Development of a Low Cost Swing-phase Control Mechanism

Seven above-knee amputees were fitted with a low-cost prosthetic knee and different low-cost swing-phase setups were clinically assessed. Clinical testing included the 20-meter walk tests utilizing a mobile computer setup connected to a potentiometer and accelerometer mounted on the prosthetic limb. As hypothesized, incorporating friction and a spring system resulted in improved gait function. Of the two spring systems evaluated, the dual spring system performed better than the single spring system resulting in increased walking velocity with decreased maximum flexion and terminal impact. The dual spring system resulted in lower terminal impact because the deactivation of the stiff spring and activation of the less stiff spring during the last 25 degrees of swing-phase before extension allows the shank to decelerate and hit the bumper at a lower velocity. The swing-phase control mechanisms evaluated have the potential to improve prosthetic function and are ideal for use in low-cost and peadiatric prostheses.MAS