Article

The purpose of this research was 1) to develop a system to measure pistoning in sagittal plane (2D), 2) to test this system
during a dynamic task (cycling), and 3) to determine the effect of prosthetic suspension. The limb/socket motion
measurement device consisted of an aluminum frame attached to the prosthetic socket. Two linear potentiometers were
attached to the frame and aligned with the longitudinal and orthogonal axes of the prosthesis. The subject wore a small
metal bracket adhered to the skin over the distal tibia that protruded through a slit cut into a prosthetic liner. The
opposite ends of the linear potentiometers were connected to the bracket. Two subjects with unilateral transtibial
amputation secondary to trauma (31
11 years, 82
15 kg) pedaled on a stationary electromagnetically braked
ergometer at 150 W and 90 rpm. The pin and cuff strap type were the two prosthetic suspensions tested. The pin
suspension produced less displacement in the superior/inferior (S/I) direction (2 vs. 4 mm). Suspension type had no effect
on the magnitude of displacement in the anterior/posterior direction (4 mm). The device could measure differences
between two different prosthetic suspension systems, but these differences were very small. Future research should
address movement of the knee center within the prosthetic socket and use the limb/socket motion measurement device
to measure pistoning during gait.

Langue : ANGLAIS