Improved Lower Limb Prosthesis Chris Bruce, Anna Chen, Grant Hofmeister
Background on Leg Prosthesis Prostheses allow amputees restored mobility. Because of the different injuries that exist, many type of prostheses exist for lower extremities. Our focus will be on Transtibial Prosthetics (Below Knee) as opposed Transfemoral Prosthetics (Above Knee)
Components of the Prosthesis Socket- Forms the connection between the residual limb and the prosthesis. Sleeve- Provides suction suspension for prosthesis. Shank (pylon)- Transfers weight from socket to the foot-ankle. Foot-ankle- Absorbs shock and impact and provides stability. http://materials.anu.edu.au/student_essays/campbell_prosthetic_leg.pdf
Current Prosthesis Design Socket is usually made of rigid material. Sleeve is made of silicone, an elastomer, which helps provide the tight fit around the stump and prosthesis and shock absorption. The shank is attached using a shuttle locking pin mechanism. Depending on the user, a variety of prosthetic feet exist.
Problems with Prosthesis The load is focused at the single pin joint. After prolonged usage, prosthesis can be painful to user. The sleeve causes chafing and skin deterioration through the shear forces that are applied. The sleeve does a poor job accommodating the change in volume of the stump during use.
Our Project Objectives Find a new material for the sleeve that will improve comfort for the user. Redesign the sleeve socket mechanism so that is capable of adjusting to stump volume changes. Improve the load distribution of prosthesis to lower pain and decrease energy consumption. www.arimed.com/images/Liners.jpg