Insights into the Function on the Knee Meniscus

The knee menisci are understood to have a variety of roles including load transmission and stability of the knee joint. To date, there has been no exploration of the role of radial tears of the menisci in inducing kinematic changes in knee joint movement. Furthermore, the function of proteoglycans in maintaining mechanical meniscus has not been explored.Load was applied to cadaveric knees in the intact state and following both a 50% and 100% radial tear of the medial (5 knees) or lateral (6 knees) meniscus. A coordinate system was developed to allow analysis of joint kinematics. Concurrently,confined compression techniques were used to apply 10% strain to meniscal samples from cadavers (30 samples) and patients suffering osteoarthritis (36 samples) in solutions of varying ionic concentration. 7 samples from an Actifit meniscal scaffold were also tested in deionised water. Resultant relaxation curves were fit using finite element modelling techniques. Human tissue samples were assayed for proteoglycan content.Radial tears of the meniscus did not induce significant changes in knee joint kinematics.Finite element modelling demonstrated that the electrostatic effect of proteoglycans contributed to ~40% of the stiffness of the meniscus. No significant difference in proteoglycan content was observed between solutions. The Actifit meniscal scaffold is stiffer than native meniscal tissue but displays similar permeability.Although radial tears do not alter the kinematics of the knee joint, there is evidence they result in abnormal loading of articular cartilage and it is hence important that they are repaired where possible. Proteoglycans play a critical role in maintaining stiffness of the meniscus - current repair strategies such as meniscal scaffolds do not attempt to recreate this function and hence may not prevent cartilage degradation. The stiffness of the Actifit meniscal scaffold may help protect a nascent meniscal repair but may also contribute to abnormal joint loading; its similar permeability will help mimic meniscal function.The knee menisci are understood to have a variety of roles including load transmission and stability of the knee joint. To date, there has been no exploration of the role of radial tears of the menisci in inducing kinematic changes in knee joint movement. Furthermore, the function of proteoglycans in maintaining mechanical meniscus has not been explored.Load was applied to cadaveric knees in the intact state and following both a 50% and 100% radial tear of the medial (5 knees) or lateral (6 knees) meniscus. A coordinate system was developed to allow analysis of joint kinematics. Concurrently,confined compression techniques were used to apply 10% strain to meniscal samples from cadavers (30 samples) and patients suffering osteoarthritis (36 samples) in solutions of varying ionic concentration. 7 samples from an Actifit meniscal scaffold were also tested in deionised water. Resultant relaxation curves were fit using finite element modelling techniques. Human tissue samples were assayed for proteoglycan content.Radial tears of the meniscus did not induce significant changes in knee joint kinematics.Finite element modelling demonstrated that the electrostatic effect of proteoglycans contributed to ~40% of the stiffness of the meniscus. No significant difference in proteoglycan content was observed between solutions. The Actifit meniscal scaffold is stiffer than native meniscal tissue but displays similar permeability.Although radial tears do not alter the kinematics of the knee joint, there is evidence they result in abnormal loading of articular cartilage and it is hence important that they are repaired where possible. Proteoglycans play a critical role in maintaining stiffness of the meniscus - current repair strategies such as meniscal scaffolds do not attempt to recreate this function and hence may not prevent cartilage degradation. The stiffness of the Actifit meniscal scaffold may help protect a nascent meniscal repair but may also contribute to abnormal joint loading; its similar permeability will help mimic meniscal function

The ionic contribution of proteoglycans to mechanical stiffness of the meniscus

Load transmission is an important function of the meniscus. In articular cartilage, proteoglycans help maintain hydration via negatively charged moieties. We aimed to investigate the influence of electrostatic effects on stiffness of meniscal tissue. Circular discs from bovine menisci of 8 mm diameter and 5 mm thickness were placed within a confined compression chamber. The apparatus was bathed in distilled water, 0.14 M PBS or 3 M PBS before being subjected to 5% ramp compressive strain and held for 300s. FEBio software was used to fit resultant relaxation curves to a non-linear poroviscoelastic model with strain dependent Holmes-Mow permeability. Analysis was conducted using one-way ANOVA with Tukey post-hoc analysis. 10 samples were tested in each solution. Significant differences (p < 0.05) were observed between the values for Young's modulus, zero strain dependent permeability and the viscoelastic coefficient for samples tested in 3 M PBS as compared to deionised water/0.14 M PBS. No significant differences were observed in the strain dependent/stiffening coefficients or the relaxation time. Approximately 79% of the stiffness of the meniscus appears attributable to ionic effects. Ionic effects play a significant role in the mechanical stiffness of the meniscus. It is important to include the influence of ionic effects when developing mathematical models of this tissue

Proteoglycans exert a significant effect on human meniscal stiffness through ionic effects

Background: Proteoglycans contribute to mechanical stiffness in articular cartilage, aiding load transmission. The magnitude of the ionic contribution of proteoglycans to the stiffness of human meniscal tissue has not been established. Methods: Thirty-six discs of human meniscal tissue were placed within a custom confined compression chamber and bathed in three solutions of increasing ionic concentration. Following a 0.3 N preload, at equilibrium, a 10% ramp compressive strain was followed by a 7200 s hold phase. A nonlinear poroviscoelastic model with strain dependent permeability was fitted to resultant stress relaxation curves. All samples were assayed for proteoglycan content. Model parameters were analysed using multivariate analysis of variance whilst proteoglycan content was compared using a univariate analysis of variance model. Findings: A significant difference (p < .05) was observed in the value of the Young's modulus (E) between samples tested in deionised water compared to those tested in solutions of high ionic concentration. No differences were observed in the zero-strain permeability or the exponential strain dependent stiffening coefficient. Proteoglycan content was not found to differ with solution; but was found to be significantly increased in the middle meniscal region of both menisci. Interpretation: Proteoglycans make a significant ionic contribution to mechanical stiffness of the meniscus, increasing it by 58% in the physiological condition. It is therefore critical that meniscal regeneration strategies attempt to recreate the function of proteoglycans to ensure normal meniscal function

Computer and robotic assisted orthopaedic knee arthroplasty surgery who drives innovations?

Computer assisted and Robotic technology in orthopaedic surgery is still not commonplace compared to un-assisted, conventional orthopaedic surgery. It may be considered somewhat surprising therefore, at a time of incredible technological progress that the computer still struggles nowadays to make its way in all orthopaedic theatres of the world.[1, 2] In June 2016, Dalton et al.[3] reviewed all patents and papers published between 1980 and 2014 related to knee surgery and sorted them into four clusters of innovations, which could be used to link patents and publications: Unicompartmental Knee Arthroplasty (UKA), Patient Specific Instrumentation (PSI), Navigation and Robotics. Three of these are part of the CAOS technology “family”. Since 2004, the ratio between patents and publications increased from approximately 1: 10 in 2004 to almost 1: 3 in 2014 showing industry-driven innovation on technology introduction in the field of knee arthroplasty

Computer and robotic assisted orthopaedic knee arthroplasty surgery : did CAOS technologies have an impact on the mainstream principles and concepts in the orthopaedic knee forum? A case study on alignment and balancing for TKA

Computer technology is ubiquitous and relied upon in virtually all professional activities. Confounding this is orthopaedic surgery where less than 5% of surgeons are using computer-assisted technologies routinely. However, the impact of Computer Assisted Orthopaedic Surgery (CAOS) may go beyond adoption in theatre. We searched pubmed for all knee arthroplasty papers concerning knee alignment and balancing between 1976 and 2016, dividing the results into those related to CAOS and those not. Results were grouped by technology. Between 2001 and 2008, the number of publications regarding knee navigation multiplied by 20 mainly focused on this topic of alignment and balancing, with alignment papers paralleled between navigation and non-navigation until 2010. After 2010, when navigation publications decline the number of articles related to the knee alignment and balancing without navigation increased granting the value of assessing accurately intraoperative kinematic data to improve Total Knee Arthroplasty (TKA) outcomes. From 2008, patient specific instrumentation (PSI) publications greatly increase, but navigation decreases, while robotic publications rise from 2014. CAOS surgery publications on the search topic of alignment and balancing increased greatly between 2001 and 2018 which may suggest the impact of CAOS technology on this important knee orthopaedic forum segment

Exogenous Gamma-Aminobutyric Acid Application Induced Modulations in the Performance of Aromatic Rice Under Lead Toxicity

Gamma-aminobutyric acid (GABA) is a non-protein amino acid and has a multi-functional role in abiotic stress tolerance. A pot experiment was conducted to assess the role of exogenous gamma-aminobutyric acid (GABA) application to modulate the growth, yield, and related physio-biochemical mechanisms in two aromatic rice cultivars, that is, Guixiangzhan (GXZ) and Nongxiang 18 (NX-18), under Pb toxic and normal conditions. The experimental treatments were comprised of Ck: without Pb and GABA (control), GABA: 1 mM GABA is applied under normal conditions (without Pb), Pb + GABA: 1 mM GABA is applied under Pb toxicity (800 mg kg−1 of soil), and Pb= only Pb (800 mg kg−1 of soil) is applied (no GABA). The required concentrations of GABA were applied as a foliar spray. Results revealed that Pb stress induced oxidative damage in terms of enhanced malondialdehyde (MDA), electrolyte leakage (EL), and H2O2 contents, while exogenous GABA application improved leaf chlorophyll, proline, protein and GABA contents, photosynthesis and gas exchange, and antioxidant defense under Pb toxicity in both rice cultivars. Moreover, glutamine synthetase (GS) and nitrate reductase (NR) activities were variably affected due to GABA application under Pb stress. The yield and related traits, that is, productive tillers/pot, grains/panicle, filled grain %, 1,000-grain weight, and grain yield were 13.64 and 10.29, 0.37% and 2.26%, 3.89 and 19.06%, 7.35 and 12.84%, and 17.92 and 40.56 lower under Pb treatment than Pb + GABA for GXZ and NX-18, respectively. Furthermore, exogenous GABA application in rice reduced Pb contents in shoot, leaves, panicle, and grains compared with Pb-exposed plants without GABA. Overall, GXZ performed better than NX-18 under Pb toxic conditions

The Prevalence of Anemia Among Internally Displaced Families in Lahej Governorate, Yemen

الخلفية: يُعد فقر الدم مشكلة صحية عامة واسعة الانتشار، لا سيما بين النازحين حيث تكون فرص الحصول على التغذية والرعاية الصحية محدودة. تُمثل الأسر النازحة داخليًا في محافظة لحج فئة ضعيفة يُحتمل أن تكون معرضة لخطر كبير.   الأهداف: تحديد مدى انتشار فقر الدم وشدته بين الأطفال والنساء النازحين داخليًا في محافظة لحج، وتقييم المعايير الدموية المرتبطة به.   المواد والطرق: أُجريت دراسة مقطعية من يوليو إلى أكتوبر 2024 على 279 فردًا (149 طفلًا و130 امرأة) من أسر نازحة داخليًا. جُمعت عينات الدم وحُللت لتركيز الهيموغلوبين ومؤشرات الدم الأخرى باستخدام تقنيات مخبرية قياسية.   النتائج: وُجد أن 22.8% من الأطفال يعانون من فقر الدم، مع انتشار أعلى قليلاً لدى الإناث (55.9%) منه لدى الذكور (44.1%). أما بين النساء، فقد وُجد فقر الدم لدى 26.2% من المشاركات، وخاصةً من تقل أعمارهن عن 45 عامًا. أظهر الأفراد المصابون بفقر الدم مستويات أقل بكثير من الهيموغلوبين، وهرمون الحمل، وقيمة كريات الدم الحمراء، ومحتوى كريات الدم الحمراء، ومحتوى كريات الدم الحمراء، ومحتوى كريات الدم الحمراء، مقارنةً بنظرائهم غير المصابين بفقر الدم.   من بين الأطفال المصابين بفقر الدم، عانى 58.8% من فقر الدم الخفيف، و35.3% من فقر الدم المتوسط، و5.9% من فقر الدم الشديد؛ وأظهرت النساء اتجاهات شدة مماثلة.   الخلاصة: لا يزال فقر الدم يُشكل مصدر قلق متوسط ​​على الصحة العامة بين الأسر النازحة داخليًا في محافظة لحج، ويؤثر بشكل خاص على النساء في سن الإنجاب والأطفال. يُوصى بالتدخلات التغذوية والصحية لمعالجة هذه المشكلة.   ما تضيفه الدراسة:   توفر هذه الدراسة أول بيانات حول انتشار فقر الدم بين النازحين داخليًا في محافظة لحج، حيث تُحدد نقص الحديد كمسبب رئيسي. تُفيد النتائج بشكل مباشر التدخلات الإنسانية في مناطق النزاع.   تشمل القيود أخذ العينات غير العشوائي ونقص المؤشرات البيوكيميائية (مثل الفيريتين) لتأكيد نقص الحديد. على الرغم من ذلك، تُوفر النتائج بيانات أساسية مهمة للتدخلات الإنسانية.Background: Anemia is a widespread public health issue, especially in displaced populations where nutrition and healthcare access are limited. Internally displaced families in Lahej Governorate represent a vulnerable group potentially at high risk. Objective: To determine the prevalence and severity of anemia among internally displaced children and women in Lahij Governorate and to assess associated hematological parameters. Method:  A crosssectional study was conducted from July to October 2024 on 279 individuals (149 children and 130 women) from internally displaced families. Blood samples were collected and analyzed for hemoglobin concentration and other hematological indices using standard laboratory techniques. Results: Among children, 22.8% were found to be anemic, with a slightly higher prevalence in females (55.9%) than males (44.1%). Among women, anemia was present in 26.2% of the participants, predominantly in those under 45 years old. Anemic individuals showed significantly lower levels of Hb, HCT, MCV, MCH, and MCHC compared to non-anemic counterparts Among anemic children, 58.8% had mild, 35.3% moderate, and 5.9% severe anemia; women showed similar severity trends." Conclusion: Anemia remains a moderate public health concern among internally displaced families in Lahij Governorate, particularly affecting women of reproductive age and children. Nutritional and health interventions are recommended to address this issue

Traffic Control via Connected and Automated Vehicles (CAVs): An Open-Road Field Experiment with 100 CAVs

The CIRCLES project aims to reduce instabilities in traffic flow, which are naturally occurring phenomena due to human driving behavior. Also called "phantom jams"or "stop-and-go waves,"these instabilities are a significant source of wasted energy. Toward this goal, the CIRCLES project designed a control system, referred to as the MegaController by the CIRCLES team, that could be deployed in real traffic. Our field experiment, the MegaVanderTest (MVT), leveraged a heterogeneous fleet of 100 longitudinally controlled vehicles as Lagrangian traffic actuators, each of which ran a controller with the architecture described in this article. The MegaController is a hierarchical control architecture that consists of two main layers. The upper layer is called the Speed Planner and is a centralized optimal control algorithm. It assigns speed targets to the vehicles, conveyed through the LTE cellular network. The lower layer is a control layer, running on each vehicle. It performs local actuation by overriding the stock adaptive cruise controller, using the stock onboard sensors. The Speed Planner ingests live data feeds provided by third parties as well as data from our own control vehicles and uses both to perform the speed assignment. The architecture of the Speed Planner allows for the modular use of standard control techniques, such as optimal control, model predictive control (MPC), kernel methods, and others. The architecture of the local controller allows for the flexible implementation of local controllers. Corresponding techniques include deep reinforcement learning (RL), MPC, and explicit controllers. Depending on the vehicle architecture, all onboard sensing data can be accessed by the local controllers or only some. Likewise, control inputs vary across different automakers, with inputs ranging from torque or acceleration requests for some cars to electronic selection of adaptive cruise control (ACC) setpoints in others. The proposed architecture technically allows for the combination of all possible settings proposed previously, that is Speed Planner algorithms × local Vehicle Controller algorithms} × {full or partial sensing} × {torque or speed control}. Most configurations were tested throughout the ramp up to the MegaVandertest (MVT)

Traffic Control via Connected and Automated Vehicles: An Open-Road Field Experiment with 100 CAVs

The CIRCLES project aims to reduce instabilities in traffic flow, which are naturally occurring phenomena due to human driving behavior. These "phantom jams" or "stop-and-go waves,"are a significant source of wasted energy. Toward this goal, the CIRCLES project designed a control system referred to as the MegaController by the CIRCLES team, that could be deployed in real traffic. Our field experiment leveraged a heterogeneous fleet of 100 longitudinally-controlled vehicles as Lagrangian traffic actuators, each of which ran a controller with the architecture described in this paper. The MegaController is a hierarchical control architecture, which consists of two main layers. The upper layer is called Speed Planner, and is a centralized optimal control algorithm. It assigns speed targets to the vehicles, conveyed through the LTE cellular network. The lower layer is a control layer, running on each vehicle. It performs local actuation by overriding the stock adaptive cruise controller, using the stock on-board sensors. The Speed Planner ingests live data feeds provided by third parties, as well as data from our own control vehicles, and uses both to perform the speed assignment. The architecture of the speed planner allows for modular use of standard control techniques, such as optimal control, model predictive control, kernel methods and others, including Deep RL, model predictive control and explicit controllers. Depending on the vehicle architecture, all onboard sensing data can be accessed by the local controllers, or only some. Control inputs vary across different automakers, with inputs ranging from torque or acceleration requests for some cars, and electronic selection of ACC set points in others. The proposed architecture allows for the combination of all possible settings proposed above. Most configurations were tested throughout the ramp up to the MegaVandertest

Needs of Young African Neurosurgeons and Residents: A Cross-Sectional Study.

Introduction: Africa has many untreated neurosurgical cases due to limited access to safe, affordable, and timely care. In this study, we surveyed young African neurosurgeons and trainees to identify challenges to training and practice. Methods: African trainees and residents were surveyed online by the Young Neurosurgeons Forum from April 25th to November 30th, 2018. The survey link was distributed via social media platforms and through professional society mailing lists. Univariate and bivariate data analyses were run and a P-value < 0.05 was considered to be statistically significant. Results: 112 respondents from 20 countries participated in this study. 98 (87.5%) were male, 63 (56.3%) were from sub-Saharan Africa, and 52 (46.4%) were residents. 39 (34.8%) had regular journal club sessions at their hospital, 100 (89.3%) did not have access to cadaver dissection labs, and 62 (55.4%) had never attended a WFNS-endorsed conference. 67.0% of respondents reported limited research opportunities and 58.9% reported limited education opportunities. Lack of mentorship (P = 0.023, Phi = 0.26), lack of access to journals (P = 0.002, Phi = 0.332), and limited access to conferences (P = 0.019, Phi = 0.369) were associated with the country income category. Conclusion: This survey identified barriers to education, research, and practice among African trainees and young neurosurgeons. The findings of this study should inform future initiatives aimed at reducing the barriers faced by this group