Added value of a user-adaptive prosthetic knee in planned gait initiation: off to a good start?

Advancements in prosthetic knee design have led to biologically inspired microprocessor-controlled prosthetic knees. The added value of these devices has been extensively studied in walking. However, trials into the activity pattern of persons with an amputation show that the majority of ambulation activities are short in duration. This means that a high percentage of ambulatory activities involves the initiating of gait. Therefore the aim of this paper is to study the added value of a user-adaptive prosthetic knee in gait initiation. Ten persons with an amputation were included and measured with their own non-microprocessor controlled prosthesis and with the Rheo Knee II. In addition, a control group of ten persons without an amputation were included. Measurements were performed using two force plates and a six-camera Vicon system. The persons with an amputation started gait alternately with their intact and prosthetic leg. The results indicated that persons with an amputation heavily rely on the intact leg for the generation of propulsive forces. In addition, the reduced role of the prosthetic leg led to a lower velocity of the centre of mass at the end of the first step in persons with an amputation when compared to the control subjects. The transition towards the Rheo Knee II had no effect on the studied outcome parameters. In conclusion, there is no effect of the transition towards a user-adaptive prosthetic knee on intact leg reliance seen during gait initiation.