Logo for the Journal of Rehab R and D

Volume 46 Number 2, 2009
   Pages 257 — 268

Abstract - Engineering design review of stance-control knee-ankle-foot orthoses

Terris Yakimovich, MASc;1 Edward D. Lemaire, PhD;1* Jonathan Kofman, PhD, PEng2

1Institute for Rehabilitation Research and Development, The Ottawa Hospital Rehabilitation Centre, Ottawa, Canada; 2Department of Systems Design Engineering, University of Waterloo, Waterloo, Canada

Abstract — Persons with quadriceps muscle weakness are often prescribed a knee-ankle-foot orthosis that locks the knee in full extension during both stance and swing phases of gait. Locking the knee results in abnormal gait patterns characterized by hip hiking and leg circumduction during swing. The stance-control knee-ankle-foot orthosis (SCKAFO), a new type of orthosis, has emerged that permits free knee motion during swing while resisting knee flexion during stance, thereby supporting the limb during weight-bearing. This article examines various SCKAFO designs, discusses the existing design limitations, and identifies remaining design challenges. Several commercial SCKAFOs have been released that incorporate different locking mechanisms. Preliminary gait studies have shown some devices to be promising; however, an important functional limitation in some SCKAFOs is dependence on specific joint angles to switch between stance and swing modes. Important design factors such as size, weight, and noise must be considered in new orthosis designs to ensure wide consumer acceptance.

Key words: assistive technology, design, gait, knee-ankle-foot orthosis, lower limb, orthosis, rehabilitation, stance, stance control, stance-control knee-ankle-foot orthosis.

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