Registration of plantar pressure images

We present an analysis of four different algorithms used to register plantar pressure images: a first one based on the matching of the external contours of the feet, a second algorithm based on the technique of phase correlation, a third one based on the direct optimization of the cross-correlation (CC) and using the Fourier transform, and a fourth and last algorithm that is based on the iterative optimization of an intensity (dis)similarity measure. In terms of accuracy, the later algorithm achieved the best registration results; on the other hand, the algorithm based on the matching of contours was the fastest, but its accuracy was inferior to the accuracy of the remaining algorithms

Spatio-temporal alignment of pedobarographic image sequences

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).This paper presents a methodology to align plantar pressure image sequences simultaneously in time and space. The spatial position and orientation of a foot in a sequence are changed to match the foot represented in a second sequence. Simultaneously with the spatial alignment, the temporal scale of the first sequence is transformed with the aim of synchronizing the two input footsteps. Consequently, the spatial correspondence of the foot regions along the sequences as well as the temporal synchronizing is automatically attained, making the study easier and more straightforward. In terms of spatial alignment, the methodology can use one of four possible geometric transformation models: rigid, similarity, affine or projective. In the temporal alignment, a polynomial transformation up to the 4th degree can be adopted in order to model linear and curved time behaviors. Suitable geometric and temporal transformations are found by minimizing the mean squared error (MSE) between the input sequences. The methodology was tested on a set of real image sequences acquired from a common pedobarographic device. When used in experimental cases generated by applying geometric and temporal control transformations, the methodology revealed high accuracy. Additionally, the intra-subject alignment tests from real plantar pressure image sequences showed that the curved temporal models produced better MSE results (p<0.001) than the linear temporal model. This paper represents an important step forward in the alignment of pedobarographic image data, since previous methods can only be applied on static images

Generation of subject-specific, dynamic, multisegment ankle and foot models to improve orthotic design: a feasibility study

ABSTRACT: BACKGROUND: Currently, custom foot and ankle orthosis prescription and design tend to be based on traditional techniques, which can result in devices which vary greatly between clinicians and repeat prescription. The use of computational models of the foot may give further insight in the biomechanical effects of these devices and allow a more standardised approach to be taken to their design, however due to the complexity of the foot the models must be highly detailed and dynamic. METHODS: Functional and anatomical datasets will be collected in a multicentre study from 10 healthy participants and 15 patients requiring orthotic devices. The patient group will include individuals with metarsalgia, flexible flat foot and drop foot. Each participant will undergo a clinical foot function assessment, 3D surface scans of the foot under different loading conditions, and detailed gait analysis including kinematic, kinetic, muscle activity and plantar pressure measurements in both barefoot and shod conditions. Following this each participant will undergo computed tomography (CT) imaging of their foot and ankle under a range of loads and positions while plantar pressures are recorded. A further subgroup of participants will undergo magnetic resonance imaging (MRI) of the foot and ankle. Imaging data will be segmented to derive the size of bones and orientation of the joint axes. Insertion points of muscles and ligaments will be determined from the MRI and CT-scans and soft tissue material properties computed from the loaded CT data in combination with the plantar pressure measurements. Gait analysis data will be used to drive the models and in combination with the 3D surface scans for scaling purposes. Predicted plantar pressures and muscle activation patterns predicted from the models will be compared to determine the validity of the models. DISCUSSION: This protocol will lead to the generation of unique datasets which will be used to develop linked inverse dynamic and forward dynamic biomechanical foot models. These models may be beneficial in predicting the effect of and thus improving the efficacy of orthotic devices for the foot and ankle

Biomechanical evaluation of insole subjected to single-leg landing

Badminton games are based on footwork techniques. Among badminton players, 92% of leg injuries have been recorded. In preventing the injuries, insoles are widely used in sports where insole’s wall height, heel cup, arch-support height, thickness, and material properties will influence the stress, displacement, and rotation angle value of foot. Furthermore, the insoles are used to treat misalignment of foot and diabetes ulcers. However, there are still lacking in the analysis on insole during single-leg landing. This study was conducted with the main aims to establish a static analysis on three different insoles of badminton athletes during single-leg landing and to modify the material of pre-fabricated insoles for better performance in terms of shock absorption during single-leg landing. Three-dimensional (3D) finite element models of ankle-foot complex consisted of skin, talus, calcaneus, navicular, three cuneiform, cuboid, five metatarsals, and five phalanges were segmented from computed tomography (CT) data. The midsole and outsole were designed using 3-Matic software and three pre-fabricated insoles; insole 1 (Yonex Active Pro Truactive), insole 2 (Li-Ning L6200LA) and insole 3 (Victor VT-XD 8) were 3D scanned. In completing the ankle joint, a total of 21 ligaments were modelled. The single-leg landing was simulated with 2.95° of ankle plantar-flexion. On the superior surface of the skin, the load of 2.57 times bodyweight was applied, and the inferior surface of the outsole was fixed. The results showed the insole 3 is the most optimum in portraying the lowest peak stress on the metatarsals (3.807 MPa). Besides, the insole 3 recorded the least displacement value (10.81 mm) and acceptable bone rotation angle (3.29°). The insole 3 with ethylene-vinyl acetate medium density (EVA MD) material perform better compared to polyvinyl chloride (PVC) and ethylene-vinyl acetate low density (EVA LD) the lowest metatarsals’ peak stress (3.554 MPa), displacement (13.08 mm), and bones rotation angle (2.93°) were recorded. Further design of the custom insole based on insole 3 and EVA MD material produced the lowest peak metatarsal stress (3.210 MPa) and displacement (8.99 mm), and bones rotation angle of 1.80°. This study contributes to the better understanding on biomechanics during single-leg landing hence lead to better insole development

Análise e quantificação de imagens pedobarográficas em Patologias do Hallux Valgus

O estudo da pressão plantar tem vindo a assumir uma elevada importância, tanto do ponto de vista da abordagem clínica ao tratamento de patologias associadas ao pé como no contexto da biomecânica ocupacional. Em particular, no domínio da ortopedia, a identificação das principais características associadas à pressão plantar pode ser importante para uma correta avaliação clínica, preparação cirúrgica e acompanhamento dos doentes. É o caso de pacientes com patologia associada ao Hallux Valgus, também conhecida por joanete. O presente trabalho tem o seu enquadramento no estudo da distribuição da pressão plantar em doentes com esta patologia. Assim, em parceria com uma equipa médica do Hospital Distrital da Figueira da Foz, foram determinados os principais parâmetros associados à pressão plantar num grupo de voluntários com indicação cirúrgica para tratamento da patologia do Hallux Valgus. Estes parâmetros foram determinados a partir de imagens pedobarográficas, obtidas a partir de uma plataforma de medição de pressões, EMED. Além dos resultados fornecidos pelo próprio software, os dados recolhidos foram também analisados tendo por base o algoritmo PEDOBAR, programado em Matlab e desenvolvido no Laboratório de Biomecânica Aplicada do ISEC. Os resultados obtidos são apresentados e discutidos

Development of a finite element modeling procedure for plantar orthosis stiffness optimization for application in diabetic foot pathology

openABSTRACT Il piede diabetico è una delle maggiori complicanze del diabete e causa alterazioni nella funzione e struttura del piede generando nel tempo ulcere. Per tale motivo il diabete è la principale causa di amputazioni non traumatiche degli arti inferiori, rappresentando quindi non solo un grave problema per il paziente ma anche un ingente onere finanziario per l’assistenza sanitaria. Uno dei metodi di prevenzione in campo ingegneristico è la progettazione di ortesi plantari in grado di ridistribuire le pressioni e ridurre i picchi pressori che si originano nelle zone ad alto rischio ulcerativo. L’obiettivo di questo studio, effettuato presso il laboratorio di Bioingegneria del movimento del dipartimento di Ingegneria dell’Informazione dell’Università di Padova, è stato quello di trovare le proprietà ottimali del materiale costituente l’ortesi attraverso una procedura iterativa di Matlab interfacciato con un software di modellazione agli elementi finiti. E’ stato utilizzato un modello FEM semplificato del complesso piede-caviglia assieme a quello di un’ortesi plantare, simulato grazie a dati da gait analysis, ricavati in quattro istanti del passo. Il modello del plantare è stato suddiviso in tre regioni : retropiede, mesopiede e avampiede. Per ognuna di queste la procedura di ottimizzazione ha generato automaticamente il valore di rigidezza ottimale che minimizza la massima pressione plantare in ogni istante del ciclo del passo. Il risultato è un ortesi plantare per pazienti diabetici con rigidezza variabile. Questo studio offre una prova quantitativa con lo scopo di poter integrare in futuro l’ottimizzazione della rigidezza dell’ortesi ad una pratica clinica standard così da poter aiutare i professionisti del settore a sviluppare plantari soggetto-specifici

Eficacia de los diferentes sistemas de descarga en el tratamiento de úlceras por pie diabético

Objetivos Los pacientes diabéticos, debido a la insuficiencia vascular y a la neuropatía, presentan un alto riesgo de padecer úlceras en los pies. Una vez que la úlcera está presente debe tratarse de la forma adecuada para evitar posibles complicaciones mayores, llegando incluso a la amputación. Aunque no existe un tratamiento de descarga estándar, sí existe evidencia científica del uso de distintos sistemas de descarga más eficaces que otros. La siguiente revisión sistemática pretende dar a conocer la eficacia de los diferentes sistemas de descarga en el tratamiento de úlceras por pie diabético. Metodología Para realizar esta revisión sistemática se han consultado distintas bases de datos bibliográficas con el fin de identificar los estudios más relevantes y tratar de conocer la evidencia científica existente actualmente acerca de la eficacia y uso de distintos sistemas de descarga como tratamiento para las úlceras de pie diabético. La búsqueda se realiza en una base de datos especializada en revisiones sistemáticas (Biblioteca Cochrane Plus) y en bases de datos de artículos originales (PubMed/Medline, Cinhal, etc.), mediante cuatro tipos de búsquedas con las palabras clave: “ulcers”, “footwear”, “felted foam”, “insoles” and “diabetic foot”. Resultados Tras la consulta en las distintas bases de datos se han pre-seleccionado un total de 160 artículos desde el año 2000 hasta la actualidad, de los cuales, 49 artículos han sido incluidos y 111 han sido excluidos, basándose en los criterios de inclusión y exclusión establecidos. Eficacia de los sistemas de descarga para úlceras por pie diabético 4 Conclusiones Los sistemas de descarga más efectivos son las descargas no extraíbles (TCC y ITCC), puesto que se asegura el cumplimiento del tratamiento por parte del paciente, pero en caso de que éstas no se puedan emplear (coste, complicaciones, etc.) existen otros sistemas efectivos (calzado, ortesis y fieltro en combinación con un calzado apropiado) para tratar las úlceras, aunque no presentan la misma velocidad de curación. Estos últimos deben considerarse como segunda opción de tratamiento o cuando los otros dispositivos estén contraindicados.Traballo fin de grao (UDC.FEP). Podoloxía. Curso 2013/201

Podiatrists’ and orthotists’ views and experiences of using plantar pressure measurement in the assessment and treatment of diabetic foot syndrome

Background: The measurement of plantar pressure is recommended as a clinical tool for risk assessment, prevention and treatment of diabetic foot ulceration. To first assess comprehensively the available evidence on the use of plantar pressure assessment (PPA) to guide footwear and insole design and modification in people with diabetic foot disease, a systematic review was undertaken. Although the current evidence supports the use of PPA in diabetic foot management, the implementation of the technology in a clinical setting faces barriers such as competency, cost, time, etc. Therefore, a qualitative study was conducted to determine the barriers and facilitators of clinical usage of PPA according to podiatrists’ and orthotists’ views and experiences in the assessment and treatment of diabetic foot syndrome.Method: The literature search for the systematic review utilised Medline/Pubmed, Scopus, Cochrane, Clinical Trials, and CINAHL databases. In terms of qualitative study, 4 Podiatrists and 2 Orthotists with and without experience of using plantar pressure measurement were recruited. Six semi-structured online interviews were conducted; the audio was recorded and transcribed. Then, inductive thematic analysis was used to analyse transcribed texts. Result: The systematic review provides support for the use of PPA to optimise footwear and insole for the prevention of ulcer recurrence, and plantar pressure reduction in the diabetic foot. The qualitative study revealed some barriers and facilitators to improve the clinical implementation of PPA. As a result, six themes have been defined: 1. The importance of training and education in clinical implementation of PPA, 2. Providing evidence for the NHS to prove the benefits of PPA, 3. Time and space, 4. Human resources 5. Specific triage 6. Cost. Clinicians were overwhelmingly in support of plantar pressure measurement to demonstrate high areas of pressure in people with diabetes. However, lack of knowledge, time and space were considered as the main barriers in clinical implementation of PPA. Conclusion: The advantages of the use of plantar pressure data for insole and footwear modifications in people with diabetes have been supported by the evidence. However, the barriers to implementation of PPA include lack of knowledge and education about the use and interpret of plantar pressure data, shortage of time and space in routine clinical practice, and high cost of purchase and implementation of this technology.Training in using plantar pressure device and interpreting the data is a key factor. Besides, providing evidence for the NHS is an important thing to bring the effectiveness of PPA into consideration. The NHS can allocate specific clinics and time to facilitate the clinical use of PPA