the Dejour classification has also been reported to have limited reliability in children with trochlear dysplasia [24]. In a recent study, Nelitz et al. [20] found that the four-type Dejour classification could not be accurately defined using quantitative measurements of trochlear geometry. They found that various quantitative measurements of trochlear dysplasia such as medial, central, and lateral trochlear height, patellar lateralization, and condylar asymmetry were variably distributed among Dejour Types A to D. When the authors grouped patients with Dejour Types B, C, and D as having high-grade dysplasia and Dejour Type A patients as low-grade dysplasia, they demonstrated that sensitivity ranged from 75% to 86% and specificity from 76% to 84% for lateral trochlear inclination, trochlear facet asymmetry and depth of trochlear groove in defining low- and high-grade dysplasia. All remaining measurements had poor sensitivity varying from 49% to 67% and poor specificity ranging from 40% to 72%. The authors found that the intra- and interobserver reliability for all measured parameters were fair to moderate for high-grade dysplasia (intraclass correlation coefficient [ICC] values varied between 0.34 and 0.58) and good to excellent for low-grade dysplasia [ICC values varied between 0.71 and 0.88]), which further exemplified that the Dejour classification scheme is unreliable for objective assessment of trochlear dysplasia. Conclusion The Dejour classification describes trochlear morphology based on lateral radiographs and axial CT or MRI images. However, its poor reliability, reproducibility, and lack of objective grading regarding the severity of trochlear dysplasia as a treatment guide implies that it has limited value. Furthermore, it could potentially be misleading if used in the clinical and research setting. The usefulness of the Dejour classification may be enhanced with the use of advanced imaging modalities such as MRI, both for quantitative grading and improving its clinical relevance. There is a need for studies evaluating various indices describing trochlear morphometry to define the severity of trochlear dysplasia and aid in treatment decisions.

BACKGROUND: During a pandemic, it is paramount to understand volume changes in Level I trauma so that with appropriate planning and reallocation of resources, these facilities can maintain and even improve life-saving capabilities. Evaluating nonaccidental and accidental trauma can highlight potential areas of improvement in societal behavior and hospital preparedness. These critical questions were proposed to better understand how healthcare leaders might adjust surgeon and team coverage of trauma services as well as prepare from a system standpoint what resources will be needed during a pandemic or similar crisis to maintain services. QUESTIONS/PURPOSES: (1) How did the total observed number of trauma activations, defined as patients who meet mechanism of injury requirements which trigger the notification and aggregation of the trauma team upon entering the emergency department, change during a pandemic and stay-at-home order? (2) How did the proportion of major mechanisms of traumatic injury change during this time period? (3) How did the proportion and absolute numbers of accidental versus nonaccidental traumatic injury in children and adults change during this time period? METHODS: This was a retrospective study of trauma activations at a Level I trauma center in New Orleans, LA, USA, using trauma registry data of all patients presenting to the trauma center from 2017 to 2020. The number of trauma activations during a government mandated coronavirus 2019 (COVID-19) stay-at-home order (from March 20, 2020 to May 14, 2020) was compared with the expected number of activations for the same time period from 2017 to 2019, called "predicted period". The expected number (predicted period) was assumed based on the linear trend of trauma activations seen in the prior 3 years (2017 to 2019) for the same date range (March 20, 2020 to May 14, 2020). To define the total number of traumatic injuries, account for proportion changes, and evaluate fluctuation in accidental verses nonaccidental trauma, variables including type of traumatic injury (blunt, penetrating, and thermal), and mechanism of injury (gunshot wound, fall, knife wound, motor vehicle collision, assault, burns) were collected for each patient. RESULTS: There were fewer total trauma activations during the stay-at-home period than during the predicted period (372 versus 532 [95% CI 77 to 122]; p = 0.016). The proportion of penetrating trauma among total activations was greater during the stay-at-home period than during the predicted period (35% [129 of 372] versus 26% [141 of 532]; p = 0.01), while the proportion of blunt trauma was lower during the stay-at-home period than during the predicted period (63 % [236 of 372] versus 71% [376 of 532]; p = 0.02). The proportion of gunshot wounds in relation to total activations was greater during the stay-at-home period than expected (26% [97 of 372] versus 18% [96 of 532]; p = 0.004). There were fewer motor vehicle collisions in relation to total activations during the stay-at-home period than expected (42% [156 of 372] versus 49% [263 of 532]; p = 0.03). Among total trauma activations, the stay-at-home period had a lower proportion of accidental injuries than the predicted period (55% [203 of 372] versus 61% [326 of 532]; p = 0.05), and there was a greater proportion of nonaccidental injuries than the predicted period (37% [137 of 372] versus 27% [143 of 532]; p < 0.001). In adults, the stay-at-home period had a greater proportion of nonaccidental injuries than the predicted period (38% [123 of 328] versus 26% [123 of 466]; p < 0.001). There was no difference between the stay-at-home period and predicted period in nonaccidental and accidental injuries among children. CONCLUSION: Data from the trauma registry at our region's only Level I trauma center indicate that a stay-at-home order during the COVID-19 pandemic was associated with a 70% reduction in the number of traumatic injuries, and the types of injuries shifted from more accidental blunt trauma to more nonaccidental penetrating trauma. Non-accidental trauma, including gunshot wounds, increased during this period, which suggest community awareness, crisis de-escalation strategies, and programs need to be created to address violence in the community. Understanding these changes allows for adjustments in staffing schedules. Surgeons and trauma teams could allow for longer shifts between changeover, decreasing viral exposure because the volume of work would be lower. Understanding the shift in injury could also lead to a change in specialists covering call. With the often limited availability of orthopaedic trauma-trained surgeons who can perform life-saving pelvis and acetabular surgery, this data may be used to mitigate exposure of these surgeons during pandemic situations. LEVEL OF EVIDENCE: Level III, therapeutic study.

Ca(2+)-dependent mechanisms are critical for successful completion of fertilization. Here, we demonstrate that CRISP1, a sperm protein involved in mammalian fertilization, is also present in the female gamete and capable of modulating key sperm Ca(2+) channels. Specifically, we show that CRISP1 is expressed by the cumulus cells that surround the egg and that fertilization of cumulus-oocyte complexes from CRISP1 knockout females is impaired because of a failure of sperm to penetrate the cumulus. We provide evidence that CRISP1 stimulates sperm orientation by modulating sperm hyperactivation, a vigorous motility required for penetration of the egg vestments. Moreover, patch clamping of sperm revealed that CRISP1 has the ability to regulate CatSper, the principal sperm Ca(2+) channel involved in hyperactivation and essential for fertility. Given the critical role of Ca(2+) for sperm motility, we propose a novel CRISP1-mediated fine-tuning mechanism to regulate sperm hyperactivation and orientation for successful penetration of the cumulus during fertilization.

Theory predicts that parallel evolution should be common when the number of beneficial mutations is limited by selective constraints on protein structure. However, confirmation is scarce in natural populations. Here we studied the major haemoglobin genes of eight Andean duck lineages and compared them to 115 other waterfowl species, including the bar-headed goose (Anser indicus) and Abyssinian blue-winged goose (Cyanochen cyanopterus), two additional species living at high altitude. One to five amino acid replacements were significantly overrepresented or derived in each highland population, and parallel substitutions were more common than in simulated sequences evolved under a neutral model. Two substitutions evolved in parallel in the alpha A subunit of two (Ala-alpha 8) and five (Thr-alpha 77) taxa, and five identical beta A subunit substitutions were observed in two (Ser-beta 4, Glu-beta 94, Met-beta 133) or three (Ser-beta 13, Ser-beta 116) taxa. Substitutions at adjacent sites within the same functional protein region were also observed. Five such replacements were in exterior, solvent-accessible positions on the A helix and AB corner of the alpha A subunit. Five others were in close proximity to inositolpentaphosphate binding sites, and two pairs of independent replacements occurred at two different alpha(1)beta(1) intersubunit contacts. More than half of the substitutions in highland lineages resulted in the acquisition of serine or threonine (18 gains vs. 2 losses), both of which possess a hydroxyl group that can hydrogen bond to a variety of polar substrates. The patterns of parallel evolution observed in these waterfowl suggest that adaptation to high-altitude hypoxia has resulted from selection on unique but overlapping sets of one to five amino acid substitutions in each lineage.

Lignocellulosic biomass is a common resource across the globe, and its fermentation offers a promising option for generating renewable liquid transportation fuels. The deconstruction of lignocellulosic biomass releases sugars that can be fermented by microbes, but these processes also produce fermentation inhibitors, such as aromatic acids and aldehydes. Several research projects have investigated lignocellulosic biomass fermentation by the baker’s yeast Saccharomyces cerevisiae. Most projects have taken synthetic biological approaches or have explored naturally occurring diversity in S. cerevisiae to enhance stress tolerance, xylose consumption, or ethanol production. Despite these efforts, improved strains with new properties are needed. In other industrial processes, such as wine and beer fermentation, interspecies hybrids have combined important traits from multiple species, suggesting that interspecies hybridization may also offer potential for biofuel research. To investigate the efficacy of this approach for traits relevant to lignocellulosic biofuel production, we generated synthetic hybrids by crossing engineered xylose-fermenting strains of S. cerevisiae with wild strains from various Saccharomyces species. These interspecies hybrids retained important parental traits, such as xylose consumption and stress tolerance, while displaying intermediate kinetic parameters and, in some cases, heterosis (hybrid vigor). Next, we exposed them to adaptive evolution in ammonia fiber expansion-pretreated corn stover hydrolysate and recovered strains with improved fermentative traits. Genome sequencing showed that the genomes of these evolved synthetic hybrids underwent rearrangements, duplications, and deletions. To determine whether the genus Saccharomyces contains additional untapped potential, we screened a genetically diverse collection of more than 500 wild, non-engineered Saccharomyces isolates and uncovered a wide range of capabilities for traits relevant to cellulosic biofuel production. Notably, Saccharomyces mikatae strains have high innate tolerance to hydrolysate toxins, while some Saccharomyces species have a robust native capacity to consume xylose. This research demonstrates that hybridization is a viable method to combine industrially relevant traits from diverse yeast species and that members of the genus Saccharomyces beyond S. cerevisiae may offer advantageous genes and traits of interest to the lignocellulosic biofuel industry.

Global aquatic ecosystems are under increasing threat from anthropogenic activity, as well as being exposed to past (and projected) climate change, however, the nature of how climate and human impacts are recorded in lake sediments is often ambiguous. Natural and anthropogenic drivers can force a similar response in lake systems, yet the ability to attribute what change recorded in lake sediments is natural, from that which is anthropogenic, is increasingly important for understanding how lake systems have, and will continue to function when subjected to multiple stressors; an issue that is particularly acute when considering management options for aquatic ecosystems. The duration and timing of human impacts on lake systems varies geographically, with some regions of the world (such as Africa and South America) having a longer legacy of human impact than others (e.g., New Zealand). A wide array of techniques (biological, chemical, physical and statistical) is available to palaeolimnologists to allow the deciphering of complex sedimentary records. Lake sediments are an important archive of how drivers have changed through time, and how these impacts manifest in lake systems. With a paucity of ‘real‐time’ data pre‐dating human impact, palaeolimnological archives offer the only insight into both natural variability (i.e., that driven by climate and intrinsic lake processes) and the impact of people. While there is a need to acknowledge complexity, and temporal and spatial variability when deciphering change from sediment archives, a palaeolimnological approach is a powerful tool for better understanding and managing global aquatic resources. WIREs Water 2017, 4:e1195. doi: 10.1002/wat2.1195 This article is categorized under: Water and Life &gt; Stresses and Pressures on Ecosystems Science of Water &gt; Water and Environmental Change Water and Life &gt; Methods

BACKGROUND: Fear avoidance can play a prominent role in maladaptive responses to an injury. In injured athletes, such pain-related fear or fear avoidance behavior may have a substantial influence on the recovery process. Specifically, it may explain why some are able to reach their preinjury abilities, whereas others are unable to return to sport. QUESTIONS/PURPOSES: (1) Is fear avoidance in athletes associated with decreased physical function after injury? (2) To what degree is fear avoidance associated with athletes' pain intensity? METHODS: In a cross-sectional study, we recruited injured athletes-defined as patients with sports-related injury, weekly engagement in sport activities, participation in competitive events as part of a team or club, self-identification as an athlete, and a desire to return to sport after recovery-from an orthopaedic sports medicine center at a major urban university hospital. Of 130 approached patients, 102 (84% men; mean ± SD age 25 ± 8.5 years) met the inclusion criteria. Participants completed a demographic questionnaire, the Athlete Fear Avoidance Questionnaire, which assesses injury-related fear and avoidance behavior specifically in an athletic population, the Pain Catastrophizing Scale, the Hospital Anxiety and Depression Scale, and two Patient-Reported Outcomes Measurement Information System measures: Physical Function Computerized Adaptive Testing (CAT) and Pain Intensity CAT. RESULTS: After controlling for age, injury region (upper versus lower extremity), catastrophic thinking, and emotional distress, we found that an increase in athletes' fear avoidance was associated with a decrease in physical function (b = -0.32; p = 0.002). The model explained 30% of the variation in physical function with 7.3% explained uniquely by fear avoidance. After controlling for initial appointment/followup, surgery for the current condition, multiple pain conditions, history of prior sport-related injury/surgery, pain medication prescription, catastrophic thinking, and emotional distress, athletes' fear avoidance was not associated with pain (b = -0.14; p = 0.249). The model explained 40% of the variation in pain intensity and pain catastrophizing (b = 0.30; p = 0.001) uniquely explained 7.1% of this variation. CONCLUSIONS: In injured athletes, fear avoidance is independently associated with decreased physical function, whereas pain catastrophizing is associated with high pain intensity. Both level of an athlete's fear avoidance and catastrophic thinking about pain should be accounted for in clinical interventions aimed at helping athletes improve recovery and return to sport. LEVEL OF EVIDENCE: Level II, prognostic study.

The root microbiome is shaped by plant root activity, which selects specific microbial taxa from the surrounding soil. This influence on the microorganisms and soil chemistry in the immediate vicinity of the roots has been referred to as the rhizosphere effect. Understanding the traits that make bacteria successful in the rhizosphere is critical for developing sustainable agriculture solutions. In this study, we compared the growth rate potential, a complex trait that can be predicted from bacterial genome sequences, to functional traits encoded by proteins. We analyzed 84 paired rhizosphere- and soil-derived 16S rRNA gene amplicon datasets from 18 different plants and soil types, performed differential abundance analysis, and estimated growth rates for each bacterial genus. We found that bacteria with higher growth rate potential consistently dominated the rhizosphere, and this trend was confirmed in different bacterial phyla using genome sequences of 3270 bacterial isolates and 6707 metagenome-assembled genomes (MAGs) from 1121 plant- and soil-associated metagenomes. We then identified which functional traits were enriched in MAGs according to their niche or growth rate status. We found that predicted growth rate potential was the main feature for differentiating rhizosphere and soil bacteria in machine learning models, and we then analyzed the features that were important for achieving faster growth rates, which makes bacteria more competitive in the rhizosphere. As growth rate potential can be predicted from genomic data, this work has implications for understanding bacterial community assembly in the rhizosphere, where many uncultivated bacteria reside.

When populations become locally adapted to contrasting environments, alleles that have high fitness in only one environment may be quickly eliminated in populations adapted to other environments, such that gene flow is partly restricted. The stronger the selection, the more rapidly immigrant alleles of lower fitness will be eliminated from the population. However, gene flow may continue to occur at unlinked loci, and adaptive divergence can proceed in the face of countervailing gene flow if selection is strong relative to migration (s > m). We studied the population genetics of the major hemoglobin genes in yellow-billed pintails (Anas georgica) experiencing contrasting partial pressures of oxygen in the Andes of South America. High gene flow and weak population subdivision were evident at seven putatively neutral loci in different chromosomal linkage groups. In contrast, amino acid replacements (Ser-beta13, Ser-beta116, and Met-beta133) in the betaA hemoglobin subunit segregated by elevation between lowland and highland populations with significantly elevated F(ST). Migration rates for the betaA subunit alleles were approximately 17-24 times smaller than for five unlinked reference loci, the alphaA hemoglobin subunit (which lacks amino acid replacements) and the mitochondrial DNA control region. The betaA subunit alleles of yellow-billed pintails were half as likely to be transferred downslope, from the highlands to the lowlands, than in the opposite direction upslope. We hypothesize that migration between the lowlands and highlands is restricted by local adaptation, and the betaA hemoglobin subunit is a likely target of selection related to high-altitude hypoxia; however, gene flow may be sufficiently high to retard divergence at most unlinked loci. Individuals homozygous for lowland alleles may have relatively little difficulty dispersing to the highlands initially but may experience long-term fitness reduction. Individuals homozygous for highland genotypes, in contrast, would be predicted to have difficulty dispersing to the lowlands if their hemoglobin alleles confer high oxygen affinity, predicted to result in chronic erythrocytosis at low elevation. Heterozygous individuals may have a dispersal advantage if their hemoglobin has a wider range of function due to the presence of multiple protein isoforms with a mixture of different oxygen affinities.

Abstract Background Fine-scale data on animal position are increasingly enabling us to understand the details of animal movement ecology and dead-reckoning, a technique integrating motion sensor-derived information on heading and speed, can be used to reconstruct fine-scale movement paths at sub-second resolution, irrespective of the environment. On its own however, the dead-reckoning process is prone to cumulative errors, so that position estimates quickly become uncoupled from true location. Periodic ground-truthing with aligned location data (e.g., from global positioning technology) can correct for this drift between Verified Positions (VPs). We present step-by-step instructions for implementing Verified Position Correction (VPC) dead-reckoning in R using the tilt-compensated compass method, accompanied by the mathematical protocols underlying the code and improvements and extensions of this technique to reduce the trade-off between VPC rate and dead-reckoning accuracy. These protocols are all built into a user-friendly, fully annotated VPC dead-reckoning R function; Gundog.Tracks , with multi-functionality to reconstruct animal movement paths across terrestrial, aquatic, and aerial systems, provided within the Additional file 4 as well as online (GitHub). Results The Gundog.Tracks function is demonstrated on three contrasting model species (the African lion Panthera leo , the Magellanic penguin Spheniscus magellanicus , and the Imperial cormorant Leucocarbo atriceps ) moving on land, in water and in air. We show the effect of uncorrected errors in speed estimations, heading inaccuracies and infrequent VPC rate and demonstrate how these issues can be addressed. Conclusions The function provided will allow anyone familiar with R to dead-reckon animal tracks readily and accurately, as the key complex issues are dealt with by Gundog.Tracks . This will help the community to consider and implement a valuable, but often overlooked method of reconstructing high-resolution animal movement paths across diverse species and systems without requiring a bespoke application.

BACKGROUND: Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, and the loss of consciousness during cemented arthroplasty; it may result in death. Its incidence has only been explored for hemiarthroplasty and THA after fracture or cancer. To our knowledge, there are no studies that comprehensively explore and compare the incidence of BCIS in other arthroplasty procedures. QUESTIONS/PURPOSES: (1) To report the incidence of BCIS in TKA, unicondylar knee arthroplasty, hip hemiarthroplasty, THA, shoulder arthroplasty, TKA, and revision THA and TKA; (2) to determine whether severe BCIS is associated with an increased risk of death within 30 days of surgery; and (3) to identify factors associated with the development of severe BCIS. METHODS: All patients undergoing cemented arthroplasty for any reason (TKA [11% cemented, 766 of 7293], unicondylar knee arthroplasty [100% cemented, 562 procedures], hip hemiarthroplasty for femur fractures [100% cemented, 969 procedures], THA [8% cemented, 683 of 8447], shoulder arthroplasty [84% cemented, 185 of 219], and revision arthroplasty of the hip and knee [36% cemented, 240 of 660]) between January 2008 and August 2019 were considered for inclusion in the current retrospective observational study. Fixation choice was dependent on surgeon preference (THA and TKA), prosthesis design (shoulder arthroplasty), or bone quality (revision arthroplasty). The following procedures were excluded because of insufficient data: < 1% (1 of 766) of TKAs, 1% (4 of 562) of unicondylar knee arthroplasties, 6% (54 of 969) of hip hemiarthroplasties, 1% (6 of 683) of THAs, 6% (12 of 185) of shoulder arthroplasties, and 14% (34 of 240) of revision procedures. This resulted in a final inclusion of 3294 procedures (765 TKAs [23%], 558 unicondylar knee arthroplasties [17%], 915 hip hemiarthroplasties [28%], 677 THA [21%], 173 shoulder arthroplasties [5%], and 206 revision arthroplasties [6%]), of which 28% (930 of 3294) had an emergent indication for surgery. Of the patients, 68% (2240 of 3294) were females, with a mean age of 75 ± 11 years. All anesthetic records were extracted from our hospital's database, and the severity of BCIS was retrospectively scored (Grade 0 [no BCIS], Grade 1 [O2% < 94% or fall in systolic blood pressure of 20% to 40%], Grade 2 [O2% < 88% or fall in systolic blood pressure of > 40%], and Grade 3 [cardiovascular collapse requiring CPR]). Procedures were dichotomized into no or moderate BCIS (Grades 0 and 1) and severe BCIS (Grades 2 and 3). The adjusted 30-day mortality of patients with severe BCIS was assessed with a multivariate Cox regression analysis. A multivariate logistic regression analysis was performed to identify factors associated with the development of severe BCIS. RESULTS: BCIS occurred in 26% (845 of 3294) of arthoplasty procedures. The incidence was 31% (282 of 915) in hip hemiarthroplasty, 28% (210 of 765) in TKA, 24% (165 of 677) in THA, 23% (47 of 206) in revision arthroplasty, 20% (113 of 558) in unicondylar knee arthroplasty, and 16% (28 of 173) in shoulder arthroplasty. Patients with severe BCIS were more likely (hazard ratio 3.46 [95% confidence interval 2.07 to 5.77]; p < 0.001) to die within 30 days of the index procedure than were patients with less severe or no BCIS. Factors independently associated with the development of severe BCIS were age older than 75 years (odds ratio 1.57 [95% CI 1.09 to 2.27]; p = 0.02), American Society of Anesthesiologists Class III or IV (OR 1.58 [95% CI 1.09 to 2.30]; p = 0.02), and renal impairment (OR 3.32 [95% CI 1.45 to 7.46]; p = 0.004). CONCLUSION: BCIS is common during cemented arthroplasty; severe BCIS is uncommon, but it is associated with an increased risk of death within 30 days of surgery. Medically complex patients undergoing hip hemiarthroplasty may be at particular risk. Patients at high risk for severe BCIS (renal impairment, ASA III/IV, and age older than 75 years) should be identified and preventive measures such as medullary lavage before cementation, femoral venting, and avoidance of excessive pressurization of implants should be taken to reduce the likelihood and consequences of BCIS. Because of the increased risk of periprosthetic fractures in uncemented hip stems, factors associated with the development of BCIS should be weighed against the risk factors for sustaining periprosthetic fractures (poor bone quality, female sex) to balance the risks of fixation method against those of BCIS for each patient. LEVEL OF EVIDENCE: Level III, therapeutic study.