An EMG-Assisted Muscle-Force Driven Finite Element Analysis Pipeline to Investigate Joint- and Tissue-Level Mechanical Responses in Functional Activities : Towards a Rapid Assessment Toolbox

Publisher Copyright: © 1964-2012 IEEE.Joint tissue mechanics (e.g., stress and strain) are believed to have a major involvement in the onset and progression of musculoskeletal disorders, e.g., knee osteoarthritis (KOA). Accordingly, considerable efforts have been made to develop musculoskeletal finite element (MS-FE) models to estimate highly detailed tissue mechanics that predict cartilage degeneration. However, creating such models is time-consuming and requires advanced expertise. This limits these complex, yet promising, MS-FE models to research applications with few participants and makes the models impractical for clinical assessments. Also, these previously developed MS-FE models have not been used to assess activities other than gait. This study introduces and verifies a semi-automated rapid state-of-the-art MS-FE modeling and simulation toolbox incorporating an electromyography- (EMG) assisted MS model and a muscle-force driven FE model of the knee with fibril-reinforced poro(visco)elastic cartilages and menisci. To showcase the usability of the pipeline, we estimated joint- and tissue-level knee mechanics in 15 KOA individuals performing different daily activities. The pipeline was verified by comparing the estimated muscle activations and joint mechanics to existing experimental data. To determine the importance of the EMG-assisted MS analysis approach, results were compared to those from the same FE models but driven by static-optimization-based MS models. The EMG-assisted MS-FE pipeline bore a closer resemblance to experiments compared to the static-optimization-based MS-FE pipeline. Importantly, the developed pipeline showed great potential as a rapid MS-FE analysis toolbox to investigate multiscale knee mechanics during different activities of individuals with KOA.Peer reviewe

Design and evaluation of a new type of knee orthosis to align the mediolateral angle of the knee joint with osteoarthritis: open-access

Abstract. Osteoarthritis (OA) is a disease which influences the performance of the knee joint. Moreover, the force and moments applied on the joint increase in contrast to normal subjects. Various types of knee orthoses have been designed to solve the mentioned problems. However, there are other problems in terms of distal migration during walking and the alignment of the orthosis which cannot be changed following the use of brace. Therefore, the main aim of the research was to design an orthosis to solve the aforementioned problems. A new type of knee orthosis was designed with a modular structure. Ten patients with knee OA participated in this research project. The force applied on the foot, moment transmitted through the knee joint and spatiotemporal gait parameters were measured by use of a motion analysis system.The results of the research showed that the loads applied on the knee joint decreased following the use of new-designed knee orthosis. Moreover, it allows alignment of the components when the subject used the brace.The new design of the knee brace can be used as an effective treatment to decrease the loads applied on the knee joint and to improve the alignment whilst walking. It is recommended that other parameters such as pain severity and the quality of life should be measured in further studies

Comparing the effectiveness of MTK-RGO orthosis in helping spinal cord injured people to stand with the functions of other available orthoses

Introduction: Most people with spinal cord injury (SCI) use wheelchair to move around in living areas. In order to improve their health status, however, these people do need to stand and walk with orthosis. Although lots of orthoses have been designed for paraplegic subjects, they still experience various problems using them. A new type of reciprocal gait orthosis was designed in the Bioengineering Unit of Strathclyde University to solve the problems of the available orthoses. Since there has been no research so far on the effectiveness of this new orthosis for paraplegic subjects, the present study was aimed to evaluate the new orthosis during standing of paraplegic subjects. Materials and Methods: Five paraplegic subjects whose lesion levels ranged from T4 to T12 participated in this clinical trial study. A control group including normal subjects matched with spinal cord injured individuals was also considered in this study. The stability of subjects was evaluated during quiet standing and when they were standing with either the new orthosis or the knee ankle foot orthosis (KAFO) performing hand tasks. Differences between the performances of paraplegic subjects while standing with each of these orthoses and between the functioning of normal and paraplegic subjects were compared via paired and two-sample t test respectively. Results: The stability of paraplegic subjects in standing with the new orthosis was better than that with the KAFO orthosis (P < 0.05). Moreover, the force applied on the crutch differed between the two types of orthoses. The functional performance of paraplegic subjects was better with the new orthosis and also as compared to that of normal subjects. Conclusion: The ability of the new orthosis to change the alignment of the components, the higher structural stiffness of the orthosis and better fitting was the main reasons for better operation of the new orthosis comparing to the KAFO. Keywords: Standing, Spinal cord injury, Functional hand task, Orthosi

An evaluation of the efficiency of endpoint control on the correction of scoliotic curve with brace : A case study

The use of braces is one of the conservative treatment approaches recommended for scoliotic subjects. However, the main question posted here is how to improve the efficiency of braces to control the scoliotic curve or to decrease its progression. The aim of this study was to evaluate the efficiency of various boundary conditions (endpoint control) of brace on the correction of scoliotic curves. Method: CT scan images of a scoliotic subject, with double lumbar and thoracic curves, was used to produce 3d model of spine. The correction of spine (decrease in scoliotic curves) was determined following the use of transverse (lateral-to-medial direction) and the combination of transverse and vertical (upward-directed force, traction) forces on spine in Abaqus software. The effects of pelvic fixation (pelvic basket of a brace) on both sides (basket enclosed pelvic in both sides), on one side (basket enclosed the pelvis in only one side), and fixation of lumbar (part of the brace encircled the lumbar area) were evaluated in this study. Results: The results of this study showed that the effect of vertical forces (traction) was more than that of transverse force. Moreover, the combination of vertical and transverse forces on lumbar and thoracic curves correction was more than that of other conditions (only transverse forces). The best correction was achieved with lumbar fixation and with combination of vertical and transverse forces. Conclusions: The use the combination of vertical and transverse forces may be suggested to correct the scoliotic curve. Moreover, the efficiency of lumbar fixation in frontal plane seems to be more than pelvic fixation to correct scoliotic curve. The outputs of this study can be used to design new braces for scoliotic subjects

Application of Computer Simulation for Productivity Improvement of Welding Unit in a Heater Manufacturing Industry: A Case Study Based on Arena

Firm’s efficiency and competitiveness are two important challenges in today’s global market that have motivated many manufacturing firms to plan novel manufacturing management strategies. Nowadays, simulation models have been used to assess different aspects of manufacturing systems. This paper introduces a welding unit of a manufacturing line of heater production as a case study and the basic application of the ARENA software. The main goal of this paper is increasing the productivity of the production line by using computer simulation. To achieve this goal, three various scenarios are compared and suggested to obtain the better improvement in productivity

Alterations in the Functional Knee Alignment Are Not an Effective Strategy to Modify the Mediolateral Distribution of Knee Forces During Closed Kinetic Chain Exercises

Pain felt while performing rehabilitation exercises could be a reason for the low adherence of knee osteoarthritis patients to physical rehabilitation. Reducing compressive forces on the most affected knee regions may help to mitigate the pain. Knee frontal plane positioning with respect to pelvis and foot (functional knee alignment) has been shown to modify the mediolateral distribution of the tibiofemoral joint contact force in walking. Hence, different functional knee alignments could be potentially used to modify joint loading during rehabilitation exercises. The aim was to understand whether utilizing different alignments is an effective strategy to unload specific knee areas while performing rehabilitation exercises. Eight healthy volunteers performed 5 exercises with neutral, medial, and lateral knee alignment. A musculoskeletal model was modified for improved prediction of tibiofemoral contact forces and used to evaluate knee joint kinematics, moments, and contact forces. Functional knee alignment had only a small and inconsistent effect on the mediolateral distribution joint contact force. Moreover, the magnitude of tibiofemoral and patellofemoral contact forces, knee moments, and measured muscle activities was not significantly affected by the alignment. Our results suggest that altering the functional knee alignment is not an effective strategy to unload specific knee regions in physical rehabilitation.Peer reviewe