G J Verkerke’s research while affiliated with University of Twente and other places

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Publications (265)


Effects of individually optimized rocker midsoles and self-adjusting insoles on the margins of stability in individuals with diabetic peripheral neuropathy
  • Article

September 2024

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2 Reads

Gait & Posture

Athra Malki

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María Baltasar Badaya

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[...]

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Juha Hijmans



Toward a disruptive, minimally invasive small finger joint implant concept: Cellular and molecular interactions with materials in vivo
  • Article
  • Full-text available

May 2024

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42 Reads

Acta Biomaterialia

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(a) Infrared marker clusters mounted on rigid plates were utilized to capture the 3-dimensional movements of lower limb segments, including pelvis, thighs, shanks, and feet. (b) The Motive software provided a view used to determine the temporal spatial local coordinate system on each limb. (c) The CT images of the left foot of the subject, whose gait measurements were taken, were depicted for reference. (d) The schematic representation shows the reaction forces (GRFs) and moments (GRMs) applied on the center of gravity of the ground (CoG) and the six major muscles (lateral gastrocnemius, medial gastrocnemius, soleus, tibialis posterior, peroneus longus, tibialis anterior), which were modelled as axial connector elements in the foot FE model. The FE model comprised cartilage layers at each joint, one encapsulated soft tissue, and 30 rigid bony structures interconnected through ligaments and plantar fascia. The bones included tibia, fibula, talus, calcaneus, navicular, cuboid, three cuneiforms, five metatarsals, five proximal phalanges, four intermediate phalanges, and five distal phalanges. The ground was constrained to move along the GRFs, and the upper surfaces of the encapsulated soft tissue, fibula, and tibia were fully fixed. (e) An illustration of foot positions relative to the ground at five gait events: heel-strike, early stance, mid-stance, late stance, and toe-off.
The rotation angles in the sagittal (left column), frontal (middle column), and transverse (right column) anatomical planes for the following joints: (a) pelvis, (b) hip, (c) knee, and (d) ankle were compared between the right (dashed red line) and left (blue line) sides of the subject and the kinematic data of healthy subjects reported in the literature [23].
The position of the Center of Pressure (CoP) and the confidence ellipse data were measured using the foot pressure scanner (PT-Scan) in the upright-standing posture. The ellipse area represents the total area of the confidence ellipse, and the path length of CoP indicates the total displacement of the CoP during the measurement. The major and minor axes of the confidence ellipse correspond to the antero-posterior and medio-lateral directions, respectively. Standard deviations (SD) in the antero-posterior and medio-lateral directions represent the deviation of the Center of Pressure on the major axis in the anterior-posterior direction and the minor axis in the medio-lateral direction, respectively.
The vertical and forward ground reaction forces (GRFs) measured by the foot pressure scanner (PT-Scan) for the subject’s left foot during the stance phase were compared to the data of GRFs and standard deviations in the literature [23].
The ground reaction compressive and shear stresses, along with the foot contact area at the interface with the ground, were calculated at each time step during the stance phase of walking.

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A Combined Musculoskeletal and Finite Element Model of a foot to predict Plantar Pressure Distribution

April 2024

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195 Reads

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4 Citations

In this study, a combined subject-specific numerical and experimental investigation was conducted to explore the plantar pressure of an individual. The research utilized finite element (FE) and musculoskeletal modeling based on computed tomography (CT) images of an ankle-foot complex and three-dimensional gait measurements. Muscle forces were estimated using an individualized multi-body musculoskeletal model in five gait phases. The results of the FE model and gait measurements for the same subject revealed the highest stress concentration of 0.48 MPa in the forefoot, which aligns with previously-reported clinical observations. Additionally, the study found that the encapsulated soft tissue FE model with hyper-elastic properties exhibited higher stresses compared to the model with linear-elastic properties, with maximum ratios of 1.16 and 1.88 MPa in the contact pressure and von-Mises stress, respectively. Furthermore, the numerical simulation demonstrated that the use of an individualized insole caused a reduction of 8.3% in the maximum contact plantar pressure and 14.7% in the maximum von-Mises stress in the encapsulated soft tissue. Overall, the developed model in this investigation holds potential for facilitating further studies on foot pathologies and the improvement of rehabilitation techniques in clinical settings.




Effects of heel apex position, apex angle and rocker radius on plantar pressure in the heel region

October 2023

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28 Reads

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1 Citation

Heliyon

Introduction Rocker shoes and insoles are used to prevent diabetic foot ulcers in persons with diabetes mellitus and loss of protective sensation, by reducing the plantar pressure in regions with high pressure values (>200 kPa) (e.g., hallux, metatarsal heads and heel). However, forefoot rocker shoes that reduce pressure in the forefoot inadvertently increase pressure in the heel. No studies focused on mitigating the negative effects on heel pressure by optimizing the heel rocker midsole, yet. Therefore, we analyze the effect of different heel rocker parameters on the heel plantar pressure. Methods In-shoe pressure was measured, while 10 healthy participants walked with control shoe and 10 different heel rocker settings. Peak pressure was determined in 7 heel masks, for all shoes. Generalized estimating equations was performed to test the effect of the different shoes on the peak pressure in the different heel masks. Results In the proximal heel, a rocker shoe with distal apex position, small rocker radius and large apex angle (100°), shows the largest significant decrease in peak pressure compared to rocker shoes with more proximally located apex positions. In the midheel and distal heel, the same rocker shoes or any other rocker shoes, analyzed in this study, do not reduce the PP more than 2 % compared to the control shoe. For the midheel and distal heel region with high pressure values (>200 kPa), rocker shoes alone are not the correct option to reduce the pressure to below 200 kPa. Conclusion When using rocker shoes to reduce the pressure in the forefoot, a heel rocker midsole with a distal apex position, small rocker radius and apex angle of 100°, mitigates the negative effects on proximal heel pressure. For the midheel and distal heel, other footwear options as an addition or instead of rocker shoes are needed to reduce the pressure.



Citations (58)


... 32,[46][47][48] All osseous structures in the current study were also assumed to possess rigidity, in accordance with previous studies. 9,21,30,49 The mild scoliotic model, designed with the absence of wedging typical in mild scoliosis 26 featured an eccentric mass distribution in front of the vertebrae, strategically placed based on CT images. It is crucial to note that the stability-based kinematics-driven musculoskeletal model of the adolescent F I G U R E 9 GPs' concave-over-convex side von Mises stress ratio (S conv=conx ) in the AIS thoracolumbar spine FEI and FEE models having healthy and concave-sided impaired LGPT + MFL muscles. ...

Reference:

Biomechanical significance of intervertebral discs on growthplate stresses in scoliotic trunks following unilateral muscle weakening: A hybrid approach of finite element and musculoskeletal modeling
A Combined Musculoskeletal and Finite Element Model of a foot to predict Plantar Pressure Distribution

... There has been a significant amount of work done on functionally graded insoles (Teixeira et al. 2021;Muir et al. 2022;Hudak et al. 2022;Channasanon et al. 2023;Shaulian et al. 2022;Kumar et al. 2023;Malki et al. 2024;Li et al. 2023;Geiger et al. 2023;Shaulian et al. 2023). These studies found a reduction in peak plantar pressure with a functionally graded insole between 16% ) and 48% (Malki et al. 2024). ...

Effects of individually optimized rocker midsoles and self-adjusting insoles on plantar pressure in persons with diabetes mellitus and loss of protective sensation
  • Citing Article
  • December 2023

Diabetes Research and Clinical Practice

... PCU foils, were tested alone or in combination with two candidates for surface modification: a dopamine-based bioadhesive film [dopamine-carboxymethylcellulose (dCMC) conjugate] and a calcium-phosphate (CaP) coating. While the use of dCMC is aimed at forming molecular bonds with tissue surfaces through carboxyl groups of carboxymethylcellulose (20) and the catechol functional groups of dopamine, the CaP coating is designed to encourage bone ingrowth to promote implant stability (21). ...

Bioactive calcium phosphate coatings applied to flexible poly(carbonate urethane) foils
  • Citing Article
  • July 2023

Surface and Coatings Technology

... Selection of cushioning materials for therapeutic footwear is mostly determined on the basis of the clinician's experiences (Malki et al., 2023;Mandolini et al., 2017;Telfer et al., 2017). Charlotte Apps and her colleagues conducted comprehensive in vivo tests using an in-shoe plantar pressure system, aiming to meticulously compare the mechanical attributes of two distinct insole designs. ...

Factors influencing the use of therapeutic footwear in persons with diabetes mellitus and loss of protective sensation: A focus group study

... By using rigid instrumentation intended for stabilization to achieve spinal fusion, these goals become conflicting. More dynamic implants, which correct the curve while allowing motion, like an internal brace, may be more appropriate for this purpose; however, these have not yet been investigated in an AIS population [12,13]. ...

Three-Dimensional Correction of Scoliosis by a Double Spring Reduction system as a Dynamic Internal Brace: A Pre-clinical Study in Göttingen Minipigs
  • Citing Article
  • November 2022

The Spine Journal

... In Europe alone, the cost of fractures has been estimated to be around EUR 37 billion [1]. In fact, they constitute at least 66% of significant physical traumas [2]. Although bone loss happens naturally with age, especially among a steadily growing elderly population, many conditions, such as autoimmune diseases, osteoporosis, menopause, and hormonal disorders, accelerate the process to a critical and sometimes Gels 2024, 10, 666 2 of 30 fatal degree [3]. ...

Bone fixation techniques for managing joint disorders and injuries: A review study
  • Citing Article
  • November 2021

Journal of the Mechanical Behavior of Biomedical Materials

... If we would simply reduce the amount of noise, would that then be enough to improve patient outcome? Unfortunately, while noise reduction has been the primary interest of many ICU-related interventions (Kim et al., 2021;Luetz et al., 2019), its effectiveness on patientcentered outcomes remains inconclusive (Delaney et al., 2019). An explanation is that the perceived meaning and quality of the perceived sounds in ICUs play a major role. ...

Overview and Strategy Analysis of Technology-Based Nonpharmacological Interventions for In-Hospital Delirium Prevention and Reduction: Systematic Scoping Review

Journal of Medical Internet Research

... Mini-pig models have also recently been utilized as a model of scoliosis to demonstrate how the biomechanical properties of the flexible, growing spine can be harnessed to induce a scoliotic deformity [60,61]. ...

Induction of a representative idiopathic-like scoliosis in a porcine model using a multi directional dynamic spring-based system

The Spine Journal

... Then, data preprocessing is needed, including data cleaning, standardization, feature extraction and other operations to generate data that meets the input requirements of the model. Then, according to the biomechanical principle and the actual situation, people need to select the characteristics related to running posture optimization, such as knee exion, center of gravity position and so on [29]. Then, appropriate machine learning algorithms, such as decision tree, neural network and SVM, can be selected to train the model. ...

Effect of different forefoot rocker radii on lower-limb joint biomechanics in healthy individuals

Gait & Posture

... These factors can lead to air leaks and, consequently, a decrease in voice quality as well as an increase in skin irritation due to repeated acts of removal and application of adhesives [12][13][14][15][16][17]. The failure to achieve a hermetic fixation of the peristomal adhesive is considered one of the factors responsible for the low usage rate of ASV (estimated between 7 and 37.5%) [18]. ...

Improving Hands-free Speech Rehabilitation in Patients With a Laryngectomy: Proof-of-Concept of an Intratracheal Fixation Device
  • Citing Article
  • January 2021

Otolaryngology Head and Neck Surgery