Infuence of the load exerted over a forearm crutch in spatiotemporal step parameters during assisted gait: pilot study

Abstract

Background: Assisted gait with forearm crutches is frequently performed during the recovery of musculoskeletal injuries of the lower limb. The amount of body weight applied to the crutch or crutches depends on the pathology and the treatment phase. The transition from assisted gait with two crutches to a single crutch is usually rec‑ ommended when the subject is able to load the 50% of the body weight upon the afected member. An altered assisted gait will cause biomechanic alterations and, therefore, longer treatments and relapses. The aim of this study was to analyze the infuence of 10, 25 and 50% of body weight applied to a forearm crutch during a uni‑ lateral assisted gait in the spatial and temporal step parameters to determine the load that produces alterations in gait biomechanics and the load that does not. Methods: Eleven healthy subjects performed normal gait (NG) and assisted gait with a forearm crutch, in which the applied loads were: comfortable (C), 25 and 50% of their body weight. Vicon System was employed for gait recording. GCH System 2.0 and GCH Control Software 1.0 controlled the loads. The variables were: step length, step period, velocity, step width and step angle. Friedman test compared all the gait modalities: NG and the diferent loads. Wilcoxon signed-rank test analyzed ipsilateral and contralateral step parameters to the crutch globally and for each subject. Results: Friedman test showed signifcant diferences between NG, C, 25 and 50%, especially for step period and velocity. Wilcoxon test had signifcant diferences only in 4 of the 20 general comparisons between ipsilateral and contralateral steps to the crutch. In the analysis by subjects, step length, step period and velocity showed 79/132, 110/132 and 58/66 signifcant diferences, respectively. Conclusions: The increase in the load exerted over a forearm crutch produced an increase in the step period, accompanied by a reduction of step length and gait veloc‑ ity. Step width and step angle were not modifed. The unloading of 25 and 50% of body weight on a single crutch is incorrect from the biomechanical point of view. Two crutches should be employed when the body weight to unload exceeds 10%.