Development of an artificial foot enabling the simulation of the natural behaviour of the human unroll of the foot during walking and running

From 3rd Congress of the International Foot and Ankle Biomechanics Community Sydney, Australia. 11-13 April 201

Evaluation of the influence of cyclic loading on a laser sintered transtibial prosthetic socket using Digital Image Correlation (DIC)

People with a transtibial amputation worldwide rely on their prosthetic socket to regain their mobility. Patient comfort is largely affected by the weight and strength of these prosthetic sockets. The use of additive manufacturing could give the prosthetist a range of new design possibilities when designing a prosthetic socket. These new design possibilities can in turn lead to improved socket designs and more comfortable prosthetic sockets. This new way of designing and producing prosthetic sockets radically differs from the manual traditional production process. This makes it difficult for prosthetists to understand how all these new design possibilities influence the mechanical properties of the additive manufactured prosthetic socket. Therefore there is a growing need for a method to evaluate the strength and stiffness of newly developed socket designs.We propose a method to evaluate the strength and stiffness of prosthetic sockets. A robotic gait simulator is used to apply realistic kinetics of amputee gait to the tested socket. A Digital Image Correlation (DIC) system is then used to measure the deformation of a prosthetic socket under different loading conditions. This way it is possible to check if plastic deformation will occur in the designed transtibial socket. Furthermore it is possible to assess the effect of cyclic loading on the 3D printed socket.To illustrate the proposed method, a transtibial prosthetic socket was designed using CAD software and produced with laser sintering PA12. DIC measurements were performed on this transtibial socket both before and after it was subjected to a cyclic load of 1 million cycles (mimicking realistic amputee gait).status: accepte

Screening Of Foot-related Musculoskeletal Problems In Non-sedentary Employees, How Can We Improve The Quantification?

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A Protocol To Test Durability Of Traditional And Additive Manufactured AFOs: Preliminary Results

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Mimicking the unroll of a prosthetic foot with a robotic gait simulator

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Development of an artificial foot enabling the simulation of the natural behaviour of the human unroll of the foot during walking and running

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Quantifying foot ortheses for an objective comparison: proposal of a new measurement protocol

The design and manufacturing of foot orthoses makes mostly use of the experience based knowledge of a CPO (certified prosthetist/orthotist) or podiatrist. With the introduction of new (digital) design and additive and subtractive manufacturing techniques on the one hand, and the emphasis on evidence based practice on the other hand, there is a growing need for the quantification of the material and structure properties of foot orthoses. Quantifying foot orthosis properties permits an objective comparison between different orthoses. For the quantification of these properties, we developed a protocol that measures the compression and force at certain reference points on the orthosis using the TA-XTplus Texture Analyser (Stable Micro Systems). First a reference coordinate system is constructed based on the patient’s location of the calcaneus, the first and fifth metatarsal head and the most proximal point between the hallux and second toe. The properties of the orthosis are measured in four different zones: the heel area, the medial arch, the area of the metatarsal heads and the forefoot area. 5 to 9 points of interest, depending on the size of the area, are measured in each zone. While the orthosis is fixed to the measuring system, different loading sequences are applied to these points of interest. The loading sequences differ in the applied force, speed of compression and the total compression. With this protocol, we aim not only to quantify the cushioning effect of the orthosis, but also to determine the influence of the orthosis structure (such as the medial arch). This is particularly important for the additive manufactured orthoses, as their properties will depend on the printed structures. To test our protocol, 3 orthoses with identical shape were produced in ethylene-vinyl acetate (EVA) in low, medium and high density (shore values of 25, 50 and 70, respectively). The orthoses were designed for a patient, with a leg length discrepancy and a mild form of scoliosis. The compression set [1], compression stiffness [1] and the height were derived from the data measured using the Texture Analyser. The results confirmed the expected differences between the orthoses in cushioning abilities. Also, there were noticeable differences between zones within an orthosis, despite the fact that the orthosis was made from a single material. In a next step, we will test different orthoses designed for the same subject by different CPOs and manufactured using traditional and new techniques.status: Published onlin

Foot inter-segment angles and rotation axes based on dynamic 3d surface point clouds

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