Reference values for gait temporal and loading symmetry of lower-limb amputees can help in refocusing rehabilitation targets

Andrea Giovanni Cutti,Gennaro Verni,Michele Raggi,Amedeo Amoresano,Gian Luca Migliore

doi:10.1186/s12984-018-0403-x

Abstract

BackgroundThe 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.MethodsSixty 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.ResultsStance 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.ConclusionsTypical 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.

Highlights

The literature suggests that optimal levels of gait symmetry might exist for lower-limb amputees
Gait speed was compared among transfemoral mechanical knee users (TFM) (1.12 ± 0.13 m/s), Transfemoral amputees using a C-leg knee (TFC) (1.17 ± 0.12 m/s), transtibial amputees (TT) (1.23 ± 0.19 m/s) and Controls (1.41 ± 0.21 m/s)
Question Q1 Figure 1 reports the number of subjects in subgroups Two-Peaks, which decreases from TT (20/23), to TFM (7/12) to TFC (10/25)

Summary

Introduction

The literature suggests that optimal levels of gait symmetry might exist for lower-limb amputees. Temporal asymmetry is typically measured based on step or stance duration; loading asymmetry based the magnitude of the first peak of the vertical ground reaction force (GRF), and the impulse of GRF [2, 3, 6, 10]. Adamczyk & Kuo [8], with a theoretical and experimental approach involving transtibial amputees, concluded that “some asymmetry may be unavoidable in cases of unilateral limb loss” due to the reduced ankle plantar flexion of the ankle, with direct consequences on stance duration, greater collision work at the sound side, greater work overall, and increased peak force at loading response [25,26,27]. Imposing symmetry can be detrimental, as observed by [27, 28]

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