A novel metamaterial approach to shape-adjustable prosthetic sockets for low-resource settings

Abstract

n low- and middle-income countries (LMICs), access to well-fitting prosthetic sockets remains limited due to high costs, restricted availability, and a shortage of trained clinical personnel. Existing prosthetic socket solutions often rely on specialised fabrication processes or result in discomfort and limited long-term acceptance, making them impractical for low-resource settings. This thesis explores a novel 3D-printed mechanical principle for shaping transradial prosthetic sockets directly on the residual limb of adults during the initial fitting process, without the need for trained clinical personnel, to reduce fabrication time and improve accessibility in low-resource settings. An iterative design process was followed in which multiple concepts were developed for a flexible inner layer capable of conforming to residual limb surface irregularities, alongside a rigid outer layer for circumferential adjustment. Selected concepts were refined and integrated into a final socket design. A functional prototype was fabricated using FDM 3D printing and evaluated through experimental testing, focusing on shape conformance, shape retention, and peak pressure behaviour. The resulting MetaWave socket consists of a waving-cell metamaterial inner layer combined with a pin-push circumferential adjustment mechanism. Experimental evaluation demonstrated that the prototype can accommodate the required circumferential range and conform to representative surface irregularities of the residual limb, while maintaining elastic behaviour under radial loading. Peak contact pressures generally remained below predefined thresholds, indicating effective pressure distribution. These results confirm the feasibility of the proposed shaping principle at a proof-of-concept level and highlight the potential of mechanically driven metamaterial structures as an accessible and adaptable approach to prosthetic socket design in low-resource settings