Design principles, biomechanical data and clinical experience with a polycentric knee offering controlled stance phase knee flexion: A preliminary report

The OTTO BOCK 3R60 prosthetic knee joint allows controlled flexion of the prosthetic knee under weightbearing in early stance phase, more closely simulating this aspect of gait than was previously possible. As the amputee transfers weight onto the prosthesis in early stance phase, this knee gradually flexes up to 15 degrees, thereby cushioning the impact of weight acceptance. In contrast to all previous polycentric knees, stability of this new design is biomechanically increased by stance flexion, rendering a locking feature unnecessary. Clinically, the amputee perceives this prosthesis as stable and comfortable. The biomechanical features of this design concept, initial clinical observations and preliminary conclusions from laboratory gait analysis are summarized.