Foot Orthosis and Sensorized House Slipper by 3D Printing

Abstract

Background: In clinical practice, specific customization is needed to address foot pathology, which must be disease and patient-specific. To date, the traditional methods for manufacturing custom functional Foot Orthoses (FO) are based on plaster casting and manual manufacturing, hence orthotic therapy depends entirely on the skills and expertise of individual practitioners. This makes the procedures difficult to standardize and replicate, as well as expensive, time-consuming and material-wasting, as well as difficult to standardize and replicate. 3D printing offers new perspectives in the development of patient-specific orthoses, as it permits addressing all the limitations of currently available technologies, but has been so far scarcely explored for the podiatric field, so many aspects remain unmet, especially for what regards customization, which requires the definition of a protocol that entails all stages from patient scanning to manufacturing. Methods: A feasibility study was carried out involving interdisciplinary cooperation between industrial engineers and podiatrists. To that end: (i) For patient-specific data acquisition, 3D scanning of the foot is compared to traditional casting. (ii) a modelling GD workflow is first created to design a process permitting easy creations of customized shapes, enabling the end user (the podiatrist) to interactively customize the orthoses. Then, (iii) a comparison is made between different printing materials, in order to reproduce the same mechanical behavior shown by standard orthoses. To do this, the mechanical properties of standard materials (Polycarbonate sheets), cut and hand-shaped, are compared with four groups of 3D printed samples: poly(ethylene glycol) (PETG), poly(acrylonitrile-butadiene.styrene) (ABS), polycarbonate (PC) and poly(lactic acid) (PLA) obtained by Fused Filament Fabrication (FFF). Results: Differences found between the foot plaster model obtained with the plaster slipper cast in a neutral position and the model of the real foot obtained with 3D scanning in the same position can be ascribed to the non-stationarity of the patient during the acquisition process, and were limited by a locking system with which no substantial differences in the almost entire sole of the foot scan were observed. Conclusions: Using the designed GD workflow, podiatrists with limited CAD skills can easily design and interactively customize foot orthoses to adapt them to the patients’ clinical needs. 3D printing enables the complex shape of the orthoses to be reproduced easily and quickly. Compared to Polycarbonate sheets (gold standard), all the printed materials were less deformable and reached lower yield stress for comparable deformation. No modifications in any of the materials as a result of printing process were observed.

Polymer-Based Additive Manufacturing for Orthotic and Prosthetic Devices: Industry Outlook in Canada

“…The authors also compared the shape capture process by 3D scanning with traditional casting and reported 3D scanning to be an excellent alternative. They also developed a generative design (GD) workflow which can be used by the technicians to modify and customize designs as per customer requirements [ 37 ]. Sharma et al examined the use of thermoplastic polyurethane (Ninjaflex and Filaflex polymer filaments) for orthotic foot insole by conducting tensile, bending and hardness tests on the printed part [ 38 ].…”

The Effects of 3D Custom Foot Orthotics with Mechanical Plantar Stimulation in Older Individuals with Cognitive Impairment: A Pilot Study

“…These were then printed in a polyurethane-based thermoplastic with a 3D printer using a fused deposition modelling (FDM) technique. We chose this process in order to standardise the insoles and guarantee higher reproducibility compared to the conventional handmade process, as previously demonstrated in a recently published study [ 28 ].…”

3D Printing of Individual Running Insoles – A Case Study

“…Foot scan of neutral calcaneal position. 3,7,22 3D scanning was performed with an Artec Eva handheld 3D scanner (Artec, USA)used software algorithms: 36 tracking Geometry+Texture, visualization of color distance, and Auto-align new scan. Feet capturing (Figure 2): (1) The standing-on-one-leg posture.…”

“…2,3,27,28 The production of a CMI that meets the biomechanical requirements for damping and support is demanding from material and mechanical points of view, knowledge, and skills. 1,[3][4][5]7,15,21,27,28 It follows from the above that a fundamental assumption for the successful designing CMIs is to understand the correlation of the foot to posture 29 and other aspects of the musculoskeletal system, 1,[3][4][5][6][7][8][9] to perceive relationships to associated diseases and cognition of the biomechanics, 1,4,5,12 weight-bearing activities 1,3,[5][6][7]9 of humans, and pathological forces 1,3,[5][6][7]13 which affect the foot. In general, the main principle in the design of CMI is the correction of deformities, 1,3,[7][8][9] reductions of painful symptoms, [3][4][5]…”

“…1,3,6,8,12 Pain in the lower limbs and muscle fatigue are characteristic symptoms of flat feet. [1][2][3][4][5][6][7][8][9][10] These severe accompanying phenomena make ordinary life miserable and are why a person seeks professional help. 3 An insole must bear the oftenextreme loads 3,8,9 in athletes.…”