Conceptual design of a polycentric knee prosthesis for transfemoral amputees in Venezuela

This research is aimed to establish the conceptual design of a knee prosthesis for transfemoral amputees in Venezuela. A state-of-the-art review was carried out and interviews with users were performed in order to state the design criteria. Taking these into account, the concept of the prosthetis was based on a voluntary control four-bar linkage prosthetic knee mechanism. This provides stability during the initial contact and stance, as well as ability to initiate voluntary flexion toward late stance before the toe-off. As for the alignment of the prosthesis, the orientation angle on the lower limb was found to be a very important parameter to bear in mind, given its incidence in the location of the instantaneous center of rotation of the mechanism (anterior or posterior) with respect to the ground reaction force vector during walking.