Poster 362: Application of Microprocessor Stance Control Knee Ankle Foot Orthoses: A Case Series Report

Stance Control knee-ankle foot orthoses (SCO) differ from their traditional locked knee counterparts by allowing free knee flexion during swing while providing stability during stance. It is widely accepted that free knee flexion during swing normalizes gait and therefore improves walking speed and reduces the energy requirements of walking. Limited research has been carried out to evaluate the benefits of SCOs when compared to locked knee-ankle foot orthoses (KAFOs). The purpose of this study was to evaluate the effectiveness of SCOs used for patients with lower limb pathology. Energy expenditure and walking velocity were measured in 10 subjects using an orthosis incorporating a Horton Stance Control knee joint. A GAITRite walkway was used to measure temporospatial gait characteristics. A Cosmed K4b2 portable metabolic system was used to measure energy expenditure and heart rate during walking. Two conditions were tested: Walking with stance control active (stance control) and walking with the knee joint locked. Ten subjects completed the GAITRite testing; nine subjects completed the Cosmed testing. Walking velocity was significantly increased in the stance control condition ( p < 0.001). There was no difference in the energy cost of walking ( p = 0.515) or physiological cost index (PCI) ( p = 0.093) between conditions. This study supports previous evidence that stance control knee-ankle foot orthoses increase walking velocity compared to locked knee devices. Contrary to expectation, the stance control condition did not decrease energy expenditure during walking.

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Examination of Knee Joint Moments on the Function of Knee-Ankle-Foot Orthoses During Walking

Journal of Applied Biomechanics ◽

10.1123/jab.29.4.474 ◽

2013 ◽

Vol 29 (4) ◽

pp. 474-480 ◽

Cited By ~ 4

Author(s):

Jan Andrysek ◽

Susan Klejman ◽

John Kooy

Keyword(s):

Knee Joint ◽

Stance Phase ◽

Knee Extension ◽

Knee Joints ◽

Foot Orthoses ◽

Variable Effect ◽

Stance Control ◽

Ankle Foot Orthoses ◽

Control Knee ◽

Load Transducer

The goal of this study was to investigate clinically relevant biomechanical conditions relating to the setup and alignment of knee-ankle-foot orthoses and the influence of these conditions on knee extension moments and orthotic stance control during gait. Knee moments were collected using an instrumented gait laboratory and concurrently a load transducer embedded at the knee-ankle-foot orthosis knee joint of four individuals with poliomyelitis. We found that knee extension moments were not typically produced in late stance-phase of gait. Adding a dorsiflexion stop at the orthotic ankle significantly decreased the knee flexion moments in late stance-phase, while slightly flexing the knee in stance-phase had a variable effect. The findings suggest that where users of orthoses have problems initiating swing-phase flexion with stance control orthoses, an ankle dorsiflexion stop may be used to enhance function. Furthermore, the use of stance control knee joints that lock while under flexion may contribute to more inconsistent unlocking of the stance control orthosis during gait.

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