Coupling an Active Pelvis Orthosis with Different Prosthetic Knees While Transfemoral Amputees Manage a Slippage: A Pilot Study

This pilot study aimed at testing the hypothesis that the effectiveness of an Active Pelvis Orthosis (APO)—mediated strategy to counteract the fall risk in transfemoral amputees (TFAs) can depend on the adopted prosthetic knee. Two TFAs with good and similar functional capabilities (k-level = 3) were asked to manage unexpected slipping like perturbations: the first used a hydraulic knee; the second a microprocessor-controlled knee. Results revealed that the APO-mediated strategy against the fall risk was more effective in the second participant. Accordingly, the adopted prosthetic knee seems to significantly condition the overall balance response despite the balance recovery is supposed to be mainly driven by the APO assistance. Therefore, the prosthetic knee should be considered a confounding factor for these types of experiments and its relevance deserves further investigations.