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

Abstract

Abstract-People with amputation are at increased risk of falling compared with age-matched, nondisabled individuals. This may partly reflect amputation-related changes to minimum toe clearance (MTC) that could increase the incidence of trips and fall risk. This study determined the contribution of an active dorsiflexing prosthesis to MTC. We hypothesized that regardless of speed or incline the active dorsiflexion qualities of the ProprioFoot would significantly increase MTC and decrease the likelihood of tripping. Eight people with transtibial amputation walked on a treadmill with their current foot at two grades and three velocities, then repeated the protocol after 4 wk of accommodation with the ProprioFoot. A mixed-model, repeated-measures analysis of variance was used to compare MTC. Curves representing the likelihood of tripping were derived from the MTC distributions and a multiple regression was used to determine the relative contributions of hip, knee, and ankle angles to MTC. Regardless of condition, MTC was approximately 70% larger with the ProprioFoot (p < 0.001) and the likelihood of tripping was reduced. Regression analysis revealed that MTC with the ProprioFoot was sensitive to all three angles, with sensitivity of hip and ankle being greater. Overall, the ProprioFoot may increase user safety by decreasing the likelihood of tripping and thus the pursuant likelihood of a fall.

Frequency and Circumstances of Falls Reported by Ambulatory Unilateral Lower Limb Prosthesis Users: A Secondary Analysis

“…More than 50% of lower limb prosthesis (LLP) users report falling at least once a year [1][2][3][4][5], placing them at high risk for adverse health outcomes such as decreased mobility and diminished quality of life [3,6,7]. Attempts to lower the prevalence of falls in LLP users have traditionally focused on developing and validating clinical tests to assess fall risk [8][9][10][11][12], designing and testing prosthetic components to improve patient safety [13][14][15][16], characterizing the biomechanics of key balance strategies to identify deficits in those at risk for falls [17][18][19][20][21][22][23], and identifying risk factors to help recognize potential fallers [2,5,7,24,25]. However, little attention has been directed toward recording, reporting, and characterizing the circumstances of falls in LLP users [1,4,7].…”

Challenging gait leads to stronger lower-limb kinematic synergies: The effects of walking within a more narrow pathway

“…For example, some of the most common tools for clinical assessment, such as the Tinnetti Performance Oriented Mobility Assessment-Gait section [18], focus on variables that reflect motion of the swing limb foot in the sagittal plane -e.g., swing limb ground clearance and forward advancement. This focus is well justified; such variables are logically related to important functional outcomes including walking speed [19] and the risk of stumbling over an unseen obstacle [2,13]. Nonetheless, variables related to the motion of the swing limb foot in the frontal plane may also have functional significance, as evidenced by recent application of the uncontrolled manifold (UCM)-based analysis [16] to the swing phase of gait [8,15].…”

Motorized Biomechatronic Upper and Lower Limb Prostheses—Clinically Relevant Outcomes

“…Relating falls to the occurrence of tripping has triggered the development of prosthetic components that shorten the hip to toe distance during the midswing phase to provide sufficient toe clearance [76]. With a motorized actuation of dorsiflexion, an A‐MPA demonstrates a 28.8 ± 1.6 mm [77] increase in midswing toe clearance, reducing the risk of tripping on unforeseen obstacles [10]. These results were collected on TTAs only, but a similar strategy to shorten the hip‐to‐toe distance in TFAs during midswing can be adjusted in the setting options of an A‐MPK solution by adequately maintaining knee flexion prior to the midswing phase [78].…”