3D-Printed Volume Adjustable Socket for Above-Knee Prostheses: Design and Development

In this thesis, I develop a 3D printed adjustable prosthetic socket for above-knee prostheses. The proposed design allows for volume adjustments to regulate the pressure exerted on the residual limb, reducing pain and skin issues, that are among the main causes of prostheses abandonment. The socket is designed to be 3D printed with lightweight materials and includes two layers for circumferential adjustments, connected to an attachment system. The attachment system is cone shaped to transfer the weight of the user to the prosthesis effectively. It also guarantees a stable and strong connection with the two socket layers trough two pin-joints. The two layers can slide one above the other, regulating the volume of the socket. A cable-driven system regulates the circumference both manually and automatically, through a BOA dial system. The dial is automatically adjusted by a motor, trough a system of gears that transfer the torque to the dial. For 3D printing, the materials are selected to reduce as much as possible the weight but guaranteeing the mechanical strength required. A silicone liner is integrated to guarantee stable connection between the limb and socket. A magnet is placed in the liner and in the attachment as suspension system, to avoid misalignment. The mechanical strength of the system was tested applying loads up to 900 N, simulating single-limb stance. I tested the adjustment system to guarantee 70 kPa of pressure on the limb, for stable and comfortable connection.