3D-Printed Volume Adjustable Socket for Above-Knee Prostheses

Traditional prosthetic sockets are rigid, passive structures that cannot accommodate daily residual limb volume fluctuations and are produced through labor-intensive processes involving environmentally and occupationally hazardous materials. This work presents a 3D-printed, volume-adjustable transfemoral socket integrating a motorized cable-driven mechanism and pressure monitoring. The design features a dual layer, concentric structure that enables uniform circumferential modulation via a BOA system, operable manually or through a DC motor. Four resistive sensors, embedded in a prosthetic liner with a magnetic suspension, provide interface pressure feedback for closed-loop control. The socket is fabricated using 3D-printed glass-filled PA12 and carbon-fiber-reinforced PEEK to optimize strength, weight, and reduce material waste by means of a more sustainable production process. Experimental validation showed that the system maintains interface pressure within the target range (70 ± 2 kPa), limits relative vertical displacement down to <6 mm under realistic tension load, and withstands static and dynamic forces up to 900 N without structural failure. This solution combines adaptive design with sustainable digital manufacturing, offering a robust foundation for next-generation wearable physical interfaces that enhance comfort and stability.