Journal of NeuroEngineering and Rehabilitation

RESEARCH Open Access Reference values for gait temporal and loading symmetry of lower-limb amputees can help in refocusing rehabilitation targets Andrea Giovanni Cutti * , Gennaro Verni, Gian Luca Migliore, Amedeo Amoresano and Michele Raggi From Second World Congress hosted by the American Orthotic & Prosthetic Association (AOPA) Las Vegas, NV, USA. 06-09 September 2017 Abstract Background: The literature suggests that optimal levels of gait symmetry might exist for lower-limb amputees. Not only these optimal values are unknown, but we also don ’ t know typical symmetry ratios or which measures of symmetry are essential. Focusing on the symmetries of stance, step, first peak and impulse of the ground reaction force, the aim of this work was to answer to three methodological and three clinical questions. The methodological questions wanted to establish a minimum set of symmetry indexes to study and if there are limitations in their calculations. The clinical questions wanted to establish if typical levels of temporal and loading symmetry exist, and change with the level of amputation and prosthetic components. Methods: Sixty traumatic, K3-K4 amputees were involved in the study: 12 transfemoral mechanical knee users (TFM), 25 C-leg knee users (TFC), and 23 transtibial amputees (TT). Ninety-two percent used the Ossur Variflex foot. Ten healthy subjects were also included. Ground reaction force from both feet were collected with the Novel Pedar-X. Symmetry indexes were calculated and statistically compared with regression analyses and non-parametric analysis of variance among subjects. Results: Stance symmetry can be reported instead of step, but it cannot substitute impulse and first peak symmetry. The first peak cannot always be detected on all amputees. Statistically significant differences exist for stance symmetry among all groups, for impulse symmetry between TFM and TFC/TT, for first peak symmetry between transfemoral amputees altogether and TT. Regarding impulse symmetry, 25% of TFC and 43% of TT had a higher impulse on the prosthetic side. Regarding first peak symmetry, 59% of TF and 30% of TT loaded more the prosthetic side. Conclusions: Typical levels of symmetry for stance, impulse and first peak change with the level of amputation and componentry. Indications exist that C-leg and energy-storage-and-return feet can improve symmetry. Results are suggestive of two mechanisms related to sound side knee osteoarthritis: increased impulse for TF and increased first peak for TT. These results can be useful in clinics to set rehabilitation targets, understand the advancements of a patient during gait retraining, compare and chose components and possibly rehabilitation programs. Keywords: Gait, Ground reaction force, Symmetry, Rehabilitation, Amputees, Prosthesis, Osteoarthritis, C-leg, Microprocessor controlled knees, Energy storage and return feet * Correspondence: ag.cutti@inail.it INAIL Prosthetic Center, Via Rabuina 14, 40054 Vigorso di Budrio, BO, Italy © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ) , which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated. Cutti et al. Journal of NeuroEngineering and Rehabilitation 2018, 15 (Suppl 1):61 https://doi.org/10.1186/s12984-018-0403-x