Assessment of low- and high-level task performance in people with transtibial amputation using crossover and energy-storing prosthetic feet: A pilot study

Background: Crossover feet incorporate features of energy-storing feet and running-specific feet. As such, crossover feet may be suitable for both daily ambulation and participation in physically demanding activities. Objectives: To compare crossover feet and energy-storing feet on performance-based tests including a range of low-level (e.g. sit-to-stand) and high-level (e.g. jogging) activities. Study design: Cross-sectional, repeated measures. Methods: Participants with transtibial amputation completed a battery of performance-based outcome measures, including the Five Times Sit-to-Stand, Timed-Up-and-Go, Four Square Step Test, and the Comprehensive High-level Activity Mobility Predictor. Participants wore duplicate prostheses fit with crossover feet and energy-storing feet to perform the tests; the order of foot conditions was randomized. Paired t tests were used to evaluate differences between feet and order of testing. Results: Data from seven participants showed improvements in all measures while using crossover feet. Improvements in the second foot condition were also observed, indicating a practice effect for all measures. However, differences between feet and order of conditions were not statistically significant (p > 0.05). Conclusion: Results of this study suggest that crossover feet may improve low- and high-level mobility outcomes. However, intervention effects are small and practice effects were observed in all outcomes. Future research is needed to evaluate the influence of practice effects on performance-based mobility measures. Clinical relevance Crossover feet may improve transtibial prosthesis users' performance compared to energy-storing feet across a range of activities, but additional research is needed. Practice effects may be an influential factor in the measurement of performance-based mobility outcomes and should be considered when performing a clinical assessment.