Stability, Safety and Support: Moving with confidence is only possible if you feel safe on your prosthetic leg, so the knee component needs to act in a predictable way, providing stability or swinging freely as needed. As your heel hits the ground during walking, weight is transferred from one leg to the other, and the prosthetic knee needs to provide resistance so that it supports your body while you swing through the sound leg for the next step and doesn't collapse under your weight. The prosthetic knee must remain stable as body weight rolls forward over the prosthetic foot during the stance phase of gait. It should respond quickly and naturally should an unexpected movement occur and also needs to support your body during actions such as standing.

Smooth and Symmetric Movement: To simulate normal gait, the prosthetic knee must smoothly flex and extend through the swing phase of gait. Effortless movement, as naturally and symmetrically as possible, helps to take the strain off other body parts such as the hip, back or sound leg that may occur if the prosthetic leg is not functioning properly. The prosthetic knee needs to adapt to your walking style, speed and environment. Achieving this will play a major role in supporting a person’s health over the long term.

No component works in isolation. A well-functioning prosthetic leg is a system of components that work together and is most effective when paired with other components.