title: Toe clearance when walking in people with unilateral transtibial amputation: effects of passive hydraulic ankle.
abstract: Most clinically available prosthetic feet have a rigid attachment or incorporate an "ankle" device allowing elastic articulation during stance, with the foot returning to a "neutral" position at toe-off. We investigated whether using a foot with a hydraulically controlled articulating ankle that allows the foot to be relatively dorsiflexed at toe-off and throughout swing would increase minimum toe clearance (MTC). Twenty-one people with unilateral transtibial amputation completed overground walking trials using their habitual prosthetic foot with rigid or elastic articulating attachment and a foot with a hydraulic ankle attachment (hyA-F). MTC and other kinematic variables were assessed across multiple trials. When using the hyA-F, mean MTC increased on both limbs (p = 0.03). On the prosthetic limb this was partly due to the device being in its fully dorsiflexed position at toe-off, which reduced the "toes down" foot angle throughout swing (p = 0.01). Walking speed also increased when using the hyA-F (p = 0.001) and was associated with greater swing-limb hip flexion on the prosthetic side (p = 0.04), which may have contributed to the increase in mean MTC. Variability in MTC increased on the prosthetic side when using the hyA-F (p = 0.03), but this did not increase risk of tripping.
authors.affiliation: Division of Medical Engineering, School of Engineering, and Division of Allied Health Professions, School of Health Studies, University of Bradford, Bradford, United Kingdom.
authors.forename: Louise
authors.initials: L
authors.lastname: Johnson
authors.forename: Alan R
authors.initials: AR
authors.lastname: De Asha
authors.forename: Ramesh
authors.initials: R
authors.lastname: Munjal
authors.forename: Jai
authors.initials: J
authors.lastname: Kulkarni
authors.forename: John G
authors.initials: JG
authors.lastname: Buckley
mesh_terms: D000328:Adult; D000671:Amputation, Surgical / Q000534:rehabilitation*; D000843:Ankle Joint / Q000502:physiology*; D001186:Artificial Limbs; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007866:Leg; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D014034:Toes / Q000502:physiology; D016138:Walking / Q000502:physiology*
keywords: amputation; dorsiflexion; gait; hydraulic ankle; prosthesis; toe clearance; transtibial; tripping; unilateral; walking speed