Dynamic Management of Excess Residual Limb Pressure With New Smart Socket Technology/Intelligent Prosthetic Socket With Variable Volume and Elevated Vacuum Systems

Overview

This study centers around the imaging of internal structures of residual limb by means of modern radiographic imaging techniques (Dynamic Radiography-DRSA). The purpose of our research is to further study the behavior of bones and soft tissue of the socket-stump interface during dynamic tasks such as walking or brisk walking. In the long term this research could prove a basis for improvements in the general design of sockets for the new generation of prosthetic devices.

There is very little known about the dynamic conditions inside a prosthetic socket, despite several research efforts based on pressure sensors, static X-ray images and/or computer simulations (FEM). The man reason is the inability of current measuring devices to track with enough resolution the in-vivo high speed kinematics of the stump-socket interface. Socket manufacturing and rectification in the field still relies on the experience and skill of the technician and feedback from the patient. This results in considerable dissatisfaction among the users and poor quantification of the socket fitting problems. For lower extremity amputees, a well-fitting socket is an important element for a successful rehabilitation. The socket provides the interface between the prosthesis and residual limb, which is designed to provide comfort, appropriate load transmission, and efficient movement control. Attaining these objectives is extremely challenging, with up to 55% of lower limb amputees reporting dissatisfaction with socket comfort, residual limb pain, and/or skin breakdown. In addition, current techniques used to produce sockets with suitable characteristics are labor and cost intensive, and depend on the work of skilled prosthetists that are relatively scarce compared to the number of amputees. Currently, there are more than 500,000 lower limb amputees in the U.S. alone, with 60,000 new ones every year. For upper extremity amputees the issues related to the efficiency of movement, load transmission and comfort become even more challenging due to the different nature of the associated motor skills and performing tasks. Similarly there are l7,350 annual upper limb amputations distal to elbow in individuals under 21 years of age in the US. In most developed countries there are 1.55 amputees per 1000 people. Most amputees wear a prosthesis for about 70 hr/week and use crutches or wheelchairs as alternative assistive devices when performing certain tasks. Current solutions do not meet the patient specific needs. It is suggested that our findings can further the understanding of the effects of slippage or harmful relative motion between stump and socket. Eventually new - and scientific based - guidelines for the fitting of artificial limbs could be recommended.