Subject-specific assessment of loading variation in the knee ligaments with a view to preoperative planning

2014 ◽  
Author(s):  
Andra Chincisan ◽  
Hon Fai Choi ◽  
Lazhari Assassi ◽  
Sean Lynch ◽  
Christof Hurschler ◽  
...  
Keyword(s):  
Preoperative Planning ◽  
Knee Ligaments ◽  
Subject Specific ◽  
Specific Assessment

scholarly journals Biomechanics of aging and osteoarthritic human knee ligaments

2021 ◽  
Author(s):  
Abby E Peters ◽  
Brendan Geraghty ◽  
Karl T Bates ◽  
Riaz Akhtar ◽  
Rosti Readioff ◽  
...  
Keyword(s):  
Knee Joint ◽  
Material Properties ◽  
Small Sample ◽  
Failure Stress ◽  
Knee Joints ◽  
Knee Ligaments ◽  
Human Knee ◽  
Subject Specific ◽  
Linear Force ◽  
And Cartilage

Background. Ligaments work to stabilize the human knee joint and prevent excessive movement. Whilst ligaments are known to decline in structure and function with aging, there has been no systematic effort to study changes in gross mechanical properties in the four major human knee ligaments due to osteoarthritis (OA). This study aims to collate material properties for the anterior (ACL) and posterior (PCL) cruciate ligaments, medial (MCL) and lateral (LCL) collateral ligaments. Our cadaveric samples come from a diverse demographic from which the effects of aging and OA on bone and cartilage material properties have already been quantified. Therefore, by combining our previous bone and cartilage data with the new ligament data from this study we are facilitating subject-specific whole-joint modelling studies. Methods. The demographics of the collected cadaveric knee joints were diverse with age range between 31 to 88 years old, and OA International Cartilage Repair Society grade 0 to 4. Twelve cadaveric human knee joints were dissected, and bone-ligament-bone specimens were extracted for mechanical loading to failure. Ligament material properties were determined from the load-extension curves, namely: linear and ultimate (failure) stress and strain, secant modulus, tangent modulus, and stiffness. Results. There were significant negative correlations between age and ACL linear force (p=0.01), stress (p=0.03) and extension (p=0.05), ACL failure force (p=0.02), stress (p=0.02) and extension (p=0.02), PCL secant (p=0.02) and tangent (p=0.02) modulus, and LCL stiffness (p=0.05). Significant negative correlations were also found between OA grades and ACL linear force (p=0.05), stress (p=0.02), extension (p=0.01) and strain (p=0.03), and LCL failure stress (p=0.05). However, changes in age or OA grade did not show a statistically significant correlation with the MCL tensile parameters. Trends showed that almost all the tensile parameters of the ACL and PCLs decreased with increasing age and progression of OA. Due to small sample size, the combined effect of age and presence of OA could not be statistically derived. Conclusions. This research is the first to correlate changes in tensile properties of the four major human knee ligaments to aging and OA. The current ligament study when combined with our previous findings on bone and cartilage for the same twelve knee cadavers, supports conceptualization of OA as a whole-joint disease that impairs the integrity of many peri-articular tissues within the knee. The subject-specific data pool consisting of the material properties of the four major knee ligaments, subchondral and trabecular bones and articular cartilage will aid reconstruction and graft replacements and advance knee joint finite element models, whilst knowledge of aged or diseased mechanics may direct future therapeutic interventions.

scholarly journals Development and evaluation of a new procedure for subject-specific tensioning of finite element knee ligaments

2021 ◽  
pp. 1-12
Author(s):  
Bhrigu K. Lahkar ◽  
Pierre-Yves Rohan ◽  
Helene Pillet ◽  
Patricia Thoreux ◽  
Wafa Skalli
Keyword(s):  
Finite Element ◽  
Knee Ligaments ◽  
Subject Specific

scholarly journals Subject-Specific Analysis of Joint Contact Mechanics: Application to the Study of Osteoarthritis and Surgical Planning

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Corinne R. Henak ◽  
Andrew E. Anderson ◽  
Jeffrey A. Weiss
Keyword(s):  
Contact Mechanics ◽  
Computational Models ◽  
Preoperative Planning ◽  
Patient Specific ◽  
Joint Mechanics ◽  
Imaging Data ◽  
Computational Biomechanics ◽  
Subject Specific ◽  
Joint Contact ◽  
Technical Considerations

Advances in computational mechanics, constitutive modeling, and techniques for subject-specific modeling have opened the door to patient-specific simulation of the relationships between joint mechanics and osteoarthritis (OA), as well as patient-specific preoperative planning. This article reviews the application of computational biomechanics to the simulation of joint contact mechanics as relevant to the study of OA. This review begins with background regarding OA and the mechanical causes of OA in the context of simulations of joint mechanics. The broad range of technical considerations in creating validated subject-specific whole joint models is discussed. The types of computational models available for the study of joint mechanics are reviewed. The types of constitutive models that are available for articular cartilage are reviewed, with special attention to choosing an appropriate constitutive model for the application at hand. Issues related to model generation are discussed, including acquisition of model geometry from volumetric image data and specific considerations for acquisition of computed tomography and magnetic resonance imaging data. Approaches to model validation are reviewed. The areas of parametric analysis, factorial design, and probabilistic analysis are reviewed in the context of simulations of joint contact mechanics. Following the review of technical considerations, the article details insights that have been obtained from computational models of joint mechanics for normal joints; patient populations; the study of specific aspects of joint mechanics relevant to OA, such as congruency and instability; and preoperative planning. Finally, future directions for research and application are summarized.

A Survey of Speech-Language Pathologists' Approaches to Assessing Social Communication Disorders in Children

2020 ◽  
pp. 1-17
Author(s):  
Kristen Izaryk ◽  
Robin Edge ◽  
Dawn Lechwar
Keyword(s):  
Best Practices ◽  
Communication Disorders ◽  
Assessment Tools ◽  
Self Report ◽  
Speech Language Pathologists ◽  
Teacher Report ◽  
Formal Assessment ◽  
Language Sampling ◽  
Specific Assessment ◽  
Social Communication Disorders

Purpose The purpose of this article is to explore and describe the approaches and specific assessment tools that speech-language pathologists are currently using to assess social communication disorders (SCDs) in children, in relation to current best practices. Method Ninety-four speech-language pathologists completed an online survey asking them to identify which of the following approaches they use to assess children with SCD: parent/teacher report, naturalistic observation, formal assessment, language sample analysis, interviews, semistructured tasks, and peer/self-report. Participants were also asked to identify specific assessment tools they use within each approach. Results Participants most commonly assess SCDs by combining interviews, naturalistic observation, language sampling, parent/teacher report, and formal assessment. Semistructured tasks and peer/self-report tools were less frequently utilized. Several established parent/teacher report and formal assessment tools were commonly identified for assessing SCDs. Most participants use an informal approach for interviews, language sampling, and naturalistic observations in their SCD assessment process. Conclusions Generally, participants follow best practices for assessing SCDs by combining several different approaches. Some considerations for future assessment are identified, including the use of established protocols in the place of informal approaches in order to make the assessment of SCDs more systematic. Future directions for research are discussed.

Deciding the Adequacy of a Set of Tests for an Specific Assessment Situation. Decision-making Strategies

1996 ◽  
Vol 12 (1) ◽  
pp. 14-22
Author(s):  
R. Esteve ◽  
A. Godoy
Keyword(s):  
Decision Making ◽  
Time Pressure ◽  
Response Mode ◽  
Information Load ◽  
Variable Pattern ◽  
Mode Effects ◽  
Moderator Effects ◽  
Specific Assessment ◽  
Information Board ◽  
Decision Importance

The aim of the present paper was to test the effects of response mode (choice vs. judgment) on decision-making strategies when subjects were faced with the task of deciding the adequacy of a set of tests for a specific assessment situation. Compared with choice, judgment was predicted to lead to more information sought, more time spent on the task, a less variable pattern of search, and a greater amount of interdimensional search. Three variables hypothesized as potential moderators of the response mode effects are also studied: time pressure, information load and decision importance. Using an information board, 300 subjects made decisions (choices and judgments) on tests for a concrete assessment situation, under high or low time pressure, high or low information load, and high or low decision importance. Response mode produced strong effects on all measures of decision behavior except for pattern of search. Moderator effects occurred for time pressure and information load.

Implementation status of antimicrobial stewardship programs in hospitals: A quantitative analysis study in Ho Chi Minh city, Vietnam

MedPharmRes ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 34-39
Author(s):  
Thi-Hai-Yen Nguyen ◽  
Truong Van Dat ◽  
Phuong-Thao Huynh ◽  
Chi-Thuong Tang ◽  
Vinh-Chau Van Nguyen ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Health Workers ◽  
Cross Sectional Study ◽  
Ho Chi Minh City ◽  
Multi Drug Resistance ◽  
Cross Sectional ◽  
Clostridioides Difficile ◽  
The Status ◽  
Specific Assessment ◽  
Implementation Status

Vietnam has one of the highest multi drug resistance in Asia. Although, despite many efforts to implement the Antimicrobial Stewardship Programs (the ASP) since 2016, studies that on the implementation policy are very lacking of this program are limited. For that reason, we conducted this cross-sectional study to analyze the viewpoint of health workers (HWs) on the implementation of the ASP at some hospitals in Ho Chi Minh City (HCMC). An assessment of 234 HWs showed that the implementation of the ASP in HCMC hospitals was above average (62.7/100.0). A barrier to the implementation consisted of the deficiency in finances, guidelines for diagnosis, and specific interventions for some common infections, such as distributing current antibiogram and monitoring rate of Clostridioides difficile infections. These were the widely recognized problems in initially implementing the ASP. Although most HWs are aware of the importance of implementing the ASP (79.1%), the specific assessment has not been recorded clearly due to the numerous neutral responses. Despite the support of the leadership, the implementation still faces many difficulties and limitations, especially in 3rd and 4th class hospitals. Besides, there was a lack of wide dissemination of information on the ASP at each unit. To generalize the status of the ASP implementation, researchers should conduct qualitative and quantitative studies with a larger scale.

A STUDY OF THE LOAD SHARING OF KNEE LIGAMENTS

2019 ◽  
Author(s):  
Juliana Emery Silva ◽  
Brenno Tavares Duarte ◽  
Rodrigo Ribeiro Pinho Rodarte ◽  
Paulo Pedro Kenedi
Keyword(s):  
Load Sharing ◽  
Knee Ligaments
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