Preliminary kinematic evaluation of a new stance-control knee-ankle-foot orthosis.
BACKGROUND
Stance-control knee-ankle-foot orthoses permit free knee motion in swing while providing knee flexion resistance in stance for individuals with quadriceps muscle weakness. However, some stance-control knee-ankle-foot orthoses require full knee extension to engage the knee-joint lock, thereby not providing knee support when climbing stairs or stepping over curbs. Stance-control knee-ankle-foot orthoses that do support a flexed knee are either heavy, bulky, expensive, offer a limited number of locking positions, or cause noise. This paper presents a preliminary kinematic evaluation of a new stance-control knee-ankle-foot orthosis that was designed to address these limitations.


METHODS
Kinematic gait analysis was performed on three male knee-ankle-foot-orthosis users with knee extensor weakness in at least one limb (mean age: 56.3 years (SD 4.0)). Three walking trials were performed with the subjects' current knee-ankle-foot-orthosis and then the new stance-control knee-ankle-foot orthosis (non-randomized before-after trial). Subjects completed a questionnaire about the new stance-control knee-ankle-foot orthosis and current knee-ankle-foot-orthosis.


RESULTS
A mean increase in knee flexion of 21.1 degrees (SD 8.2) during swing and a greater total knee range of motion was found when walking with the new stance-control knee-ankle-foot orthosis. Two knee-ankle-foot-orthosis users experienced a reduction in pelvic obliquity and hip abduction angle abnormalities when walking with the stance-control knee-ankle-foot orthosis. Two out of three subjects preferred walking with the new stance-control knee-ankle-foot orthosis over their prescribed knee-ankle-foot-orthosis.


CONCLUSIONS
The new stance-control knee-ankle-foot orthosis permitted improved gait kinematics for knee-ankle-foot-orthosis users while providing knee support in stance and free knee motion in swing at appropriate instants in the gait cycle. Overall, the new stance-control knee-ankle-foot orthosis provided more natural gait kinematics for orthosis users compared to conventional knee-ankle-foot-orthoses.
Yakimovich
Terris
T
Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, Canada.
Lemaire
Edward D
ED
Kofman
Jonathan
J
D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000379:methods; D019544:Equipment Failure Analysis; D005684:Gait; D020233:Gait Disorders, Neurologic / Q000503:physiopathology* / Q000534:rehabilitation*; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D007866:Leg / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology* / Q000534:rehabilitation*; D009989:Orthotic Devices; D010865:Pilot Projects; D011187:Posture; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D016896:Treatment Outcome