Restricting ankle motion via orthotic bracing reduces toe clearance when walking over obstacles

Evangelopoulou, E; Twiste, M; Buckley, J

Abstract

Background: When trans-tibial amputees cross obstacles leading with their prosthesis, foot clearance is achieved using compensatory swing-phase kinematics. Such compensation would suggest able-bodied individuals normally use swing-phase ankle dorsiflexion to attain adequate obstacle clearance, however, direct evidence of such contribution is equivocal. The present study determined the contribution of sagittal plane ankle motion in achieving lead-limb clearance during obstacle negotiation.


Methods: 12 male able-bodied individuals (ages 18-30) completed obstacle crossing trials while walking on a flat surface. Lead-limb (right) ankle motion was manipulated using a knee-ankle-foot orthosis. Trials were completed with the ankle restricted at a neutral angle or unrestricted (allowing ~ ±15 plantar/dorsiflexion).


Findings: Restricted ankle motion caused significant increase in trail-limb foot placement distance before the obstacle (p=0.005); significant decrease in vertical toe clearance (p<0.003), vertical heel clearance (p=0.045) and lead-limb foot placement distance after the obstacle (p=0.045); but no significant changes in knee angle at instant of crossing or in average walking speed.


Interpretation: The shifts in foot placements altered the part of swing that the lead-limb was in when the foot crossed the obstacle, which led to a decrease in clearance. These adaptations may have been due to being unable to dorsiflex the ankle to ‘lift’ the toes in mid-swing or to being unable to plantarflex the ankle during initial contact following crossing, which changed how the lead-limb was to be loaded. These findings suggest individuals using ankle bracing or those with ankle arthrodesis, will have reduced gait safety when negotiating obstacles.

Citation

Evangelopoulou, E., Twiste, M., & Buckley, J. (2016). Restricting ankle motion via orthotic bracing reduces toe clearance when walking over obstacles. Gait & Posture, 43, 251-256. https://doi.org/10.1016/j.gaitpost.2015.10.006

• Journal Article Type: Article
• Acceptance Date: Oct 4, 2015
• Online Publication Date: Oct 19, 2015
• Publication Date: Jan 1, 2016
• Deposit Date: Dec 8, 2015
• Journal: Gait & Posture
• Print ISSN: 0966-6362
• Publisher: Elsevier
• Volume: 43
• Pages: 251-256
• DOI: https://doi.org/10.1016/j.gaitpost.2015.10.006
• Publisher URL: http://dx.doi.org/10.1016/j.gaitpost.2015.10.006
• Related Public URLs: http://www.gaitposture.com/