Article

This article evaluates the design of a variable impedance prosthetic (VIPr) socket for a transtibial amputee using computer-
aided design and manufacturing (CAD/CAM) processes. Compliant features are seamlessly integrated into a three-dimensional
printed socket to achieve lower interface peak pressures over bony protuberances by using biomechanical data acquired
through surface scanning and magnetic resonance imaging techniques. An inverse linear mathematical transformation
spatially maps quantitative measurements (bone tissue depth) of the human residual limb to the corresponding prosthetic
socket impedance characteristics. The CAD/CAM VIPr socket is compared with a state-of-the-art prosthetic socket of similar
internal geometry and shape designed by a prosthetist using conventional methods. An active bilateral transtibial male
amputee of weight 70 kg walked on a force plate
Y
embedded 5-m walkway at self-selected speeds while synchronized ground
reaction forces, motion capture data, and socket-residual limb interface pressures were measured for the evaluated sockets.
Contact interface pressure recorded (using Teksan F-Socket
i
pressure sensors) during the stance phase of several completed
gait cycles indicated a 15% and 17% reduction at toe-off and heelstrike, respectively, at the fibula head region while the
subject used a VIPr socket in comparison with a conventional socket of similar internal shape. A corresponding 7% and 8%
reduction in pressure was observed along the tibia. Similar trends of high-pressure reductions were observed during quiet
single-leg standing with the VIPr socket in comparison with the conventional socket. These results underscore the possible
benefits of spatially varying socket wall impedance based upon the soft tissue characteristics of the underlying residual limb
anatomy.

Langue : ANGLAIS