Journal articles on the topic 'TKD on-axis'
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1
Shen, Yitian, Jingchao Xu, Yongsheng Zhang, Yongzhe Wang, Jimei Zhang, Baojun Yu, Yi Zeng, and Hong Miao. "Spatial Resolutions of On-Axis and Off-Axis Transmission Kikuchi Diffraction Methods." Applied Sciences 9, no. 21 (October 23, 2019): 4478. http://dx.doi.org/10.3390/app9214478.
Abstract:
Spatial resolution is one of the key factors in orientation microscopy, as it determines the accuracy of grain size investigation and phase identification. We determined the spatial resolutions of on-axis and off-axis transmission Kikuchi diffraction (TKD) methods by calculating correlation coefficients using only the effective parts of on-axis and off-axis transmission Kikuchi patterns. During the calculation, we used average filtering to evaluate the spatial resolution more accurately. The spatial resolutions of both on-axis and off-axis TKD methods were determined in the same scanning electron microscope at different accelerating voltages and specimen thicknesses. The spatial resolution of the on-axis TKD was higher than that of the off-axis TKD at the same parameters. Furthermore, with an increase in accelerating voltage or a decrease in specimen thickness, the spatial resolutions of the two configurations could be significantly improved, from tens of nanometers to below 10 nm. At a voltage of 30 kV and sample thickness of 74 nm, both on-axis and off-axis TKD methods exhibited the highest resolutions of 6.2 and 9.7 nm, respectively.
2
Brodu, Etienne, Emmanuel Bouzy, Jean-Jacques Fundenberger, Julien Guyon, Antoine Guitton, and Yudong Zhang. "On-axis TKD for orientation mapping of nanocrystalline materials in SEM." Materials Characterization 130 (August 2017): 92–96. http://dx.doi.org/10.1016/j.matchar.2017.05.036.
3
Ernould, Clément, Benoît Beausir, Jean-Jacques Fundenberger, Vincent Taupin, and Emmanuel Bouzy. "Characterization at high spatial and angular resolutions of deformed nanostructures by on-axis HR-TKD." Scripta Materialia 185 (August 2020): 30–35. http://dx.doi.org/10.1016/j.scriptamat.2020.04.005.
4
Ernould, Clément, Benoît Beausir, Jean-Jacques Fundenberger, Vincent Taupin, and Emmanuel Bouzy. "Global DIC approach guided by a cross-correlation based initial guess for HR-EBSD and on-axis HR-TKD." Acta Materialia 191 (June 2020): 131–48. http://dx.doi.org/10.1016/j.actamat.2020.03.026.
5
Crouzier, Loïc, Nicolas Feltin, Alexandra Delvallée, Francesco Pellegrino, Valter Maurino, Grzegorz Cios, Tomasz Tokarski, et al. "Correlative Analysis of the Dimensional Properties of Bipyramidal Titania Nanoparticles by Complementing Electron Microscopy with Other Methods." Nanomaterials 11, no. 12 (December 10, 2021): 3359. http://dx.doi.org/10.3390/nano11123359.
Abstract:
In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano-bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron-transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM-in-SEM (or T-SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X-ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab-initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration.
6
Wollschläger, Nicole, Ines Häusler, Erik Ortel, Vasile-Dan Hodoroaba, Laurie Palasse, and Kai Dirscherl. "Characterization of Porous, TiO2 Nanoparticle Films Using On-Axis TKD in SEM -a New Nano-Analysis Tool for a Large-Scale Application." Microscopy and Microanalysis 23, S1 (July 2017): 542–43. http://dx.doi.org/10.1017/s1431927617003397.
7
Jiang, Qing, Yao Chen, Qi Shuai, Fulin Liu, Lang Li, Chao He, Hong Zhang, Chong Wang, Yongjie Liu, and Qingyuan Wang. "Fatigue-Induced HCP-to-FCC Phase Transformation Resulting in Two FCC-Zr Variants in Pure Zirconium." Materials 16, no. 18 (September 14, 2023): 6215. http://dx.doi.org/10.3390/ma16186215.
Abstract:
This study utilized transmission electron microscopy (TEM) and on-axis transmission Kikuchi diffraction (TKD) to investigate the fatigue-induced HCP-to-FCC phase transformation in industrial pure zirconium under a stress ratio of R = 0.1. The results show that fatigue damages result from phase deformations during cyclic loadings. The fatigue-induced FCC-Zr phases exhibit a B-type orientation relationship with the HCP-Zr matrix. Notedly, due to the different growth directions of Shockley partial dislocations relative to nucleation points, there are two FCC-Zr variants after the HCP-to-FCC phase transformation. The content of these two variants accounts for 65% and 35% of the total FCC-Zr, respectively, appearing as lamellae morphology embedded parallelly within the matrix. The distribution of the two variants includes isolated distribution and adjacent distribution. For the adjacent distribution, a twinning relationship is observed between the two variants. Meanwhile, as an intermediate transition stage of the HCP-to-FCC phase transformation, stacking faults are observed at the boundaries of the FCC-Zr lamellae. These findings offer insights into the microstructural features and formation mechanisms of fatigue-induced HCP-to-FCC phase transformation.
8
Chia, Joanne S. J., Jennifer L. McRae, Peter J. Cowan, and Karen M. Dwyer. "The CD39-Adenosinergic Axis in the Pathogenesis of Immune and Nonimmune Diabetes." Journal of Biomedicine and Biotechnology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/320495.
Abstract:
Diabetes mellitus encompasses two distinct disease processes: autoimmune Type 1 (T1D) and nonimmune Type 2 (T2D) diabetes. Despite the disparate aetiologies, the disease phenotype of hyperglycemia and the associated complications are similar. In this paper, we discuss the role of the CD39-adenosinergic axis in the pathogenesis of both T1D and T2D, with particular emphasis on the role of CD39 and CD73.
9
Klemetti, Miira M., Sruthi Alahari, Martin Post, and Isabella Caniggia. "Distinct Changes in Placental Ceramide Metabolism Characterize Type 1 and 2 Diabetic Pregnancies with Fetal Macrosomia or Preeclampsia." Biomedicines 11, no. 3 (March 17, 2023): 932. http://dx.doi.org/10.3390/biomedicines11030932.
Abstract:
Disturbances of lipid metabolism are typical in diabetes. Our objective was to characterize and compare placental sphingolipid metabolism in type 1 (T1D) and 2 (T2D) diabetic pregnancies and in non-diabetic controls. Placental samples from T1D, T2D, and control pregnancies were processed for sphingolipid analysis using tandem mass spectrometry. Western blotting, enzyme activity, and immunofluorescence analyses were used to study sphingolipid regulatory enzymes. Placental ceramide levels were lower in T1D and T2D compared to controls, which was associated with an upregulation of the ceramide degrading enzyme acid ceramidase (ASAH1). Increased placental ceramide content was found in T1D complicated by preeclampsia. Similarly, elevated ceramides were observed in T1D and T2D pregnancies with poor glycemic control. The protein levels and activity of sphingosine kinases (SPHK) that produce sphingoid-1-phosphates (S1P) were highest in T2D. Furthermore, SPHK levels were upregulated in T1D and T2D pregnancies with fetal macrosomia. In vitro experiments using trophoblastic JEG3 cells demonstrated increased SPHK expression and activity following glucose and insulin treatments. Specific changes in the placental sphingolipidome characterize T1D and T2D placentae depending on the type of diabetes and feto-maternal complications. Increased exposure to insulin and glucose is a plausible contributor to the upregulation of the SPHK-S1P-axis in diabetic placentae.
10
Apelfröjd, S., and S. Eriksson. "Evaluation of Harmonic Content from a Tap Transformer Based Grid Connection System for Wind Power." Journal of Renewable Energy 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/190573.
Abstract:
Simulations done in MATLAB/Simulink together with experiments conducted at the Ångströms laboratory are used to evaluate and discuss the total harmonic distortion (THD) and total demand distortion (TDD) of a tap transformer based grid connection system. The grid connection topology can be used with different turbine and generator topologies and is here applied on a vertical axis wind turbine (VAWT) with a permanent magnet synchronous generator (PMSG) and its operational scheme. The full variable-speed wind conversion system consists of a diode rectifier, DC link, IGBT inverter, LCL-filter, and tap transformer. The full variable-speed operation is enabled by the use of the different step-up ratios of the tap transformer. In the laboratory study, a full experimental setup of the system was used, a clone of the on-site PMSG driven by a motor was used, and the grid was replaced with a resistive load. With a resistive load, grid harmonics and possible unbalances are removed. The results show a TDD and THD below 5% for the full operating range and harmonic values within the limits set up by IEEE-519. Furthermore, a change in tap, going to a lower step-up ratio, results in a reduction in both THD and TDD for the same output power.
11
Liersch, Ruediger, Michael Bayer, Christoph Biermann, Iris Appelmann, Christoph Schliemann, Christian Schwoeppe, Torsten Kessler, Carsten Mueller-Tidow, Wolfgang Berdel, and Rolf Mesters. "Expression of Osteopontin in the Bone Marrow of Patients with Acute Myeloid Leukemia." Blood 114, no. 22 (November 20, 2009): 4694. http://dx.doi.org/10.1182/blood.v114.22.4694.4694.
Abstract:
Abstract Abstract 4694 BACKGROUND AND OBJECTIVES Osteopontin (OPN) is a secreted glycoprotein that is widely expressed in various kinds of cells and is involved in normal tissue remodelling processes as well as in certain diseases such as tumorigenesis and tumor metastasis. In the bone marrow (BM) OPN is predominantly secreted by osteoblasts and hematopoietic cells, which have been shown recently to express the OPN-binding integrins alpha4beta1 and alpha9beta1. In addition, OPN has been defined as an important factor for hematopoietic stem cells (HSCs). OPN suppressed the proliferation of HSCs in vitro and may regulate the hematopoietic stem cell pool. Increased serum OPN concentrations have been reported in chronic myeloid leukemia (CML), multiple myeloma (MM) and acute myeloid leukemia (AML). DESIGN AND METHODS We investigated the expression of OPN in newly diagnosed AML patients by immunohistochemistry (n=84), enzyme-linked immunoassays (ELISA) of blood /bone marrow sera (n=40) and on the RNA level by analyzing microarray data (n=261). RESULTS Expression of OPN was increased in AML patients bone marrow sera (ELISA) as well as in bone marrow blasts (IHC) Patients expressing high levels of OPN within the bone marrow (IHC: > 10 arbitrary units [AU]; ELISA: > 10 ng/ml) had significantly shorter overall survival (OS) than those with lower OPN levels. In contrast, blood OPN levels showed no predictive value. There was no correlation found between OPN expression and FAB-subtypes M0 to M7 or different karyotypes. Multivariate analysis identified the already known risk factors karyotype, blast clearance (day 16) and the level of OPN expression as independent prognostic factors for OS. Furthermore, analyses of microarray data from 261 patients of a different cohort confirmed OPN as a prognostic marker. In detail, high OPN expression demonstrated a negative predictive value for EFS and OS. Subgroup analysis revealed a significant difference in EFS and OS for OPN levels above the median in FLT3-ITD/TKD mutation negative leukemias, only. No difference was found in FLT3-mutated leukemias or in patients with favorable cytogenetics such as t(8/21) or inv (16). INTERPRETATION AND CONCLUSIONS These data provide evidence for OPN as prognostic marker in AML. OPN might be of pathogenetic relevance in AML. Although the mechanism is not yet understood modulation of the OPN axis might be a promising approach to improve the outcome of AML patients in the future. Disclosures: No relevant conflicts of interest to declare.
12
Fan, Yeying, Qian Ma, Guangshun Wei, Zhiming Cui, Yuanfeng Zhou, and Wenping Wang. "TAD-Net: tooth axis detection network based on rotation transformation encoding." Graphical Models 121 (May 2022): 101138. http://dx.doi.org/10.1016/j.gmod.2022.101138.
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Fan, Yeying, Qian Ma, Guangshun Wei, Zhiming Cui, Yuanfeng Zhou, and Wenping Wang. "TAD-Net: tooth axis detection network based on rotation transformation encoding." Graphical Models 121 (May 2022): 101138. http://dx.doi.org/10.1016/j.gmod.2022.101138.
14
Wang, Jialong, Anhua Long, Xuefei Wang, Yakui Zhang, and Dacheng Han. "Improved Calculation Method of TAD for Intertrochanteric Fractures." Applied Bionics and Biomechanics 2022 (December 6, 2022): 1–6. http://dx.doi.org/10.1155/2022/7729959.
Abstract:
Purpose. To investigate the relative position of femur fixed screws using intramedullary systems for intertrochanteric fractures and to improve the accurate measurement method of the tip-to-apex distance (TAD) while providing a theoretical basis for the clinical treatment of such fractures. Methods. In the anteroposterior (AP) radiographs of the hip joint, the femoral neck axis through the femoral head geometry point was designated as the X-axis, while the line perpendicular to the X-axis passing through the femoral head geometry point was designated as the Y-axis. In the lateral radiographs of the hip joint, the line perpendicular to the X-axis passing through the femoral head geometry point was identified as the Z-axis. The head of the nail tip’s location projected on the three axes was described as AAP, B in the AP radiographs; and ALAT, C in the lateral radiograph. The TAD was described as XAP and XLAT. The radius of the femoral head was D. All distance units were expressed in mm. Results. When the lateral projection angle was standardized, the AAP was equal to the ALAT, while the X A P 2 = B 2 + D − A A P 2 a n d X L A T 2 = C 2 + D − A L A T 2 . When the lateral projection angle was not standardized, the value of C had no significant change; however, the D − A L A T value changed. Conclusions. The measurement value did not match the actual values of TAD when the lateral projection angle was not standardized, possibly leading to a misinterpretation during clinical work. The XLAT should be amended using the formula X L A T 2 = C 2 + D − A A P 2 .
15
Zagon, Ian S., Joseph W. Sassani, Indira Purushothaman, and Patricia J. McLaughlin. "Dysregulation of the OGF–OGFr pathway correlates with elevated serum OGF and ocular surface complications in the diabetic rat." Experimental Biology and Medicine 245, no. 15 (July 8, 2020): 1414–21. http://dx.doi.org/10.1177/1535370220940273.
Abstract:
Diabetes often presents with ocular surface complications including dry eye, keratopathy, and altered sensitivity, along with systemic disorders. A common theme associated with corneal surface defects is decreased cellular proliferation. The opioid growth factor (OGF)–OGF receptor (OGFr) regulatory axis maintains epithelial homeostasis and can be modulated by naltrexone, an opioid receptor antagonist, to block OGF–OGFr interaction and increase cellular replication. Complete blockade using naltrexone accelerates cell proliferation, increases the rate of re-epithelialization in corneal surface abrasions, reverses dry eye, and restores corneal surface sensitivity in animal models of type 1 and type 2 diabetes. Data on the efficacy of naltrexone in these models suggest that the OGF–OGFr axis is dysregulated in diabetes. In the present study, we investigated the OGF–OGFr axis by assessing serum and tissue levels of OGF and OGFr during the development of streptozotocin-induced hyperglycemia and postulated a mechanism of action. We correlated the dysregulation of the OGF–OGFr axis with the onset and magnitude of corneal surface complications (e.g. tear fluid production, corneal surface sensitivity) in type 1 diabetes (T1D). Serum levels of OGF increased in both uncontrolled T1D and insulin-controlled (T1D-INS) male rats within four weeks of streptozotocin injection. Serum OGFr levels were significantly reduced in diabetic rats on weeks 3 and 8 post streptozotocin. Tear production was significantly reduced, and corneal sensitivity measurements were abnormal in both T1D and T1D-INS animals within four weeks of streptozotocin. Corneal re-epithelialization was delayed in T1D rats, but not in T1D-INS animals; however, expression levels of the inhibitory growth factor OGF and its receptor, OGFr, were elevated in the corneal epithelium more than 2-fold in both diabetic groups. These data demonstrate for the first time that dysregulation of the OGF–OGFr axis in the diabetic cornea is associated with the onset and magnitude of ocular surface complications. Impact statement This research extends our knowledge about the presence and role of the OGF–OGFr regulatory axis in type 1 diabetes (T1D) and demonstrates specific targets within the pathway that are dysregulated. Serum levels of OGF, an inhibitory growth factor, are significantly elevated in male T1D rats, and OGFr serum values are increased in T1D. The onset of elevated OGF corresponds to the onset of ocular surface complications including dry eye, delayed corneal epithelial repair, and abnormal corneal surface sensitivity in T1D. Systemic insulin does not protect against elevated OGF levels or the onset of dry eye and sensitivity. These data are the first to associate some ocular surface defects in T1D with alterations in the OGF–OGFr pathway.
16
Elhachimi, Fouad E. "HPAT Axis Dysfunction and Type II Diabetes Review." Journal of Quality in Health Care & Economics 5, no. 6 (2022): 1–4. http://dx.doi.org/10.23880/jqhe-16000308.
Abstract:
According to the CDC, 1 in 10 or more than 34 million Americans have diabetes, and approximately 90 to 95% have type II diabetes (T2D). Between 1990 and 2010, the number of new diagnoses doubled yearly, and the number of patients living with diabetes tripled. This review establishes a direct association between the hypothalamic-pituitary-adrenal and thyroid (HPAT) axis dysregulation and T2D. In this review, we will focus on the compelling evidence that shows the progressive dysregulation of the HPAT axis and the increased values of circulating cortisol which is involved in the formation of visceral obesity through thyroid hormones, which play a crucial role in regulating energy and metabolism by controlling insulin production and glucose homeostasis, and how the HPAT axis plays a significant role in preventing or causing the development of T2D.
17
Taziev, Rinat, and Victor Atuchin. "Analysis of SAW Temperature Properties in KTiOPO4 Single Crystal." Materials 16, no. 1 (December 21, 2022): 69. http://dx.doi.org/10.3390/ma16010069.
Abstract:
The surface acoustic wave (SAW) properties of potassium titanyl phosphate (KTiOPO4, KTP) single crystal were evaluated by numerical methods. The phase velocity, electromechanical coupling coefficient, power flow deflection angle, and temperature coefficient of delay (TCD) were determined for different crystal cuts of KTP. It was shown that SAW has the electromechanical coupling coefficient of 0.59% and the TCD of 62 ppm/°C on the Z-cut and wave propagation direction along the crystal X + 70°-axis. For the Z-cut and wave propagation direction along the X-axis, the pseudo-surface wave (PSAW) is characterized by the coupling coefficient of 0.46% and the TCD value of 57 ppm/°C. The Bleustein–Gulyaev (BG) wave has the TCD value of 35 ppm/°C and 41 ppm/°C on the Y- and X-cuts of KTP, respectively.
18
MacIsaac, Richard J. "Glucagon-like peptide-1 receptor agonists and the cardiorenal axis in Type 2 diabetes: a focus on dulaglutide." Future Cardiology 17, no. 3 (May 2021): 459–73. http://dx.doi.org/10.2217/fca-2020-0210.
Abstract:
Results from cardiovascular outcomes trials (CVOTs) in people with Type 2 diabetes (T2D), such as the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) study with dulaglutide, have led to a shift toward glucose lowering therapies that provide broad benefits, including cardiovascular (CV) risk reduction and renoprotection. Dulaglutide reduces atherosclerotic CV outcomes (hazard ratio 0.88; 95% CI: 0.79–0.99) and composite kidney outcomes (hazard ratio 0.85; 95% CI: 0.77–0.93) in people with T2D with high risk or established CV disease. The cardiologists’ role has now expanded to include not only screening for T2D and treating risk factors, but also recommending or incorporating glucose-lowering agents with proven CV benefit into the care of their patients with T2D.
19
SNELL-BERGEON, JANET K., JANE E. B. REUSCH, AMY D. BAUMGARTNER, MELANIE CREE-GREEN, and KRISTEN J. NADEAU. "1559-P: Differential Effects of Type 1 (T1D) and Type 2 Diabetes (T2D) on the Growth Hormone (GH)-Insulin-Like Growth Factor (IGF) Axis in Youth." Diabetes 68, Supplement 1 (June 2019): 1559—P. http://dx.doi.org/10.2337/db19-1559-p.
20
Tibbo, Meagan E., Afton K. Limberg, Kevin I. Perry, Mark W. Pagnano, Michael J. Stuart, Arlen D. Hanssen, and Matthew P. Abdel. "Effect of Coronal Alignment on 10-Year Survivorship of a Single Contemporary Total Knee Arthroplasty." Journal of Clinical Medicine 10, no. 1 (January 4, 2021): 142. http://dx.doi.org/10.3390/jcm10010142.
Abstract:
Debate remains regarding the utility of mechanical axis alignment as a predictor of durability after total knee arthroplasty (TKA). Our study aimed to assess the effects of coronal alignment on implant durability, clinical outcomes, and radiographic results with a single fixed-bearing TKA design. All patients undergoing primary cemented TKA of a single design (Stryker Triathlon) from 2005–2007 with >10 years of follow-up and available pre-operative and post-operative hip–knee–ankle radiographs were included (n = 89). Radiographs were measured to determine coronal alignment and assessed for loosening. Mean preoperative mechanical axis alignment was −6° ± 6.7° (varus, range, −16°–23°), while mean post-operative alignment was −1° ± 2.7° (varus, range, −3°–15°). The aligned group was defined as knees with a post-operative mechanical axis of 0° ± 3° (n = 73) and the outlier group as those outside this range (n = 16). No patients underwent revision. Ten-year survivorship free from any reoperation was 99% and 100% in the aligned and outlier groups, respectively (p = 0.64). Knee Society scores improved significantly in both groups (p < 0.001) and did not differ at final follow-up (p = 0.15). No knees demonstrated radiographic evidence of loosening. Post-operative mechanical axis alignment within 3° of neutral was not associated with improved implant durability, clinical outcomes, or radiographic results at 10 years following primary TKA.
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S., Hiranyakumar, Shivaraj Nadagouda, and Vishnu Harikrishnan. "A study on radiological outcomes of accelerometer based hand held navigation system in total knee arthroplasty." International Journal of Research in Orthopaedics 6, no. 3 (April 22, 2020): 556. http://dx.doi.org/10.18203/issn.2455-4510.intjresorthop20201727.
Abstract:
<p class="abstract"><strong>Background:</strong> The goal of obtaining more accurate component alignment in total knee arthroplasty (TKA) has led to the development of techniques like portable accelerometer-based handheld navigation system, computer assisted system, patient specific instrumentation. Among which hand held navigation has showed promising results for achieving accurate resection and alignment and only few studies were done to assess radiological outcome or the effective component alignment using portable accelerometer-based hand held navigation system in TKA.</p><p class="abstract"><strong>Methods:</strong> TKA using portable accelerometer-based hand held navigation system (Smith and Nephew- knee align) was done on 25 knees with primary osteoarthritis. Preoperative and post-operative mechanical axis and component alignments were measured using hip-to-ankle radiographs.<strong></strong></p><p class="abstract"><strong>Results:</strong> Among the femoral components, 92.0% were placed within 90°±2° to the femoral mechanical axis in the coronal and 96.0% of the tibial components were placed within 90°±2° to the mechanical axis in the coronal plane, 94.3% of the TKAs had an overall lower extremity alignment within 3° of neutral to the mechanical axis, based on postoperative hip-to-ankle radiographs.</p><p class="abstract"><strong>Conclusions:</strong> The degree of accuracy in positioning the femoral and tibial component in TKA using portable accelerometer-based hand held navigation system (knee align) is very much promising and is an effective intraoperative tool for reducing the proportion of outliers for component placement and thus decreasing the chances of instability and early wear and tear of the components in TKA.</p>
22
Lee, Seung Yeol, Soon-Sun Kwon, and Kyoung Min Lee. "Changes in the Mechanical Axis and Weight-Bearing Line of the Ankle After Varus Knee Correction." Foot & Ankle Orthopaedics 4, no. 4 (October 1, 2019): 2473011419S0026. http://dx.doi.org/10.1177/2473011419s00269.
Abstract:
Category: Ankle, Hindfoot Introduction/Purpose: Varus limb malalignment results in an imbalance of force transmission to the knee joint, resulting in a concentrated load in the medial compartment. A varus knee correction may affect the ankle and subtalar joint, because the weight-bearing load on the lower extremity extends from the hip to the foot. A previous study suggested that the true mechanical axis of the lower limb should be calculated with a line from the center of the femoral head to the lowest point of the calcaneus, not to the center of the tibial plafond. Therefore, we performed this study to evaluate changes in the mechanical axis and weight- bearing line of the ankle after varus knee correction. Methods: Patients with a varus knee who were followed-up after they had undergone high tibial osteotomy (HTO) or total knee replacement arthroplasty (TKA) at an age of >20 years, and who had undergone preoperative and postoperative scanogram were included in this study. The hip-knee-ankle (HKA) angle, mechanical axis, and weight-bearing line (line from the center of the femoral head to the lowest point of the calcaneus) were measured on the radiographs. The point at which the mechanical axis and weight-bearing line passed through the tibial plafond was the ankle joint axis point. The postoperative change in the ankle joint axis point on the mechanical axis and weight-bearing line according to the HKA angle correction was adjusted by multiple factors using a linear mixed model. Results: A total of 257 limbs from 198 patients were included in this study. The preoperative HKA was 7.3 ± 4.7° and corrected to 0.4 ± 3.8°. Although the ankle axis points on both axes moved laterally after HTO and TKA, the ankle joint axis of the weight- bearing line showed a significant larger lateral movement (22.5±35.7%) (Fig.) than that of the mechanical axis (15.7±16.0%) in terms of rate of change (p = 0.006). The ankle joint axis point on the weight-bearing line moved laterally by 0.9% per degree of postoperative HKA angle decrease (p < 0.001). The change in the ankle joint axis point on the mechanical axis was not statistically significant after HTO and TKA (p = 0.223). Conclusion: The mechanical axis and weight-bearing line of the ankle moved laterally after the varus knee correction. The ankle joint axis on the weight-bearing line moved laterally as the HKA angle decreased after the surgery, whereas the varus knee correction did not significantly affect the ankle joint axis on the mechanical axis. The varus knee correction might affect the subtalar joint as well as the ankle joint. Therefore, we believe that our findings warrant consideration in pre- and postoperative evaluations using the weight-bearing line of patients undergoing varus knee correction.
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Schiapparelli, Filippo-Franco, Felix Amsler, and Michael Hirschmann. "The type of approach (medial versus lateral) influences TKA component rotation in total knee arthroplasty - a clinical study using 3D-CT." Orthopaedic Journal of Sports Medicine 6, no. 4_suppl2 (April 1, 2018): 2325967118S0001. http://dx.doi.org/10.1177/2325967118s00010.
Abstract:
The purpose of this study was to investigate if the type of approach (medial parapatellar approach (MPA) versus lateral parapatellar subvastus approach with tibial tubercle osteotomy (LPA)) influences the rotation of femoral and/or tibial component and leg axis in total knee arthroplasty (TKA). This study included 200 consecutive patients in whom TKA was performed using either a parapatellar medial (n=162, MPA) or parapatellar lateral subvastus approach with tibial tubercle osteotomy (n=38, LPA). All patients underwent clinical follow-up, standardised radiographs and computed radiography (CT). TKA components’ position and the whole leg axis were assessed on 3D reconstructed CT scans (sagittal, coronal and rotational). Mean values of TKA component position and the whole leg alignment of both groups were compared using a T-test. The tibial component was graded as internally rotated (< 3° of external rotation (ER)), neutral rotation (equal or between 3° and 6° of ER) and and externally rotated (>6° ER). The femoral component was graded as internally rotated (< 3° of internal rotation (IR)), neutral rotation (equal or between -3° IR and 3° of ER) and externally rotated (>3° ER). There was no significant difference in terms of whole leg axis after TKA between both groups (MPA: 0.2° valgus ± 3.4; LPA: 0.0° valgus ± 3.5). Means of tibial component position were 2.7° ER ± 6.1 (MPA) and 7.6° ER ± 5.4 (LPA). Patients of group LPA presented a significantly less internally rotated (LPA: 18.4%; MPA: 48.8%) and more externally rotated (LPA: 52.6%; MPA: 22.8%) tibial component (p<0.001). No significant differences were seen for the femoral component position, tibial valgus/varus and tibial slope. The type of approach significantly influences the tibial TKA component rotation. It appears that a MPA tends to internally rotate the tibial TKA component and a LPA tends to externally rotate the tibial TKA.
24
Hattori, Yosuke. "Reliability of the Posterior Condylar Axis as an Alternative Reference for Femoral Rotation in Japanese Patients with Varus Knee Osteoarthritis Undergoing Total Knee Arthroplasty." Journal of Orthopedics & Bone Disorders 6, no. 2 (2022): 1–9. http://dx.doi.org/10.23880/jobd-16000225.
Abstract:
Background: This study aimed to assess the reliability of the posterior condylar axis (PCA), the most widely used alternative reference for the surgical transepicondylar axis (sTEA), as a reference for appropriate femoral rotational alignment in total knee arthroplasty (TKA) by comparing variances with other alternative reference axes. Methods: A total of 305 knees in 233 Japanese patients who underwent TKA due to varus knee osteoarthritis were assessed in this study. Variances and relationships between alternative references were determined. Angles of alternative reference axes relative to the sTEA in the axial plane were measured using computer software based on computed tomography. Results: The PCA line was 3.0°±1.8° (range, -2.1° to 8.8°) internally rotated relative to the sTEA. No significant differences were observed in the PCA angle relative to the sTEA angle between males and females. The variance with respect to the sTEA was significantly smaller in the order of anatomical transepicondylar axis (aTEA), PCA, and antero-posterior axis (APA). The variance of the APA and that of the femoral anterior tangent line (FAT) did not significantly differ, while the variance of the FAT was significantly smaller than that of the trochlear anterior line (TAL). The proportion of outliers for PCA (>3° away from the average value) was 9.8%. The PCA was weakly correlated with the aTEA, APA, FAT, and TAL. Conclusions: In terms of variance with respect to the sTEA, the PCA was second to aTEA in reliability as an alternative reference axis, and was on average 3.0°±1.8° internally rotated relative to the sTEA. Our findings suggest that the PCA is a reliable and reproducibly identifiable alternative axis for accurately determining femoral rotational alignment in TKA.
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Mahoney, Ormonde M., and Tracy Kinsey. "The Effect of Mechanical Axis Correction on the Incidence of Aeseptic Loosening after TKA." Journal of Arthroplasty 24, no. 2 (February 2009): e65. http://dx.doi.org/10.1016/j.arth.2008.11.079.
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Arnetz, Lisa, Neda Rajamand Ekberg, Kerstin Brismar, and Michael Alvarsson. "Gender difference in adrenal sensitivity to ACTH is abolished in type 2 diabetes." Endocrine Connections 4, no. 2 (June 2015): 92–99. http://dx.doi.org/10.1530/ec-15-0003.
Abstract:
ObjectiveDysfunction of the hypothalamus–pituitary–adrenal (HPA) axis has been implicated in type 2 diabetes (T2D). The aim of this study was to investigate the impact of T2D and gender on the HPA axis.MethodsSynthetic ACTH (1 μg) was administered to 21 subjects with T2D (age 62 (54–70) years, 11 men/ten women, HbA1c 49±2 mmol/mol, treated with diet or oral antidiabetic drugs) and 38 controls (age 58 (41–67) years, 20 men/18 women). Fasting basal B-glucose, serum cortisol, insulin, IGF1 and IGFBP1 concentrations were measured, and sampling for all but IGF1 was repeated 30, 60, and 90 min after ACTH injection. Patients took 0.25 mg dexamethasone at 2200–2300 h and returned the next morning for the measurement of serum cortisol concentration.DesignCross-sectional study.ResultsPatients with T2D had similar fasting serum cortisol, IGF1 and IGFBP1 concentrations; however, serum cortisol concentration after administration of dexamethasone did not differ between the groups. Healthy women exhibited higher peak cortisol levels compared with healthy men (675±26 vs 582±21 nmol/l, P=0.014), while the peak levels were equally high in men and women with T2D, resulting in a higher peak level in men with T2D compared with healthy men (691±42 vs 582±21 nmol/l, P=0.024). Serum cortisol concentration after administration of dexamethasone did not differ between the groups, nor did IGF1 and IGFBP1.Novelty of the findingsSome studies have previously indicated disturbed regulation of the hypothalamus–pituitary–adrenal (HPA) axis in subjects with type 2 diabetes (T2D); however, much remains unknown in this area. To the best of our knowledge, this is the first study to show that the gender difference in the adrenal response to ACTH (with greater reactivity in women) is abolished in T2D. While the clinical implications cannot be determined by this paper, it is known that gender differences exist in the pathogenesis and complications of T2D. Thus, our findings suggest that further research into gender differences in the HPA axis is warranted.ConclusionsGender differences in adrenal response to ACTH were abolished in T2D. Men with T2D had a higher peak cortisol compared with controls. Further studies are needed to elucidate the clinical implications.
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Salzmann, Mikhail, Peter Fennema, Roland Becker, and Hagen Hommel. "Does Postoperative Mechanical Axis Alignment Have an Effect on Clinical Outcome of Primary Total Knee Arthroplasty? A Retrospective Cohort Study." Open Orthopaedics Journal 11, no. 1 (November 29, 2017): 1330–36. http://dx.doi.org/10.2174/1874325001711011330.
Abstract:
Background: There is an ongoing debate whether patients with constitutional varus should be restored to neutral mechanical alignment following total knee arthroplasty (TKA). Objective: The aim of this retrospective cohort study is to determine whether mild unintentional postoperative varus alignment (3°–6°) influences TKA outcome in patients with and without preoperative varus alignment due to medial osteoarthritis of the knee. Methods: We analyzed 172 consecutive TKA cases between April 2011 and May 2014. Patients were divided into four groups based on their preoperative and postoperative hip-knee-ankle angles (HKA): preoperative varus ≤ 3° with postoperative varus position ≤ 3° (Group 1, n = 47); preoperative varus >3° with postoperative varus ≤ 3° (Group 2, n = 104); preoperative varus ≤ 3° with postoperative varus malalignment > 3° (Group 3, n = 3); and preoperative varus > 3° with postoperative varus malalignment > 3° (Group 4, n = 18). Patients were followed up until 2 years postoperatively. Results: Knee Society Score and Western Ontario and McMaster University Osteoarthritis Index scores for all study groups increased following TKA, with no postoperative differences at any time point. Group 4 performed significantly better on the Forgotten Joint Score than Group 2 (p = 0.019). Group 4 performed significantly better on the High Flexion Knee Score than Group 2 (p = 0.004) and Group 1 (p = 0.019). All other between-group differences were not statistically significant. Conclusion: Residual postoperative varus alignment of the lower limb does not appear to adversely affect clinical outcome following TKA for varus-type osteoarthritis.
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Zinoviev, M. P., R. V. Paskov, S. K. Sergeev, and D. V. Rimashevsky. "RESIDUAL DEFORMITY AFTER BILATERAL KNEE ARTHROPLASTY: IMPACT ON SHORT TERM OUTCOMES." Traumatology and Orthopedics of Russia 24, no. 2 (July 6, 2018): 19–28. http://dx.doi.org/10.21823/2311-2905-2018-24-2-19-28.
Abstract:
Purpose— to evaluate the impact of frontal positioning of prosthesis components after bilateral Tka on short term functional outcomes. Material and Methods. The authors performed a retrospective analysis of teleroentgenograms of 466 patients after bilateral Tka with initial varus deformity. Functional and roentgenological outcomes were evaluated at average in 16,4±2,9 months postoperatively. Mean preoperative varus deformity was 10° (from 5 to 25°), initial angle between the anatomical and mechanical femoral axis (FVa) was 6,7±2° (from 3 to 12°). The neutral axis of both lower limbs (Hka = 180±0,5°) was obtained in 99 (21,2%) out of 466 patients. Residual deformity in one of the limbs above 3° with the neutral alignment of the contralateral limb was observed in 44 (9,4%) patients, bilateral residual deformity – in 32 (6,9%) patients. Other 291 patients demonstrated the deviation from mechanical axis in the range from 1 to 3° (±0,5°). all patients were divided into three groups: first group consisted of 10 patients with neutral axis of one limb and varus deformity of the other limb above 3°; second group — 10 patients with bilateral residual varus deformity above 3°; third group — 12 patients with neutral axis of both limbs (Hka = 180°). The angle of residual deformity averaged 3,7° (from 3,2 to 5,1°).Results.No statistically significant differences between the groups were observed for dynamometric parameters and SF-36 scores, as well as for functional kSS scores (p>0,05). However, the authors reported in patients of the first group a stance phase on the side of residual varus deformity longer at 15% (p<0,05) and transfer phase shorter at 17% (p<0,05) as compared to contralateral limb (with neutral alignment, Hka = 180°), which is indicative of load asymmetry and can have a negative impact at a later stage.Conclusion. Symmetrical residual varus deformity of lower limbs in the rage of 3,2–5,1° has no negative impact of short term clinical and functional outcomes of Tka. Muscular function and gait properties in patients with neutral axis of the lower limbs and in patients with symmetrical residual varus deformity after Tka were similar 16,4±2,9 months postoperatively.
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Wang, Zhibing, Xingwang Cheng, Yuan Zhang, Xia Zhang, and Yue Zhou. "Restoration of Constitutional Alignment in TKA with a Novel Osteotomy Technique." Journal of Knee Surgery 33, no. 02 (January 16, 2019): 190–99. http://dx.doi.org/10.1055/s-0038-1677508.
Abstract:
AbstractMany studies have shown that restoration of the preoperative constitutional varus may lead to a normal knee status in total knee arthroplasty (TKA). It is also known that coronal femoral lateral bowing contributes to constitutional varus of the femoral shaft, and bilateral femoral lateral bowing (BFLB) can decelerate medial knee osteoarthritis progression. In this sense, the BFLB should be reserved in TKA. To date, no study has yet reported the technique to reserve BFLB in TKA. Our study showed that the proximal and distal femur had no significant geometric difference between patients with varus knees and BFLB (> 5°) and volunteers with healthy knees and straight femoral shaft. So, the virtual center of femoral head fell on the distal femoral mechanical axis (DMA) after accurate correction of the bowing, indicating that the DMA should be the femoral original constitutional mechanical axis (CA). Subsequently, the distal femoral osteotomy was performed perpendicular to DMA in TKA, and the postoperative angle formed by DMA and tibial mechanical axis (TMA) was measured to assess whether CA was restored successfully. In this study, the gap balance was achieved without medial collateral ligaments release, and the patient's CA was successfully restored (range of DMA–TMA angle 178.2°–179.9°). This study provides a novel technique to restore preoperative CA in patients with varus knees and BFLB. It is found that the distal femur should be cut perpendicular to DMA, so the lower limb alignment and soft tissue strains can be restored to the preoperative state, and the knees would be stable and in a natural status after TKA.
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Han, Dong, Wen-Qi Wei, Ming Ming, Zihao Wang, Ting Wang, and Jian-Jun Zhang. "Epitaxial GaSb films directly grown on on-axis Si(001) with low defect density by MBE." Applied Physics Letters 122, no. 16 (April 17, 2023): 163501. http://dx.doi.org/10.1063/5.0140992.
Abstract:
In recent years, GaSb-on-Si direct heteroepitaxy has been highly desirable to extend the operating wavelength range into mid-infrared and high-mobility applications, such as free-space communications, gas sensing, and hyperspectral imaging. High-quality GaSb films on Si remain challenging due to the high density of defects generated during the growth. For this purpose, epitaxial GaSb films were grown by molecular beam epitaxy on on-axis Si(001). Due to the large lattice mismatch (12.2%) between GaSb and Si, here, we proposed a radical design and growth strategy with the primary objective of achieving the annihilation of antiphase boundaries (APBs) and the reduction of threading dislocation density (TDD). Benefitting from a V-grooved Si hollow structure, we demonstrated the growth of emerging-APB-free GaSb film on Si(001) with low mosaicity. Moreover, by introducing InGaSb/GaSb dislocation filtering layers, the atomically flat surface root mean square roughness is improved to 0.34 (on Si) and 0.14 nm (on GaAs/Si). Moreover, the corresponding TDD can be reduced to 3.5 × 107 and 2 × 107 cm−2, respectively, one order of magnitude lower than the minimum value found in the literature. These reported results are a powerful lever to improve the overall quality of epitaxial Si-based antimonide, which is of high interest for various devices and critical applications, such as laser diodes, photo-detectors, and solar cells.
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Lee, Diana K., Matthew J. Grosso, David P. Trofa, Julian J. Sonnenfeld, H. John Cooper, Roshan P. Shah, and Jeffrey A. Geller. "Incidence of Femoral Component Malrotation Using Posterior Condylar Referencing in Total Knee Arthroplasty." Journal of Knee Surgery 33, no. 10 (May 20, 2019): 971–77. http://dx.doi.org/10.1055/s-0039-1688931.
Abstract:
AbstractProper femoral component rotation in total knee arthroplasty (TKA) is important, given the prognostic impact of a poorly positioned component. The purpose of this observational study was to determine the incidence of femoral component malrotation using posterior condylar axis (PCA) referencing. A total of 100 knees in 92 patients with varus gonarthritis of the knee undergoing primary TKA using a standard medial parapatellar approach were evaluated intraoperatively. After distal femoral resection, the standard femoral sizing guide referencing the posterior condylar axis was used to set femoral component rotation. This was then compared with both the transepicondylar (TEA) and trochlear anteroposterior axes (TRAx). Disparites were recorded and corrected in line with the epicondylar axis. Rotational adjustment for addition of further external rotation was made in 13 (13.0%) cases. In seven cases, the medial pin sites were raised between 1 and 3 mm, and in six cases, the lateral pin site was lowered between 1 and 3 mm (based on risk of notching the femoral cortex). It is critical to not rely exclusively on the PCA to confirm rotational positioning of the femoral component as predicted by posterior condylar referencing guides. Intraoperative adjustment and confirmation using the TEA and TRAx occurred in 13% of primary TKA cases, which might have, otherwise, had a significant effect on the clinical outcome.
32
Hwang, Jun Kyu, Ho Meong Lee, Yang Won No, Gye Young Park, Chong Wung Park, Jae Kyung Park, Seong Hwan Jeong, et al. "Effect of Inhaled Fluticasone Propionate on Hypothalamic-Pituitary-Adrenal Axis in Bronchial Asthma Patient." Tuberculosis and Respiratory Diseases 51, no. 1 (2001): 25. http://dx.doi.org/10.4046/trd.2001.51.1.25.
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McLaughlin, Patricia J., Joseph W. Sassani, David Diaz, and Ian S. Zagon. "Elevated Opioid Growth Factor Alters the Limbus in Type 1 Diabetic Rats." Journal of Diabetes and Clinical Research 5, no. 1 (June 5, 2023): 1–10. http://dx.doi.org/10.33696/diabetes.4.054.
Abstract:
Ocular surface complications occur in more than 50% of individuals diagnosed with diabetes. The financial and health-related burden of diabetes is increasing annually. Several major ocular complications associated with diabetes involve the limbus. The vascular limbus, adjacent to the avascular cornea, is the source of circulating growth factors, elevated glucose, and cytokines for the cornea. The Opioid Growth Factor (OGF) - Opioid OGF Receptor (OGFr) axis is comprised of its effector peptide, OGF, [Met5]-enkephalin and the nuclear-associated receptor, OGFr, and has been demonstrated to be dysfunctional in diabetes with elevated serum and tissue levels of the inhibitory growth factor OGF recorded in corneal tissue. Little is known regarding the impact of OGF-OGFr axis dysregulation in diabetes on the functioning of the limbus constituents in support of corneal homeostasis. Adult male and female Sprague-Dawley rats were rendered hyperglycemic through intraperitoneal injections of streptozotocin (T1D); a subset of T1D rats received topical naltrexone (NTX) applied to the cornea and limbus daily for 8 weeks. At 4 and/or 8 weeks of hyperglycemia, different cohorts of animals were euthanized, eyes removed and processed for assessment of limbal morphology, expression of OGF, OGFr, cytokeratin 15, a marker for limbal cells, and Ki-67, a marker of proliferation. Limbal epithelial morphology (cell diameter, packing density) was altered in T1D male and female rats. OGF and OGFr were overexpressed in the limbus and CK15 expression was decreased, relative to normal control rats of the same sex. Blockade of the OGF- OGFr axis with NTX reversed limbal epithelial cell defects, and reduced OGF limbal tissue levels to those recorded in non-diabetic rats. In summary, OGF-OGFr axis dysregulation was observed in the limbus of T1D rats, contributing to the altered limbal morphology and delayed corneal surface healing observed in diabetic animals.
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Koenen, Paola, Marco M. Schneider, Matthias Fröhlich, Arne Driessen, Bertil Bouillon, and Holger Bäthis. "Reliable Alignment in Total Knee Arthroplasty by the Use of an iPod-Based Navigation System." Advances in Orthopedics 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/2606453.
Abstract:
Axial alignment is one of the main objectives in total knee arthroplasty (TKA). Computer-assisted surgery (CAS) is more accurate regarding limb alignment reconstruction compared to the conventional technique. The aim of this study was to analyse the precision of the innovative navigation system DASH® by Brainlab and to evaluate the reliability of intraoperatively acquired data. A retrospective analysis of 40 patients was performed, who underwent CAS TKA using the iPod-based navigation system DASH. Pre- and postoperative axial alignment were measured on standardized radiographs by two independent observers. These data were compared with the navigation data. Furthermore, interobserver reliability was measured. The duration of surgery was monitored. The mean difference between the preoperative mechanical axis by X-ray and the first intraoperatively measured limb axis by the navigation system was 2.4°. The postoperative X-rays showed a mean difference of 1.3° compared to the final navigation measurement. According to radiographic measurements, 88% of arthroplasties had a postoperative limb axis within ±3°. The mean additional time needed for navigation was 5 minutes. We could prove very good precision for the DASH system, which is comparable to established navigation devices with only negligible expenditure of time compared to conventional TKA.
35
Lu, Z., R. Hiskes, S. A. DiCarolis, R. K. Route, R. S. Feigelson, F. Leplingard, and J. E. Fouquet. "Epitaxial LiNbO3 thin films on sapphire substrates grown by solid source MOCVD." Journal of Materials Research 9, no. 9 (September 1994): 2258–63. http://dx.doi.org/10.1557/jmr.1994.2258.
Abstract:
C-axis LiNbO3 epitaxial films have been grown on c-plane sapphire substrates by solid source metal-organic chemical vapor deposition (MOCVD) using the tetramethylheptanedionate sources, Li(thd) and Nb(thd)4. Stoichiometric LiNbO3 films were deposited from Li(thd)-rich source compositions. Rocking curve FWHM values as low as 0.044°were measured on films grown at 710 °C. Rocking curve peak widths became broader as films were grown at progressively lower substrate temperatures. Single prism coupling experiments revealed clearly visible optical waveguiding, with optical attenuation values as low as 2 dB/cm in the best films.
36
Burssens, Arne, Dries De Roo, Alexej Barg, T. Van den Bossche, Daniel Pfeufer, Charles L. Saltzman, and Jan Victor. "The Hindfoot Alignment in Total Knee Arthroplasty: A Systematic Review." Foot & Ankle Orthopaedics 4, no. 4 (October 1, 2019): 2473011419S0012. http://dx.doi.org/10.1177/2473011419s00124.
Abstract:
Category: Hindfoot Introduction/Purpose: Patients with a hindfoot deformity pose a particular challenge when performing a total knee arthroplasty (TKA). This could be attributed to the lack of insights concerning hindfoot alignment outcome. Our objective was to perform a systematic review of the literature to investigate the influence of TKA on hindfoot alignment and vice-versa. Methods: This systematic review was performed in accordance to PRISMA guidelines; the original protocol is registered on PROSPERO (ID: 106980). The following electronic databases were searched to identify capable studies: Pubmed, EMBASE, Web of Science, Google Scholar, and Cochrane Library. To ensure the quality of the review, a quality assessment was performed according to the MINORS criteria. The mean MINORS score was 9.5 (range 7-12) and concurred with a good quality of the obtained studies. Results: Sixteen identified articles met the review criteria: six prospective cohort studies, nine retrospective studies, and one case-control study. Five articles reporting on clinical outcomes were identified; a pre-operative hindfoot deformity negatively influenced TKP outcome (N=4) or demonstrated no influence (N=1). Thirteen articles reporting on radiographic outcomes were identified. Five studies reported a significant improvement (P < 0.05) of hindfoot alignment after TKA, two studies demonstrated improvement limited to valgus hindfeet, seven studies observed a significant (P < 0.05) correlation between knee and hindfoot alignment, and two studies reported the association between hindfoot OA in patients undergoing TKA. Two studies reporting biomechanical outcomes were identified; these reported a shift of the weighbearing axis after TKA as a result of the remaining hindfoot deformity. Conclusion: TKA can improve the alignment of valgus hindfeet, but improvement was less pronounced in varus hindfeet. Furthermore, a worse clinical outcome is expected after TKA in patients with concomitant ankle OA. A remaining hindfoot deformity shifts the weightbearing axis, which could shorten the survival of the total knee prosthesis.
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Schroeder, Lennart, and Gregory Martin. "In Vivo Tibial Fit and Rotational Analysis of a Customized, Patient-Specific TKA versus Off-the-Shelf TKA." Journal of Knee Surgery 32, no. 06 (May 25, 2018): 499–505. http://dx.doi.org/10.1055/s-0038-1653966.
Abstract:
AbstractIn total knee arthroplasty (TKA), surgeons often face the decision of maximizing tibial component fit and achieving correct rotational alignment at the same time. Customized implants (CIMs) address this difficulty by aiming to replicate the anatomical joint structure, utilizing data from patient-specific knee geometry during the manufacturing. We intraoperatively compared component fit in four tibial zones of a CIM to that of three different off-the-shelf (OTS) TKA designs in 44 knees. Additionally, we assessed the rotational alignment of the tibia using computed tomography (CT)-based computer aided design model analysis. Overall the CIM device showed significantly better component fit than the OTS TKAs. While 18% of OTS designs presented an implant overhang of 3 mm or more, none of the CIM components did (p < 0.05). There was a larger percentage of CIMs seen with optimal fit (≤1 mm implant overhang to ≤1 mm tibial bone undercoverage) than in OTS TKAs. Also, OTS implants showed significantly more component underhang of ≥3 mm than the CIM design (37 vs. 18%). The rotational analysis revealed that 45% of the OTS tibial components showed a rotational deviation of more than 5 degrees and 4% of more than 10 degrees to a tibial rotational axis described by Cobb et al. No deviation was seen for the CIM, as the device is designed along this axis. Using the medial one-third of the tibial tubercle as the rotational landmark, 95% of the OTS trays demonstrated a rotational deviation of more than 5 degrees and 73% of more than 10 degrees compared with 73% of CIM tibial trays with more than 5 degrees and 27% with more than 10 degrees. Based on our findings, we believe that the CIM TKA provides both better rotational alignment and tibial fit without causing overhang of the tibial tray than the three examined OTS implants.
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Marchand, Robert, Anton Khlopas, Nipun Sodhi, Caitlin Condrey, Nicolas Piuzzi, Rickesh Patel, Ronald Delanois, and Michael Mont. "Difficult Cases in Robotic Arm-Assisted Total Knee Arthroplasty: A Case Series." Journal of Knee Surgery 31, no. 01 (November 22, 2017): 027–37. http://dx.doi.org/10.1055/s-0037-1608839.
Abstract:
AbstractSagittal deformity of the knee is commonly corrected to neutral biomechanical axis (±3 degrees) during total knee arthroplasty (TKA), which is a widely accepted goal. Recent advances in surgical technology have made it possible to accurately plan and fulfill these goals. One of these is robotic-assisted TKA, which has been noted to help increase accuracy and precision of restoring a neutral mechanical axis. While there are data confirming the ability of robotic devices to better correct knee alignment than the manual technique, there is a lack of data concerning the use of the robotic devices in more complex cases, such as those in patients with severe varus or valgus deformity, as well as in flexion contractures. Therefore, the purpose of this case study is to present three cases in which the robotic-assisted TKA device was used to correct a severe varus and severe valgus deformities. Based on this case series, it should be noted that the robotic device can also help correct severe varus/valgus deformities and flexion contractures.
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Selim, Amr, Nawfal Al-Hadithy, Nader Diab, Abdulla Ahmed, Khaled Abdel Kader, Mohamed Hegazy, Hazem Abdelazeem, and Ahmed Barakat. "PROPOSAL OF A MODIFIED TIP APEX DISTANCE FOR PREDICTION OF LAG SCREW CUT-OUT IN TROCHANTERIC HIP FRACTURES." Orthopaedic Proceedings 106-B, SUPP_6 (May 2, 2024): 12. http://dx.doi.org/10.1302/1358-992x.2024.6.012.
Abstract:
Lag screw cut-out is a serious complication of dynamic hip screw fixation in trochanteric hip fractures. Lag screw position is recognised as a crucial factor influencing the occurrence of lag screw cut-out. We propose a modification of the Tip Apex Distance (TAD) and hypothesize that it could enhance the reliability of predicting lag screw cut-out in these injuries.A retrospective study of hip fracture cases was conducted from January 2018 to July 2022. A total of 109 patients were eligible for the final analysis. The modified TAD was measured in millimetres, based on the sum of the traditional TAD in the lateral view and the net value of two distances in the anteroposterior (AP) view. The first distance is from the lag screw tip to the opposite point on the femoral head along the lag screw axis, while the second distance is from that point to the femoral head apex. The first distance is a positive value, whereas the second distance is positive if the lag screw is superior and negative if it is inferior. Receiver operating characteristic (ROC) curve analysis was used to assess the reliability of various parameters for evaluating the lag screw position within the femoral head.Factors such as reduction quality, fracture pattern according to the AO/OTA classification, TAD, Calcar-Referenced TAD, Axis Blade Angle, Parker’s ratio in the AP view, Cleveland Zone 1, and modified TAD were statistically associated with lag screw cut-out. Among the tested parameters, the novel parameter exhibited 90.1% sensitivity and 90.9% specificity for predicting lag screw cut-out at a cut-off value of 25 mm, with a p-value < 0.001.The modified TAD demonstrated the highest reliability in predicting lag screw cut-out. A value of 25 mm may potentially reduce the risk of lag screw cut-out in trochanteric hip fractures.
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Clatworthy, Mark. "Outcome & Survival Analysis of Conventional Measured Resection, Neutral Alignment Attune TKA vs CAS Anatomic Tibia, Balanced Femur, Constitutional Alignment Attune TKA." Orthopaedic Journal of Sports Medicine 5, no. 5_suppl5 (May 1, 2017): 2325967117S0015. http://dx.doi.org/10.1177/2325967117s00156.
Abstract:
Objectives: Arthroplasty knee surgeons have traditionally performed a measured resection technique with a neutral mechanical axis. We have recently developed a new total knee arthroplasty technique whereby the tibia is cut anatomically and the femoral component position is determined using a balanced approach utilizing a computer assisted ligament tension device with aim of restoring constitutional alignment. This study compares the Oxford scores and survival of these two techniques for Attune TKA’s. Method: The New Zealand Joint Registry has requested Oxford Knee Scores at six months on all Attune Total Knee Replacements performed. 1088 scores have been returned. 716 have been performed using a conventional measured resection technique aiming for a neutral mechanical axis. 362 have been performed using the CAS anatomic tibia, balanced femur (ATBF) technique aiming for constitutional alignment. Oxford scores are compared alone and with a multivariate analysis including age, sex, surgeon level, fixed vs mobile, public vs private, operative time and cruciate retaining vs cruciate substituting Results: Mean Oxford Conventional TKA univariate Oxford Score is 38.1 Mean Oxford CAS ATBF TKA univariate Oxford Score is 40.7 p=<0.001 Mean Oxford Conventional TKA multivariate Oxford Score is 36.9 Mean Oxford CAS ATBF TKA multivariate Oxford Score is 39.1 p=<0.001 The CAS ATBF had 10% less poor and fair scores and 15% more excellent scores Non infection conventional TKA has 0.71 failures per 100 component years Non infection CAS ATBF TKA has 0.25 failures per 100 component years. Conclusion: The CAS assisted anatomic tibia balanced femur TKA has a significantly higher Oxford score with a three times lower non infection failure rate at three years
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Joseph, Léopold, Cécile Batailler, Sébastien Lustig, and Elvire Servien. "Accuracy of Accelerometer-Based Navigation System Perseus for the Tibial Cut in Total Knee Arthroplasty: No Superiority Compared to Mechanical Instrumentation in Current Practice." Applied Sciences 13, no. 5 (February 25, 2023): 2952. http://dx.doi.org/10.3390/app13052952.
Abstract:
Knee alignment after total knee arthroplasty (TKA) is essential for implant survival. Several studies on accelerometer-based navigation systems have given controversial results, with or without improvement in knee alignment. The aim was to evaluate the accuracy of an accelerometer-based navigation system for tibial resection during total knee arthroplasty. Twenty TKAs performed with an accelerometer-based navigation system were included in this prospective–comparative study. They were matched (on age, body mass index, and preoperative mechanical axis of the lower limb) in a 2:1 ratio with TKA performed with a conventional technique. The objective of this study was to determine the accuracy of the Perseus System for making the tibial cut on TKA. The primary endpoint was the tibial mechanical angle (TMA) measured on radiographic images at two months postoperatively. Secondary endpoints were the tibial slope and the mechanical axis of the lower limb (HKA angle, Hip-Knee-Ankle). The mean TMA in the accelerometer group was 87.6 ± 2.1° versus 89.1 ± 1.6° in the control group (p < 0.01). The tibial slope in the accelerometer group was 90.0 ± 1.9° versus 89.9 ± 1.3° in the control group (not significant). The mean HKA was 177.7 ± 1.8° in the accelerometer group and 177.5 ± 2.2° in the control group (not significant). This accelerometer-based navigation system during TKA did not improve the accuracy of the tibial cut compared to the conventional technique, but it restored the tibial slope.
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Schiffner, Erik, Michael Wild, Bertram Regenbrecht, Alberto Schek, Mohssen Hakimi, Simon Thelen, Pascal Jungbluth, and Johannes Schneppendahl. "Neutral or Natural? Functional Impact of the Coronal Alignment in Total Knee Arthroplasty." Journal of Knee Surgery 32, no. 08 (September 7, 2018): 820–24. http://dx.doi.org/10.1055/s-0038-1669788.
Abstract:
AbstractTotal knee arthroplasty (TKA) is a very successful procedure. The alignment in TKA has been identified as being of importance to prevent early implant failure and patient dissatisfaction. Our hypothesis was that patients with a preoperative varus deformation remaining in a slight varus alignment as their natural alignment after TKA will have superior clinical results compared with patients who are restored in neutral alignment. A total of 115 patients were corrected from varus to neutral (varus–neutral) and in 33 patients a preoperative varus alignment was kept in varus (varus). Standardized preoperative and postoperative full-length hip–knee–ankle radiographs under full weight-bearing conditions were performed in all patients. The patients' knees were categorized preoperatively and postoperatively based on the angle between mechanical femoral axis and mechanical tibial axis. Knees with alignment between ± 3 degrees were categorized as neutrally aligned, whereas alignment within ≤ –3 degrees was categorized as varus. The Knee Injury Osteoarthritis Outcome Score (KOOS) and Oxford Knee Score were determined retrospectively. The varus group scored significantly better in total KOOS (p < 0.05) compared with the varus–neutral group. Also, a trend was visible in the Oxford Knee Score but this was not significant (p > 0.05). This trend was even more evident in varus knees which were slightly undercorrected. The results support the assumption that leaving a residual varus alignment after TKA leads to better functional outcomes in TKA for patients with preoperative varus osteoarthritis.
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Lychagin, Alexey, Mikhail Elizarov, Andrey Gritsyuk, Yaroslav Rukin, Pavel Elizarov, Anastasiya Rokityanskaya, Vadim Cherepanov, Andrey Drogin, Andrey Gritsyuk Jr, and Ivan Vyazankin. "Robot-assisted Knee Arthroplasty: Randomized Clinical Trial." Open Access Macedonian Journal of Medical Sciences 10, B (March 2, 2022): 559–64. http://dx.doi.org/10.3889/oamjms.2022.8685.
Abstract:
BACKGROUND: Osteoarthritis of the knee joint leads to a decrease in the volume of movements, a violation of the sliding of articular surfaces, and a change in the axis of the limb under load, which affects the biomechanics of walking. AIM: This study aims to compare the results of robot-assisted total knee arthroplasty (TKA) and manual techniques, their influence on the biomechanical and podometric parameters of the patient’s walk. METHODS: A prospective randomized study of 68 patients was carried out in the period from 2020 to 2021. Our follow-up period was 1 year. All patients were performed arthroplasty of one knee joint. The main Group “A” included 33 patients TKA with the use of an active robotic setting “TSolution-One” (“THINK Surgical, Inc.” [Fremont, California, USA]); the comparison Group “B” consisted of 35 patients with manual technic of TKA. We studied pain syndrome on the visual analog scale, functional state on the Oxford Knee Score (OKS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC), the volume of ROM movements, and the deviation of the mechanical axis by teleroentgenography of the lower limb. Objective analysis of limb function was performed on the «Alter-G» and the «C-mill». RESULTS: Post-operative pain syndrome on the 1st day after surgery in Group A is stronger by 7.9%, but by the 5th day after surgery in Group A, the pain syndrome is lower by 14.3%. ROM in Group A is better by 16% by 3 months after surgery, after 1 year by 10%. The positioning accuracy of the implant in Group A is 30% better. There are no statistically significant differences in the OKS and WOMAC scales between the groups. The results of restoring normal step in Group A are 13.5% better than in Group B. CONCLUSIONS: Robot-assisted TKA gives more accurate alignment of the mechanical axis, which improves the biomechanics of walking.
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Selim, Amr, Nawfal Al-Hadithy, Nader M. Diab, Abdulla Mohamed Ahmed, Khaled Fawzy Abdel Kader, Mohamed Hegazy, Hazem Abdel Azeem, and Ahmed Samir Barakat. "Proposal of a modified tip apex distance for prediction of lag screw cut-out in trochanteric hip fractures." SICOT-J 9 (2023): 28. http://dx.doi.org/10.1051/sicotj/2023026.
Abstract:
Introduction: Lag screw cut-out is a serious complication of dynamic hip screw fixation of trochanteric hip fractures. The lag screw position has been acknowledged as one of the important factors affecting the lag screw cut-out. We propose a modification of the Tip Apex Distance (TAD) and hypothesise that it could improve the reliability of predicting lag screws cut-out in these injuries. Materials and Methods: A retrospective study was conducted for hip fracture entries in the period from Jan 2018 to July 2022. A hundred and nine patients were suitable for the final analysis. The modified TAD was measured in millimetres based on the sum of the traditional TAD in the lateral view and the net value of two distances in the AP view, the first distance is from the tip of the lag screw to the opposite point on the femoral head along the axis of the lag screw while the second distance is from that point to the femoral head apex. The first distance is a positive value, whereas the second distance is positive if the lag screw is superior and negative if inferior. A receiver operating characteristic curve was used to evaluate the reliability of the different parameters assessing the lag screw position within the femoral head. Results: Reduction quality, fracture pattern as per the AO/OTA classification, TAD, Calcar Referenced TAD, Axis Blade Angle, Parker’s ration in the AP view, Cleveland Zone 1, and modified TAD were statistically associated with lag screw cut-out. Among the tested parameters, the modified TAD had 90.1% sensitivity and 90.9% specificity for lag screw cut-out at a cut-off value of 25 mm with a P-value < 0.001. Conclusion: The modified TAD had the highest reliability in the prediction of lag screw cut-out. A value ≤ 25 mm could potentially protect against lag screw cut-out in trochanteric hip fractures.
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Yamamoto, Yuji, S. Harada, Kazuaki Seki, Atsushi Horio, Takato Mitsuhashi, and Toru Ujihara. "Effect of Surface Polarity on the Conversion of Threading Dislocations in Solution Growth." Materials Science Forum 740-742 (January 2013): 15–18. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.15.
Abstract:
We investigated the dislocation behaviors during the solution growth on Si-face and C-face off-axis 4H-SiC seed crystals by using synchrotron X-ray topography. On Si-face, almost all threading screw dislocations (TSDs) and threading edge dislocations (TEDs) are converted into Frank-type defects and basal plane dislocations (BPDs), respectively. On the other hand, on C-face, TSDs were hardly converted. Some of TEDs were converted to BPDs and BPD-TED reconversion was often occurred. Therefore, to reduce density of threading dislocations in the grown crystal, it is better to use Si-face off-axis seed crystal.
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Deckey, David G., Christian S. Rosenow, Jens T. Verhey, Joseph C. Brinkman, Cory K. Mayfield, Henry D. Clarke, and Joshua S. Bingham. "Robotic-assisted total knee arthroplasty improves accuracy and precision compared to conventional techniques." Bone & Joint Journal 103-B, no. 6 Supple A (June 1, 2021): 74–80. http://dx.doi.org/10.1302/0301-620x.103b6.bjj-2020-2003.r1.
Abstract:
Aims Robotic-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to incorporate soft-tissue laxity data into the plan prior to bone resection should reduce variability between the planned polyethylene thickness and the final implanted polyethylene. The purpose of this study was to compare accuracy to plan for component positioning and precision, as demonstrated by deviation from plan for polyethylene insert thickness in measured-resection RA-TKA versus M-TKA. Methods A total of 220 consecutive primary TKAs between May 2016 and November 2018, performed by a single surgeon, were reviewed. Planned coronal plane component alignment and overall limb alignment were all 0° to the mechanical axis; tibial posterior slope was 2°; and polyethylene thickness was 9 mm. For RA-TKA, individual component position was adjusted to assist gap-balancing but planned coronal plane alignment for the femoral and tibial components and overall limb alignment remained 0 ± 3°; planned tibial posterior slope was 1.5°. Mean deviations from plan for each parameter were compared between groups for positioning and size and outliers were assessed. Results In all, 103 M-TKAs and 96 RA-TKAs were included. In RA-TKA versus M-TKA, respectively: mean femoral positioning (0.9° (SD 1.2°) vs 1.7° (SD 1.1°)), mean tibial positioning (0.3° (SD 0.9°) vs 1.3° (SD 1.0°)), mean posterior tibial slope (-0.3° (SD 1.3°) vs 1.7° (SD 1.1°)), and mean mechanical axis limb alignment (1.0° (SD 1.7°) vs 2.7° (SD 1.9°)) all deviated significantly less from the plan (all p < 0.001); significantly fewer knees required a distal femoral recut (10 (10%) vs 22 (22%), p = 0.033); and deviation from planned polyethylene thickness was significantly less (1.4 mm (SD 1.6) vs 2.7 mm (SD 2.2), p < 0.001). Conclusion RA-TKA is significantly more accurate and precise in planning both component positioning and final polyethylene insert thickness. Future studies should investigate whether this increased accuracy and precision has an impact on clinical outcomes. The greater accuracy and reproducibility of RA-TKA may be important as precise new goals for component positioning are developed and can be further individualized to the patient. Cite this article: Bone Joint J 2021;103-B(6 Supple A):74–80.
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Sumner, Bonnie, John McCamley, David J. Jacofsky, and Marc C. Jacofsky. "Comparison of Knee Kinematics and Kinetics during Stair Descent in Single- and Multi-Radius Total Knee Arthroplasty." Journal of Knee Surgery 33, no. 10 (August 7, 2019): 1020–28. http://dx.doi.org/10.1055/s-0039-1692652.
Abstract:
AbstractDespite continuing advances, nearly 20% of patients remain dissatisfied with their total knee arthroplasty (TKA) outcomes. Single-radius (SR) and multiradius (MR) TKA designs are two commonly used knee replacement designs based on competing theories of the flexion/extension axis of the knee. Our aim was to characterize stair descent kinematics and kinetics in SR and MR TKA subjects. We hypothesized that 1 year after TKA, patients who received SR TKA will more closely replicate the knee kinematics and kinetics of healthy age-matched controls during stair descent, than will MR TKA patients. SR subjects (n = 12), MR subjects (n = 12), and age-matched controls (n = 12) descended four stairs affixed to force platforms, while 10 infrared cameras tracked markers attached to the body to collect kinematic and kinetic data. Both patient groups had improvements in stair descent kinetics and kinematics at the 1-year postoperative time point. However, SR TKA subjects were indistinguishable statistically from age-matched controls, while MR TKA subjects retained many differences from controls. Similar to previous reports for level walking, the SR knee design performs closer to healthy controls than MR knees during stair descent. This study demonstrates that patients who receive SR TKA have more improved kinematic normalization during stair descent postoperatively than those who received an MR TKA.
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Nam, Dong-Woo, Kang-Been Lee, Hyun-Jo Pyo, Min-Jae Jeong, Seo-Hee Yang, Won-Ho Kim, and Hyung-Kwan Jang. "A Study on Core Skew Considering Manufacturability of Double-Layer Spoke-Type PMSM." Energies 14, no. 3 (January 26, 2021): 610. http://dx.doi.org/10.3390/en14030610.
Abstract:
The spoke-type permanent magnet synchronous motor (PMSM), which is a general ferrite magnetic flux-concentrated motor, has a low portion of reluctance torque at the total torque magnitude. Therefore, as a way to increase the reluctance torque, there is a double-layer spoke-type PMSM that can maximize the difference in inductance between the d-axis and the q-axis. However, in the double-layer spoke-type PMSM, cogging torque, torque ripple, and total harmonic distortion (THD) increase with reluctance torque, which is the main cause of vibration and noise. In this paper, a method is proposed that provides the same effect as skew without dividing stages of the permanent magnet by dividing the core of the rotor into two types so that it is easy to manufacture according to the number of stages, unlike extant skew methods. Based on the method, the reduction in cogging torque and THD was verified by finite element analysis (FEA).
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Savinov, Alexei, Ilian Radichev, Lilia Maneva-Radicheva, Christina Amatya, Camille Parker, Jacob Ellefson, Clive Wasserfall, Mark Atkinson, and Paul Burn. "Nardilysin-dependent proteolysis of cell-associated VTCN1: A novel pathway and biomarker of type 1 diabetes development. (P4117)." Journal of Immunology 190, no. 1_Supplement (May 1, 2013): 133.12. http://dx.doi.org/10.4049/jimmunol.190.supp.133.12.
Abstract:
Abstract Hyper-active T cell responses towards pancreatic β-cells highlight type 1 diabetes (T1D). V-set domain-containing T cell activation inhibitor-1 (VTCN1) protein, a B7-like negative co-stimulatory molecule, acts inhibiting T cell activation. Here, we unveil the general defect within VTCN1 pathway, common for diabetes-prone mice and subset of T1D patients. Specifically, gradual loss of VTCN1 from antigen-presenting cells and pancreatic islets progressed alongside natural T1D development and compromised VTCN1 functionality, potentiating hyper-proliferation of diabetogenic T cells. Mechanistically, loss of membrane-tethered VTCN1 relied on proteolytic cleavage mediated by the metalloproteinase nardilysin (NRD1). Cleaved soluble VTCN1 fragment (sVTCN1) was detected at high levels in peripheral blood of 47% of pediatric T1D patients, compared to 5% of healthy subjects. Blood sVTCN1 levels correlated with the disease aggressiveness and duration, highlighting potential use of sVTCN1 as the new T1D biomarker. Discovered VTCN1-NRD1 axis identifies NRD1 as a novel target for future anti-diabetic therapeutics.
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Assi, Chahine, Jad Mansour, Camille Samaha, Pascal Kouyoumdjian, and Kaissar Yammine. "Angular limit for coronal joint deformity correction using intramedullary guidance in total knee arthroplasty. A pilot study." SICOT-J 6 (2020): 22. http://dx.doi.org/10.1051/sicotj/2020019.
Abstract:
Introduction: Post-operative misalignment of the lower limb mechanical axis following total knee arthroplasty (TKA) is thought to be associated with clinical failure. In a balanced knee, a neutral global mechanical axis following the use of intra-medullary (IM) guidance does not necessarily imply a horizontal TKA joint line. Using femoral and tibial axes separately would be more accurate in evaluating TKA alignment. Thus, the aim of the study is to define a pre-operative mechanical tibial and/or femoral angle threshold value for post-operative optimal alignment correction using IM guides. Methods: This single-center prospective continuous pilot study included 50 patients treated with a TKA for primitive osteoarthritis. Femoral and tibial cuts were performed using intramedullary (IM) guide. Three angles were calculated and analyzed pre and post-operatively on standing antero-posterior views using long-leg radiographs: femorotibial angle (FTA), mechanical femoral angle (MFA), and mechanical tibial angle (MTA). Statistical analysis was performed for the whole sample and for the three following FTA subgroups; normo-axial, varus and valgus. Results: The pre-operative MTA is the only parameter for which a threshold value was observed; when pre-operative MTA exceeded the value of 94°, an optimal correction might not be obtained post-operatively. Discussion: Our results suggest that the bony correction obtained via IM guiding depends exclusively on the primary deformation of the tibia. In cases of a varus of more than 94°, the IM guide was found to yield sub-optimal corrections. Thus, other solutions need to be investigated.