An evaluation of computer aided design of below-knee prosthetic sockets

Forty-eight below-knee amputees compared sockets designed using CANFIT computer aided design (CAD) software with sockets designed using conventional methods. Each subject was fitted by one prosthetist who used conventional techniques and one who used the CANFIT system to design the socket. Prosthetists alternated design methods for each new subject. The prosthetist using the conventional techniques was allowed up to 2 design attempts and the prosthetist using the CANFIT system was allowed up to 5 design attempts. After 2 design attempts with each method 21% of the subjects preferred the CANFIT design socket. Following up to 5 attempts 54% preferred the CANFIT designed socket. A jury of experts made an assessment of the CANFIT system and of CAD in prosthetics. The jury did not think that the version of the system tested was cost effective but that at the rate that it was improving it would become such within 3 to 5 years. The jury noted that, as well as monetary benefits, CAD presents the possibility of benefits in other areas such as research and teaching. A number of specific suggestions regarding the use and development of CAD in prosthetics were also made.     

An instrument for monitoring stump oedema and shrinkage in amputees.

A new system for measuring the cross-sectional area profiles of amputation stumps and whole limbs has been designed at the Amputee Research Centre. The instrument consists of a cylindrical tank supported on an elevator. The tank is raised to the height of the amputation stump and filled with water. A graph of the cross-sectional area profile of the amputation stump is generated by a mini-computer as the elevator descends. The cross-sectional area (A) is calculated from the expression: formula: (see text) where Hw = height of water in the tank He = height of the elevator Ac = a constant, related to the size of the measuring tank. This paper describes the instrument, which may find application in many other areas where there is a need to study shape.