Enhancing patient specific diabetic foot insoles through customised Additive Manufacturing for improved cushioning properties

An insole is a silhouette of the foot found in the shoe and is considered, typically, an item of clothing. The insole is in fact, a medical aid to cushioning repetitive exposure of everyday activities to the plantar surface; otherwise known as the sole of the foot. The adoption of orthotic treatment is prevalent within the diabetic sector. The complication of diabetes is numerous, including foot problems that can lead to amputations in extreme cases. The management of Diabetic Foot (DF) is through the use of cushioning materials, typically foam, which is currently the gold standard. The appropriateness of the material is in question, limited by the porosity and customisation available to provide full protection to patients.

Additive Manufacturing (AM) has become a powerful tool for assistive device fabrication. The process of manufacturing provides complex geometric shapes, customised fits, and mechanical properties not possible in traditional manufacturing methods. Computer aided design (CAD) and digital fabrication methods (DFM) enable an approach that can implement 3D scanning of anatomical patient data, mechanically informed lattice design, and elastomeric materials to enhance patient specific cushioning to the exact pressure exposure to the plantar surface.

The research undertaken in this thesis investigates the feasibility of implement a complete customised digitised insole process into the NHS. The intent is to appeal to practitioners and patients and enhance comfort of cushioning using CAD to develop future approaches. Results indicated the feasibility of replicating foam through AM with informed mechanical lattices, increasing customisation and workflow to enhance comfort and cushioning. These findings evidence a new, more efficacious approach to DF insole design engineering using AM.