Stump/socket pressure profiles of the pressure cast prosthetic socket.
OBJECTIVE
The aim was to evaluate stump/socket interface pressure in amputees wearing a socket developed by a pressure casting system.Design. Five unilateral transtibial amputees wore a pressure cast socket and walked at a self-selected speed.


BACKGROUND
The socket produces equally distributed pressure at the stump/socket interface, deviating from the conventional belief that pressure varies in proportion to the pain threshold of different tissues in the stump.


METHODS
The socket was fabricated while the subject placed his stump in a pressure chamber. Pressure was applied while he adopted a normal standing position. A specially built strain gauged type pressure transducer was used for measuring pressure distribution. Pressure and gait parameters were measured simultaneously while the subjects were standing and walking.


CONCLUSIONS
The pressure cast technique was able to provide comfortable fitting sockets. A hydrostatic pressure profile was not evident during standing or gait. Results also showed that no standard pressure profile for the pressure cast socket was observed. This was expected as no rectifications were done on the pressure cast socket. Pressure profiles at 10%, 25% and 50% of gait cycle did not correlate with the pressure profiles previously proposed.


CONCLUSIONS
The hydrostatic theory is an attractive concept in socket design as it produces a stump/socket pressure profile that is evenly distributed. Furthermore, it is a method that is easily implemented, independent of a prosthetist's skill and experience and reduces manufacturing time. However, there is still controversy surrounding the efficacy of this hydrostatic theory.
Goh
J C H
JC
Department of Orthopaedic Surgery, The National University of Singapore, 5 Lower Kent Ridge Rd, Singapore 119074, Singapore. dosgohj@nus.edu.sg
Lee
P V S
PV
Chong
S Y
SY
D000328:Adult; D000671:Amputation, Surgical / Q000534:rehabilitation; D000672:Amputation Stumps / Q000503:physiopathology*; D002370:Casts, Surgical; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D006874:Hydrostatic Pressure; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D011312:Pressure; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D016138:Walking / Q000502:physiology