Influence of gait training and prosthetic foot category on external work symmetry during unilateral transtibial amputee gait

Background: Prosthetic foot prescription guidelines lack scientific evidence and are concurrent with an amputee's concurrent with an amputee's Medicare Functional Classification Level (K-Level) and categorization of prosthetic feet. Objective: To evaluate the influence of gait training and four categories of prosthetic feet (K1, K2, K3, and microprocessor ankle/foot) on Symmetry in External Work for K-Level-2 and K-Level-3 unilateral transtibial amputees. Design: Randomized repeated-measures trial. Methods: Five K-Level-2 and five K-Level-3 subjects were tested in their existing prosthesis during Session 1 and again in Session 2, following 2 weeks of standardized gait training. In Sessions 3-6, subjects were tested using a study socket and one of four randomized test feet. There was an accommodation period of 10-14 days with each foot. Symmetry in External Work for positive and negative work was calculated at each session to determine symmetry of gait dynamics between limbs at self-selected walking speeds. Results: K-Level-2 subjects had significantly higher negative work symmetry with the K3 foot, compared to K1/K2 feet. For both subject groups, gait training had a greater impact on positive work symmetry than test feet. Conclusion: Higher work symmetry is possible for K-Level-2 amputees who are trained to take advantage of K3 prosthetic feet designs. There exists a need for an objective determinant for categorizing and prescribing prosthetic feet.