Our study of the suction patellar-tendon bearing prosthesis showed that there is better contact between the stump and the prosthesis than there is with a strap-suspended patellar-tendon bearing prosthesis. The average difference in displacement between the two is 1.15 centimeters and the difference in the excursion is primarily due to the difference in the movement of the soft tissues. With more soft tissue, movement of the stump is greater, and reduced movement gives a better sense of stability and a smoother gait.