Kinetic asymmetry in unilateral transfemoral amputees: Gait biomechanics and reliability assessments
Tsung-Yeh Chou, Kristin Reeves, Danielle Melton, David Doherty, Payam ZandiyehBackground
Individuals with unilateral transfemoral amputation (TFA) commonly experience gait-related loading asymmetries, elevating their risks of lower limb injuries and degenerative changes. To evaluate the effects of interventions on these asymmetries, it is crucial to assess test-retest reliability and establish minimum detectable changes (MDCs) for loading-related measures. Determining them for these measures would help distinguish meaningful interventional effects from daily variability. This study evaluated test-retest reliability and established MDC values for ground reaction force (GRF) during treadmill walking in individuals with TFA and compared GRF outcomes between the amputated and intact limbs.
Methods
Ten participants underwent 2 study visits, 1 month apart. Ground reaction force data were collected during treadmill walking at a self-selected speed. Outcome measures included loading rates, unloading rates, braking impulses, and propulsive impulses, normalized by body weight. Intersession reliability and MDC values were computed with intraclass correlation analysis. Side-to-side differences were analyzed using repeated-measures ANOVAs. Ground reaction force time series were compared using statistical parametric mapping (SPM-1d).
Results
Braking and propulsion impulses demonstrated good-to-excellent reliability (intraclass correlation coefficients >0.82) in both limbs, whereas intact limb loading rates showed poor reliability. Higher loading rate but lower propulsion impulses were detected in the amputated limb, with differences in propulsion impulses exceeding MDC values. SPM-1d analyses detected side-to-side differences in GRF waveforms at the beginning and the end of the stance phase in superior-inferior and anterior-posterior directions.
Conclusion
Impulse outcomes are reliable measures, promising for future investigation of treatment effectiveness in longitudinal gait studies in individuals with TFA.