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Correlation of Transtibial Prosthetic Alignment Quality and Step-by-Step Variance of Gait

Fiedler, Goeran PhD; Johnson, Mariah Susan MSPO

JPO: Journal of Prosthetics and Orthotics: January 2017 - Volume 29 - Issue 1 - p 19–25
doi: 10.1097/JPO.0000000000000113
CME Article

Introduction The quality of lower-limb prosthetic alignment cannot easily be measured directly but may be described by its effects on gait comfort and efficiency. It is known that gait stability and step variability are correlated, as are gait stability and prosthetic alignment. This study investigated the hypothesis that prosthetic alignment and step variability are correlated. This would have the implication that step variability can be measured to assess the quality of prosthetic alignment (and possibly other relevant factors such as prosthetic fit and componentry selection).

Materials and Methods Twelve experienced users of transtibial prostheses were subjected to a protocol that introduced malalignments of their prosthetic ankle plantarflexion angle in a randomized crossover design. Perceived alignment quality was recorded via a visual analog scale. Step-by-step variability in horizontal ground reaction forces and axial ankle torsion moment was measured using a prosthesis-integrated load cell and was statistically compared with the degree of misalignment by bivariate correlation analysis.

Results Findings suggest that variance in axial torsion moment and step duration may be correlated to alignment quality.

Conclusions Subjective patient feedback is the recommendable criterion for alignment assessment in active and experienced users of prostheses. Further research is recommended before step variance may help assess prosthetic alignment quality in patients with less experience in prosthetic use.

GOERAN FIEDLER, PhD, and MARIAH SUSAN JOHNSON are affiliated with the University of Pittsburgh, School of Health and Rehabilitation Sciences, Prosthetics & Orthotics, Pennsylvania.

Funding for this work was received from the American Orthotic and Prosthetic Association.

Disclosure: The authors declare no conflict of interest.

Correspondence to: Goeran Fiedler, PhD, Department of Rehabilitation Science and Technology University of Pittsburgh, Suite 403, Bakery Square, Pittsburgh, PA 15206; email: gfiedler@pitt.edu

© 2017 by the American Academy of Orthotists and Prosthetists.