Article

OBJECTIVE: To examine how an extension constraint knee brace affects active and
passive standing knee joint alignment, dynamic balance, and gait mechanics.
DESIGN: Repeated-measures, within-subjects design.
SETTING: Research laboratory.
PARTICIPANTS: Persons (N = 24) with no current diagnosed gait dysfunction or
neuromuscular limitations that limit activities of daily living. METHODS: All
subjects were tested with use of dynamic balance and gait analysis. Dynamic
balance was examined with the Lower Quarter Y Balance Test. Gait analysis was
conducted at a freely chosen walking speed for 2 conditions: (1) use of a brace
with free range of motion (FROM) and (2) use of a brace with 30-degree extension
constraint (ECON). In a subset of subjects, radiographs were used to examine
standing knee alignment for 3 conditions: (1) FROM, (2) use of a knee ECON brace
in a relaxed position; and (3) use of a knee ECON brace with maximal volitional
quadriceps contraction. MAIN OUTCOME MEASURES: Peak knee flexion, knee flexion
range of motion, peak vertical ground reaction force during weight acceptance and
propulsion, and maximum reach distance in the anterior, posteromedial, and
posterolateral directions were measured. RESULTS: Differences in dynamic balance
were observed between ECON and FROM for the anterior reach. Peak knee flexion
increased 3.2 degrees and peak knee extension decreased 7.4 degrees in the ECON
condition. Vertical GRF values were found to increase bilaterally during ECON at
midstance but decreased bilaterally during propulsion. Radiographic images
revealed that the ECON elicited a 22.2 degrees flexion contracture with minimal
quadriceps activation but only reduced motion by 4.8 degrees with maximal
volitional quadriceps activation. CONCLUSIONS: Extension constraint knee braces
alter joint alignment, dynamic balance, knee mechanics during gait, and vertical
loading during gait. However, the changes in motion observed were lower than
those induced by the constraining mechanism.
CI - Copyright (c) 2014 American Academy of Physical Medicine and Rehabilitation.
Published by Elsevier Inc. All rights reserved.

Langue : ANGLAIS