Creating a data-driven module to provide the parameters for custom made orthopaedic insole design optimisation

Additive Manufacturing (AM), also known as 3D printing, is gaining popularity, especially in the medical sector. It offers significant benefits for MedTech solutions, such as 3D-printed joints, implants, and medical devices. AM provides the freedom to design unique, complex geometries and it enables small batch production. The use of stronger materials reduces product weight or volume, which broadens the spectrum of use. This empowers, amongst others, medical professionals to deliver efficient personalised solutions that precisely fit each patient’s body, not only for (surgical) body parts but also for orthopaedic and podiatric products.

Orthopaedic or podiatric products play a vital role in repairing and supporting the musculoskeletal system, addressing various issues like sports injuries, joint pain, and back problems. One example of such products is bespoke insoles, which fall within the specialty of the M3DSoles consortium. The project consortium consists of PLT Products BV and Voetencentrum Wender, in collaboration with the Fraunhofer Innovation Platform for Advanced Manufacturing (FIP-AM@UT), the University of Twente and the Fraunhofer Institute for Production Technology IPT. PLT Products is a renowned manufacturer and outsourcing partner of professional footwear, specialising in the production of custom-made insoles, amongst which 3D printed ones. Voetencentrum Wender is a market-leading, innovative foot care company, whose core activity is to provide medical services in the foot care industry.

In the realm of insoles, acknowledging the distinctiveness of each individual’s physical condition and unique feet, every insole produced is a bespoke product tailored to meet the specific needs of the patient.

The innovative, personalised 3D printed insoles developed by PLT Products comprise of two fundamental components. The bottom part of the insole, which is partly standardised, can be individually adjusted according to the foot position, diagnosis, and the underlying medical need. This part is finished with a cushioning cover layer, which stimulates even pressure distribution under the foot. This approach ensures that each patient receives a tailor-made solution that optimally addresses their specific needs and enhances overall quality of life.

The AMP project M3DSoles will enhance the design of patient-specific insoles, by optimising key parameters of the insoles shape through simulations. This approach ensures a higher level of personalisation for the soles. For faster optimisation results, a data-driven module will be developed, which recommends property settings based on the patient specific variables entered.

Upon completion of the project, the module is expected to offer valuable advice on parameters such as insole geometry, thickness, size, and material of the end product. The module will be an intelligent tool in the optimisation of personalised solutions and enhance the quality of life of the patient.

Industry partners

APPROACH

The M3DSoles project employs a comprehensive and iterative approach to design optimisation for personalised 3D-printed insoles. The process begins with the acquisition of foot geometry through advanced scanning techniques, which captures detailed anatomical data essential for accurate model construction. This geometry is then used to create a series of parametric 2D models representing various cross-sections of the foot, each corresponding to specific metatarsal areas. These models serve as the foundation for Finite Element (FE) analysis, which simulates stress and pressure distribution across the foot-insole interface under various load conditions. The FE models are iteratively refined based on simulation outcomes, incorporating patient specific factors such as weight, foot morphology, and the selected loading scenario.

To enhance insole personalisation, a data-driven optimisation algorithm leverages accumulated FE simulation data to fine tune design. This involves adjusting parameters such as insole thickness, arch support, and material properties to optimise comfort and functionality. The optimised design is validated through virtual testing. These designs are also 3D printed as physical prototypes. This methodology tailors insoles to meet specific biomechanical needs, enabling adjustments and improvements based on user feedback and research findings. Although preliminary, these developments show potential for clinical use as methods evolve to reduce assumptions and simplifications, requiring further refinement.

OUTCOME

Through a combination of advanced modelling and data-driven optimization, the M3DSoles project has successfully enhanced insole performance for the surrogate patient foot problem and the efficiency of the design process. By leveraging surrogate-patient-specific data and computational tools, the insoles created under the M3DSoles framework offer significant improvements in pressure distribution. Results within current practice are unfortunately not possible yet, due to limitations of data gathering and analysis of patient specific parameters.

The implementation of the 2.5D model demonstrated enhanced efficiency, yielding accurate results with significantly reduced computational time compared to 3D simulations of foot-insole interaction. This modelling capability facilitated the identification of areas experiencing high stress and enabled targeted optimizations in insole design. As a result, the design process became more efficient, yielding a better fit for surrogate-patients and reducing the need for manual intervention during the design phase.

Key results of the surrogate model include:

• Improved pressure in high-stress areas by redistribution
• Data-driven module tailored designs to individual foot geometry and pressure distribution needs, improving overall
insole effectiveness
• Efficiency in design optimization through leveraging computer aided techniques reducing both cost and time to market

While the outcomes of the project show promise, significant development is still required to seamlessly integrate this technology into routine clinical practice. Despite these challenges, the M3DSoles project has established a robust foundation for the future of personalized insole manufacturing, effectively aligning with the latest advancements in computational design and additive manufacturing.

This project was made possible through the Regio Deal supported by the Province of Overijssel and the Dutch State.

FOR MORE INFORMATION ON M3DSOLES, FEEL FREE TO REACH OUT TO

Celal Soyarslan

Celal Soyarslan

Senior Research Engineer

Sikander Naseem

Sikander Naseem

Research Engineer

Niklas Bäckel

Research Assistant - Fraunhofer Institute for Production Technology IPT

    Frank Ellenbroek

    UT - MSc Student assistant