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Medical Engineering & Physics

Carla G Barberio, Tahseen Chaudhry, Dominic M Power, Simon Tan, Bernard M Lawless, Daniel M Espino, Joanne C Wilton
Cubital tunnel syndrome is the most prevalent neuropathy of the ulnar nerve and its aetiology is controversial. Potential replacement materials should display similar viscoelastic properties. The purpose of this study was to assess the feasibility and merit of quantifying the frequency-dependent viscoelastic properties of proximal and distal sections of the human ulnar nerve. Four ulnar nerves (n = 4) were dissected from the elbows of human cadavers and sectioned at the level of the cubital tunnel into proximal and distal sections...
December 13, 2018: Medical Engineering & Physics
Hamed Ziaeipoor, Saulo Martelli, Marcus Pandy, Mark Taylor
Multivariate Linear Regression-based (MLR) surrogate models were explored to reduce the computational cost of predicting femoral strains during normal activity in comparison with finite element analysis. The musculoskeletal model of one individual, the finite-element model of the right femur, and experimental force and motion data for normal walking, fast walking, stair ascent, stair descent, and rising from a chair were obtained from a previous study. Equivalent Von Mises strain was calculated for 1000 frames uniformly distributed across activities...
December 11, 2018: Medical Engineering & Physics
Clay J Kincaid, Austin C Vaterlaus, Nathan R Stanford, Steven K Charles
Although tremor is one of the most common movement disorders, it is evaluated using relatively coarse clinical scales. We propose to measure tremor in clinical settings using the Leap Motion Controller (LMC), which is a markerless motion capture sensor that has a low cost, zero set-up time, and dynamic accuracy of 1.2 mm. However, the frequency response of the LMC has not been characterized, so its ability to track oscillations such as tremor is unknown. To characterize the frequency response of the LMC, we measured the position of a mannequin hand simultaneously with the LMC and a high-resolution encoder while the mannequin hand oscillated at various combinations of frequency (1-15 Hz) and amplitudes (0...
November 28, 2018: Medical Engineering & Physics
Sangbaek Park, Seungju Lee, Jeongro Yoon, Soo-Won Chae
Contact pressures in the articular cartilage during gait affect injuries and the degenerative arthritis of knee and ankle joints. However, only contact forces at the knee and ankle joints during gait can be estimated by using a rigid body dynamic model. The contact pressure distribution can be obtained quantitatively for a static posture by using finite element (FE) analysis in most cases. The purpose of this study is to develop a new method to obtain the contact pressure distribution at the knee and ankle joints during gait by integrating FE analysis with rigid body dynamic analysis...
November 24, 2018: Medical Engineering & Physics
Cléber G Corrêa, Fátima L S Nunes, Edith Ranzini, Ricardo Nakamura, Romero Tori
Computer-based simulation for medical procedures training has been gaining relevance, as well the use of haptic devices for developing fine motor skills in such simulations. The purpose of this paper is to present a review of the state-of-the-art in virtual needle insertion training simulation based on haptic interaction. A systematic review method was applied to gather documentation that enables a rigorous audit of the process stages and results. We established a classification system based on certain characteristics of the studies analyzed, including: main procedures and target body regions in medical applications; ways to generate haptic feedback; devices; types of environment; and user validation...
November 20, 2018: Medical Engineering & Physics
Caroline A Grant, Melissa Johnston, Clayton J Adam, J Paige Little
Externally visible deformities are cosmetic features of great concern for Adolescent Idiopathic Scoliosis (AIS) patients. Current assessment techniques for AIS do not fully encompass the external deformity. A non-invasive method capable of capturing superficial anatomy, such as 3D scanning, would enable better qualitative and quantitative evaluation of cosmesis. This study aimed to quantify the accuracy of commonly available scanners, in assessing posterior asymmetry in AIS. The technique of 3D surface deviation analysis was proposed as a suitable method for comparing the models created by each scanner...
November 19, 2018: Medical Engineering & Physics
Yongtao Lu, Di Zuo, Junyan Li, Yiqian He
Finite element (FE) analysis can be used to predict bone mechanical environments that can be used for many important applications, such as the understanding of bone mechano-regulation mechanisms. However, when defining the FE models, uncertainty in bone material properties may lead to marked variations in the predicted mechanical environment. The aim of this study is to investigate the influence of uncertainty in bone material property on the mechanical environment of bone. A heterogeneous FE model of a mouse tibia was created from micro computed tomography images...
November 12, 2018: Medical Engineering & Physics
Hadi El Daou, K C Geoffrey Ng, Richard Van Arkel, Jonathan R T Jeffers, Ferdinando Rodriguez Y Baena
The use of robotic systems combined with force sensing is emerging as the gold standard for in vitro biomechanical joint testing, due to the advantage of controlling all six degrees of freedom independently of one another. This paper describes a novel robotic platform and the experimental protocol used for hip joint testing. An experimental protocol implemented optical tracking and registration techniques in order to define the position of the hip joint centre of rotation (COR) in the coordinate system of the robot's end effector...
November 9, 2018: Medical Engineering & Physics
Ming Xu, James Yang, Isador Lieberman, Ram Haddas
This paper examines the stress distribution in the posterior fusion fixation, spinal range of motion (ROM), and the screw-bone interaction force obtained from various fixation methods of short-segment spine surgical alignment (SA) under five loading conditions (axial compression, flexion, extension, lateral bending, and axial rotation) provided by a FE spine model. The implant-instrumented FE spine model was validated against the experimental data in the literature. Among different fixation methods, fusing more spinal segments might help distribute the spinal load on the pedicle-screw to reduce the stress, screw force, and instability of the spine (range of motion)...
October 18, 2018: Medical Engineering & Physics
Jasna Leder Horina, Bert van Rietbergen, Tanja Jurčević Lulić
Many hypotheses have been formulated to explain orthodontic tooth movement. However, none of them can satisfactorily explain how small static orthodontic forces can induce bone remodelling. Our hypothesis assumes that small orthodontic forces do not lead to bone remodelling response directly, but rather indirectly by offsetting the tooth, leading to changes in bone loading during chewing that far exceed the changes caused by the orthodontic force alone. We developed a finite element model of a tooth with the periodontal ligament and the surrounding bone, and calculated the changes in strain energy density caused by the chewing force alone, the orthodontic force alone, and the combined action of the chewing and orthodontic forces...
December 2018: Medical Engineering & Physics
Hadi El Daou, James D Calder, Joanna M Stephen
Ankle sprains are the most common sports injury. Gaining a better understanding of ankle mechanics will help improve current treatments, enabling a better quality of life for patients following surgery. In this paper, the development of a robotic system for ankle joint testing is presented. It is composed of an industrial robot, a universal force/torque sensor and bespoke holders allowing high repositioning of specimens. A specimen preparation protocol that uses optical tracking to register the ankle specimens is used...
December 2018: Medical Engineering & Physics
Rafael Caldas, Diego Rátiva, Fernando Buarque de Lima Neto
Gait analysis is relevant for the functional diagnostic of several musculoskeletal disorders. Walking patterns can be analyzed using techniques such as video processing and inertial measurement units (IMU). In this work, a Self-Organizing Maps (SOM) algorithm is applied to reduce the complexity of kinematic features obtained by IMU sensors of a sample of 40 individuals. Our system provides a simpler data representation (2-D graphic) than conventional methods, which often applies statistical analysis. We have tested the proposed method to analyze typical and simulated limping gait pattern under well-controlled conditions...
December 2018: Medical Engineering & Physics
Samuel H L Smith, Anthony M J Bull
Body segment parameters such as segment mass, centre of mass and moment of inertia, serve as important inputs for musculoskeletal modelling. These parameters are normally derived from regression tables; however, can be poorly representative of the study population with variations of up to 40% recorded between different tables. More recent methods, such as 3D scanning, present a rapid and accurate way to produce subject-specific body segment parameters for use in musculoskeletal models. An infra-red 3D scanner was used to produce full-body scans of 95 males and females...
December 2018: Medical Engineering & Physics
Zoran Domitran, Danko Brezak, Tomislav Staroveski, Miho Klaic, Tomislav Bruketa
The aim of this study was to perform a finite element and experimental comparative analysis of the mechanical characteristics of surgical drill bits used in bone and joint surgery applications with and without an irrigation channel. Internally cooled drills are very efficient in maintaining the drilling temperature below the critical level. However, a cooling channel could potentially have a negative influence on the drill structure, particularly in the flutes zone. A commercially available type of surgical drill bit without irrigation channel and a modified variant with the built-in channel were simultaneously loaded with torque, axial and bending forces with magnitudes similar to and higher than those utilized in clinical practice...
December 2018: Medical Engineering & Physics
Jung-Joon Cha, Jinhwan Kim, Joho Yun, Yangkyu Park, Jong-Hyun Lee
Endothelial cells have many important roles in the cardiovascular system, such as controlling vasomotor actions and hemostasis. In the event of endothelial cell dysfunction, the risk of cardiovascular disease increases. Therefore, the objective of this study was to investigate the early detection and diagnosis of endothelial cell dysfunction. Injury and restoration in vascular endothelial cells exposed to ischemic stress may affect changes in the electrical impedance. We measured the status of the endothelial cell layer by using microelectrochemical impedance spectroscopy...
December 2018: Medical Engineering & Physics
Tomas A Correa, Bidyut Pal, Richard J van Arkel, Felice Vanacore, Andrew A Amis
BACKGROUND: Revision total knee arthroplasty (RTKA) has poorer results than primary total knee arthroplasty (TKA), and the prostheses are invasive and cause strain-shielding of the bones near the knee. This paper describes an RTKA system with extracortical fixation. It was hypothesised that this would reduce strain-shielding compared with intramedullary fixation. METHODS: Twelve replica tibiae were prepared for full-field optical surface strain analysis. They were either left intact, implanted with RTKA components with cemented intramedullary fixation stems, or implanted with a novel design with a tibial tray subframe supported by two extracortical fixation plates and screw fixation...
December 2018: Medical Engineering & Physics
Jie Yao, Bin Yang, Yuxing Wang, Yubo Fan
Patellofemoral (PF) pain is a common knee disease. Patella tracking has a significant correlation with PF pain, therefore it could be used as an index for diagnosis and treatment evaluation. Previous research has proposed a method for measuring in vivo patella tracking by means of an interpolation algorithm. The present study aimed to quantify the effect of the interpolation parameters on the accuracy of the patella tracking with a motion capture experiment. The precise patella tracking of 5 knee specimens was collected and compared with the interpolated tracking...
December 2018: Medical Engineering & Physics
Richard Ballas, Nicolas Peyrot, Paul Allard, Teddy Caderby, Pascal Edouard, Georges Dalleau
Shoulder performance and sensorimotor control assessments help to identify shoulder instabilities and document the rehabilitation progress. Testing seated subjects in a position of hand prehension requires less controlled adjustments to maintain body balance in a clinically relevant situation. The objective of this work was to determine the test-retest repeatability of a novel shoulder stability test in seated subjects with the ipsi-lateral hand in prehension during four arm loading conditions. Able-bodied subjects were seated on a rigid chair fixed to a force plate...
December 2018: Medical Engineering & Physics
M Giorgi, E Dall'Ara
It is well known that bone has an enormous adaptive capacity to mechanical loadings, and to this extent, several in vivo studies on mouse tibia use established cyclic compressive loading protocols to investigate the effects of mechanical stimuli. In these experiments, the applied axial load is well controlled but the positioning of the hind-limb between the loading endcaps may dramatically affect the strain distribution induced on the tibia. In this study, the full field strain distribution induced by a typical in vivo setup on mouse tibiae was investigated through a combination of in situ compressive testing, µCT scanning and a global digital volume correlation (DVC) approach...
December 2018: Medical Engineering & Physics
Florian Schellenberg, William R Taylor, Adam Trepczynski, Renate List, Ines Kutzner, Pascal Schütz, Georg N Duda, Silvio Lorenzetti
Standard musculoskeletal simulation tools now offer widespread access to internal loading conditions for use in improving rehabilitation concepts or training programmes. However, despite broad reliance on their outcome, the accuracy of such loading estimations, specifically in deep knee flexion, remains generally unknown. The aim of this study was to evaluate the error of tibio-femoral joint contact force (JCF) calculations using musculoskeletal simulation compared to in vivo measured JCFs in subjects with instrumented total knee endoprostheses during squat exercises...
November 2018: Medical Engineering & Physics
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