Researchers compared biomechanical outcomes of a 3D-printed prosthetic foot and two conventional prosthetic feet in people with a transtibial amputations. The results of the related study suggested that commercially available 3D-printed feet should incorporate systematically better adjustments, for example, for stiffness, to enhance prosthetic performance.
Ten people with unilateral transtibial amputations were fitted with prosthetic feet (the Mercuris ComfyStep, the Össur Assure, and the Ottobock DynamicMotion), using their current, well-fitting sockets. The participants had at least one week of familiarization for each foot before gait analyses were conducted using a 3D motion analysis system during level-ground walking. The research team calculated and compared the kinematics and kinetics, and the rollover shape (ROS) length and radius for each foot.
According to the study’s authors, their analysis indicated that the participants’ sound side gait parameters were comparable when using the different feet, but there were differences on the affected side. The statistical analysis revealed that the 3D-printed foot differed significantly compared with the conventional feet in reduced range of motion, increased plantarflexion moment, reduced plantarflexion power, a larger ROS radius, a less favorable energy ratio, and higher overall stiffness.
“Whether these differences have a negative clinically relevant effect remains unclear,” the authors wrote.
The study, “Biomechanical comparison of a 3D-printed prosthetic foot with conventional feet in people with transtibial amputation—a prospective cohort study,” was published in Prosthetics and Orthotics International.