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

Abstract

BackgroundAssisted 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 recommended when the subject is able to load the 50% of the body weight upon the affected member. An altered assisted gait will cause biomechanic alterations and, therefore, longer treatments and relapses. The aim of this study was to analyze the influence of 10, 25 and 50% of body weight applied to a forearm crutch during a unilateral 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.MethodsEleven 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 different loads. Wilcoxon signed-rank test analyzed ipsilateral and contralateral step parameters to the crutch globally and for each subject.ResultsFriedman test showed significant differences between NG, C, 25 and 50%, especially for step period and velocity. Wilcoxon test had significant differences 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 significant differences, respectively.ConclusionsThe 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 velocity. Step width and step angle were not modified. 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%.Electronic supplementary materialThe online version of this article (10.1186/s12938-018-0527-z) contains supplementary material, which is available to authorized users.

Versatile GCH Control Software for Correction of Loads Applied to Forearm Crutches During Gait Recovery Through Technological Feedback: Development and Implementation Study

“…However, effectiveness does not only refer to the intervention itself, in this case based on technological feedback, but also extends to the (global or analytical) initial, continuous, and final assessments of each essential gait parameter [ 52 ]. GCH Control Software evaluates the maximum force applied to the crutches in each support and therefore indirectly the unloading of the affected lower limb, which is one of the essential parameters [ 1 , 39 ] in assisted gait with two-stage partial unloading. This peak clinical moment matches the midstance phase of the affected limb (ie, where the limb remains upright and with single stance or without the help of the other limb in the air; midswing phase of the contralateral limb) [ 53 , 54 ].…”

“…Examples of such applications include sprained knees [ 36 ] or ankles [ 37 ], surgery for knee meniscopathies [ 38 ], and hip arthroplasties [ 21 ]. Consequently, the load exerted on the body part in question is an essential assisted gait parameter [ 39 ], and therefore this load must be objectified and controlled to optimize it in line with the pathology, recovery process phase, and user's characteristics. Another factor is the current tendency to strongly recommend that the affected lower limb support as much weight as possible without damaging the injury.…”

Point-Mass Biomechanical Model of the Upper Extremity During Lofstrand Crutch-Assisted Gait

“…Lofstrand crutches allow for unloading body weight over the handle while the cuff controls the wrist ulnar deviation. Used by people who need to load more weight in the arms than a cane allows, they are able to unload up to 50% body weight [2]- [4]. Depending on user conditions, they will use a certain technique crutch gait pattern, among which we can find four-point reciprocal gait, three-point gait, two-point reciprocal gait, swing-though gait, swing-to gait or gait with one crutch [5], [6].…”