Patients' Burden Using Microprocessor-stance-and-swing-control Knee-ankle-foot Orthoses and Outcomes Compared to Those With Prior Traditional Knee-ankle-foot-orthosis.

Abstract

Background: Patients with neuromuscular knee instability who are fitted with orthotic devices experience issues such as pain, falls, mobility limitations, and restricted participation.

Objectives: To analyze the burden of disease in patients using a microprocessor-stance-and-swing-control orthosis (MP-SSCO) and, if they had a previous orthosis, to compare their outcomes to those with previous use of a traditional knee-ankle-foot-orthosis (KAFO) under real-world conditions.

Methodology: A structured cross-sectional survey was conducted in six orthotic and prosthetic clinics in Germany. Individuals who had been using an MP-SSCO (C-Brace) for at least six months, answered an internet-based survey to rate their current and recall previous device outcomes and experience. The questionnaire was self-developed based on established questionnaire design principles and pretested. Patients' well-being dimensions were analyzed with Likert scales. Experiences with current and previous orthotic devices were compared. Falls were analyzed both with and without outliers.

Findings: 21 individuals who had used a MP-SSCO for an average duration of two years participated. Fourteen patients had prior experience with a traditional KAFO orthosis. Among them, 78.6% recalled experiencing falls, with a combined annual frequency of 67.9 (SD=167.0, Median=12.0) events. After excluding the two outliers (624 and 182 falls), a mean of 12.1 falls per patient per year was reported (range: 0 to 54, SD=15.9, Median=8.5). With the MP-SSCO, only 42.7% reported falls with an annual frequency of 5.3 (SD=17.0, Median=0.0) falls (p<0.01). After excluding outliers for MP-SSCO users, the average number of falls was 0.5 per year (range 0 to 3, SD=0.9, Median=0.0). This value was significantly lower compared to the previous orthosis (p<0.01). With their previous KAFO, 57.1% of the participants reported being able to walk downstairs, 14.3% to descend stairs with reciprocal gait, and 42.9% to vary their walking speeds. In contrast, 90.5% of MP-SSCO users reported being capable of descending stairs, 81.0% reported to descend stairs with reciprocal gait (p<0.01), and 76.2% claimed they had the ability to walk with varying speeds (p=0.03). Additionally, 71.4% of the respondents experienced an improvement in their engagement in activities with the MP-SSCO. 50.0% reported pain with the previous orthosis, compared to 38.1% with the MP-SSCO. Pain intensity was higher for the previous orthosis use (3.8) compared to MP-SSCO use (2.8) on a 1-5 scale (p=0.06). 93.3% of the participants regarded the MP-SSCO as superior, noting an enhanced quality of life (QoL) compared to the previous orthosis.

Conclusion: Advanced orthotic technology may positively impact outcomes such as fall frequency, activities of daily living, fear of falling and pain. However, in this study, results from the previous orthosis use might have been influenced by recall bias.