The effect of carbon fiber custom dynamic orthosis use and design on center of pressure progression and perceived smoothness in individuals with lower limb trauma

Background: Carbon-fiber custom dynamic orthoses are used to improve gait and limb function following lower limb trauma in specialty centers. However, the effects of commercially available orthoses on center of pressure progression and patient perception of orthosis smoothness during walking are poorly understood. Methods: In total, 16 participants with a unilateral lower extremity traumatic injury underwent gait analysis when walking without an orthosis, and while wearing monolithic and modular devices, in a randomized order. Device alignment, stiffness, participant rating of perceived device smoothness, center of pressure velocity, and ankle zero moment crossing were assessed. Findings: The modular device was approximately twice as stiff as the monolithic device. Alignment, smoothness ratings, peak magnitude of center of pressure velocity, and zero moment crossing were not different between study devices. The time to peak center of pressure velocity occurred significantly later for the modular device compared to the monolithic and no orthosis conditions, with large effect sizes observed. Interpretation: Commercially available orthoses commonly used to treat limb trauma affect the timing of center of pressure progression relative to walking without an orthosis. Despite multiple design differences, monolithic and modular orthoses included in this study did not differ with respect to other measures of center of pressure progression. Perceived smoothness ratings were approximately 40% greater with the study orthoses as compared to previous studies in specialty centers, which may be due to a more gradual center of pressure progression, as indicted by lower peak magnitude of center of pressure velocity with both study orthoses.