A recent study compared the effectiveness of four categories of prosthetic feet during ramp ambulation in individuals with a unilateral transtibial amputation who were classified as either a K2- or K3-level ambulator. The objective of the study, published June 12 online before print in the journal Prosthetics and Orthotics International, was to determine differences in symmetry in external work between the prosthetic feet during ramp ascent and descent. According to the researchers, the category of prosthetic foot appears to have a greater influence on symmetry in external work during decline walking than incline walking. Further, K2 participants achieved greater symmetry from K3 dynamic response prosthetic feet with either J-shaped or microprocessor ankles while descending ramps. According to the study, the findings support the prescription of K3 feet for K2 amputees who frequently negotiate ramps.
For the study, ten participants completed six testing sessions during which symmetry in external work was calculated using Tekscan® F-Scan® in-shoe sensors. Between the first and second testing sessions, the participants received standardized functional prosthetic training. In sessions three through six, the participants tested four feet-a SACH foot (K1); a stationary attachment flexible endoskeleton (SAFE foot) (K2); the Össur Flex-Foot® Talux (K3); and the Össur PROPRIO FOOT® microprocessor ankle-using a study socket and had a ten to 14-day accommodation period with each foot.
The researchers found that K2 participants demonstrated higher symmetry in external work values when using the Talux or the PROPRIO FOOT compared to the SACH foot. K3 participants also had higher symmetry in external work values with the Talux foot than the SACH foot. Ramp ascent symmetry in external work values were not significantly different between feet.