Frontal plane dynamic margins of stability in individuals with and without transtibial amputation walking on a loose rock surface

Abstract

Uneven walking surfaces pose challenges to balance, especially in individuals with lower extremity amputation. The purpose of this study was to determine if lateral stability of persons with unilateral transtibial amputation (TTA) is compromised when walking on a loose rock surface. Thirteen TTA and 15 healthy controls walked over level ground and over a loose rock surface at four controlled speeds. Dependent measures, including medial-lateral center of mass (COM) motion, step width variability, lateral arm swing velocity, and mean and variability of the minimum margins of stability (MOSmin), were compared between subject groups and across conditions. TTA had greater average MOSmin than Control subjects (p = 0.018). TTA exhibited decreased MOSmin on their prosthetic limbs compared to their intact limbs (p = 0.036), while Control subjects did not exhibit side to side differences. Both groups increased MOSmin with increasing walking speed (p ≤ 0.001). There was no difference in the average MOSmin between walking surfaces (p = 0.724). However, the variability of MOSmin was greater on the rocks compared to level ground. Both subject groups increased step width, step width variability, COM range of motion and peak COM velocity when walking on the rock surface. TTA exhibited greater variability of both step width and MOSmin, which suggests that they made larger step-to-step, corrective responses, more often, to achieve the same average result.

Correlations between measures of dynamic balance in individuals with post-stroke hemiparesis

“…This measure is based on foot placement while accounting for body CoM position and velocity and has been used to assess dynamic balance in young healthy individuals in destabilizing environments (e.g., McAndrew Young et al, 2012), older adults while stepping to targets (Hurt and Grabiner, 2015), amputees (e.g., Bolger et al, 2014; Gates et al, 2013; Hof et al, 2007) and post-stroke individuals (e.g., Hak et al, 2013; Kao et al, 2014). Similarly, whole-body angular-momentum has been used to assess dynamic balance in a number of patient populations including post-stroke hemiparetic individuals (Nott et al, 2014), amputees (e.g., Pickle et al, 2014; Sheehan et al, 2015; Silverman and Neptune, 2011) and older adults (e.g., Pijnappels et al, 2005b).…”

Active dorsiflexing prostheses may reduce trip-related fall risk in people with transtibial amputation

“…Joint kinematics at instance of minimum toe clearance, in degrees, presented as average ± standard deviation for level-only condition at selfselected velocity and as estimated marginal means ± standard error across both level and incline condition (at self-selected velocity). In general, the evidence supporting the use of microprocessor-controlled prosthetic feet for improving balance, function, and/or mobility of people with amputation is limited and has only recently begun to appear in the literature (e.g., references [25][26][27][28][29][30]). At present, there are few English-written studies of the ProprioFoot, and those that exist have focused on socket pressures [31], hip and knee kinematics and kinetics [32][33], gait economy [34][35], and related aspects of gait [36][37] but not on MTC.…”

Dynamic stability of individuals with transtibial amputation walking in destabilizing environments

“…Determining how persons with amputation respond to destabilizing situations is critical to better understand why they fall and to develop effective interventions. Previous studies report mixed results when comparing various measures of stability in patients with amputation to unimpaired controls during unperturbed walking (Lamoth et al, 2010; Wurdeman et al, 2013), when walking over irregular terrain (Lamoth et al, 2010; Curtze et al, 2011; Gates et al, 2013), or when explicitly perturbed (Hak et al, 2013). This study determined how patients with transtibial amputation responded to perturbations known to substantially destabilize walking humans (McAndrew et al, 2010; 2011).…”

“…On irregular surfaces, patients with amputation walk with wider steps, but have exhibited inconsistent results for various measures of “stability” (Lamoth et al, 2010; Curtze et al, 2011; Gates et al, 2012; 2013). Perhaps either the stability measures used in those studies did not adequately capture the effects of the perturbations, or the perturbation paradigms imposed were not sufficiently challenging to elicit appropriate responses.…”